1. © 2010 Pearson Education, Inc. Lectures by Chris C. Romero, updated by Edward J. Zalisko PowerPoint ® Lectures for Campbell Essential Biology, Fourth Edition – Eric Simon, Jane Reece, and Jean Dickey Campbell Essential Biology with Physiology, Third Edition – Eric Simon, Jane Reece, and Jean Dickey Chapter 14 How Biological Diversity Evolves

2. © 2010 Pearson Education, Inc.

3. What Is a Species? The biological species concept defines a species as –“A group of populations whose members have the potential to interbreed and produce fertile offspring” Species is a Latin word meaning: –“Kind” or –“Appearance.”

4. Branching Evolution (results in speciation) Nonbranching Evolution (no new species) PATTERNS OF EVOLUTION Figure 14.1

5. Diversity within one species Similarity between different species Figure 14.2

6. Postzygotic barriers Gametes Viable, fertile offspring Zygote Prezygotic barriers Reduced hybrid viability Reduced hybrid fertility Hybrid breakdown Temporal isolation Habitat isolation Behavioral isolation Mechanical isolation Gametic isolation Figure 14.UN1 Prezygotic barriers prevent mating or fertilization between species. Reproductive Barriers between Species

7. Temporal Isolation Skunk species that mate at different times Figure 14.4a

8. Habitat Isolation Garter snake species from different habitats Figure 14.4b

9. Mating ritual of blue-footed boobies Behavioral Isolation Figure 14.4c

10. Mechanical Isolation Snail species whose genital openings cannot align Figure 14.4d

11. Sea urchin species whose gametes cannot fuse Gametic Isolation Figure 14.4e

12. Hybrid Breakdown Reduced Hybrid FertilityReduced Hybrid Viability POSTZYGOTIC BARRIERS Donkey Mule Horse Figure 14.5

13. © 2010 Pearson Education, Inc. Speciation or a new Species can form by: –Allopatric speciation, due to geographic isolation –Sympatric speciation, without geographic isolation

14. Ammospermophilus harrisii Ammospermophilus leucurus Figure 14.7

15. © 2010 Pearson Education, Inc. Sympatric Speciation Sympatric speciation occurs: –While the new species and old species live in the same time and place –If a genetic change produces a reproductive barrier between the new and old species

16. © 2010 Pearson Education, Inc. What Is the Tempo of Speciation? There are two contrasting models of the pace of evolution: –The gradual model, in which big changes (speciations) occur by the steady accumulation of many small changes –The punctuated equilibria model, in which there are –Long periods of little change, equilibrium, punctuated by –Abrupt episodes of speciation

17. Punctuated model Graduated model Time Figure 14.10

18. Wing claw (like reptile) Teeth (like reptile) Long tail with many vertebrae (like reptile) Feathers Fossil Artist’s reconstruction Figure 14.11

19. © 2010 Pearson Education, Inc. Bird wings are modified forelimbs that were previously adapted for non-flight functions, such as: –Thermal regulation –Courtship displays –Camouflage The first flights may have been only glides or extended hops as the animal pursued prey or fled from a predator.

20. Chimpanzee fetus Chimpanzee adult Human adult (paedomorphic features) Human fetus Figure 14.13

21. Figure 14.14

22. © 2010 Pearson Education, Inc. Geologists have established a geologic time scale reflecting a consistent sequence of geologic periods.

23. Kingdom Animalia Domain Archaea Earliest organisms Domain Bacteria Domain Eukarya Kingdom Fungi Kingdom Plantae The protists (multiple kingdoms) Figure 14.25 The three-domain classification system

24. Eutherians (5,010 species) Millions of years ago Monotremes (5 species) Marsupials (324 species) Ancestral mammal Reptilian ancestor Extinction of dinosaurs 250 200 150100 50 65 0 Figure 14.26a

25. Table 14.1

26. © 2010 Pearson Education, Inc. Mass Extinctions

27. Evolution Connection: Rise of the Mammals Mass extinctions: –Have repeatedly occurred throughout Earth’s history –Were followed by a period of great evolutionary change © 2010 Pearson Education, Inc.

28. Fossil evidence indicates that: –Mammals first appeared about 180 million years ago –The number of mammalian species –Remained steady and low in number until about 65 million years ago and then –Greatly increased after most of the dinosaurs became extinct

29. © 2010 Pearson Education, Inc. Hierarchical Classification Binomial species name: Dendroica fusca Taxa

30. © 2010 Pearson Education, Inc. Difference between homologous and derived traits Homologous bones in forelimbs Wings are derived traits An example of convergent evolution

31. © 2010 Pearson Education, Inc. Convergent Evolution of Wings Insects Birds Pterosaurs Bats

32. © 2010 Pearson Education, Inc. Fossils are reliable chronological records only if we can determine their ages, using: –The relative age of fossils, revealing the sequence in which groups of species evolved, or –The absolute age of fossils, requiring other methods such as radiometric dating

