1. Evolution

2. served on the HMS Beagle that sailed on a 5 year expedition
Charles Darwin (1809 – 1882)
served on the HMS Beagle that sailed on a 5 year expedition
his job was to collect, study, and store biological specimens

3. Charles Darwin
one of the locations was the Galapagos Islands, west of South America

4. Charles Darwin Darwin collected many species of finch
he hypothesized that a few birds migrated from the mainland and adapted to the different island environments

5. Ideas that Shaped Darwin’s Thinking
Hutton and Lyell
came up with the idea of gradualism, which explains how it took long periods of time to produce geographical features

6. Ideas that Shaped Darwin
Jean Baptiste Lamarck
one of the first scientists to recognize that living things have changed over time

7. Lamarck’s theory for evolution
all organisms continually change in order to reach perfection
organisms can alter their bodies by the principle of use and disuse
he claimed that acquired characteristics could be inherited

8. Ideas that Shaped Darwin
Thomas Malthus
he stated in his essay The Principle of Population that if the human population continued to grow, sooner or later there would not be enough resources for everyone

9. Ideas that Shaped Darwin
Artificial selection (please add)
Darwin observed how humans could change organisms by selection of specific traits
The mustard plant has produced many vegetable varieties: broccoli, cauliflower, mustard greens, brusell sprouts, cabbage.

10. Darwin’s Theory for Evolution
Darwin was forced to publish when another scientist, Alfred Wallace, came up with a similar idea
Darwin’s book, Origin of Species, stirred up controversy for the next decade

12. Darwin’s Theory for Evolution
Natural Selection
not all individuals survive when competing for resources
(“struggle for existence”)

13. Darwin’s Theory for Evolution
the individuals who survive are best adapted to their environment
(“survival of the fittest”)
nature acts on the variation within a population

14. Darwin’s Theory for Evolution
after many generations, the population may change to resemble the best adapted individuals
(“descent with modification”)

15. Natural selection in insecticide-resistant bugs

16. Evidence for Evolution

17. Evidence for Evolution
Fossils
there should be intermediate stages found in the fossil record

19. Evidence for Evolution
Anatomy
homologous structures are modified structures that show common ancestry
same on inside, different on outside

20. Evidence for Evolution
analogous structures are different in arrangement but have a similar function
different on inside, same on outside

21. Evidence for Evolution
vestigial structures have no current purpose, but may have functioned in an ancestor

22. Evidence for Evolution
Embryology
similarities in embryo structure suggest evolution from a common ancestor

23. Evidence for Evolution
Biochemistry
DNA or amino acid sequences can be compared to see how closely related 2 species are

24. Blending Butterflies

25. Examples of Adaptations
Concealing coloration.

26. Examples of Adaptations
Disruptive Coloration

27. Examples of Adaptations
Disguises

28. Examples of Adaptations
Counter shading

29. Examples of Adaptations
Mimicry

30. Create your own hidden butterfly!
Select one type of camouflage.
Color/shade it just right.
Place it in it’s habitat!

31. How Populations Evolve

32. Evolution of Populations
variation is the inheritable differences within the
same species
the gene pool is all of the
genes present in a population
changes in the frequencies of alleles is microevolution
a population is the smallest unit that can evolve

33. Finding allele frequencies

34. Sources of Genetic Variation
mutation - a permanent change in DNA
genetic drift – chance events can change the gene pools of small populations

35. Sources of Genetic Variation
migration of individuals into and/or out of a population can change allele frequencies
non-random mating (similar to selective breeding; only certain traits are desired)
natural selection

36. 3 Patterns of Natural Selection
stabilizing selection
favors average individuals in a population

37. 3 Patterns of Natural Selection
directional selection
favors one of the extreme forms of a trait

38. 3 Patterns of Natural Selection
disruptive selection
individuals of both extreme forms are favored over the average

39. Speciation
a species is a group of organisms that can interbreed and produce fertile offspring
Geographic isolation
a physical barrier separates a population into groups (organisms adapt to their isolated environment)

40. Geographic isolation

41. Speciation Reproductive Isolation
Occurs when organisms are prevented from producing fertile offspring
occurs when mating behaviors/ times/seasons don’t match
occurs when genetics aren’t similar enough

42. Various Patterns for Evolution

43. Following these mass extinctions new species arise
Rates of Speciation
mass extinctions have wiped out a large number of Earth’s history
Following these mass extinctions new species arise

44. Rates of Speciation
1. Darwin proposed that evolution was a slow, steady process
small adaptive changes accumulate over time
this idea is known as gradualism

45. Rates of Speciation
punctuated equilibrium states that speciation occurs in relatively quick bursts
The bursts of change are then followed by long periods of stability

46. Patterns of Macroevolution
divergent evolution is the pattern of evolution in which many different species can be traced back to a common (same) ancestor
the different species adapted to different environments
this is also called adaptive radiation

47. Divergent Evolution
Evolution often happens among island chains because there are different habitats

48. Patterns of Macroevolution
convergent evolution occurs when distantly related organisms evolve similar traits