2. Evidence of evolution
•1. Fossils – the remains and traces
of organism. It is found mainly
within the strata of sedimentary
rocks.
- formed if the living things
are dead and their remains are
buried by sediments.
- their age was
determined by radioactive dating
using C14.
3. • 2. Comparative structure
• A. Homologous structure – same origin but
different function
The diagram shows the structure are similar due to
common ancestry.
4. • B. Analogous Structure – different origins but have
similar functions.
5. 3. Embryo
development - refers
to the different stages in
the development of an
embryo.
- Embryology is
important to
understanding a
species' evolution,
since some
homologous structures
can be seen only in
embryo development.
The diagram shows that
the organisms share the
common ancestry.
6.
7. Basic Mechanism of Evolution
1. Gene flow is a mechanism that will
cause the gene pool of two population
to change.
8. Basic Mechanism of Evolution
2. Genetic Mutation are changes to an
organism's DNA that create diversity within a
population by introducing new alleles.
9. Basic Mechanism of Evolution
3. Genetic drift may cause gene variants to
disappear completely and thereby reduce genetic
variation.
11. - This theory did not fully explain, how evolution
occurred, due to the variation some individuals would be better
adjusted towards the surroundings than the other. Adaptive
modifications are caused through the struggle for existence. According
to Darwin, the variations are gradual (continuous) and those which are
helpful in the adaptations of an organism towards its surroundings
would be passed on the next generation while the others disappear.
12. Lamarck’s Theory vs Darwin’s
Theory of Evolution
• Lamarck’s theory proposed that acquired traits
can be inherited.
• Darwin’s theory proposed that the only genetic
traits can be inherited.
13. Basic Mechanism of Evolution
4. Natural selection – the Organisms that are more
adapted to their environment are more likely to survive
and pass on the genes that aided their success
14. Biodiversity
•Adaptations - is any
heritable trait that helps an
organism, such as a plant or
animal, survive and reproduce
in its environment.
•Camouflage - also called
cryptic coloration, is a defense
mechanism or tactic that
organisms use to disguise
their appearance, usually to
15. •Mimicry - refers to the act performed by
organisms to resemble other organisms or
inanimate objects to gain an advantage in their
surroundings.
16. • Warning coloration (or
aposematism) is how
animals let other animals
know that they are
poisonous or dangerous. It
is the exact opposite of
camouflage. Warning colors
are usually some
combination of red, yellow,
black and white. An
unidentified tree frog from
the Congo with warning
coloration.
17. Population
• The total number of same species who are living in a particular
area in a particular period.
18. Limiting Factors that Depend on
Population Density
•1. Diseases and parasites – Infectious
and parasites spread faster in densely
populated areas.
•2. Competition for resources -
unlimited in resources, population will
grow; limited resources , population
decrease.
•3. Predation- plenty of prey –
predators will increase their numbers.
• Prey will decrease their numbers.
•4. Emigration- organisms leave and go
to a new area where there is enough
19. Factors that can Cause
Population Size
1.Birth rate (Natality) – refers to
the number of births in a population
2.Death rate (mortality) – refers to
the number of organisms that are
dying in a population.
•If the birth rate is greater than the
death rate, a population will GROW.
•If the death rate is greater than the
birth rate, then the population will
20. Role of Hormones:
• In Male: FSH and LH – stimulate the secretion of
testosterone.
In Female: FSH and LH – stimulate the secretion of
estrogen and progesterone
LH – stimulates the production of sex hormones.
Progesterone - to prepare the endometrium (lining of your uterus) for a
fertilized egg to implant and grow.
Estrogen - regulates the menstrual cycle
Testosterone - plays a key role in the development of male reproductive tissues
such as testicles and prostate, as well as promoting secondary sexual
characteristics such as increased muscle and bone mass, and the growth of
body hair.
Prolactin – stimulate the production of milk.
21. •Irregular menstruation occur if the
pituitary gland does not produce
enough FSH and LH
•Menstrual phase is the first stage of the
menstrual cycle. This phase starts when an egg
from the previous cycle isn't fertilized.