33. © 2010 Pearson Education, Inc. Radiometric dating: –Is the most common method for dating fossils –Is based on the decay of radioactive isotopes –Helped establish the geologic time scale

34. Carbon-14 in shell Time (thousands of years) Radioactive decay of carbon-14 How carbon-14 dating is used to determine the vintage of a fossilized clam shell Carbon-14 radioactivity (as % of living organism’s C-14 to C-12 ratio) 100 75 0 50 25 0 5.6 50.4 11.216.8 22.4 28.0 33.6 39.244.8 Figure 14.15

35. © 2010 Pearson Education, Inc. Plate Tectonics and Macroevolution The continents are not locked in place. Continents drift about the Earth’s surface on plates of crust floating on a flexible layer called the mantle. The San Andreas fault is: –In California –At a border where two plates slide past each other

36. Figure 14.16

37. The Process of Science: Did a Meteor Kill the Dinosaurs? Observation: About 65 million years ago, the fossil record shows that: –The climate cooled –Seas were receding –Many plant species died out –Dinosaurs (except birds) became extinct –A thin layer of clay rich in iridium was deposited © 2010 Pearson Education, Inc.

38. Question: Is the iridium layer the result of fallout from a huge cloud of dust that billowed into the atmosphere when a large meteor or asteroid hit Earth? Hypothesis: The mass extinction 65 million years ago was caused by the impact of an extraterrestrial object. Prediction: A huge impact crater of the right age should be found somewhere on Earth’s surface.

39. © 2010 Pearson Education, Inc. Results: Near the Yucatán Peninsula, a huge impact crater was found that: –Dated from the predicted time –Was about the right size –Was capable of creating a cloud that could have blocked enough sunlight to change the Earth’s climate for months

40. Chicxulub crater Figure 14.18-3

41. © 2010 Pearson Education, Inc. CLASSIFYING THE DIVERSITY OF LIFE Systematics focuses on: –Classifying organisms –Determining their evolutionary relationships Taxonomy is the: –Identification of species –Naming of species –Classification of species

42. © 2010 Pearson Education, Inc. Some Basics of Taxonomy Scientific names ease communication by: –Unambiguously identifying organisms –Making it easier to recognize the discovery of a new species Carolus Linnaeus (1707–1778) proposed the current taxonomic system based upon: –A two-part name for each species –A hierarchical classification of species into broader groups of organisms

43. © 2010 Pearson Education, Inc. Naming Species Each species is assigned a two-part name or binomial, consisting of: –The genus –A name unique for each species The scientific name for humans is Homo sapiens, a two part name, italicized and latinized, and with the first letter of the genus capitalized. Homo sapiens or Homo sapiens

44. © 2010 Pearson Education, Inc. Classification: A Work in Progress Linnaeus: –Divided all known forms of life between the plant and animal kingdoms –Prevailed with his two-kingdom system for over 200 years In the mid-1900s, the two-kingdom system was replaced by a five-kingdom system that: –Placed all prokaryotes in one kingdom –Divided the eukaryotes among four other kingdoms

45. Jaguar (Panthera onca) Lion (Panthera leo) Tiger (Panthera tigris) Leopard (Panthera pardus) Figure 14.19 Panthera pardus Panthera tigris Panthera leo Panthera onca

46. © 2010 Pearson Education, Inc. The taxonomic hierarchy extends to progressively broader categories of classification, from genus to: –Family –Order –Class –Phylum –Kingdom –Domain

47. Leopard (Panthera pardus) Species Panthera pardus Genus Panthera Family Felidae Order Carnivora Class Mammalia Phylum Chordata Kingdom Animalia Domain Eukarya Figure 14.20

48. © 2010 Pearson Education, Inc. Classification and Phylogeny The goal of systematics is to reflect evolutionary relationships. Biologists use phylogenetic trees to: –Depict hypotheses about the evolutionary history of species –Reflect the hierarchical classification of groups nested within more inclusive groups

49. Panthera pardus (leopard) Species Genus Felidae Order Carnivora Family Canis Lutra Panthera Mephitis Canidae Mustelidae Canis lupus (wolf) Canis latrans (coyote) Lutra lutra (European otter) Mephitis mephitis (striped skunk) Figure 14.21

50. © 2010 Pearson Education, Inc. The Cladistic Revolution Cladistics is the scientific search for clades. A clade: –Consists of an ancestral species and all its descendants –Forms a distinct branch in the tree of life

51. Hair, mammary glands Long gestation Gestation Duck-billed platypus Iguana Outgroup (reptile) Ingroup (mammals) Beaver Kangaroo Figure 14.23 Cladogram

52. Lizards and snakes Crocodilians Saurischian dinosaurs Ornithischian dinosaurs Pterosaurs Birds Common ancestor of crocodilians, dinosaurs, and birds Figure 14.24 Cladogram

53. © 2010 Pearson Education, Inc. In the late 20th century, molecular studies and cladistics led to the development of a three-domain system, recognizing: –Two domains of prokaryotes (Bacteria and Archaea) –One domain of eukaryotes (Eukarya)