1. Review of evolution
Evolution: organisms change over time.
Natural selection: nature selects what traits increase/decrease fitness. Fit traits get passed down. This drives evolution.

2. Review of evolution

3. WWBAT use 4 types of evidence as proof of evolution….
Our objective
WWBAT use 4 types of evidence as proof of evolution….
….last class we did DNA and fossils……

4. Embryology Which one is the cow?
cat cow horse human

5. Embryology
Embryos are eukaryotic organisms in their earliest stages of development.

6. Embryology

7. Embryology
All embryos look almost identical in the early stages of development—that’s not a coincidence! The similarities in this stage represents a common ancestor that all the organisms evolved from.

8. The fact that all animal embryos are so similar shows that ALL animals evolved from the SAME common ancestor

9. Embryology
Embryos will be most similar in early stages/different in latest stages.

10. Structures-Anatomy
Comparing the anatomical (body) structure of organisms shows the process of evolution.

11. Structures
There are 3 structures that prove evolution…
Homologous structures
Analogous structures
Vestigial structures

12. Structures
Homologous structures: 2 organisms have the SAME structure (but not necessarily the same function) because they have a recent common ancestor.
Proof: shows they evolved from a common ancestor.

13. Humans, cats, whales, and bats all inherited their forearm from the same common ancestor

14. Homologous structures prove evolution by showing how one structure can evolve to meet a variety of functions.

15. Structures
Analogous structures: 2 organisms have different structures but the SAME function because they evolved separately.
Proof: in same the environment, natural selection will select for similar traits in less related organisms

16. No recent common ancestor!!!
Insects, bird, and bat wings evolved completely separately. Unrelated organisms will evolve similar adaptations in response to similar environmental pressures!
No recent common ancestor!!!

17. Structures
Vestigial structures: structures that are no longer used for anything.
Proof: unless it decreases fitness, the trait will hang around.

18. Letter “c” = hind legs of a baleen whale skeleton
Vestigial = no longer used!!!

20. Blind salamanders have eye sockets!?!?
They live in caves. Siiick.

22. VESTIGIAL Guided Practice (GP)
Is this structure…
(A) Homologous, (B) Vestigial, (C) Analogous?
Snakes don’t have legs, but they do have hip and leg bones.
After revealing the correct answer, ask random students to explain how the structure supports evolution
VESTIGIAL

23. HOMOLOGOUS Guided Practice (GP)
Are these structures…
(A) Homologous, (B) Vestigial, (C) Analogous?
Cat embryos and human embryos both have tails.
After revealing the correct answer, ask random students to explain how the structure supports evolution
HOMOLOGOUS

24. VESTIGIAL Guided Practice (GP)
Is this structure…
(A) Homologous, (B) Vestigial, (C) Analogous?
The human appendix – a small organ next to the intestines – doesn’t seem to do anything at all.
After revealing the correct answer, ask random students to explain how the structure supports evolution
VESTIGIAL

25. ANALOGOUS Guided Practice (GP)
Are these structures…
(A) Homologous, (B) Vestigial, (C) Analogous?
Dolphins and sharks both have fins, but they evolved completely differently.
After revealing the correct answer, ask random students to explain how the structure supports evolution
ANALOGOUS

26. HOMOLOGOUS Guided Practice (GP)
Are these structures…
(A) Homologous, (B) Vestigial, (C) Analogous?
Alligators and bats have the same bone structure in their forelimbs (front legs for alligators, wings for bats).
After revealing the correct answer, ask random students to explain how the structure supports evolution
HOMOLOGOUS

27. ANALOGOUS Guided Practice (GP)
Are these structures…
(A) Homologous, (B) Vestigial, (C) Analogous?
Birds and insects both have wings, but they developed in completely different ways.
After revealing the correct answer, ask random students to explain how the structure supports evolution
ANALOGOUS

28. VESTIGIAL Guided Practice (GP)
Is this structure…
(A) Homologous, (B) Vestigial, (C) Analogous?
Humans have wisdom teeth (third molars), even though they are not needed to chew up food.
After revealing the correct answer, ask random students to explain how the structure supports evolution
VESTIGIAL

29. EXIT TICKET.
1. Explain how the study of embryos provides proof of evolution.
2. Insects and birds both have eyes but they are not the same anatomical structure. What type of structures are these?
homologous structures
analogous structures
fossilized structures
biochemical structures
3. Whales and mice have similar skeletal structure in their limbs. What type of structures are these?

30. Exit Procedure Exit tickets in the EXIT TICKET BOX ONLY.
Put your binder away BUT NOT YOUR HOMEWORK FOLDER
Notes IN THEIR PLASTIC SHEETS back on the front table