Exam 2 Study Guide. All questions will be over these concepts, voc.docx

Exam 2 Study Guide. All questions will be over these concepts,
vocabulary, and facts
Chp 10:
Cell Cycle
Genome
Mitosis
Chp11:
Meiosis
Gamete
Haploid & Diploid cell
Sexual reproduction
Chp12:
Gregor Mendel
Traits
Genotype & Phenotype
Allele
Dominant Trait & Recessive trait
Homozygous & Heterozygous
Punnet Square (concept. You will not do one on the exam)
Predictable Genetic frequencies (pedigree, farming genetic
disorders)
Wild Type
Law of Segregation
Law of Independent assortment
Chp14:
DNA
Backbone
Nucleic Acid
Nucleotides
Base

Base Pair
Codon
Gene
Chromosome
DNA Polymerase (concept, vocab word)
Helicase (concept, vocab word)
Okazaki Fragment (concept, vocab word)
Proof Reading
Telomeres
DNA bases (4) and which bind
RNA: Uracil
Steps of DNA Replication (just listing the steps: min 5 max 10,
depending on word choice)
Chp 15:
The Central Dogma of Biology
Transcription (steps, concepts)
Translation (steps, concepts)
tRNA
Mutation
Biotechnology
Chp 18:
Evolution
Natural Selection
Charles Darwin & Alfred R. Wallace
“Survival of the fittest” is incorrect.
Adaptation
Species
Hybrid (species): Postzygotic & Prezygotic
Speciation
Allopatric Speciation
Sympatric Speciation
Adaptive Radiation
Gradual Speciation & Punctuated Equilibrium
Chp 19:

Evolution
Evolution cumulative functions of: (know each)
Mutation, Genetic Drift, Migration, Natural Selection
Chance (involved with Evolution): Fixation, Founder Effect,
Population Bottleneck
Natural Selection: 3 conditions for occurrence; what it looks
like; what it does/does not do
Convergent Evolution
Evolution’s influence over, but not its “purpose”
Species are the basic unit of Biodiversity
Chp 20:
Phylogeny
Phylogenetic Trees/models
Concept of “shared ancestry”
Taxonomy: concept, define, & list 8 hierarchical categories
Convergent Evolution
Molecular Systematics & DNA Homology
Compare Phylogeny verse the “species concept”
Chp 21-29:
Biodiversity
Flora, Fauna, Biota
Virus (concept, importance to Evolution by Natural Selection)
Importance of “Domain”
Prokaryotes: Define, importance/role in Nature
Stromatolites as evidence
Biofilms
Protists: define, importance/role in Nature
Fungi: Define, importance/role in Nature
3 descriptors of Fungi
Fungal DNA
Hyphae & Mycelium
Decomposer
Mycorrhizae

Plants:
Ancestry (phylogeny)
Plants: Define, importance/role in nature
3 defining descriptors of Plants
Specific adaptations for evolution to land
3 problems all plants (as a phylogenetic group) face
Non-vascular Plant
Vascular Plant
Vascular Seed Plant
Vascular Tissue: Xylem & Phloem
Roots, True leaves
Waxy Cuticle
Important role of Ecological Succession of Plants to Life
Seed Plants:
Seed: define, role/importance of to a plant, water &
reproduction
Spermatophytes
Gymnosperm
Angiosperm,
Flower & Fruit
Flower: Stamen, Carpel, Petal, Ovary)
Herbivory
Pollination & Pollinators: Trickery, Bribery, coevolution of
Importance of Plants to Humans
Humans and Plants coevolution
The life of a bee is very different from the life of a flower, but
the two organisms are related. Both are members the domain
Eukarya and have cells containing many similar organelles,

genes, and proteins.
Chp 20 Phylogenies and the History of Life
Objectives:
Scientific Organization of Life
Evolutionary Relationships of Life
The “birds” and the “Bees”…
All life is related but different?
It’s not a comparison of visual similarities or differences,
but a look at “shared ancestry.”
Would we have one without the other?
Phylogeny describes the relationships of an organism, such as
from which organisms it is thought to have evolved, to which
species it is most closely related, and so forth. Phylogenetic
relationships provide information on shared ancestry but not
necessarily on how organisms are similar or different.
Fig 20.2 Both of these phylogenetic trees shows the relationship
of the three domains of life—Bacteria, Archaea, and Eukarya—
but the (a) rooted tree attempts to identify when various species
diverged from a common ancestor while the (b) unrooted tree
does not
Phylogenetic Trees have limitations in explaining “Shared
ancestry”
proximity on the “tree” not equal shared “attributes”.
Five primary lines of evidence:
The fossil record
Biogeography

Comparative anatomy and embryology
Molecular biology
Laboratory and field experiments
3
Here we review the five primary lines of evidence
demonstrating the occurrence of evolution:
1. The fossil record—physical evidence of organisms that lived
in the past.
2. Biogeography—patterns in the geographic distribution of
living organisms.
3. Comparative anatomy and embryology—growth,
development, and body structures of major groups of organisms.
4. Molecular biology—the examination of life at the level of
individual molecules.
5. Laboratory and field experiments—implementation of the
scientific method to observe and study evolutionary
mechanisms.
This ladder-like phylogenetic tree of vertebrates is rooted by an
organism that lacked a vertebral column. At each branch point,
organisms with different characters are placed in different
groups based on the characteristics they share.
SO how does Science organize living things?
Science of Taxonomy- “arrangement law” or rules of grouping
organisms into greater and greater detailed inclusive groups.

Dogs are great examples! WE know their taxonomic
organization very well since Humans created the “dog” from a
common ancestor shared by wolves.
Fig 20.5 The taxonomic classification system uses a hierarchical
model to organize living organisms into increasingly specific
categories. The common dog, Canis lupus familiaris, is a
subspecies of Canis lupus, which also includes the wolf and
dingo.
Carolus Linnaeus and Systema Naturae
A scientific name consists of two parts:
1. Genus
2. specific epithet
Equus quagga is a Zebra
Canis lupus familiaris
is a dog
HOW do we name species? We need an organizational system!
Hierarchical System
Inclusive broad categories at the top…
…leading to more and more inclusive specific categories
to the target organism
With the huge number of species on earth, such a classification
system is particularly important. Biologists use the system
developed by the Swedish biologist Carolus Linnaeus in the
mid-1700s and published in his book called Systema Naturae
(“System of Nature”).

Here’s how it works (Figure 10-9 Name that zebra. Equus
quagga): Every species is given a scientific name that consists
of two parts, a genus (plural = genera) and a specific epithet.
Linnaeus gave humans the name Homo sapiens, meaning “wise
man.” Homo is the genus and sapiens is the specific epithet.
(The genus is capitalized and the genus and specific epithet are
both italicized.) The redwood tree has the name Sequoia
sempevirens.
6
So can you remember the Linnaean System?
Inconcievable!
It’s not really…
King Phillip Called Out For Good Soup.
Kingdom, Division, Class, Order,Family, Genus, Species
But… Need Domain: Dread King Phillip…
Domain: Eukarya
Kingdom: Plantae
Phylum: Magnoliophyta

Class: Magnoliopsida
Order: Fabales
Family: Leguminosae
Subfamily: Faboideae
Genus: Archis
Species: hypogaea
Or binomial nomenclature
as Arachis hypogaea
Those are really annoyingly long names! Can we use an easier
one? WE DO… but “common names” can lead to confusion.
“Anybody want a peanut?” said Animalia Chordata Vertebrata
Mammalia Theria Eutheria Primates Anthropoidea Hominidae
Homo sapiens
Or… Homo sapiens, or Human, or Andrea the Giant, or André
René Roussimoff (His “name” tells us his family lineage.)
Or common name
a “Peanut.”
(https://en.wikipedia.org/wiki/André_the_Giant)
Or can get really technical…
https://en.wikipedia.org/wiki/Human_taxonomy
We can figure out Evolutionary relationships.
Geographic patterns of species’ distributions reflect their
evolutionary histories.

Large isolated habitats also have interesting biogeographic
patterns.
Australia and Madagascar are filled with unique organisms that
are clearly not closely related to organisms elsewhere.
In Australia, for example, marsupial species, rather than
placental mammals, fill all of the usual roles.
There are marsupial “wolves,” marsupial “mice,” marsupial
“squirrels,” and marsupial “anteaters” (Figure 8-37 Evidence
for evolution: biogeography).
They physically resemble their placental counterparts for most
traits, but molecular analysis shows that they are actually more
closely related to each other, sharing a common marsupial
ancestor.
Their relatedness to each other is also revealed by similarities
in their reproduction; females all give birth to offspring at a
relatively early state of development, and the offspring finish
their development in a pouch.
The presence of marsupials in Australia is not simply because
marsupials are better adapted than placentals to the Australian
habitat.
When placental organisms have been transplanted in Australia
they do just fine, often thriving to the point of endangering the
native species.
9
Convergent Evolution: all developed from different original
structures.
Analogy:
Analogous structures, not the same, but a “wing” to fly.
b/c adaptions via NS works!

Evolutionary relationships
Why are there similarities that we can classify into inclusive
groups?
Misleading appearances… “wing”
Not all adaptations that appear similar actually share ancestors.
We see flying mammals (bats) and flying insects (fruit flies)
(Fig. 8-40 Evidence for evolution: convergent evolution and
analogous structures). Similarly, dolphins and penguins live in
similar habitats and have flippers that help them to swim.
In both examples, however, the analogous structures all
developed from different original structures.
Natural selection—in a process called convergent evolution—
uses the different starting materials available (such as a flipper
or a forelimb) and modifies them until they serve similar
purposes, much as we saw in the marsupial and placental
mammals in Figure 8-41.
10
Fig 20.7 (left, wings) The shared bone construction shows
homology and evidence for a common ancestor.
Fig 18.7 (right, bones) The similar construction of these
appendages indicates that these organisms share a common
ancestor. From our book and Wikipedia
https://en.wikipedia.org/wiki/Homology_(biology)
Homology: In the context of biology, homology is the existence
of shared ancestry between a pair of structures, or genes, in
different species.[1] A common example of homologous
structures in evolutionary biology are the wings of bats and the
arms of primates.[1] Evolutionary theory explains the existence

of homologous structures adapted to different purposes as the
result of descent with modification from a common ancestor.
DNA Homology or Molecular Systematics
Molecular biology reveals that common genetic sequences link
all life forms.
Related vs. unrelated individuals?
The more distantly you and another individual are related, the
more your DNA differs.
Compare their DNA sequences for individual genes. (Using Gel
Electrophoresis!)
In Rhesus monkeys, 138 amino acids are found in both Rhesus
monkey and human hemoglobin (blood).
When we examine the similarity of DNA among related
individuals within a species, we find that they share a greater
proportion of their DNA than do unrelated individuals.
This is not unexpected; you and your siblings got all of your
DNA from the same two parents, while you and your cousins
each got half of your DNA from the same two grandparents.
The more distantly you and another individual are related, the
more your DNA differs.
12
Recency of Common Ancestry
THM

