1. The Theory of Evolution

2. Evolutionary biology addresses fundamental questions
Why are there so many different kinds of organisms?
Why are organisms so proficient at life tasks: finding food, acquiring mates, fighting disease, and avoiding predators?

3. OVERVIEW: Four Main Points to the Theory of Evolution.
Variation exists within populations.
Some individuals of a population are better suited to their environment.
Over time, traits that make certain individuals of a population able to survive and reproduce tend to spread in that population.
There is clear proof from fossils and many other sources that living species evolved from organisms that are now extinct.

4. Does Variation Exist Within the Genes of every population or species (the result of random mutations)?

5. Is this variation Heritable?

6. Natural Selection Acts on These Heritable Variations of Traits.
Working definition of Natural Selection:
Natural Selection is the process by which populations change in response to their environment. Individuals better adapted to the environment leave more offspring than those individuals not suited to the environment.

7. HOW ABOUT A REAL LIFE EXAMPLE, BEYOND THE CARTOONS.
Do individuals who are better suited to their environment really leave more offspring than others?
HOW ABOUT A REAL LIFE EXAMPLE, BEYOND THE CARTOONS.
Day
Day
Day

8. Real Life Examples of Evolution
Natural Selection in Action

9. Industrial Melanism

11. A hypothesis for the explaining the increase in dark moths was formed using Darwin’s theory of evolution by natural selection.
Hypothesis: The dark variety was camouflaged on the soot-darkened bark and so are not eaten by birds.

12. The Experiment
Populations of light and dark peppered moths were raised in the laboratory.
Moths were marked so they could be identified later
Moths were released into two separate wooded areas.
Birmingham= Heavily polluted
Dorset = unpolluted

13. Results

14. Overcoming Misconceptions
The darkened trees did not cause the darker variant of moth to appear.
The darker characteristic was already present in the population.
The “new” environment merely favored the survival of the darker moths.

15. Beyond the Fossil Record
Evidence of Evolution
Beyond the Fossil Record

16. How Does Anatomy and Structure Show Evidence of Ancestry?
Comparing the anatomy of different types of organisms often reveals basic similarities in body structures, even though their functions may be very different.

17. Common Ancestor
A Species from which two or more species have diverged.

19. Homologous Structures
Structures that share common ancestry.

21. Analogous Structures
Analogous structures have similar forms, but they are not due to common ancestry.

23. Vestigial Structures
Vestigial structures are anatomical structures of organisms in a species, which have lost much or all of their original function.
Structures that are considered to be evidence for an organisms evolutionary past.

24. Flightless Cormorant of the Galapagos

26. Vestigial Pelvis of the Whale

27. Femur and Pelvis of Whale

28. How is Embryonic Development Evidence for Evolution?
The evolutionary history of organisms is seen in the development of embryos.

30. What are some common structures that vertebrate embryos share?
Tail bud
Pharyngeal pouches
Buds that become limbs

32. How are Biological Molecules a Record of Evolution?
Species that share common ancestry more closely, have more amino acid sequence in common.
Species that have diverged from a distant common ancestor have more differences in amino acid sequences.

33. The Hemoglobin Protein shows common ancestry.

34. Hemoglobin Comparison
Species
Amino acid differences
Gorilla 1
Rhesus monkey 8
Mouse 27
Chicken 45
Frog 67
Lamprey
125

35. Great Moments in Evolution

38. What is the Fossil Record?
Working definition: All the fossils known to science.
Provides snapshots of the past
Illustrate a panorama of evolutionary change over time

39. Nice Striations!

41. What’s a Fossil, You Ask? The remains or traces of once-living things.
shells, teeth, bones, footprints, leaf impressions, and petrified wood.

44. “Endless forms most beautiful and most wonderful” – Charles D.

47. Is the Fossil Record Complete?
No, it most certainly isn’t.

48. The probability that any particular organism that once existed, is part of the fossil record today is rare.
For Three Good Reasons. . .
Fossil formation is a rare event
Fossils survival is a rare event
An exceedingly small fraction of surviving fossils will ever be found

49. John Day Fossil Beds

53. Transitional Forms in Horse Evolution

65. Lahars: Pyroclastic Mud Flows