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

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 – layer found in

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 Story time…

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

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

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 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

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

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

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 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

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

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

Figure 22.14 Mammalian forelimbs: Homologous structures Human Cat Whale Bat

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

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 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

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

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

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

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

Figure 22.18 A transitional fossil linking past and present