1. Evolutionary Theory and Evidence
Evolution Notes Part 1

2. Evolutionary Theory What is evolution? Change over time
The process by which modern organisms have descended from ancient organisms

3. The theory of Evolution
Evolution is known as the gradual change in the characteristics of a species over time.
A species is a group of organisms whose members look alike and successfully reproduce among themselves.

4. Early Ideas on Earth’s Animals
Aristotle believed that species were fixed creations arranged by their complexity
This idea lasted 2000 years

5. Contributor’s to Darwin’s thinking include:
Hutton – theory of geological change (gradualism)
changes in earth due to slow continuous processes
Thomas Malthus- struggle for existence (resources)
Jean-Baptiste Lamarck – Stated that changes are adaptation to environment acquired in an organism’s lifetime
Also stated that changes were passed to offspring (Inheritance of Acquired Traits)
Law of use and disuse – organisms could change size or shape of organs by using them or not using them.
- if a body part were used; it got stronger
- if a body part was not used it deteriorated

6. Contributor’s to Darwin’s thinking include:
Jean-Baptiste Lamarck-
Tendency toward perfection- organisms are continually changing and acquiring features that help them live more successfully in their habitat
Ex: Bird ancestors wanted to fly, so they tried until wings developed.
Charley Lyell- uniformitarianism
geologic processes still changing earth
Georges Cuvier- Species extinction (catastrophism) evidence Fossils
species disappear due to a catastrophic event to earth’s crust

7. Charles Darwin Who was Charles Darwin? What did he study?
British naturalist who traveled around the world on the H.M.S. Beagle
Observed living things, making observations and collecting evidence that led to his proposed hypothesis about how life changes over time

8. Charles Darwin
What was the name of the book he wrote and what was it about?
On the Origin of Species established evolution by common descent as the dominant scientific explanation of diversification in nature.

9. Darwin’s Theory What are the main points of Darwin’s theory?
Organisms vary from each other and the variety is inherited
Organisms produce more offspring than can survive
Since more organisms are produced than can survive, they compete for limited resources
Each organism has different advantages and disadvantages in the struggle for existence
Species alive today are descended with modification from ancestral species

10. Evidence for Evolution
What evidences are there for evolution?
Fossils – remains or traces of organisms, some of which no longer exist.

11. Evidence for Evolution
a. Fossils also provide evidence for evolution. Fossils are the remains of once-living things that are preserved in Earth’s rocks.

12. Evidence for Evolution
b. Fossils have found that many simpler life forms exist early in Earth’s history.
c. The oldest fossils found are bacteria that lived 3.8 billion years ago.

13. Evidence for Evolution Molecular
2. Comparative biochemistry – DNA and proteins that show similar structures are also evidence of common ancestry
What evidences are there for evolution?

14. Evidence for Evolution
a. All living things contain similar DNA, RNA, and proteins.
b. By comparing DNA sequences of two organisms, scientists can determine whether or not the organisms are closely related.
c. The relationship can then be used to construct evolutionary pathways.

15. How many amino acid sequence differences between humans and:
Horse?
Tuna?
Monkey?

16. 1. Why can it be said that proteins behave like molecular clocks?
2. What would account for the one or two differences among two species DNA?
3. If the amino acid sequence is similar, will the DNA sequence also be similar

17. Evidence for Evolution
Other kinds of evidence that support organic evolution are adaptations.
Anatomical
Physiological
Behavioral

18. Evidence for Evolution Anatomical
What evidences are there for evolution?
3. Homologous structures – body parts that have different mature forms but develop from the same embryonic tissues – evidence of descent from a common ancestor

19. about these structures?
What do you notice
about these structures?

20. Evidence for Evolution Anatomical
A. Homologous structures have different function but the SAME structures. These similarities indicates that the organisms probably had a common (the SAME) evolutionary origin.

21. about these structures?
AND … what do you notice
about these structures?

22. Evidence for Evolution Anatomical
B. Analogous structures have body parts that are similar in function but different in structure. These indicate that the organisms had different yet related ancestors.

23. Evidence for Evolution Anatomical
What evidences are there for evolution?
4. Similarities in embryology –
early stages of embryonic development show similarities that suggest common ancestry

24. Embryology
a. The study of the development of embryos is the field of embryology.
b. Studies of certain embryos indicate evolution from a common ancestor.

25. Evidence for Evolution Anatomical
What evidences are there for evolution?
5. Vestigial structures – traces of homologous organs that are very small and no longer used by the modern organism

26. Functionless Structures ??
Some body structures, such as the human appendix and the eyes of cave fish, have reduced forms. We call these vestigial structures.
These structures support the theory of evolution because they show structural changes over time.

27. Evidence for Evolution Anatomical
What evidences are there for evolution?
6. Some adaptations involve changes in the structure of body parts: mimicry and camouflage.
a. Mimicry enables an organism to copy the appearance of another species.
b. Camouflage is a structural adaptation that enables an organism to blend in with its surroundings.

28. MIMICRY

29. Milk Snake
Coral Snake

30. CAMOUFLAGE

31. Evidence of Evolution Physiological Adaptations
7. Some adaptations are physiological or changes in an organisms metabolic processes.
Keep in mind that all things are made up of cells and the organelles are structurally and functionally similar in most organisms.

32. Physiological Adaptations
Organisms are constantly changing to adapt to their environment. Take a look at organisms that have been exposed to antibiotic and pesticides. The organisms that survive have become selected because they are physiologically more resistant.

33. Imagine that there are 10 bacteria growing on your hand.

34. You use Germ-x to clean your hand everyday.

35. After 4 days, there are still 3 bacteria on your hands that have survived.

36. Is there anything special about these bacteria. Yes
Is there anything special about these bacteria? Yes..they have something about their DNA that has made them different and strong enough to survive. So now what will happen?

37. Those 3 that are “resistant” will undergo Mitosis.

38. And after a week, your hands will be covered with tons of bacteria that are ALL resistant to Germ-X. 