Chapter 22 Descent with Modification A Darwinian View

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

Chapter 22: Descent with Modification: A Darwinian View of Life 1. What do you know about evolution? 2. What is evolution? - Gradual change over time 3. What is paleontology? - Study of fossils - Allows for relative dating – older or younger – layer found in

Chapter 22: Descent with Modification: A Darwinian View of Life 1. What do you know about evolution? 2. What is evolution? 3. What is paleontology? 4. What was Lamarck’s view? - Inheritance of acquired characteristics - Evolution within an organism’s lifetime – use & disuse - Examples – Blacksmith, giraffe 5. What was Darwin’s view? - Descent with modification – tree of life - REPRODUCTION of the fittest - not SOTF - Story time…

Figure 22. 5 The voyage of HMS Beagle England EUROPE NORTH AMERICA ATLANTIC OCEAN PACIFIC OCEAN Galápagos Islands HMS Beagle in port SOUTH AMERICA AUSTRALIA Cape of Good Hope Andes Darwin in 1840, after his return AFRICA Tasmania Cape Horn Tierra del Fuego New Zealand

Chapter 22: Descent with Modification: A Darwinian View of Life 1. What do you know about evolution? 2. What is evolution? 3. What is paleontology? 4. What was Lamarck’s view? - Inheritance of acquired characteristics - Evolution within an organism’s lifetime – use & disuse - Examples – Blacksmith, giraffe 5. What was Darwin’s view? - Descent with modification – tree of life - REPRODUCTION of the fittest - not SOTF - Studied Galapagos finches

Figure 22. 6 Beak variation in Galápagos finches (a) Cactus eater. The long, sharp beak of the cactus ground finch (Geospiza scandens) helps it tear and eat cactus flowers and pulp. (c) Seed eater. The large ground finch (Geospiza magnirostris) has a large beak adapted for cracking seeds that fall from plants to the ground. (b) Insect eater. The green warbler finch (Certhidea olivacea) uses its narrow, pointed beak to grasp insects.

Chapter 22: Descent with Modification: A Darwinian View of Life 1. What do you know about evolution? 2. What is evolution? 3. What is paleontology? 4. What was Lamarck’s view? - Inheritance of acquired characteristics - Evolution within an organism’s lifetime – use & disuse - Examples – Blacksmith, giraffe 5. 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

Sirenia Hyracoidea (Manatees (Hyraxes) and relatives) Mammuthus Stegodon Platybelodon Mammut Deinotherium Elephas Loxodonta cyclotis maximus africana (Africa) (Asia) (Africa) Barytherium Moeritherium Millions of years ago Years ago Figure 22. 7 Descent with modification

Chapter 22: Descent with Modification: A Darwinian View of Life 1. What do you know about evolution? 2. What is evolution? 3. What is paleontology? 4. What was Lamarck’s view? 5. What was Darwin’s view? 6. 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

Figure 22. 9 Variation in a population

Figure 22. 11 Camouflage as an example of evolutionary adaptation (a) A flower mantid in Malaysia (b) A stick mantid in Africa

Chapter 22: Descent with Modification: A Darwinian View of Life 1. What do you know about evolution? 2. What is evolution? 3. What is paleontology? 4. What was Lamarck’s view? 5. What was Darwin’s view? 6. 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 7. What is artificial selection? - Selective breeding to encourage the occurrence of desirable traits

Figure 22. 10 Artificial selection Terminal bud Lateral buds Brussels sprouts Cabbage Flower cluster Leaves Cauliflower Broccoli Kale Flower and stems Stem Wild mustard Kohlrabi

Chapter 22: Descent with Modification: A Darwinian View of Life 1. What do you know about evolution? 2. What is evolution? 3. What is paleontology? 4. What was Lamarck’s view? 5. What was Darwin’s view? 6. Summarizing Darwin’s view 7. What is artificial selection? 8. 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

Figure 22. 14 Mammalian forelimbs: Homologous structures Human Cat Whale Bat

Chapter 22: Descent with Modification: A Darwinian View of Life 1. What do you know about evolution? 2. What is evolution? 3. What is paleontology? 4. What was Lamarck’s view? 5. What was Darwin’s view? 6. Summarizing Darwin’s view 7. What is artificial selection? 8. 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

Figure 22. 15 Anatomical similarities in vertebrate embryos Pharyngeal pouches Post-anal tail Chick embryo Human embryo

Chapter 22: Descent with Modification: A Darwinian View of Life 1. What do you know about evolution? 2. What is evolution? 3. What is paleontology? 4. What was Lamarck’s view? 5. What was Darwin’s view? 6. Summarizing Darwin’s view 7. What is artificial selection? 8. 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

Figure 22. 16 Comparison of a protein found in diverse vertebrates Species Percent of Amino Acids That Are Identical to the Amino Acids in a Human Hemoglobin Polypeptide 100% Human Rhesus monkey 95% Mouse 87% Chicken 69% Frog Lamprey 54% 14%

Chapter 22: Descent with Modification: A Darwinian View of Life 1. What do you know about evolution? 2. What is evolution? 3. What is paleontology? 4. What was Lamarck’s view? 5. What was Darwin’s view? 6. Summarizing Darwin’s view 7. What is artificial selection? 8. 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

Fig. 22. 17 Different geographic regions, different mammalian “brands” NORTH AMERICA Sugar glider AUSTRALIA Flying squirrel

Chapter 22: Descent with Modification: A Darwinian View of Life 1. What do you know about evolution? 2. What is evolution? 3. What is paleontology? 4. What was Lamarck’s view? 5. What was Darwin’s view? 6. Summarizing Darwin’s view 7. What is artificial selection? 8. What is the evidence for evolution? - Homologous structures - Comparative embryology - Molecular biology - Biogeography – geographical distribution of species - Fossils

Figure 22. 18 A transitional fossil linking past and present