1. What is Evolution???
• Very simply evolution is……..
– Descent with modification
OR
– Change in the genetic make-up of a
population over time

2. Evidence for Evolution
FAME summarizes the evidence that evolution has
occurred:
• F – fossil evidence (remains of ancient
organisms)
• A – anatomical structures (body parts)
• M – molecular evidence
(DNA/RNA/ATP)
• E – embryological (embryos look similar
from one species to the next)

3. How do we know evolution
happens?
EVIDENCE!!!!

4. 1. Evidence for evolution: Fossils
Succession of Horse teeth and feet
over time:
Fossils can reveal:
•What kind of organisms
lived in the past.
•How the organisms
changed over time.
•What the organisms ate.
•How the organisms
moved.
•What the climate was like.

5. 2. Evidence for evolution: Anatomy
Homologous structures: similar structures that have
different functions based on common ancestor

6. Vestigial Structures – structures that have little or
no function
Ex: Pelvis and femur in whales
Appendix in humans

7. Analogous structures
Comparative structures without a
common ancestor
•have similar function
•have different structures
Insect wing
bird wing
bat wing
Pterosaur wing

8. 3. Evidence for evolution: Molecules
• Comparison of DNA, RNA, Amino acid
sequence, or ATP among species
• More distantly related organisms have
more differences in genes
Compare # differences
Horse and
zebra 1
Horse and
gorilla
2
Horse and
chimpanzee 3
Human and
chimpanzee 0
Human and
gorilla 1

9. 4. Evidence for evolution: embryology
• Embryos are the early stages of development of an
organism
• Embryos of many organisms resemble each other

10. Examples of Evolution
• industrial melanism (Kettlewell's moths in
England) – the darkening of populations
of organisms due to pollution
• dog breeds – artificial selection
• viruses & vaccines
• bacteria & resistance to antibiotics
• Insects and other pests become resistant
to pesticides

11. Species formation
• Speciation – the process by which a new
species forms
• Divergence – the accumulation of differences
between groups; leads to new species
• Reproductive Isolation – condition in which two
populations of the same species cannot breed
(due to geographic separation, a difference in
mating period, or any other reproductive barrier),
two populations eventually become more and
more different, which leads to speciation

12. Two Models of Evolution
• Punctuated
equilibrium – periods
of rapid change
followed by long
periods of no change
• Gradualism – gradual
change over long
periods of time