CHAPTER 16 EVOLUTION OF POPULATIONS

1. CHAPTER 16EVOLUTION OF POPULATIONS

2. Section Outline • 16–1 Genes and Variation • How Common is Genetic Variation? • Do you know how heredity works? • Did Darwin know how heredity works? How does variation appear? • Modern synthesis. Variation and Gene Pools Relative frequency of alleles Sources of Genetic Variation 1. Mutations • Gene Shuffling Single-Gene and Polygenic Traits Frequency of Phenotype Phenotype (height)

3. 16–2 Evolution as Genetic Change • A. Natural Selection on Single-Gene Traits Allele Frequencies (p/q) in a Gene PoolParent Population, p dominant; q recessive

4. Originalpopulation Frequency of individuals Phenotypes (fur color) Originalpopulation Evolvedpopulation Stabilizing selection Disruptive selection Directional selection 0 when environmental conditions are varied in a way that favors both extremes over the intermediate form. narrow the range in population variability toward some intermediate form. B. Natural Selection on Polygenic Traits move the modal (most common) form toward one of the extremes.

5. Originalpopulation Bottleneckingevent Survivingpopulation Section Outline • 16–2 Evolution as Genetic Change • Genetic Drift • In addition to natural selection, genetic drift and gene flow can contribute to evolution • Genetic drift is a change in the gene pool of a population due to chance. Genetic drift can alter allele frequencies in a population • Genetic drift can cause the bottleneck effector the founder effect

6. Section Outline • 16–2 Evolution as Genetic Change D. Evolution Versus Genetic Equilibrium 1. Random Mating 2. Large Population – no genetic drift 3. No Movement Into or Out of the Population – no gene flow 4. No Mutations 5. No Natural Selection • Gene flowis the movement of individuals or gametes (alleles) between populations due to immigration or emigration. It can alter allele frequencies in a population • Nonrandom matingis more often the case, particularly among animals, where choice of mates is often an important part of behavior. • Natural selection • -- Leads to differential reproductive success in a population.

7. A. harrisi A. leucurus Section Outline • 16–3 The Process of Speciation A. Isolating Mechanisms 1. Behavioral Isolation 2. Geographic Isolation 3. Temporal Isolation

8. Figure 14.3D Postzygotic Barriers • Operate after hybrid zygotes are formed

9. 16–3 The Process of Speciation • Testing Natural Selection in Nature • Speciation in Darwin’s Finches Fruit eater Seed eater insect eater Cactus eater

10. Cactus-seed-eater (cactus finch) 2 B 1 A B B 3 C C 4 C C B D D C 5 D Tool-using insect-eater (woodpecker finch) Seed-eater (medium ground finch) • 16–3 The Process of Speciation • C. Speciation in Darwin’s Finches • 1. Founders Arrive • 2. Separation of Populations • 3. Changes in the Gene Pool • 4. Reproductive Isolation • 5. Ecological Competition • 6. Continued Evolution Darwin’s finches (14 closely related species, distinguished by morphology and habitat) of the Galápagos island chain are excellent examples of the results of island speciation Figure 14.8B

11. Concept Map Geographic isolation Behavioral isolation Temporal isolation Physical separation Behavioral differences Different mating times Section 16-3 Reproductive Isolation results from Isolating mechanisms which include produced by produced by produced by which result in Independentlyevolving populations which result in Formation ofnew species

12. CHAPTER 17THE HISTORY OF EARTH • 17–1 The Fossil Record • A. Fossils and Ancient Life • B. How Fossils Form • Interpreting Fossil Evidence • Geologic Time Scale

13. 17–1 The Fossil Record • A. Fossils and Ancient Life • How Fossils Form • Interpreting Fossil Evidence • 1. Relative Dating Dead organisms are buried by layers of sediment, which forms new rock. The preserved remains may later be discovered and studied. Water carries small rock particles to lakes and seas.