Estimates of evolutionary relatedness made from:
Comparative anatomy
Embryology
The fossil record
“Molecular clocks” (next slide)
All living organisms share the same genetic code.
The degree of similarity in the DNA of different species can
reveal how closely related they are and the amount of time that
has passed since they last shared a common ancestor.
The differences in the amino acid structure of the beta
hemoglobin chain (and remember that this structure is governed
by an allele or alleles of a particular gene) seem to indicate that
humans have more recently shared a common ancestor with
Rhesus monkeys than with dogs.
And that we have more recently shared an ancestor with dogs
than with birds or lampreys.
These findings are just as we would expect, based on estimates
of evolutionary relatedness made from comparative anatomy and
embryology as well as those based on the fossil record.
It is as if there is a molecular clock that is ticking.
The longer two species have been evolving on their own, the
greater the number of changes in amino acid sequences—or
“ticks of the clock”—that occur (Figure 8-42 An evolutionary
clock).
13
The molecular clock is a technique (a tool) to help understand

when two species diverged (split). This is possible because
DNA is inherited, thus the changes are inherited, and the
accumulated difference in the DNA can lead to greater
understanding of the “time since” organisms shared a common
ancestor.
14
20.14 Three alternate hypotheses of eukaryotic and prokaryotic
evolution are (a) the nucleusfirst hypothesis, (b) the
mitochondrion-first hypothesis, and (c) the eukaryote-first
hypothesis.
What Molecular Systematics or DNA Homology showed us?
It allowed us to go back Billions of years ago and show us that
some cell organelles have there own DNA.
Endosymbiosis lead to the Domains.
We are currently not sure what came first, but we do know it
happened, since it is represented in living things today. More
research!
“Species are not always easily defined”
is the THM.
Lots of empirical data must be collected and compared.
Biologists, like all humans, can be biased. When investigating

the natural world, for example, they often focus on plants and
animals, to the exclusion of the rest of the earth’s rich
biodiversity.
This gets them into trouble when it comes to a concept such as
the biological species concept. While the biological species
concept is remarkably useful when describing most plants and
animals, it falls short of representing a universal and definitive
way of distinguishing many life forms (Figure 10-10: A useful
concept that can’t always be easily applied).
16
SO we can use this “Tree Model” The history of life can be
imagined as a tree.
Phylogeny: Evolutionary history of organisms
Nodes: The common ancestor points at which species diverge
“Common Ancestor”
Does not show which organism is more “advanced” just where
groups are related
Charles Darwin proposed and documented that species could in
fact change and give rise to new species. With Darwin, the
classification of species acquired a new goal and a more
important function. In The Origin of Species Darwin wrote:
“Our classifications will come to be, as far as they can be so
made, genealogies.” That is, Darwin proposed that the
classifications of organisms would resemble family trees that
link parents and offspring over long periods of time. With these
words, Darwin was the first to link classification with
evolution.
17

What do we USE Evolutionary Trees for?
Are humans more advanced, evolutionarily, than Fish, Birds,
Rats, or Mice?
Can bacteria be considered “lower” organisms?
Construction evolutionary trees requires comparing similarities
and differences between organisms.
… of what we can SEE to compare.
1980s- Biologist began using DNA as a tool to compare
organisms.
90% to 98.9 - 99% homology
But ~40% of genes are expressed differently
Beginning in the 1980s, biologists began using molecular
sequences rather than physical traits to generate evolutionary
trees. The rationale for this approach is that organisms inherit
DNA from their ancestors and so as species diverge, their DNA
sequences also diverge, becoming increasingly different. As
more time that passes following the splitting of one species into
two, the differences in their DNA sequences becomes greater.
By comparing how similar the DNA sequences are between two
groups, it is possible to estimate how long it has been since they
shared a common ancestor (Figure 10-18 DNA sequences reveal

evolutionary relatedness).
19
Explore the Hillis Plot. Humans are in the top let of the circle.
You can Zoom in/out.
http://www.zo.utexas.edu/faculty/antisense/tree.pdf
Hillis Plot web link, organization based on the genomes of
organism so far sequenced…
http://www.zo.utexas.edu/faculty/antisense/downloadfilestol.ht
ml
Ultimately:
Evolutionary trees are best constructed by comparing DNA
sequences among organisms rather than comparing physical
similarities.
Why?
Convergent evolution can cause distantly related organisms to
appear much more closely related, but it doesn’t increase their
DNA sequence similarity.
Let’s look at a case that illuminates why the original methods
were weaker (Figure 10-20 Looks can be deceiving).
Initially, biologists thought that the African golden moles
belonged in the order insectivores, which includes shrews,
hedgehogs, and other moles. This belief seemed reasonable
because these animals have many characteristics in common:
They are small, they have long, narrow snouts, their eyes are

tiny, and they live in underground burrows. Biologists thought
that this group of characteristics evolved just once, and that
every species in the insectivore order possessed these
characteristics because they inherited them from a common
ancestor.
The DNA evidence revealed that the African golden moles are
actually more closely related to elephants than they are to the
insectivores, including all of the other mole species!
21
THM Learning Objectives:
Every species on earth falls into one of three domains.
Each species on earth is given a unique name, using a
hierarchical system of classification.
Classification is determined by many factors, but DNA is the
clearest.
Species are not always easily defined.
Difficult to determine when one species has changed into
another (Speciation)
It may NOT be possible to identify an exact point
(ancestry/time) at which the change occurred.
Fossils- past species? “Lost intermediate” species?
Molecular Systematics. DNA homology?
Find it before it goes extinct?

STOP thinking with a Humancentric view of Evolution by
Natural Selection.
24
Chapter 14
Chapter 15
Biotechnology
DNA
DNA replication
Genes coding for Proteins
Gene Expression (abbreviated)
1. DNA
2. Proteins
3. structures
We’ve covered what a cell is, cell division, some basic
genetics… but what are we trying to cover with genes?
Not... Terrible biology puns.
Life and all it’s structures with their functions:
1. acquire energy 2. manage waste 3. reproduce
DNA. Deoxyribonucleic Acid. What is it?

It’s a “code” for structures (first slide) and functions.
A ”program for Life to complete” 1 and 2, with the goal of 3.
Ultimately Life wants to make more Life…. Cell’s (1&2) want
to make more (3) cells (Cell Theory).
Or... DNA codes for how to make more DNA!
Reproduction or “sex” is simply the goal of making new better
DNA (genetic variation) in an offspring as resulting from parent
selection and Evolution by Natural Selection.
Do we wear the sexy jeans to attract the other person in the sexy
different jeans so we can mix our genes?
We are not really sure... But lets explore what DNA is. Why it’s
important in Biology.
Learning Objectives: We are going to run through the concept
of DNA, focus on what I lecture on. Our book has a lot of
information for an Intro course, but it’s good... It’s all there.
Describe what DNA is and what it does.
Explain the process of gene expression.
Explain the causes and effects of damage to the genetic code.
Discuss biotechnology.
Describe biotechnology and its implications for human health.
DNA “Double Helix”
* Nucleic acids vs nucleotides
14.2 DNA Vocabulary!
Backbone: Sugar-phosphate (very stable, easy for cell to make.

It’s Sugar!)
Nucleic Acids: (chp2) 1 of 4 types of
Macromolecules used by Life
Nucleotides: A,T,C,G + Backbone segment
Base: A,T,C,G
Base Pair: “matched pairs” of bases
A –(Hydrogen bond)- T
G –(Hydrogen bond)- C
*Codon: Sets of 3 mRNA base pairs to
code for a protein (by a ribosome)
The DNA molecule contains instructions for the development
and functioning of all living organisms. (Neat History of
discovering this 14.1)
DNA (deoxyribonucleic acid) is a nucleic acid, a
macromolecule that stores information.
It consists of individual units called nucleotides, which have
three components: a molecule of sugar, a phosphate group
(containing four oxygen atoms bound to a phosphorous atom),
and a nitrogen-containing molecule called a base.
The physical structure of DNA is frequently described as a
“double helix.”
What exactly is a double helix?
Picture a long ladder twisted around like a spiral staircase and
you’ll have a good idea of what a DNA molecule looks like
(Figure 5-4 Overview of the structure of DNA).
The molecule has two distinct strands, like the vertical sides of
a ladder.

These are the “backbones” of the DNA molecule and each is
made from two alternating molecules: a sugar, then a phosphate,
then another sugar, then a phosphate, and so on.
The sugar is always deoxyribose, and the phosphate molecule is
always the same, too.
It is the shapes of the backbone molecules that cause the DNA
“ladder” to twist.
5
Fig 14.5 Each nucleotide is made up of a sugar, a phosphate
group, and a nitrogenous base. The sugar is deoxyribose in DNA
and ribose in RNA.
Fig 14.7 DNA has (a) a double helix structure and (b)
phosphodiester bonds. The (c) major and minor grooves are
binding sites for DNA binding proteins during processes such as
transcription (the copying of RNA from DNA) and replication.
The work of pioneering scientists (a) James Watson, Francis
Crick, and Maclyn McCarty led to our present day
understanding of DNA. Scientist Rosalind Franklin discovered
(b) the X-ray diffraction pattern of DNA, which helped to
elucidate its double helix structure. (credit a: modification of
work by Marjorie McCarty, Public Library of Science)
Movie: Race for the Double Helix
I think Rosalind Franklin got shafted of the fame she deserved
7

Why is DNA considered the universal code for all life on Earth?
It can be deciphered, read, written, and referenced, copied, and
more!
Fig 24.9 DNA can be separated on the basis of size using gel
electrophoresis. (credit: James Jacob, Tompkins Cortland
Community College)
Genes are sections of DNA that contain instructions for making
proteins.
Why are proteins important?
Our code, the DNA, is packed into out cells.
14.10 A eukaryote contains a well-defined nucleus, whereas in
prokaryotes, the chromosome lies in the cytoplasm in an area
called the nucleoid.
With in the Nucleus the DNA is packaged up into
Chromosomes.
(going back to Cell Division, Mitosis and Meiosis)
chromosome. Copies & alleles- like paired socks!

