Chapter 22: Descent with Modification: A Darwinian View of Life

1. Chapter 22: Descent with Modification: A Darwinian View of Life • What do you know about evolution? • What is evolution? • Gradual change over time • What is paleontology? • -Study of fossils • -Allows for relative dating - “older” or “younger” - depends on layer

2. Chapter 22: Descent with Modification: A Darwinian View of Life • What do you know about evolution? • What is evolution? • What is paleontology? • What was Lamarck’s view? • Inheritance of acquired characteristics • Viewed for 150 years as being wrong…but he could • be partially right! (epigenetics) • Evolution within an organism’s lifetime – use & disuse • Examples – Blacksmith, giraffe • What was Darwin’s view? • Descent with modification – tree of life • REPRODUCTION of the fittest • not SOTF

3. England EUROPE NORTH AMERICA ATLANTIC OCEAN PACIFIC OCEAN Galápagos Islands HMS Beagle in port AFRICA SOUTH AMERICA Darwin in 1840, after his return AUSTRALIA Cape of Good Hope Andes Tasmania Cape Horn New Zealand Tierra del Fuego Figure 22.5 The voyage of HMS Beagle

4. Chapter 22: Descent with Modification: A Darwinian View of Life • What do you know about evolution? • What is evolution? • What is paleontology? • What was Lamarck’s view? • Inheritance of acquired characteristics • Evolution within an organism’s lifetime – use & disuse • Examples – Blacksmith, giraffe • What was Darwin’s view? • Descent with modification – tree of life • REPRODUCTION of the fittest • not SOTF • Studied Galapagos finches

5. (a) Cactus eater. The long,sharp beak of the cactusground finch (Geospizascandens) helps it tearand eat cactus flowersand pulp. (c) Seed eater. The large groundfinch (Geospiza magnirostris)has a large beak adapted forcracking seeds that fall fromplants to the ground. (b) Insect eater. The green warbler finch (Certhidea olivacea) uses itsnarrow, pointed beak to grasp insects. Figure 22.6 Beak variation in Galápagos finches

6. Chapter 22: Descent with Modification: A Darwinian View of Life • What do you know about evolution? • What is evolution? • What is paleontology? • What was Lamarck’s view? • Inheritance of acquired characteristics • Evolution within an organism’s lifetime – use & disuse • Examples – Blacksmith, giraffe • What was Darwin’s view? • Descent with modification – tree of life • REPRODUCTION of the fittest • not SOTF • Studied Galapagos finches • 1859 – The Origin of Species – 2 main points • Descent with Modification (evolution) f/ common ancestor • Natural selection is the mechanism of evolution

7. Sirenia (Manatees and relatives) Loxodonta cyclotis (Africa) Elephas maximus (Asia) Loxodonta africana (Africa) Hyracoidea (Hyraxes) Years ago Stegodon Mammut Mammuthus Deinotherium Platybelodon Millions of years ago Barytherium Moeritherium Figure 22.7 Descent with modification

8. Chapter 22: Descent with Modification: A Darwinian View of Life • What do you know about evolution? • What is evolution? • What is paleontology? • What was Lamarck’s view? • What was Darwin’s view? • Summarizing Darwin’s view • Natural selection = differential reproductive success • Natural selection occurs through interactions between the environment and the variability among individual organisms in a population

9. Figure 22.9 Variation in a population

10. (a) A flower mantidin Malaysia (b) A stick mantidin Africa Figure 22.11 Camouflage as an example of evolutionary adaptation

11. Chapter 22: Descent with Modification: A Darwinian View of Life • What do you know about evolution? • What is evolution? • What is paleontology? • What was Lamarck’s view? • What was Darwin’s view? • Summarizing Darwin’s view • Natural selection is differential reproductive success • Natural selection occurs through interactions between the environment and the variability among individual organisms in a population • The product of natural selection is the adaptation of a population of organisms to their environment • What is artificial selection? • - Selective breeding to encourage the occurrence of desirable traits

12. Lateral buds Terminal bud Brussels sprouts Cabbage Flower cluster Leaves Cauliflower Kale Stem Flower and stems Broccoli Wild mustard Kohlrabi Figure 22.10 Artificial selection

13. Chapter 22: Descent with Modification: A Darwinian View of Life • What do you know about evolution? • What is evolution? • What is paleontology? • What was Lamarck’s view? • What was Darwin’s view? • Summarizing Darwin’s view • What is artificial selection? • What is the evidence for evolution? • Homologous structures – similar structures with different functions show signs of evolution from a common ancestor, may be vestigial organs

14. Human Cat Bat Whale Figure 22.14 Mammalian forelimbs: Homologous structures

15. Chapter 22: Descent with Modification: A Darwinian View of Life • What do you know about evolution? • What is evolution? • What is paleontology? • What was Lamarck’s view? • What was Darwin’s view? • Summarizing Darwin’s view • What is artificial selection? • What is the evidence for evolution? • Homologous structures – similar structures with different functions show signs of evolution from a common ancestor, may be vestigial organs • Comparative embryology • Pharyngeal gill slits • Post-anal tail

16. Pharyngeal pouches Post-anal tail Chick embryo Human embryo Figure 22.15 Anatomical similarities in vertebrate embryos

17. Chapter 22: Descent with Modification: A Darwinian View of Life • What do you know about evolution? • What is evolution? • What is paleontology? • What was Lamarck’s view? • What was Darwin’s view? • Summarizing Darwin’s view • What is artificial selection? • What is the evidence for evolution? • Homologous structures – similar structures with different functions show signs of evolution from a common ancestor, may be vestigial organs • Comparative embryology • Pharyngeal gill slits • Post-anal tail • Molecular biology

18. Percent of Amino Acids That Are Identical to the Amino Acids in a Human Hemoglobin Polypeptide Species 100% Human Rhesus monkey 95% Mouse 87% Chicken 69% Frog 54% 14% Lamprey Figure 22.16 Comparison of a protein found in diverse vertebrates

19. Chapter 22: Descent with Modification: A Darwinian View of Life • What do you know about evolution? • What is evolution? • What is paleontology? • What was Lamarck’s view? • What was Darwin’s view? • Summarizing Darwin’s view • What is artificial selection? • What is the evidence for evolution? • Homologous structures – similar structures with different functions show signs of evolution from a common ancestor, may be vestigial organs • Comparative embryology • Pharyngeal gill slits • Post-anal tail • Molecular biology • Biogeography – geographical distribution of species

20. NORTH AMERICA Sugar glider AUSTRALIA Flying squirrel Fig. 22.17 Different geographic regions, different mammalian “brands”

21. Chapter 22: Descent with Modification: A Darwinian View of Life • What do you know about evolution? • What is evolution? • What is paleontology? • What was Lamarck’s view? • What was Darwin’s view? • Summarizing Darwin’s view • What is artificial selection? • What is the evidence for evolution? • Homologous structures • Comparative embryology • Molecular biology • Biogeography – geographical distribution of species • Fossils

22. Figure 22.18 A transitional fossil linking past and present