1. Evidence of Evolution

2. What is Natural Selection?
What is evolution?
= The change of a species population over generations
What is Natural Selection?
= organisms best suited to their environment reproduce more successfully
Over generations their favorable traits increase in their population

3. DARWIN Survival of The Fittest
Fossil
Record
Biogeography
DARWIN
EVIDENCE?
Comparative
Anatomy
RESEARCH?
Survival of
The Fittest
Comparative
Embryology
Biochemistry/
DNA

4. CE – Comparative Embryology FR – Fossil Record B – Biogeography
“CElia and FRed Bought CAndy Before Dinner”
CE – Comparative Embryology
FR – Fossil Record
B – Biogeography
CA – Comparative Anatomy
BD – Biochemistry/DNA

5. Fossil Evidence What does fossil evidence show about evolution?
Fossils in the lower layers of the Earth are older and less complex than fossils in the upper layers
How are fossils formed?
Sedimentary rocks, molding and casting by wind or water

7. (no, scientists did not go on DATES with the fossils!)
Dating of fossils
(no, scientists did not go on DATES with the fossils!)
How did scientists determine relative age (or approximate age) of rocks and fossils?
Process called relative dating
They can compare ages between fossils in different layers to determine which is older or younger

8. Dating of Fossils
How do scientists determine absolute age of rocks and fossils?
Age is determined by measuring the amount of radioactive evidence
Carbon 12
Carbon 14
Half-life

9. Geographic Distribution (Biogeography)
What is biogeography?
= the study and comparison of fossils and living organisms and where they are located (geographical distribution)
Animals on islands look like others on the closest land mass rather than far away distances

10. Biogeography cont. In other words…
Two species evolve similar characteristics based on similar environments

11. Homologous Structures
What is the definition of homologous structures?
= similar features that occur in most organisms because they came (originated) from a common or shared ancestor
What are some examples?
Example: human and penguin arm

12. Homologous Structures
Very similar skeletal structure

13. Analogous Structures What are analogous features?
Similar structures found in organisms that have the same function, but have different embryological development in response to living in similar environments
What are some examples?
Example: bird and bee wings

14. Analogous Structures
Both organisms can hover to feed on flowers, BUT there is NO ANATOMICAL OR EMBRYOLOGICAL SIMILARITY between the wings.
Their wings evolved INDEPENDENTLY AND DIFFERENTLY

15. Vestigial Structures What is a vestigial structure or organ?
Functionless structure that occurs in organisms in the present, but had a function in an ancient species
Give an example.
Example:
tailbone in humans
pelvic bone in whales and snakes
Appendix in humans

16. These do not have a function

17. No function for these structures

18. Embryonic Development (Embryology)
How do scientists use similarities in early development as evidence for evolution?
They observe the embryos to determine similar structures.
This shows that they share a common ancestor

19. Embryonic Development (Embryology)
For example each embryo had gills and a tail in the beginning stages of development

20. Biochemistry and DNA
In organisms, amino acid sequences are very similar, BUT not exact. An example would be Hemoglobin.
How do scientists believe if organisms are closely related or not?
The more-similar the homologous proteins in different species, the more closely related

21. Patterns of Evolution Explain coevolution and provide an example
The change in two or more species in close association with each other
Example: plants and animals that feed off of them (humming bird and the plant it feeds on)
Butterfly and the plant

22. coevolution

23. Patterns of Evolution
Explain convergent evolution and provide an example
Unrelated species can develop similar characteristics
Example: shark, penguin, and porpoise
Share similar characteristics that suit their environment
Long stream-lined body
Fins that match in appearance and function

25. Patterns of Evolution
Explain divergent evolution and provide an example
Two or more related populations or species become more dissimilar over time (they adapt to their environment)
Example: finches – related species but have different beaks due to different environments