Fig 13.5 a Karyotype- Chromosomal map
Rubber Band Demo
Genome:
“Complete” DNA
Chromosome:
One “bundle”.
Organization of pairs (alleles)
Gene: Specific code. Usually referring to the allele in use
(phenotype) but can refer to either/both (genotype).
Genes code for traits or specific functions that are “built”. The
code is to build a protein. (review 4 macromolecules of life)
The full set of DNA present in an individual organism is called
its genome.
In prokaryotes, including all bacteria, the information is
contained within circular pieces of DNA.
In eukaryotes, including humans, this information is laid out in
long linear strands of DNA. Rather than having the genome
contained in one super-long DNA strand, eukaryotic DNA exists
as numerous smaller, more manageable pieces, called

chromosomes.
Humans, for example, have three billion base pairs, divided into
23 unique pieces of DNA (and we have two copies of each
piece: one from our mother and one from our father, for a total
of 46 chromosomes and six billion base pairs in every cell).
11
Trait: Single Characteristic or “feature”
Inheritable Genetic Variation
=
Each gene is the instruction set for producing one particular
molecule, usually a protein.
For example, there is a gene that codes for fibroin, the chief
component of silk.
And, there is a different gene that codes for triacylglyceride
lipase, an enzyme that breaks down dietary fat.
Within a species, individuals sometimes have slightly different
instruction sets for a given protein and these instructions can
result in a different version of the same trait.
These alternate versions of a gene that codes for the same
character are called alleles (above “Different versions of the
same thing”).
And any single feature of an organism is referred to as a trait.
A simple hypothetical example will clarify the meaning of these
terms: The color of a daisy’s petals is a trait.
The instructions for producing this trait are found in a gene that
controls petal color.
However, this gene may have many different alleles; one allele
may specify the trait of red petals, another may specify white

petals, and yet another may specific yellow petals.
Similarly, one allele for eye color in fruit flies may carry the
instructions for producing a red eye, while another slightly
different allele may be the instructions for brown eyes.
12
Insert figure 5-8
Not all DNA contains instructions for making proteins.
It is debatable whether humans are the most complex species on
the planet, but surely we must be more complex than an onion.
But we’re not if you measure complexity by the amount of DNA
an organism has: An onion has more than five times as much
DNA as a human (Above- Is the size of an organism’s genome
related to its complexity).
We don’t fare any better when compared to some other
seemingly simple organisms, either.
The salamander species Amphiuma means, for example, has
about 25 times as much DNA as we do, and one species of
amoeba—a single-celled organism—has almost 200 times as
much!
13
The Proportion of the DNA
That Codes for Genes
Is the non coding DNA “Junk DNA” ?

The description in the first part of this chapter about what DNA
is and how genes code for proteins is logical and tidy, but it
doesn’t completely explain what we observe in cells.
In humans, for example, genes make up less than 5% of the
DNA (Above- “Junk DNA”?).
In many species, the proportion of the DNA that codes for genes
is even smaller.
In virtually all eukaryotic species, the amount of DNA present
far exceeds the amount necessary to code for all of the proteins
present in the organism.
The fact is, a huge proportion of base sequences in DNA do not
code for anything and has no obvious purpose. Many biologists
even call it “junk DNA.” Yet, we are learning some of it does
have a purpose… much to still learn.
In what types of organisms do we find the most “junk DNA”?
Bacteria and viruses tend to have very little non-coding DNA;
with genes making up 90% or more of their DNA.
It is in the eukaryotes (with the exception of yeasts) that we see
the explosion in the amount of non-coding DNA, about 25% of
which occurs within genes and 75% of which occurs between
genes (above Non-coding regions of DNA).
14
DNA Replication, fig 14.14
DNA video- (Drew Berry) replication starts at 1:45min.
Helicase rotates (unzips, zips) at speeds of 10,000 rpm
(rotations per minute). Better than most jet engine turbines.
https://www.youtube.com/watch?v=4PKjF7OumYo

A replication fork is formed when helicase separates the DNA
strands at the origin of replication. The DNA tends to become
more highly coiled ahead of the replication fork. Topoisomerase
breaks and reforms DNA’s phosphate backbone ahead of the
replication fork, thereby relieving the pressure that results from
this supercoiling. Single-strand binding proteins bind to the
single-stranded DNA to prevent the helix from re-forming.
Primase synthesizes an RNA primer. DNA polymerase III uses
this primer to synthesize the daughter DNA strand. On the
leading strand, DNA is synthesized continuously, whereas on
the lagging strand, DNA is synthesized in short stretches called
Okazaki fragments. DNA polymerase I replaces the RNA primer
with DNA. DNA ligase seals the gaps between the Okazaki
fragments, joining the fragments into a single DNA molecule.
(credit: modification of work by Mariana Ruiz Villareal)
15
The process of DNA replication can be summarized as follows:
DNA unwinds at the origin of replication.
Helicase opens up the DNA-forming replication forks; these are
extended bidirectionally.
Single-strand binding proteins coat the DNA around the
replication fork to prevent rewinding of the DNA.
Topoisomerase binds at the region ahead of the replication fork
to prevent supercoiling.
Primase synthesizes RNA primers complementary to the DNA
strand.
DNA polymerase starts adding nucleotides to the 3'-OH end of

the primer.
Elongation (replication) of both the lagging and the leading
strand continues.
RNA primers are removed (by exonuclease activity). No primer
= stop replication.
Gaps in lagging strand are filled (edited) by DNA pol by
adding dNTPs.
The gap between the two DNA fragments is sealed by DNA
ligase, which helps in the formation of the DNA strand.
Key vocab in DNA replication:
Replication fork
Single-strand
Single-strand binding protein
Primer (primase)
Leading Strand
Lagging Strand
Okazaki Fragments
Polymerase
Ligase
-ase: is an enzyme. Enzymes start chemical reactions
16
Crash Course #10- (Hank Greene)
https://www.youtube.com/watch?v=8kK2zwjRV0M
Unwinding the DNA to copy the base pairs, made of
nucleotides, which are one of the 4 macromolecules called

Nucleic Acids
Fig 14.7
Mutations can lead to changes in the protein sequence encoded
by the DNA. Fig 14.21
Proof Reading and Mutation-
Proofreading by DNA polymerase corrects errors during
replication Fig 14.6
There is a problem with linear Eukaryotic DNA.
What happens at the ends of the DNA? Like a ladder… you can
only climb so far on it... The proteins can “fall off”
GO back and look at Step 5 and 8 of DNA replication?
DNA is “lost” during replication.
Telomeres- ends of linear chromosomes of nucleotide sequence
that code for no protien (nonsense, junk DNA) A little bit of the
end of a telomere (chromosome) is lost during every replication.
Telomeres: Cell Odometer or “Countdown clock”
The telomere is like a protective cap at the end of the DNA.
Every time a cell divides, the telomere gets a bit shorter.
Example: some Cancer cells don’t loose telomeres, they have
“forgotten how to die”
Why evolve this feature?

Genetic disorde involving Telomere mediated syndromes.
”Aging too fast as a of loss telomere control?
“Progeria” Most do not live past their mid-teens, expected life
span 13 years of age.
The amazing human, Sam Berns:
https://www.youtube.com/watch?v=36m1o-tM05g
Chapter 15- Expressing Genes and Proteins
Fig 15.1
Origami Analogy from Chp 2. Proteins are the building blocks
of Life.
The Central Dogma-
Instructions on DNA are transcribed onto messenger RNA.
Ribosomes are able to read the genetic information inscribed on
a strand of messenger RNA and use this information to string
amino acids together into a protein. Fig 15.3
Codon- every 3 nucleotides code for an amino acid. String the
amino acids together and get “protein”
20 amino acids. Humans can make a few, but must eat the rest.
Transcription- Reading the DNA and making an mRNA of that
code.
Translation- Reading the mRNA as a template to make a

protein.
I like analogies… and cookies.
…. And good video:
https://www.youtube.com/watch?v=zwibgNGe4aY
Ribosome
How does a gene (a sequence of bases within a section of DNA)
affect a flower’s color or the shape of a nose or the texture of a
dog’s fur (the phenotype)?
The process occurs in two main steps: transcription, in which a
copy of a gene’s base sequence is made, and translation, in
which that copy is used to direct the production of a protein.
Overview of the steps from gene to genome presents an
overview of the processes of transcription and translation.
In transcription, which occurs in the nucleus in eukaryotes, the
gene’s base sequence or code is copied into a middle-man
molecule called mRNA.
This is like copying the information for the chocolate chip
cookie recipe out of the cookbook and onto a piece of paper.
In translation, the mRNA moves out of the nucleus and into the
cytoplasm of the cell where the messages encoded in the mRNA
molecules are used to build proteins.
Crash course again:
https://www.youtube.com/watch?v=itsb2SqR-R0
23

INDEX CARD for cookie recipe
In transcription, a single copy of one specific gene within the
DNA is made.
Continuing our cookbook analogy, transcription is like copying
a single recipe from the cookbook onto an index card.
It happens in four steps (above- Transcription: copying the base
sequence of a gene).
Step 1 – Recognize, Bind, and Unwind: To start the
transcription process, a large molecule, the enzyme RNA
polymerase, recognizes a promoter site, a part of the DNA
molecule that indicates the start of a gene, and, in effect, tells
the RNA polymerase to “Start here.” At the promoter site, the
molecule binds to one strand of the DNA and, like a court
reporter transcribing everything that is said in a courtroom,
begins to read the gene’s message. At the point where the RNA
polymerase binds to the promoter, the DNA molecule unwinds
just a bit, so that only one strand of the DNA can be read.
Step 2 – Transcribe - As the DNA strand is processed through
the RNA polymerase, the RNA polymerase builds a copy—
called a “transcript”—of the gene from the DNA molecule. This
copy is called messenger RNA (mRNA) because once the copy
of the gene is created, it can move elsewhere in the cell and its
message can be translated into a protein.
The mRNA strand is constructed from four different molecules
called ribonucleotides (which are almost identical to DNA
nucleotides, consisting of a sugar-phosphate complex with a
nitrogen-containing base attached), each of which pairs up with
an exposed base on the now unwound and separated DNA:

If the DNA strand has a Thymine (T), an Adenine (A) is added
to the mRNA.
If the DNA strand has a Adenine (A), a Uracil (U) is added to
the mRNA.
If the DNA strand has a Guanine (G), a Cytosine (C) is added to
the mRNA.
If the DNA strand has a Cytosine (C), a Guanine (G) is added to
the mRNA.
Because our court reporter transcribes a specific sequence of
DNA letters (the gene), the mRNA transcript carries the DNA’s
information. And because it is separate from the DNA, the
mRNA transcript can move throughout the cell, to the places
where the information is needed, while leaving the original
information within the DNA.
Step 3 – Terminate: When the RNA polymerase encounters a
sequence of bases on the DNA at the end of the gene (called a
termination sequence), the court reporter molecule stops
creating the transcript and detaches from the DNA molecule. At
that point, the mRNA molecule is released as a free-floating
single-strand copy of the gene.
Step 4 – Capping and Editing: In prokaryotic cells, once the
mRNA transcript separates from the DNA, it is ready to be
translated into a protein.
In most eukaryotes, however, the transcript must first be edited
in several ways.
First, a cap and a tail may be added at the beginning and end of
the transcript.
Like a front and back cover to a book, these serve to protect the
mRNA from damage and help the protein-making machinery
recognize the mRNA.
Second, because (as we saw in the previous section) there may
have been non-coding bits of DNA transcribed, those sections—
the introns—are snipped out.