•Follicular phase - the pituitary gland in the brain
releases a hormone to stimulate the production
of follicles on the surface of an ovary. During
this phase, your uterus lining also thickens in
preparation for pregnancy.
22. •Ovulation phase –a mature egg is released
from the ovary, happens at day 14.
•Luteal phase – formation of the corpus
luteum, which produces progesterone,
which help thicken the lining of your uterus.
•The menstrual cycle is on average 28 days
in length. It begins with menses during the
follicular phase, followed by ovulation and
ending with the luteal phase
23. •If fertilization and implantation
don’t take place the estrogen and
progesterone decrease.
•Taking birth control pills, affect the
menstrual cycle it because the level
of estrogen and progesterone in the
body will reduce.
•Negative feedback mechanism - serves to
reduce an excessive response and keep a variable
within the normal range.
•Positive feedback mechanism - rising levels of
hormones feedback to increase hormone
24. Nervous system
• The nervous system is made up of the
brain and the spinal cord.
• Brain – has three major parts: cerebrum,
cerebellum and Brain stem
• Cerebrum- control muscle functions and control
speech, thought, emotions, reading, writing, and
learning.
• Cerebellum- helps keep balance and
locomotion.
• Brain stem - helps regulate your breathing, heart
25. •Peripheral nervous system (PNS)
- is that part of your nervous system that lies
outside your brain and spinal cord.
- subdivided into the somatic nervous system and
the autonomic nervous system.
•Somatic nervous system - is involved with actions that
are done consciously and signals are sent from the
skin and muscles to the central nervous system and
vice versa.
•Autonomic nervous system - controls the actions that
are involuntary such as the function of organs and
26. •Sympathetic system controls “fight-or-flight” responses.
In other words, this system prepares the body for
strenuous physical activity.
•Parasympathetic system regulates “rest and digest”
functions. It helps the body to conserve energy.
•Homeostasis - is the state of steady internal, physical,
chemical, and social conditions maintained by living
systems. This is the condition of optimal functioning for
the organism and includes many variables, such as
body temperature and fluid balance, being kept within
certain pre-set limits.
27. • The nervous and endocrine systems work together to detect
external and internal signals, transmit and integrate
information, and maintain homeostasis.
• Hormone - chemicals that coordinate different functions in
your body by carrying messages through your blood to your
organs, skin, muscles and other tissues.
• Pancreas it secretes insulin and glucagon.
- Glucagon increases blood sugar levels .
- Insulin decreases blood sugar levels.
* Thymus - It makes white blood cells, called lymphocytes,
which protect the body against infections
28.
29. •The nucleotides are Bases,
Phosphate and sugar.
•RNA sugar is ribose
•Five-carbon sugar in DNA is called
deoxyribose.
•In RNA – A is pair with U
•In DNA – A is pair with T
•The start codon is AUG – Methionine
•The stop codon are: UAA, UAG, UGA
30. • mRNA – carries the instructions to make proteins.
• tRNA - a type of RNA molecule that helps decode a
messenger RNA (mRNA) sequence into a protein.
• rRNA – hold tightly the mRNA using its
information to assemble the amino acids in
correct order.
• DNA replication - the process by which a double-
stranded DNA molecule is copied to produce two identical
DNA molecules
• Transcription - the process of making an RNA copy of a
gene's DNA sequence. This copy, called messenger RNA
(mRNA), carries the gene's protein information encoded in
DNA.
32. Mutation – change in DNA
sequence.
•Types of
Chromosomal
mutation;
•1. Deletion - a
type of mutation that
involves the loss of
one or more
nucleotides from a
segment of DNA.
33. •2. Insertion -
is a type
of mutation that
involves the
addition of one or
more nucleotides
into a segment of
DNA.
34. •3. Duplication
- a type of
mutation in which
one or more copies
of a DNA segment
(which can be as
small as a few
bases or as large
as a major
chromosomal
35.
36. Genetic Disorders
•Cri du chat – deletion of
chromosome 5
•Down Syndrome – trisomy 21
•Edward’s syndrome – Trisomy 18
•Jacobsen syndrome – deletion of
terminal 11 q
•Klinefelter’s syndrome – XXY
•Turner’s syndrome – 45 X, XO
