The Living Environment
the year so far ...

What does it mean to be
alive?

Characteristics of Life
M
R
L
S
T
R
N
G
R

Characteristics of Life
Metabolism
Regulation
Locomotion
Synthesis
Transport
Respiration
Nutrition
Growth
Reproduction

Cells are the building
blocks of life

Every organelle has a
job to do

And they each help to
maintain homeostasis

Ecology

Ecology is all about
relationships

Biotic Factors depend
upon Abiotic Factors

Everything eats
everything else

Energy Flows Through
the System

Things move from the
simple to the complex

Nutrients Come and Go

and Biodiversity is King

Genetics

4 Parts of Genetics

Inheritance

Rules of Inheritance
There are different versions of each trait.
Traits are inherited from your parents.
You inherit one version of each trait from
each of your parents.
You need both versions of the trait to show
(express) the trait* (*except not always).
Not all versions of a trait are equal.

Inheritance Concepts
Dominant - only one version of the gene
needs to be present for the trait to be
expressed.
Recessive - both versions of the gene need
to be present for the trait to be expressed.
Incomplete dominance - a blending of the
two versions of the trait.
Co-dominance - both versions of the traits
are expressed.

Genes and Chromosomes
Chromosomes are made of DNA.
Humans have 23 pairs of chromosomes.
Genes are sections of a particular
chromosome.
Each gene is a recipe for a specific protein.
The recipe is a string of nitrogenous bases.
Any change to the recipe is called a
mutation.

The structure of DNA
DNA is a double helix or twisted ladder.
Backbone - sugar (deoxyribose) and
phosphate
Rungs - nitrogenous basis (Adenine, Thymine,
Guanine, Cytosine)

RNA Structure
RNA is a single-stranded molecule.
Backbone - sugar (ribose) and phosphate
Rungs - nitrogenous basis (Adenine, Uracil,
Guanine, Cytosine)

DNA Replication
The DNA molecule unzips (thanks to
enzymes).
Each strand builds a complimentary strand.
One becomes two.

Protein Synthesis, part 1
A section of the DNA is unzipped (again
thanks to enzyme action).
A strand of mRNA makes a copy of the
recipe for a particular protein.
The mRNA leaves the nucleus and attaches
to a ribosome.

Protein Synthesis, part 2
The mRNA is attached to the ribosome.
Strands of tRNA (with only 3 bases) pair up
with the strand of mRNA.
tRNA carries amino acids, which bond
together to form proteins.
When complete, the mRNA and tRNA move
on to make more proteins, the protein goes to
do whatever it is supposed to do.

Mitosis
Type of cell division used for growth and
repair.
One cell becomes two cells.
The parent and offspring are genetically
identical.
Mitosis happens in phases (IPMAT).

Mitosis

Meiosis
Type of cell division used to make sperm or
egg cells (gametogenesis).
One cell becomes four cells.
The parent and offspring are genetically
different, and the offspring cells have half
the number of chromosomes as the parent
(haploid).
Meiosis happens in phases (IPMAT X 2).

Meiosis

Evolution

Species Change Over
Time

Evidence for Evolution
Fossil Record
Homologous Structures
Analogous Structures
Vestigial Structures
Embryonic Development

Fossil Record

Homologous and
Analogous Structures

Vestigial Structures &
Embryonic Development

Why it works

How it works

Reproduction

Asexual Reproduction
Offspring and parents are genetically
identical.
Allows for the least amount of genetic
variation.
There are many types.

Sexual Reproduction
Offspring and parents are genetically
different.
Allows for the most amount of genetic
variation.
Fertilization and embryonic development can
occur inside or outside the body.

Embryonic Development
The fertilized egg (zygote) develops into a
mature organism.
Typically has many stages.
Involves cleavage, patterning, differentiation,
growth.

Menstrual Cycle
Prepares an egg for fertilization.
Prepares the woman’s body for an embryo.

Human Body Systems

What to know
The parts
What the parts do
How does this system help maintain
homeostasis?
How does this system work with others to
maintain homeostasis?
If the functions are interrupted, that’s a
disease

The body systems work
together to maintain
homeostasis

Other important stuff

Diffusion
Stuff moves from where there is more to
where there is less ... until a balance is
reached.

Surface Area to Volume
Ratio
A comparison between the amount of space
on the surfaces of an object and the amount
of space that object occupies

On the outside
(make it as small as
possible)

On the inside
(make it as big as possible)

Enzymes
Enzymes are proteins that make chemical
reactions go faster.
Enzymes are specific to one chemical
reaction.
Enzymes are not used up by the reactions in
which they participate.
Enzymes fit with the molecules they act on
like a lock and key.
Anything that changes the shape of an
enzyme (like heat) changes what it does.

Enzymes

Feedback Mechanisms
This is an important way that regulation
happens in our bodies.
Feedback mechanisms are like thermostats --
they manage an area of homeostasis around
a certain set point.
In order to work, there have to be receptors,
set points, and controls.

Feedback Mechanisms

Hormones
Hormones are chemical messengers that tell
other parts of the body what to do and
when.
9 endocrine glands make over 100 hormones.
Cells have receptors for hormones. If they
have receptors for a specific hormone, that
hormone can effect the cell. Otherwise, it
cannot.

Hormones

Some themes
The more biodiversity, the healthier the
ecosystem.
The more genetic variation, the more ability
organisms have to adapt and survive.
Every part of a system is connected to every
other part (cells/organelles, bodies/body
systems, biotic/abiotic, genes/chromosomes).
Humans can have positive or negative impacts
on the rest of the world.

The End
(for now....)