Once the mRNA transcript has been edited, it is ready to leave
the nucleus for the cytoplasm where it will be translated into a
protein.
24
Insert figure 5-15
The translation of an mRNA molecule into a sequence of amino
acids (that will then fold into the complex threedimensional
shape of a protein) occurs in three steps.
Step 1 – Recognize and Initiate Protein-Building: Translation
begins in the cell’s cytoplasm when a ribosome, essentially a
two-piece protein-building factory, recognizes and assembles
around a “start sequence”—which is always the bases A, U, and
G next to each other—on the mRNA transcript. As the
ribosomal subunits assemble themselves into a ribosome, one
side of a tRNA molecule also recognizes the start sequence and
binds to the mRNA at that point. That initiator tRNA has the
amino acid methionine bound to its other side. This will be the
first amino acid in the protein that is to be produced (although
occasionally in eukaryotes it is edited out).
Step 2 - Elongate: After the mRNA start sequence, the next
three bases on the mRNA specify which amino-acid-carrying
tRNA molecule should bind to the mRNA next. If the next three
bases on the mRNA transcript are GUU, for example, a tRNA
molecule that recognizes that sequence will attach to the mRNA
at that point. The GUU-recognizing tRNA molecule always has
the amino acid valine attached. The ribosome then facilitates
the connection of this second amino acid to the first.

The process continues in the same manner. The next three bases
on the mRNA specify the next amino acid to be added to the
first two. And the three bases after that specify the fourth amino
acid and so on. This is the beginning of protein synthesis
because all proteins are chains of amino acids, like beads on a
string.
The mRNA continues to be “threaded” through the ribosome,
with the ribosome moving down the mRNA strand reading and
translating its message in little three-base chunks. Each three-
base sequence specifies the next amino acid, lengthening the
growing amino acid strand. After the amino acid carried by a
tRNA molecule is attached to the growing protein, the tRNA
molecule detaches from the mRNA and floats away.
Step 3 - Terminate: Eventually, the ribosome arrives at the
three-base sequence on the mRNA that signals the end of
translation. Once the ribosome encounters this sequence, the
assembly of the protein is complete. Translation ends and the
amino acid strand and mRNA molecule are released from the
ribosome. When it is complete, the protein—such as insulin or a
digestive enzyme—may be used within the cell or packaged for
delivery via the bloodstream to somewhere else in the body
where it is needed.
Following the completion of translation, the mRNA strand may
remain in the cytoplasm to serve as the template for producing
another molecule of the same protein.
In bacteria an mRNA strand may last from a few seconds to
more than an hour; in mammals, mRNA may last several days.
Depending on how long it lasts, the same mRNA strand may be
translated hundreds of times.
Eventually, it is broken down by enzymes in the cytoplasm.
25

In translation, the mRNA copy of the information from DNA is
used to build functional molecules.
Several ingredients must be present in the cytoplasm for
translation to occur
Free amino acids
Ribosomal units
Transfer RNA
Translation is the second step in the
two-step process by which DNA
directs the synthesis of proteins.
In translation, the information from a
gene that has been carried by the
nucleotide sequence of an mRNA is
read, and ingredients present in the
cell’s cytoplasm are used to produce
a protein.
Once the mRNA molecule moves out of the cell’s nucleus and
into the cytoplasm, the translation process begins.
In translation, the information carried by the nucleotide
sequence of the mRNA is read and ingredients present in the
cell’s cytoplasm are used to produce a protein.
The process of translation is like the combining and baking of
the ingredients listed in our chocolate chip cookie recipe to
produce a cookie.

26
Review:
How do genes work?
Nucleus + Ribosomes + Cytoplasm (holding all the amino acids)
Genotype
All of the genes contained in an organism
Phenotype
The physical manifestations of the instructions
THM- The genes in strands of DNA are a “storehouse” of
information or an instruction book.
The process by which this information is used to build an
organism occurs in two main steps:
Transcription, in which a copy of the a gene’s base sequence is
made
Translation, in which that copy is used to direct the production
of a protein
SHOWN by the cool photo next…
The genes in strands of DNA are a storehouse of information, an
instruction book, but they are only one part of the process by
which an organism is built.
If all of the genes that an organism has—its genotype—are like
the recipes in a cookbook, the physical manifestations of the
instructions—the organism’s phenotype—are the cookies, the
macaroni and cheese, the french toast, and all the other foods
described by the recipes.

And, just as you have to assemble ingredients, mix them, then
bake the dough to get a cookie, there are several steps in the
production of the molecules, tissues, and even behaviors that
make up a phenotype.
27
Learning Objectives.
Vocab to be able to explain:
HOLY COOKIES… that’s a lot of info... Yes. That’s why there
are Major level Biology classes
DNA is a universal language that provides the instructions for
building all the structures of all living organisms.
The full set of DNA an organism carries is called its genome.
In prokaryotes, the DNA occurs in circular pieces.
In eukaryotes, the genome is divided among smaller, linear
strands of DNA called chromosomes.
A gene is a sequence of bases in a DNA molecule that carries
the information necessary for producing a functional product,
usually a protein molecule via mRNA.
Mutations &
Biotechnology
Our book… though “free” is good for our class, but this
information is NOT found directly from our book.
This is where all the previous information allows us to start

leaving the “single cell” and move into multicellular
organisms... After this we will start into evolution and the
different forms of Life.
It’s a BIG... HUGE step in cognative understanding. We will
cover the info in the videos at the end of this lecture.
Mutation: Damage to the genetic code has a variety of causes
and effects.
What causes a mutation, and what are its effects?
Alteration of the sequence of bases in DNA can
lead to changes in the structure and function of the proteins
produced.
have a range of effects. (good, bad, *neutral)
Damage to the genetic code can interfere with normal
development (structure) or function.
Only need to know what is a genetic mutation. Types are for a
Genetics class.
Mutations generally fall into two types: point mutations and
chromosomal aberrations. Point mutations and chromosomal
aberrations. In point mutations, one base pair is changed,

whereas in chromosomal aberrations, entire sections of a
chromosome are altered.
Point mutations are mutations in which one nucleotide base pair
in the DNA is replaced with another or in which a base pair is
inserted or deleted. Insertions and deletions can be much more
harmful than substitutions because they can alter the reading-
frame for the rest of the gene. Remember that the amino acid
sequence of a protein is determined by reading the bases on an
mRNA molecule three at a time and attaching the specific amino
acid that is specified by that sequence. If a single base is added
or removed, the three-base groupings get thrown off and the
sequence of amino acids stipulated will be all wrong. It’s almost
like putting your hands on a computer keyboard, but offset by
one key to the left or right, and then typing what should be a
normal sentence. It comes out as gibberish.
Chromosomal aberrations are changes to the overall
organization of the genes on a chromosome. Chromosomal
aberrations are like the manipulation of large chunks of text
within a paper. They can involve the complete deletion of an
entire section of DNA, the moving of a gene from one part of a
chromosome to another, or the duplication of a gene with the
new copy inserted elsewhere on the chromosome. In any case, a
gene’s expression—the production of the protein the gene’s
sequence codes for—can be altered when it is moved, as can the
expression of the genes around it.
31
Because they can change the protein produced, mutations can
disrupt normal processes and harm the individual.

It turns out that many—perhaps even most—mutations are
neutral, having neither a positive nor a negative effect on an
organism’s phenotype. Based on a recent study, researchers
estimate that the rate of germ line mutations is approximately
10 – 8 per base pair per generation.
A paradoxical fact about mutations is that they are essential to
evolution. Those mutations that don’t kill an organism, or
reduce its ability to survive and reproduce, can be beneficial.
Every genetic feature in every organism was, initially, the result
of a mutation.
32
Take-home message
Extremely rarely, mutations may have a beneficial effect.
They play an important role in evolution.
Sickle Cell Anemia: Mutation in human Blood cells that allow
for immunity to Malaria, but comes at a risk. Mutation at the
extreme causes an “abnormality” like Sickle Cell Anemia.
In the next section, we examine how even tiny changes in the
base-pair sequence of DNA can lead to errors in protein
production and profound health problems.
33
Faulty genes, coding for faulty enzymes, can lead to sickness or
an advantage.
How can people respond so differently to alcohol?
A single difference in a single pair of bases in their DNA.
Isabella joins her friends in sipping wine during a dinner party.

As the meal progresses, her companions become tipsy. Their
conversations turn racy, their moods relaxed. They refill their
glasses, reveling in a little buzz. Not so for Isabella. Before her
first glass is empty, she experiences a “fast-flush” response:
Her face turns crimson, her heart begins to race, and her head
starts to pound. Worse still, she soon feels the need to vomit.
How can people respond so differently to alcohol? It comes
down to a single difference in a single pair of bases in their
DNA, a single difference that can influence dramatically a
person’s behavior, digestion, respiration, and general ability to
function. The single base pair change leads to the production of
a non-functional enzyme, and the lack of a functional version of
this enzyme leads to physical illness. Let’s look at the details.
34
From mutation to illness in just four steps:
A mutated gene codes for a non-functioning protein, usually an
enzyme.
The non-functioning enzyme can’t catalyze the reaction as it
normally would, bringing it to a halt.
3. The molecule with which the enzyme would have reacted
accumulates, like a blocked assembly line.
4. The accumulating chemical causes sickness and/or death.
Although the details differ from case to case, the overall picture
is the same when it comes to many, if not most inherited
diseases. The pathway from mutation to illness includes just

four short steps:
1. A mutated gene codes for a non-functioning protein,
commonly an enzyme.
2. The non-functioning enzyme can’t catalyze the reaction as it
normally would, bringing it to a halt.
3. The molecule with which the enzyme would have reacted
accumulates, like a blocked assembly line.
4. The accumulating chemical causes sickness and/or death.
The fact that most genetic diseases involve illnesses brought
about by faulty enzymes suggests some strategies for treatment.
These include administering medications containing the normal-
functioning version of the enzyme. For instance, lactose-
intolerant individuals can consume the enzyme lactase which
gives them for a short while the ability to digest lactose.
Alternatively, lactose-intolerant individuals can reduce their
consumption of lactose-containing foods to keeps the chemical
from accumulating, thus reducing the problems that come from
its overabundance.
35
Genes can be “altered”.
When ”We” do it on purpose it’s called
Biotechnology
What is it? What impact will it have
on us, for us, the future?
Genetic Engineering.
the deliberate modification of the
characteristics of an organism by
manipulating its genetic material.
Recombinant DNA Technology:
A series of procedures that are used to join

together (recombine) DNA segments. A
recombinant DNAmolecule is constructed
from segments of two or more different
DNAmolecules.
How do you create a plant resistant to being eaten by insects?
Or a colony of bacteria that can produce human insulin?
Although there are many different uses of biotechnology, there
is a surprisingly small number of recurring themes and tools
used. Each of these applications, for example, utilizes a similar
sequence of steps and applications. Five important tools and
techniques of most biotechnology procedures:
1. Chop up the DNA from a donor organism that exhibits the
trait of interest.
2. Amplify the small amount of DNA into more useful
quantities.
3. Insert the different DNA pieces into bacterial cells or viruses.
4. Grow separate colonies of the bacteria or viruses, each
containing a different inserted piece of donor DNA.
5. Identify the colonies that have received the DNA containing
the trait of interest.
36
Almost everyone in the United States consumes genetically
modified (transgenic) foods regularly without knowing it.
Benefits out way the risks?

