1. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings –Varieties of life forms Figure 1.4C-F

2. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings All organisms have evolutionary adaptations –Inherited characteristics that enhance their ability to survive and reproduce blue-footed booby Large, webbed feet help propel the bird through water at high speeds Clown, Fool, or Well Adapted?

3. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings –A streamlined shape, large tail, and nostrils that close are useful for diving –Specialized salt-secreting glands manage salt intake while at sea

4. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Charles Darwin synthesized the Theory of Evolution by natural selection –Theory vs hypothesis Evolution is the core theme of biology Evolution explains the unity and diversity of life Figure 1.6A

5. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings The voyage of the Beagle Figure 13.1B North America Great Britain Europe Africa Equator Australia Tasmania New Zealand Cape of Good Hope South America Andes Cape Horn Tierra del Fuego Galápagos Islands Pacific Ocean Atlantic Ocean

6. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings species are fixed Earth is about 6,ooo yrs old Prevalent ideas at Darwin’s time

7. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings New ideas proposed Fossils indicated the earth was very old Lyell, a geologist, argued that land forms changed constantly. Lamarck proposed that organisms changed and these changes were passed to progeny.

8. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Darwin became convinced that the Earth was old and continually changing –He concluded that living things also change, or evolve over generations –He also stated that living species descended from earlier life-forms: descent with modification Mex. marine snail shells on high mtns

9. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Darwin observed that –organisms produce more offspring than the environment can support –organisms vary in many characteristics –these variations can be inherited Darwin proposed natural selection as the mechanism of evolution

10. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings natural selection explains the mechanism of evolution Figure 1.6B (1) Population with varied inherited traits (2) Elimination of individuals with certain traits (3) Reproduction of survivors Pesticide-resistant insects Antibiotic-resistant bacteria

11. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Charles Darwin, 1874 Figure 13.1x2 Alfred Wallace

12. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Darwin cartoon Figure 13.1x3

13. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Evolution happens when populations of organisms with inherited variations are exposed to environmental factors that favor the reproductive success of some individuals over others –Natural selection is the editing mechanism –Evolution is based on adaptations Figure 1.6C

14. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings –Hominid skull Fossils provide strong evidence for evolution Figure 13.2A, B –Petrified trees

15. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings –Ammonite casts –Fossilized organic matter in a leaf Figure 13.2C, D

16. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings –Scorpion in amber –“Ice Man” – acid bogs Figure 13.2E, F

17. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Mammoth tusks Figure 13.2x4

18. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings fossils show that organisms have appeared in a historical sequence Many fossils link early extinct species with species living today –hind leg bones of fossil whales Figure 13.2G, H

19. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings –Biogeography –Comparative anatomy –Comparative embryology Other evidence for evolution Figure 13.3A HumanCatWhaleBat

20. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings –Molecular biology - protein “clocks” Figure 13.3B HumanRhesus monkeyMouseChickenFrogLamprey Last common ancestor lived 26 million years ago (MYA), based on fossil evidence 80 MYA 275 MYA 330 MYA 450 MYA

21. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Populations are the units of evolution Figure 13.6

22. 1.What is evolving? gene pool, microevolution 2.Four agents of evolution 3. Types of natural selection

23. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Populations are the units of evolution A population is a group of interbreeding individuals A species is a group of populations whose individuals can interbreed and produce fertile offspring Figure 13.6

24. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings gene pool = total collection of genes in a population at any one time Microevolution is a change in the relative frequencies of alleles in a gene pool What is evolving?

25. Four agents of microevolution 1. Mutation changes alleles 2. Genetic drift = random changes in allele frequency Bottleneck Founder effect

26. LARGE POPULATION = 10,000 SMALL POPULATION = 10 allele frequency = 1,000 10,000 = 10%allele frequency = 1 10 = 10% 50% of population survives, including 450 allele carriers 50% of population survives, with no allele carrier among them allele frequency = 450 5,000 = 9% allele frequency = 0505 = 0% little change in allele frequency (no alleles lost) dramatic change in allele frequency (potential to lose one allele) Genetic drift - effects of population size :

27. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Founder effect Figure 13.11B, C Bottleneck effect

28. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings 3.Gene flow can change a gene pool due to the movement of genes into or out of a population ex. Migration 4.Natural selection leads to differential reproductive success Nonrandom mating changes genotype frequency but not allele frequency.

29. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Natural selection - results in the accumulation of traits that adapt a population to its environment - the only agent of evolution that results in adaptation.

30. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Darwinian fitness is an individual’s contribution to the gene pool of the next generation compared to other individuals; i.e., number of progeny Production of fertile offspring is the only score that counts in natural selection What is an organism’s evolutionary fitness?

31. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings There are three general outcomes of natural selection Figure 13.19 Frequency of individuals Original population Phenotypes (fur color) Original population Evolved population Stabilizing selectionDirectional selectionDiversifying selection

32. beak depth 1976 1978 Average beak depth, 1978 Average beak depth, 1976 Beak depth (mm) Shift of average beak depth during drought 567891011121314 0 20 40 60 80 Number of individuals

33. Infant deaths Infant births Percent of infant deaths Percent of births in population Birth weight in pounds 0 10 20 30 40 50 60 70 23456789101188 0 5 10 15 20 Natural selection tends to reduce variability in populations.

34. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings 1.The diploid condition preserves variation by “hiding” recessive alleles (Bb) 2.Balanced polymorphism (2+ phenotypes stable in population) may result from: a. heterozygote advantage Aa > aa and AA b. frequency-dependent selection c. variation of environment for a population Why doesn’t natural selection eliminate all genetic variation in populations?

35. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Many populations exhibit polymorphism and geographic variation Figure 13.13

36. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings 3. Some variations may be neutral, providing no apparent advantage or disadvantage –Example: human fingerprint patterns Not all genetic variation may be subject to natural selection Figure 13.16

37. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Low genetic variability may reduce their capacity to survive as humans continue to alter the environment –cheetah populations have extreme genetic uniformity Endangered species often have reduced variation Figure 13.17

38. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Sexual selection leads to the evolution of secondary sexual characteristics Sexual selection may produce sexual dimorphism Why do male and female animals differ in appearance? Figure 13.20A, B

39. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings This is due to: –historical constraints –adaptive compromises –chance events –availability of variations Natural selection cannot fashion perfect organisms

40. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings appearance alone does not always define a species Figure 14.1A –Example: eastern and western meadowlarks What is a species?

41. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings What is a species? Naturally interbreeding populations - potentially interbreeding - reproductively isolated from other species What about asexually reproducing organisms? Extinct species? Shy species?

42. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings When geographically isolated, species evolution may occur –gene pool then changes to cause reproductive isolation = allopatric speciation When does speciation occur? MECHANISMS OF SPECIATION Figure 14.3

43. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings A ring species may illustrate the process of speciation Figure 14.1C OREGON POPULATION 1 2 COASTAL POPULATIONS Yellow- eyed Monterey 3 Sierra Nevada Yellow- blotched Gap in ring Large- blotched INLAND POPULATIONS

44. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Reproductive barriers between species Habitat - different locations Timing - mating, flowering Behavioral - mating rituals, no attraction Mechanical - structural differences Gametic - fail to unite Hybrid weak or infertile

45. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Hybrid sterility is one type of postzygotic barrier –A horse and a donkey may produce a hybrid offspring, a mule –Mules are sterile Figure 14.2C

46. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Sympatric speciation No geographical isolation Mutation creates reproductive isolation Polyploidization Hybridization

47. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Specialists - Galapagos finches Generalists - horseshoe crabs, cockroaches New environments - ecological niche When does speciation occur?

48. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Adaptive radiation on an island chain - specialization for different niches Figure 14.4B Species A from mainland 1 A 2 B B 3 B C 4 C C 5 B C D C D

49. Figure 15.9 Medium ground finch Cactus ground finch Small tree finch Large ground finch Small ground finch Large cactus ground finch Sharp-beaked ground finch Vegetarian finch Seed eaters Ground finches Cactus flower eaters Bud eaters Tree finches Insect eaters Medium tree finch Large tree finch Mangrove finch Woodpecker finch Green warbler finch Gray warbler finch Warbler finches Common ancestor from South America mainland

50. Figure 15.8 No predestined goal of evolution

51. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Continental drift is the slow, steady movement of Earth’s crustal plates on the hot mantle Continental drift has played a major role in macroevolution Figure 15.3A Pacific Plate North American Plate Nazca Plate South American Plate African Plate Eurasian Plate Split developing Indo-Australian Plate Edge of one plate being pushed over edge of neighboring plate (zones of violent geologic events) Antarctic Plate

52. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings influenced the distribution of organisms –Continental mergers triggered extinctions –Separation of continents caused the isolation and diversification of organisms Figure 15.3B Millions of years ago Eurasia CENOZOIC MESOZOIC PALEOZOIC North America Africa India South America Antarctica Australia Laurasia Gondwana Pangaea

53. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Speciation - how much change is needed? Gradual vs. jerky Evidence: –Fossil record –Genetic differences between species –Homeotic genes

54. Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings homeotic genes control body development Single mutation can result in major differences in body structure Figure 11.14 Mouse chromosomes Mouse embryo (12 days) Adult mouse Fly chromosomes Fruit fly embryo (10 hours) Adult fruit fly