14. 17–1 The Fossil Record • Interpreting Fossil Evidence • 2. Radioactive Dating Age of fossil with respect to another rock or fossil (that is, older or younger) Age of a fossil in years Comparing depth of a fossil’s source stratum to the position of a reference fossil or rock Determining the relative amounts of a radioactive isotope and nonradioactive isotope in a specimen Imprecision and limitations of age data Difficulty of radioassay laboratory methods Comparing Relative and Absolute Dating of Fossils Relative Dating Absolute Dating Can determine Is performed by Drawbacks

15. 17–1 The Fossil Record • D. Geologic Time Scale • 1. Eras • 2. Periods Ceno- zoic Meso- zoic Humans Paleozoic Colonization of land Animals Origin of solar system and Earth Precambrian 4 1 Proterozoic Archaean Prokaryotes years ago Billions of 3 2 Multicellular eukaryotes Single-celled eukaryotes Atmospheric oxygen

16. 17–2 Earth’s Early History Early Earth was hot; atmosphere contained poisonous gases. Earth cooled and oceans condensed. Simple organic molecules may have formed in the oceans.. Small sequences of RNA may have formed and replicated. First prokaryotes may have formed when RNA or DNA was enclosed in microspheres. Later prokaryotes were photosynthetic and produced oxygen. An oxygenated atmosphere capped by the ozone layer protected Earth. First eukaryotes may have been communities of prokaryotes. Multicellular eukaryotes evolved. Sexual reproduction increased genetic variability, hastening evolution.

17. Synthesis of Prebiotic Molecules in an Experimental Atmosphere Mixture of gases simulating atmospheres of early Earth Spark simulating lightning storms Cold water cools chamber, causing droplets to form Water vapor Liquid containing amino acids and other organic compounds

18. Cytoplasm Plasma membrane DNA Ancestral prokaryote Endoplasmic reticulum Nucleus Nuclear envelope Aerobic heterotrophic prokaryote Photosynthetic prokaryote Mitochondrion Mitochondrion Ancestral heterotrophic eukaryote Plastid Ancestral photosynthetic eukaryote

19. Geologic Time Scale with Key Events (millions of years ago) Era Period Time Key Events Cenozoic Mesozoic Paleozoic Precambrian Time Quaternary Tertiary Cretaceous Jurassic Triassic Permian Carboniferous Devonian Silurian Ordovician Cambrian 1.8–present 65–1.8 145–65 208–145 245–208 290–245 363–290 410–363 440–410 505–440 544–505 650–544 • Glaciations; mammals increased; humans • Mammals diversified; grasses • Aquatic reptiles diversified; flowering plants; mass extinct • Dinosaurs diversified; birds • Dinosaurs; small mammals; cone-bearing plants • Reptiles diversified; seed plants; mass extinction • Reptiles; winged insects diversified; coal swamps • Fishes diversified; land vertebrates (primitive amphibians) • Land plants; land animals (arthropods) • Aquatic arthropods; mollusks; vertebrates (jawless fishes) • Marine invertebrates diversified; most animal phyla • Anaerobic, then photosynthetic prokaryotes; eukaryotes, then multicellular life

20. Unrelated Related Intense environmental pressure Similar environments Inter-relationshiops Small populations Different environments Convergent evolution Punctuated equilibrium Adaptive radiation Coevolution Extinction • 17–4 Patterns of Evolution • A. Extinction • B. Adaptive Radiation • C. Convergent Evolution • Coevolution • E. Punctuated Equilibrium • F. Developmental Genes and Body Plans Species that are form in under under in in can undergo can undergo can undergo can undergo can undergo

21. 18–1 Finding Order in Diversity A. Why Classify? • Assigning Scientific Names C. Linnaeus’s System

22. The diversity of life can be arranged into Three domains (protozoans and algae, falling into multiple kingdoms)

23. Figure 18-12 Key Characteristics of Kingdoms and Domains Classification of Living Things DOMAIN KINGDOM CELL TYPE CELL STRUCTURE NUMBER OF CELLS MODE OF NUTRITION EXAMPLES Bacteria Eubacteria Prokaryote Cell walls with peptidoglycan Unicellular Autotroph or heterotroph Streptococcus, Escherichia coli Archaea Archaebacteria Prokaryote Cell walls without peptidoglycan Unicellular Autotroph or heterotroph Methanogens, halophiles Protista Eukaryote Cell walls of cellulose in some; some have chloroplasts Most unicellular; some colonial; some multicellular Autotroph or heterotroph Amoeba, Paramecium, slime molds, giant kelp Fungi Eukaryote Cell walls of chitin Most multicellular; some unicellular Heterotroph Mushrooms, yeasts Eukarya Plantae Eukaryote Cell walls of cellulose; chloroplasts Multicellular Autotroph Mosses, ferns, flowering plants Animalia Eukaryote No cell walls or chloroplasts Multicellular Heterotroph Sponges, worms, insects, fishes, mammals