Norman Borlaug-
https://en.wikipedia.org/wiki/Norman_Borlaug
Green Revolution-
https://en.wikipedia.org/wiki/Green_Revolution
You’re existence, due to Human population size, is due to this
man.
Scared? Don’t be! Know the biology and History first.
Transgenic vs GMO (genetically modified food)
http://boingboing.net/2013/03/25/the-case-of-the-poison-
potato.html
http://science.time.com/2013/05/14/modifying-the-endless-
genetically-modified-crop-debate/
http://www.slate.com/articles/health_and_science/science/2015/
07/are_gmos_safe_yes_the_case_against_them_is_full_of_fraud
_lies_and_errors.html
…and so much more. Actually by definition humans today are
“GMO”. Yup... Sorry, but it’s true.
37
Biotechnology has led to important improvements in agriculture
by using transgenic plants and animals to produce more
nutritious food.
Even more significant is the extent to which biotechnology has
reduced the environmental and financial costs of producing
food:
Through the creation of herbicide-resistant and insect-resistant
crops

The ecological and health risks of such widespread use of
transgenic species are not fully understood and are potentially
great.
Biotechnology IS the potential…
The treatment of diseases and production of medicines are
improved with biotechnology.
Preventing diseases
Curing diseases
Treating diseases
The treatment of diabetes, recombinant E. coli making insulin
You can’t always get what you want. In the best of all worlds,
biotechnology would prevent humans from ever getting
debilitating diseases. Next best would be to cure diseases once
and for all. But these noble goals are not always possible, so
biotechnology often is directed at the more practical goal of
treating diseases, usually by producing medicines more
efficiently and more effectively than they can be produced with
traditional methods.
Biotechnology has achieved some notable successes in
achieving this goal.
The treatment of diabetes is one such success story.
39

Cloning & Gene Therapy: Difficulties not a reality… yet.
Gene Therapy:
1. Difficulty getting the working gene into the specific cells
where it is needed
2. Difficulty getting the working gene into enough cells and at
the right rate to have a physiological effect
3. Difficulty arising from the transfer organism getting into
unintended cells
4. Difficulty regulating gene
Cloning—ranging from genes to organs to individuals—offers
both promise and perils. (Dolly in 1997)
Smoked too much? It’d be nice to clone new lungs for you?
Ethics?
Bioethics?

Is extinction… really permanent?
http://ngm.nationalgeographic.com/2013/04/125-species-
revival/zimmer-text
Cloning took center stage in the public imagination in 1997,
when Ian Wilmut, a British scientist, and his colleagues first
reported that they had cloned a sheep—which they named Dolly.
Their research was based on ideas that went back to 1938, when
Hans Spemann first proposed the experiment of removing the
nucleus from an unfertilized egg and replacing it with the
nucleus from the cell of a different individual. Although the
process used by Wilmut and his research group was difficult and
inefficient, it was surprisingly simple in concept (Fig. 5-43).
They removed a cell from the mammary gland of a grown sheep,
put its nucleus into another sheep’s egg from which the nucleus
had been removed, induced the egg to divide, and transplanted
it into the uterus of a surrogate mother sheep. Out of 272 tries,
they achieved just one success. But that was enough to show
that the cloning of an adult animal was possible.
41
DNA as an individual identifier: the uses and abuses of DNA
fingerprinting
http://blogs.smithsonianmag.com/artscience/2013/05/creepy-or-
cool-portraits-derived-from-the-dna-in-hair-and-gum-found-in-
public-places/
DNA fingerprinting is now used extensively in forensic
investigations, in much the same way that regular fingerprints

have been used for the past 100 years. But traditional
fingerprinting is limited in its usefulness for many crimes
because no actual fingerprints are left behind. DNA
fingerprinting, on the other hand, is not so limited because DNA
samples more frequently are left behind, usually in the form of
semen, blood, hair, skin, or other tissue. As a consequence, this
technology has been directly responsible for bringing thousands
of criminals to justice and, perhaps as importantly, for
establishing the innocence of more than 200 people who were
wrongly convicted of murder and other capital crimes. Let’s
examine how DNA fingerprinting is done, why it is such a
powerful forensic tool, and why it is not foolproof.
42
What IS a genetic finger print?
STR- Short Tandem Repeats
THM 5.17 Comparisons of highly variable DNA
regions have forensic value in identifying tissue
specimens and determining the individual from
whom they came.
Fool proof as a “finger print”?

The DNA from different humans is almost completely identical.
More than 99.9% of the DNA sequences of two individuals are
the same because we’re all of the same species and thus share a
common evolutionary history. Even so, in a genome of three
billion base pairs, one-tenth of a percent difference still
translates to about three million base-pair differences. These
differences are responsible for the fact that all individuals have
their own unique genome. Thus, when we are trying to evaluate
whether the DNA from a crime scene matches that from a
suspect, the analysis focuses on the parts of our DNA that
differ. There are thousands of these highly variable regions in
the human genome.
Among the thousands of variable regions in the human genome,
one particular type is used for the determination of a person’s
genetic fingerprint. These regions are called STRs (for short
tandem repeats) and are characterized by having a short
sequence (commonly four or five nucleotides) that repeats over
and over a dozen or more times.
An individual—we’ll call her Individual A—has two copies of
each chromosome, one from her mother and one from her father.
At one STR location (on chromosome 3,
for example), the number of times the sequence repeats is likely
to differ on the maternal and the paternal copies of that
chromosome in Individual A. The sequence may repeat 14 times
on the maternal copy of chromosome 3 and it may repeat only 3
times on the paternal copy that she carries. in such a case,
Individual A is said to have two different alleles for this STR
region: 14 and 3. In contract, in Individual B, for the same STR
region on chromosome 3, the sequence may repeat 5 and 11
times (Fig. 5-46).
43

It’s a BIG... HUGE step in cognative understanding. We will
cover the info in the videos at the end of this lecture.
Please watch in this order please:
#18 https://www.youtube.com/watch?v=WhFKPaRnTdQ
#17- https://www.youtube.com/watch?v=9sjwlxQ_6LI
Gattaca. Watch it.
Want to have all this apply to Humans in a SciFi movie?
Chapter 18 Evolution, Species
Chapter 19 Populations
Species
Populations
1
Understanding how science works allows one to easily
distinguish science from non-science.

Thus, to understand biological evolution, or any other science,
it is essential to begin with the nature of science. (Chp 1)
http://www.evolution.berkeley.edu/evosite/nature/
2
Chapter 18 Objectives
Evolution
Species
Speciation
Chapter 19 Objectives
Population Evolution
Population Genetics
Adaptive Evolution
These two chapters are have a lot of the same Biological
concepts in common. The
difference is in observing the concepts at a “singular species” or
“individual” organism in Chp 18.
Observing the concepts at a “population”, “all the individuals”
or “group”, “selection of individuals” representing an organism
in Chp 19
There is a lot more unique vocabulary.
Some of the GREATEST misconceptions of Science are a result

of NOT understanding the vocabulary.
The characteristics of individuals in a population can change
over time.
We can observe such change in nature and can cause such
change to occur.
Before Darwin, most people believed that all species had been
created separately and were unchanging.
Chp 18: All species of living organisms, from bacteria to
baboons to blueberries, evolved at some point from a different
species. Although it may seem that living things today stay
much the same, that is not the case—evolution is an ongoing
process.
4
What happened to change the “current” thinking?
Accepting a “non static” view of the Living world.
Mendels work was not known to other scientists yet.
Vocabulary needed to be invented.
Natural selection
The consequence of certain individual organisms in a population
being born with characteristics that enable them to survive
better and reproduce more than the offspring of other
individuals in the population.
Darwin and Wallace couldn’t look at “cells”… they were

observing the macro world: “Nature”
Evolution
Is a genetic (biological) change in the population “over time”
Becomes the current vocabulary b/c Mendel’s added work.
5
What happened? In a word: evolution.
That is, there was a genetic change in the population of fruit
flies living in the cage.
Every fly in the generation 60 population, even the fly with the
worst starvation resistance, is still more than seven times better
at resisting starvation than the best fly in the original
population.
This evolution is the result of natural selection.
We’ll discuss natural selection in more detail later, but it is the
consequence of certain individual organisms in a population
being born with characteristics that enable them to survive
better and reproduce more than the offspring of other
individuals in the population.
In this experiment, the 20% of fruit flies that were the most
starvation resistant had a huge reproductive advantage over
less-resistant flies because they were the only flies within the
population that survived to reproduce.
What happened is that two important and unexpected patterns
were observed in Nature and verified:
Glyptodonts and armadillos
Darwin noted unexpected patterns among fossils he found and

living organisms he observed while on the voyage of the
Beagle.
His book, Origin of the Species:
1842 first Draft
14 years in a drawer!
1859 “The Origin of Species”
Alfred Russel Wallace?
He did it too… different location, but still of “Nature”. This is
“verification”.
Traits exhibited by species
Similarity between the fossils of extinct species and the
living species in that same area
These favorable variations are preserved over time
6
Traits (DNA, Chromosomes, alleles, genes)
Preserved (Reproduction, Cell Division)
variation (Meiosis, mutation)
Darwin noticed two important and unexpected patterns on his
voyage that would be central to his discovery of a mechanism
for evolution.
The first involved the finches he collected and donated to the
Zoological Society of London.
Darwin had assumed that they were the equivalent of tall and
short, curly-haired and straight-haired people.
That is, Darwin thought that all the finches were of the same
species, but with different physical characteristics or traits,
such as body size, beak shape, or feather color.
The Zoology Society, however, could see from their physical
differences that there were 13 unique species—a different

species from every one of the Galapagos Islands that Darwin
had visited.
Moreover, although they were different species, they all
resembled very closely the single species of finches living on
the closest mainland, in Ecuador.
This resemblance seemed a suspicious coincidence to Darwin.
Perhaps the island finches resembled the mainland species
because they used to be part of the same mainland population.
Over time, they may have separated and diverged from the
original population and gradually formed new—but similar—
species.
Darwin’s logic was reasonable, but his idea flew in the face of
all of the scientific thinking of the day.
Figure 8-6 Darwin observed unexpected patterns.
“Survival of the Fittest” is incorrect:
Fitness is a measure of the relative amount of reproduction of
an individual with a particular phenotype, as compared with the
reproductive output of individuals with alternative phenotypes.
An individual’s fitness can vary, depending on the environment
in which the individual lives.
THM: Better word choice is “Survival of the best adapted.”
(Got tools?)
Adaptation—the process by which organisms become better
matched to their environment and the specific features that
make an organism more fit—occurs as a result of Natural
Selection (N.S.)…
N.S. does not lead to perfect organisms. So “fittest” is
incorrect.
Evolution in general, and natural selection specifically, do not
“guide” organisms toward “better-ness” or perfection. It is not a

“directed process”. It just is. It is what happens.
If the environment changes, the alleles (the tools) causing the
traits (tool function) favored by natural selection may change,
too.
Why doesn’t natural selection “lead” to the production of
perfect organisms?
Environments can change more quickly than an organism can
adapt (Got tool?) via N.S. to the new environment pressures.
All possible alleles are not produced by mutation. (no tools)
There is not always a single optimum adaptation for an
environment. (wrong tool)
7
Artificial Selection? (Farming) how does that change Evolution
by Natural Selection as a concept? Does or doesn’t it?
I’m going to skip the order of Chapter 18 around. Please read
chapter 18!
Organise and connect previous information we have covered
into Chpt 18. Everything in class leads up to supporting this
information.
Lets make the connections! Chp 18 is great, I’m just going to
mix in Chp 1-
Chapter 14-15 lecture do this too.)
But first... Evolution is “just a theory”.

In science, a “theory” is understood to be a body of thoroughly
tested and verified explanations for a set of observations of the
natural world. The theory of evolution describes facts about the
living world.
In contrast, a “theory” in common vernacular is a word meaning
a guess or suggested explanation; this meaning is more akin to
the scientific concept of “hypothesis.”
When critics of evolution say evolution is “just a theory,” they
are implying that there is little evidence supporting it and that it
is still in the process of being rigorously tested.
This is a mischaracterization. Miss use of the vocabulary and
incorrect.
What is “fact”: In the most basic sense, a scientific fact is an
objective and verifiable observation, in contrast with a
hypothesis or theory, which is intended to explain or
interpret facts.
8
Evolution does not explain the “origin of Life”. (NEXT SLIDE)
It is a common misunderstanding that evolution includes an
explanation of life’s origins.
The theory does not try to explain the origin of life. Origin of
Life and Theory of Evolution are two different questions. The
theory of evolution explains how populations change over time
and how life diversifies the origin of species.

It does not shed light on the beginnings of life including the
origins of the first cells, which is how life is defined. The
mechanisms of the origin of life on Earth are a particularly
difficult problem because it occurred a very long time ago, and
presumably it just occurred once.
Importantly, biologists believe that the presence of life on
Earth precludes the possibility that the events that led to life on
Earth can be repeated because the intermediate stages would
immediately become food for existing living things. (4
Macromolecules of Life)
However, once a mechanism of inheritance was in place in the
form of a molecule like DNA either within a cell or pre-cell,
these entities would be subject to the principle of natural
selection.
:
Origin of Life? … and now we’ve come full circle back to the
previous chapters
Life on earth most likely originated from nonliving materials.
Cells and self-replicating systems evolved together to create the
first life.
“Life”= The ability to replicate, 2. The ability to carry our some
sort of metabolism (consume energy, remove waste) and
Membranes “make metabolism a greater possibility” (a “cell”
separates a space from the environment)

Emperical: information based on, concerned with, or verifiable
by observation and data that is reproducible via
experimentation.
10
A theory in science has survived significant efforts to discredit
it by scientists.
“Wrong or “failure” to answer” is good! When Science asks
questions and all the possibilities are explored and the data
(answers to these questions) comes back not supporting the
original questions, this is an advancement of knowledge.
When all the questions are answered “No” then the only
questions left can be “yes”.
That’s Science!
Four “mechanisms” can give rise to Evolution by Natural
Selection!
Evolution occurs when the allele frequencies in a species
population changes. Chp 18
Populations evolve. Chp 19
Evolution and Natural Selection, are not the same thing. They
occur together.
First… lets talk about a “species”.
Biological Species Concept

Species: singular kind of organisms
Species are natural populations of organisms that:
Interbreed with each other or could possibly interbreed
Cannot interbreed with organisms outside their own group
(reproductive isolation)
Biologists use the word species to label different kinds of
organisms.
According to the biological species concept: Species are natural
populations of organisms that interbreed with each other or
could possibly interbreed, and that cannot interbreed with
organisms outside their own group.
13
Fig 18.9 The (a) poodle and (b) cocker spaniel can reproduce to
produce a breed known as (c) the cockapoo.
Wolf to a Cockapoo? Species isn’t what it “looks” like…
Fig 18.10 The (a) African fish eagle is similar in appearance to
the (b) bald eagle, but the two birds are members of different
species.
Two Key Features of the Biological Species Concept:
1. Populations of individuals that interbreed with each other or
could possibly interbreed
2. “Natural” populations: Populations that cannot interbreed
with organisms outside their own group

THM
Notice that the biological species concept completely ignores
physical appearance when defining a species and instead
emphasizes reproductive isolation, the inability of the
individuals from two populations to produce fertile offspring
with each other, thereby making it impossible for them to
exchange genes.
Let’s clarify two important features of the biological species
concept.
First, it says that members of a species are either actually
interbreeding or could possibly interbreed. This emphasis means
that just because two individuals are physically separated, they
aren’t necessarily in different species. A person living in the
United States and a person living in Iceland, for example, may
not be able to mate because of the distance between them, but if
they were brought to the same location, they could mate if they
wanted to. So we do not consider them to be reproductively
isolated.
Second, our definition refers to “natural” populations. This
distinction is important because in captivity occasionally
individuals may interbreed that which would not interbreed in
the wild, such as zebra and horse Interbreeding is not enough to
equal a new species.
15

“Interbreeding” has to deal with biological compatibility at the
egg and sperm as barriers to reproduction
1. Prezygotic barriers
2. Postzygotic barriers (hybrids)
Remember what a zygote is? A fertlized egg, by sperm,
containing all the DNA to proceed with Cell Theory and grow
into a functional organism.
There are two types of barriers that prevent individuals of
different species from reproducing: prezygotic barriers and
postzygotic barriers. (Remember, an egg that has been fertilized
by a sperm cell is a zygote.)
Figure 10-8 Barriers to reproduction. With postzygotic barriers
to reproduction, even if fertilization does occur, the animal
(such as the mule, on the right) is usually sterile.
17
Speciation
Click through this interactive site
(http://openstaxcollege.org/l/bird_evolution) to see how island
birds evolved in evolutionary increments from 5 million years
ago to today.
Allopatric Speciation is a simpler concept. It involves
geographic separation of populations from a parent species and
subsequent evolution.
“allopatric” meaning “other homeland.”

18
As species “move” and travel across landscapes, this concept
leads to adaptive radiation: a species relocating and capitalizing
on specific niches in their geography and habitat.
Fig 18.3- The honeycreeper birds illustrate adaptive radiation.
From one original species of bird, multiple others evolved, each
with its own distinctive characteristics.
Divergence can occur if no physical barriers are in place to
separate individuals who continue to live and reproduce in the
same habitat?
The answer is yes.
The process of speciation within the same space is called
sympatric speciation; the prefix “sym” means same, so
“sympatric” means “same homeland”
Speciation can also occur among populations that overlap
geographically. This type of speciation is called sympatric
speciation. Among animals it is rare for populations of the same
animal to become reproductively isolated when they coexist in

the same area, so this method of speciation is relatively
uncommon. But among plants it is common
20
We’ve defined “species”, now lets discuss how to change a
species.
Look at Fig 18.23
Evolution by Natural Selection isn’t always “slow”… “Time” is
important to keep in mind.
“Time” is important to keep in mind. Life has been on this
planet for an estimated 3.8 Billion years ago.
21
Chapter 19: Populations. It’s a group effort!
All life on Earth is related. Scientists consider evolution a key
concept to understanding life. Natural selection is one of the
most dominant evolutionary forces. Natural selection acts to
promote traits and behaviors that increase an organism’s
chances of survival and reproduction, while eliminating those
traits and behaviors that are to the organism’s detriment. But
natural selection can only, as its name implies, select—it cannot
create.
Evolutionary forces that act upon populations and thus species.
This combination of processes has led to the world of life we
see today.

22
Mechanisms of Evolutionary Change
Mutation
2. Genetic drift
3. Migration
4. Natural selection
Evolution is genetic
change in a population.
A single individual “changing” is not enough…
23
Natural selection is one way that evolution can occur, but it is
not the only agent of evolutionary change.
It is one of four. They are:
1. Mutation
2. Genetic drift
3. Migration
4. Natural selection
Keeping in mind that evolution is genetic change in a
population, we’ll now explore each of these four forces, which
are all capable of causing such genetic changes.
Mutation is an alteration of the base-pair sequence in an
individual’s DNA.

If such an alteration changes an allele in an individual’s
gamete-producing cells, this constitutes evolution within the
population. It is an inheritable change.
Mutations can be caused by high-energy sources or chemicals in
the environment and also can appear spontaneously.
Mutation is the only way that new alleles can be created within
a population, and so generates the variation on which natural
selection can act.
Mutation—a direct change in the DNA of an individual—is the
ultimate source of all genetic variation.
24
Genetic drift is a random change in allele frequencies
in a population.
Why the Cleft Chin?
The important factor that distinguishes genetic drift from
natural selection:
The change in allele frequencies is not related to the alleles’
influence on reproductive success.
…but is a significant agent of evolutionary change primarily in
small populations (why?)
25
Imagine that in a population there are two alleles present for a

particular trait such as a cleft chin.
It is a dominant trait, so individuals with either one or two
copies of the dominant allele (CC or Cc) exhibit the cleft chin.
Now suppose that two heterozygous (Cc) people have one child.
Which combination of alleles will that child receive?
It is impossible to predict because it depends completely upon
which sperm fertilizes which egg—the luck of the draw.
If their sole child inherited a recessive allele from each parent,
would the population’s allele frequencies be different?
Yes. After all, there is now another individual in the population,
and that individual has two recessive alleles (cc).
There are slightly more recessive alleles in the population.
And because a change in allele frequencies has occurred,
evolution has happened.
It is equally likely that this couple’s only child would have
received two of the dominant alleles (CC), rather than the
recessive alleles.
In either case, because a change in allele frequencies has
occurred, evolution has happened.
3 important outcomes of Genetic Drift:
Drift It’s about the alleles! Why? Alleles in Gamete formation =
“v_______!”
Genetic drift can lead to fixation for one allele for a gene in a
population.
If this happens, there is no more variability in the population
for this gene.
Genetic drift reduces the genetic variation in a population by
chance. It is a big reason WHY we use vocab of a population vs
an individual.
Two special cases of genetic drift that are important in the
evolution of populations
Founder effect- a group gets lost and finds a pass to a new

valley, or crosses a shallow sand bar to an island on a rare low
tide… never to return to the original population by chance.
Group (family, pack, flock, troupe) huddling in a tree during a
storm. Tree falls into the water... Holding on, end up on the
beaches of Hawaii... or Galapagos Island.
Population bottlenecks- chance catastrophe. A volcanic
eruption, flood, etc will kill any individual with better alleles…
it’s just random Luck who survives. (This does include disease,
genocide and war etc.)
26
One of the most important consequences of genetic drift is that
it can lead to fixation for one allele for a gene in a population.
This occurs when an allele’s frequency in a population reaches
100% (and the frequency of all other alleles of that gene
become 0%).
If this happens, there is no more variability in the population
for this gene; all individuals will always produce offspring
carrying only that allele (until new alleles arise through
mutation).
For this reason, genetic drift reduces the genetic variation in a
population.
27
One way that genetic drift occurs: founder effect.
The Amish population in the United States is believed to have

been established by a small number of founders who happened
to carry the allele for polydactyly—the condition of having
extra fingers and toes.
As a consequence, today this trait, while still rare, occurs much
more frequently among the Amish than among the rest of the
U.S. population One way that genetic drift occurs: founder
effect).
28
Another way that genetic drift occurs: bottleneck effect).
Occasionally, a famine, disease or rapid environmental change
may cause the deaths of a large proportion (sometimes as much
as 90% or more) of the individuals in a population.
Because the population is reduced to a small fraction of its
original size, this reduction is called a bottleneck.
If the catastrophe is equally likely to strike any member of the
population, the remaining members are essentially a random
small sample of the original population.
For this reason, they may not possess the same allele
frequencies as the original population.
Thus, the consequence of such a population bottleneck would be
evolution through genetic drift
Just such a population bottleneck occurred in the cheetah near
the end of the last ice age, about 10,000 years ago.
Although the cause is unknown—possibly environmental
cataclysm or human hunting pressures—it appears that nearly
all cheetahs died.
And although the population has rebounded, all cheetahs living
today can trace their ancestry back to a dozen or so lucky
individuals that survived the bottleneck.
As a result of this past instance of evolution by genetic drift,

there is almost no genetic variation left in the current
population of cheetahs. (And, in fact, a cheetah will accept a
skin graft from any other cheetah much as identical twins will.)
Migration into or out of a population may change allele
frequencies.
Migration, and gene flow, leads to a change in allele
frequencies in a population as individuals move into or out of
the population.
The third agent of evolutionary change
This movement from population to population within a species
distinguishes migration from the founder effect, in which
individuals migrate to a new habitat, previously unpopulated by
that species.
If migrating individuals can survive and reproduce in the new
population, and also carry a different proportion of alleles than
the individuals in their new home, then the recipient population
experiences a change in allele frequencies and, consequently,
experiences evolution.
And because alleles are simultaneously lost from the initial
population, that population too will experience a change in its
allele frequencies.
29
The 4th Agent of Evolutionary Change:
When three simple conditions are satisfied, evolution by natural
selection occurs.
There must be variation for the particular trait within a

population: an allele is present.
That variation must be inheritable.
Individuals with this allele, version of the trait, must produce
more offspring than those with a different version of the trait.
Not just ‘reproduce’ in #, but generations must go on to
reproduce more= over TIME
30
The fourth agent of evolutionary change is natural selection.
This is the mechanism that Darwin identified in The Origin of
Species, in which he noted that three conditions are necessary
for natural selection to occur.
Let’s examine
What does Nat. Selection “Look like?”
THM
Natural selection is a mechanism of evolution that occurs when
there is heritable variation for a trait, and individuals with one
version of the trait have greater reproductive success than
individuals with a different version of the trait.
OR
It can also be thought of as the elimination of alleles from a
population that reduce the reproductive rate of individuals
carrying them relative to the reproductive rate of individuals
who do not carry the alleles

31
If you carry a trait that makes you a slower running rabbit, for
example, you are more likely to be eaten by the fox and
removing the losers.
If running speed is a heritable trait (and it is), the next
generation in a population contains fewer slow rabbits.
Over time, the population is changed by natural selection.
It evolves.
32
That’s it. Natural selection—certainly one of the most
influential and far-reaching ideas in the history of science—
occurs when three basic conditions are met (Figure 8-19
Evolution by natural selection: A summary):
1. Variation for a trait
2. Heritability of that trait
3. Differential reproductive success based on that trait
When these three conditions are satisfied, evolution by natural
selection is occurring.
It’s nothing more and nothing less; no mysterious black box is
required.
Over time, the traits that lead some organisms to have greater
reproductive success than others will increase in frequency in a
population while traits that reduce reproductive success will
fade away.
"Survival of the fittest" is a misnomer.
Why?

Think of White and Black Moths. Or in the book, white and
sandy colored mice.
33
“Survival of the fittest” is a misleading phrase becauseit is the
individuals that have the greatest reproductive output that are
the most fit in any population. It becomes a more meaningful
phrase if we consider it a description of the fact that the alleles
that increase an individual’s fitness will “survive” in a
population more than the alleles that decrease an individual’s
fitness.
THM Natural selection can cause the evolution of complex
traits and behaviors. NS does not “design” or ”plan” Life.
Often, structures appear because they serve some other purpose.
AND
The evidence for evolution is overwhelming
The Pygmy seahorse, 2cm, (Hippocampus bargibanti) is so well
camouflaged by the coral it lives near that the first specimens
were discovered only after coral had been collected and put in
an aquarium.
34
We have seen that natural selection can change allele
frequencies and modify the frequency with which simple traits
like fur color or turkey breast size appear in a population.
But what about complex traits including behaviors that involve
numerous physiological and neurological systems?

For instance, can natural selection improve maze running ability
in rats?
Natural selection is a driving force in evolution and can
generate populations that are better adapted to survive and
successfully reproduce in their environments. But natural
selection cannot produce the perfect organism. Natural selection
can only select on existing variation in the population; it does
not create anything from scratch.
NS is limited by a population’s existing genetic variance
becuase any given individual may carry some beneficial alleles
and some unfavorable alleles.
It is the net effect of these alleles, or the organism’s fitness,
upon which natural selection can act.
Finally, it is important to understand that not all evolution is
adaptive. While natural selection selects the “fittest”
(adaptable) individuals and often results in a more fit
population overall, other forces of evolution, including genetic
drift and gene flow, often do the opposite: introducing
deleterious alleles to the population’s gene pool.
Evolution has no purpose—it is not changing a population into a
preconceived ideal. It is simply the sum of the various forces
described in this chapter and how they influence the genetic and
phenotypic variance of a population.
Natural Selection can not “make” the perfect organism.
Cells are the “basic units of Life”
Species are the basic units of biodiversity.

SO… from now on we will not talk about “cells” but Species,
because now you understand the inner workings of Life. You
know the “code”…
You know the Matrix.
Now we look at the Construct… the world you live in… “there
is no spoon.”
So... What IS a species?
If ALL life is related…
Why?
How?
Can we “organize” Life to
show how and why it’s all
Related?
Yes… in Chp 20
This is a big moment in conceptual understanding of Biology. It
is the moment when you add up all the individual “facts” that
are micro- small, abstract, from molecules to Cells, DNA, to
how DNA gets moved around and selected for… and NOW tie

or combine them to the macro world. TO apply the “concepts”
that are “not physical” but are “acts, occurrences, chance
events” that are a basis to the biological foundation to a large
global view of the Biosphere.
This is where Darwin, Wallace, Mendel and many many others
had to start Historically with the macro large view and then
figure out how/where the discoveries of the micro- information
ties in.
Understanding Evolution by Natural Selection will cognitively
simplify and bring logic and reason to explain the Natural
World.
“All knowledge is tennable.”
36
Cell Division
Chp 10 Mitosis
11 Meiosis
12 Genetics
There are different types of cell division for an important
biological reason.
We have discussed the simplistic goals
of Life in 2 of the 3 categories of Acquire Energy in our
previous chapters of Chemistry and Metabolism. (waste is in
here)
The 3rd goal is to “Reproduce”.

Lets explore WHY this step so important to Biology?
Cell division by fission in Staphylococcus aureus, a disease-
causing bacterium having resistance to multiple antibiotics.
Highlights of Chapter 10
Cell Division
Cell Cycle
Cancer and the Cell Cycle
Prokaryotic Cell Division
Remember: Cell Theory (Chp 4, “What is a Cell” lecture, slide
6)
What is Cell Division?
Divide as in to cleave into two. Make 2 out of 1.
This keeps with Cell Theory.
The process of Cell Theory is called the Cell Cycle
It comes in two types: Mitosis and Meiosis
Cell Cycle- an orderly sequence of events that describes the
stages of a cell’s life from the division of a single parent cell to
the production of two new daughter cells. The mechanisms
involved in the cell cycle are highly regulated.
Why is here a “cycle” that is highly regulated or controlled?
Genome- is all the DNA of an organism. (we will go over what
DNA is later).
Remember- DNA is a nucleic acid represents 1 of the 4
macromolecules of Life. Nucleic Acids are used to store

information. DNA is a code.
DNA codes for EVERYTHING concerning the cell. It regulated
Cell function including Division, so it must be copied for each
new daughter cell.
Cell Cycle during division: We’ll take it in 4 steps.
Remember- Goal is to make 2 cells from 1.
G1 phase- The cell grows. “g”-grow.
S phase- copy genome (DNA). “s”-synthesis of DNA
G2 phase- the cells “recovers” (rests), grows, copying
organelles, dismantling cytoskeleton
Mitosis- “all Copies done” & energy ready = Nucleus & cell
divide
Mitosis- the dividing of a cell and its genome. In a eukaryote
that included the nucleus and all organelles.
Fig 10.5
THM- of Cell Division
Eukaryotic cells alternate in a cycle between cell division and
other cell activities. Living or dividing.
The cell division portion of the cycle is called the mitotic
phase.
The remainder of the cell cycle, called interphase, consists of
two gap phases (during which cell growth and other metabolic
activities occur) separated by a DNA synthesis phase, S phase,
during which the genetic material is replicated.
Once ALL DNA is replicated… a cell divides.

5
There is a time for everything in the eukaryotic cell cycle.
The alternation of activities between cell division and other
processes is called the cell cycle.
The cell cycle describes the series of phases that leads to cell
division.
These phases are divided into a cell division phase, called
mitosis, and a phase of growth and non-reproductive activities,
called interphase.
Because interphase is further subdivided, four distinct phases of
the cycle are recognized.
A eukaryotic cell moves through the phases in this order and is
always somewhere within this cycle.
The phases are: mitosis and the three phases of interphase—Gap
1, DNA synthesis, and Gap 2.
6
Cancer and the Cell Cycle: 10.4
What is cancer? Cancer is “uncontrolled” cell growth.
Looking at Mitosis- when a cell divides, Genome must duplicate
a copy for each new daughter cell.
This process is called replication. IF an error occurs in the code
this is a mutation. If the error is in the code to control Mitosis,

then “division is uncontrolled”.
There are genes (code) called tumor suppressor genes that
regulate an replication errors.
This is why Mitosis is highly regulated cell cycle.
But why do EUKARYOTIC cells divide?
* Why are there two process for cell division? Mitosis and
Meiosis
7
Life’s 3 Goals: 1. Consume Energy. 2. Get rid of waste. 3
Reproduce
Two different kinds of cell categories:
MITOSIS - * Somatic cells: Any cell forming the body of an
organism (goals 1&2)
Meiosis - * Germ cell: Any cell that gives rise to the gametes
of an organism that reproduces sexually. (goal 3)
The organization and distribution (heredity) of the DNA is
different.
Mitosis and Meiosis solve these requirements.
Basically… Cells (*multicellular organisms) need to grow and
replace themselves

1. Growth. During growth and development, organisms get
bigger and must add new cells. In fact, if you want to see cell
division in action, one sure-fire place to look is at the tip of a
plant root because that is one of the fastest growing parts of a
plant, at about half an inch per day (Figure 6-7 Part 1 Reasons
for mitosis).
2. Replacement. Cells also must be replaced when they die. The
wear and tear that comes from living can physically damage
cells. The daily act of shaving, for example, damages thousands
of cells on a man’s face (Figure 6-7 Part 2 Reasons for mitosis).
It’s nothing to worry about, though. Microscopic views of
human skin reveal several distinct layers, with the outermost
layers—the layers under assault during shaving—made up
primarily from dead cells. These cells help protect us from
infection and also reduce the rate at which the underlying living
cells dry out. The living cells that exist just below the layers of
dead cells are being produced at a high rate by mitosis; they can
also be harmed if you’re not careful.
8
Prokaryotic Cell Division- That “other cell” from Chapter 4.
Mitosis and next Meiosis are how Eukaryotes divide, but there
is more than one kind of cell on Earth.
Prokaryotes undergo a cellular process called binary fission.
This is the usual form of asexual replication for bacteria.
Prokaryotes are less complicated organisms, thus it is a simple
identical copy.
Single celled Eukaryotes that “copy themselves” still undergo
Mitosis, which is still a process of making an identical copy.

Copy the DNA: Genomes are circular or linear.
Eukaryotes have much more DNA.
In eukaryotes, genetic information is organized into linear
chromosomes.
Eukaryotic chromosomes float freely in the nucleus.
As a method for storing genetic information, DNA has complete
market saturation. All life on earth uses it. This is pretty
remarkable considering the tremendous diversity of life that
exists on earth—from bacteria to plants and animals. One way
in which different organisms’ DNA varies is in how it is
organized into chromosomes.
10
Highlights of Chapter 11 Meiosis and Sexual Reproduction.
Process of Meiosis
Sexual Reproduction
As mentioned in Chp 4 & 5: all cells come from preexisting
cells (Cell Theory), an egg is a “single cell”, but how and why
does a multicellular organism made of trillions of cells start
from a single cell?
What about the DNA?
Why are there two forms of cellular division?

Remember: Two different kinds of cell divisions for eukaryotes.
There are two versions because of sex.
Let’s use humans as our eukaryotic example. We are mammals
and a eukaryote.
Of the trillions of cells in you most tissues and organs use
Mitosis to grow and repair you. They are copies of copies… etc
Your sexual organs have secialized Germ Cells to form eggs and
sperm. Egg and sperm are called haploid cells. Haploid cells
have half the DNA of the parent.
Sex has the goal of joining the DNA (1/2 mom) in an egg
(oocyte) and the DNA (1/2 Dad) in one sperm to make a new
(1:whole) cell (zygote) that will grow mitoticly into a new
human of another trillion cells. The secret is that this new
individual is not an exact copy of the parents.
MITOSIS - * Somatic cells: Any cell forming the body of an
organism (goals 1&2)
Meiosis - * Germ cell: Any cell that gives rise to the gametes
of an organism that reproduces sexually. (goal 3)
The organization and distribution (heredity) of the DNA is
different.
Mitosis and Meiosis solve these requirements.
What is Meiosis?
Meiosis- is nuclear division that forms haploid cells.
Mitosis occurs almost everywhere in an animal’s body. Meiosis
only occurs in one place.

Where?
What’s the “goal” of this other form of cell duplication?
Hint: It’s not directly
about the “cell”
A simple look at Meiosis
Figure 6-19 (not in your book) Meiosis reduces the genome by
half in anticipation of combining it with another genome.
13
Meiosis is more complicated. It has to essentially ”double” the
steps of Mitosis.
I prefer the simpler version for our needs of this class. DON’T
get lost in memorizing all the steps... That’s for biology majors.
Why not learn the steps of Meiosis now?
Know WHY Meiosis happens.

Know the difference
between
Mitosis and
Meiosis
Notice!
Look at “outcome”
Know the difference between Mitosis and Meiosis-
Diploid cells with full genomes undergo Mitosis, and
special diploid germ cells undergo Meiosis to make
haploid cells.
Fig 11.8
Know why Meiosis happens- Sex. To make an offspring
with genetic variation to the parents original DNA.
Our bodies have a problem to solve relating to cell division. We
are sexually reproducing organisms; that is, when offspring are
created, they carry the genetic material from two individuals.
But think about the difficulties this presents. If reproductive
cells were produced through mitosis, both parents would
contribute a full set of genes—that is, 23 pairs of chromosomes
in humans—to create a new individual; the new offspring would
inherit 46 pairs of chromosomes in all. And when that
individual reproduced, if she contributed 46 pairs of
chromosomes and her mate also contributed 46 pairs, their
offspring would have 92 pairs of chromosomes. Where would it
end? The genome would double in size every generation. That
wouldn't work at all. At the very least, within a few generations
cells would be so overloaded with chromosomes that they would

explode.
16
Know why Meiosis happens- Sex. The evolution of sex is
important because it increases the chance to produce better
offspring as a result of the genetic variation created by Meiosis.
Meiosis performs genetic recombination called a “crossover”.
What? Sex!
Two parents do not make an identical child every time. Each
offspring is a “little different” mix of the parents. (excluding
genetic twins)
During a step of Meiosis the chromosomes swap DNA. This
occurs in the mom and dad. Thus a each creation of an egg
produces a different egg.
Same with sperm
Crossover occurs between non-sister chromatids of homologous
chromosomes. The result is an exchange of genetic material
between homologous chromosomes.
Occurs when making 1 egg in mother. This mother get her DNA
from her Dad and Mom.
DNA (blue-Dad) (Red-Mom)
Egg #1
X
= Genetic mix?
Sex!
sperm
What are the costs and benefits of sexual reproduction?

Sexual reproduction leads to offspring that are all genetically
different from each other and from either parent in three
different ways (Meiosis + fertilization)
Asexual Reproduction (Mitosis & Binary fission) is fast! Some
bacteria split every 20 min/generation. But all “new”
generations are the “same” (mutations?)
Sexual reproduction takes 2.
At costs of…
At great benefits of…
There are fundamentally different ways that cells and organisms
can reproduce. On one hand there is mitosis and asexual
reproduction via binary fission. On the other hand, there is
meiosis and sexual reproduction. Is one method better than the
other? It depends. In fact, the more appropriate question is:
what are the advantages and disadvantages of each and under
what conditions do the benefits outweigh the costs?
Crossing over and meiosis: creating many different
combinations of alleles.
Crossover can occur during the creation of haploid cells within
one parent and then again during fertilization and the combining
of the egg/sperm during the first mitosis event. It will occur
again when that new individual Germ Cells undergo Meiosis to
produce egg or sperm.
18
Why is “sex” a big deal?

Life cycles of organisms from single to multicellular that
preform sex have evolved a way to make consecutive
generations that have the “chance to be an improvement” from
the previous generations to face the uncertain future.
Read “The Red queen Hypothesis” in your book. 11.2, page 313.
This genetic variation created during EVERY generation
between EVERY member of a species is a major concept in the
process of Evolution by Natural Selection.
This genetic variation is also why a curious Scientist named J.
Gregor Mendel set to work on the biological process of
inheritance… or also called Genetics. Chapter 12
19
Meiosis
Gametes- a cell that will combine at fertilization (sexual
reproduction) to produce offspring. A reproductive cell.
Diploid- refers to cells that have two copies of each
chromosome (in humans that is two sets of 23= 46)

Exam 2 Study Guide. All questions will be over these concepts, voc.docx

Exam 2 Study Guide. All questions will be over these concepts, voc.docx

Recommended

Recommended

More Related Content

Similar to Exam 2 Study Guide. All questions will be over these concepts, voc.docx

Similar to Exam 2 Study Guide. All questions will be over these concepts, voc.docx (20)

More from SANSKAR20

More from SANSKAR20 (20)

Recently uploaded

Recently uploaded (20)

Exam 2 Study Guide. All questions will be over these concepts, voc.docx