Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Chapter 22: Descent with Modification: A Darwinian View of Life

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure 22.1 A marine iguana, well-suited to its rocky habitat in the Galápagos Islands

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure 22.2 The historical context of Darwin’s life and ideas Linnaeus (classification) Hutton (gradual geologic change) Lamarck (species can change) Malthus (population limits) Cuvier (fossils, extinction) Lyell (modern geology) Darwin (evolution, natural selection) Mendel (inheritance) Wallace (evolution, natural selection) 1750 American RevolutionFrench Revolution U.S. Civil War Hutton proposes his theory of gradualism Malthus publishes “Essay on the Principle of Population.” 1809 Lamarck publishes his theory of evolution Lyell publishes Principles of Geology. 1831–1836 Darwin travels around the world on HMS Beagle. Darwin begins his notebooks on the origin of species Darwin writes his essay on the origin of species Wallace sends his theory to Darwin The Origin of Species is published Mendel publishes inheritance papers. 1865

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure 22.3 Fossils from strata of sedimentary rock

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure 22.4 Acquired traits cannot be inherited

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure 22.5 The voyage of HMS Beagle England EUROPE NORTH AMERICA Galápagos Islands Darwin in 1840, after his return SOUTH AMERICA Cape of Good Hope Cape Horn Tierra del Fuego AFRICA HMS Beagle in port AUSTRALIA Tasmania New Zealand PACIFIC OCEAN Andes ATLANTIC OCEAN

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 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.

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 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) Loxodonta cyclotis (Africa)

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure 22.8 Overproduction of offspring

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure 22.9 Variation in a population

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure Artificial selection Terminal bud Lateral buds Brussels sprouts Cabbage Flower cluster Leaves Cauliflower Flower and stems BroccoliWild mustard Kohlrabi Stem Kale

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure Camouflage as an example of evolutionary adaptation (a)A flower mantid in Malaysia (b)A stick mantid in Africa

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure Can predation pressure select for size and age at maturity in guppies? Reznick and Endler transplanted guppies from pike-cichlid pools to killifish pools and measured the average age and size of guppies at maturity over an 11-year period (30 to 60 generations). EXPERIMENT Pools with killifish, but not guppies prior to transplant Experimental transplant of guppies Predator: Killifish; preys mainly on small guppies Guppies: Larger at sexual maturity than those in “pike-cichlid pools” Predator: Pike-cichlid; preys mainly on large guppies Guppies: Smaller at sexual maturity than those in “killifish pools”

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings RESULTS After 11 years, the average size and age at maturity of guppies in the transplanted populations increased compared to those of guppies in control populations Weight of guppies at maturity (mg) Age of guppies at maturity (days) Control Population: Guppies from pools with pike-cichlids as predators Experimental Population: Guppies transplanted to pools with killifish as predators 76.1 Males Females Males Females CONCLUSION Reznick and Endler concluded that the change in predator resulted in different variations in the population (larger size and faster maturation) being favored. Over a relatively short time, this altered selection pressure resulted in an observable evolutionary change in the experimental population.

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure Evolution of drug resistance in HIV Patient No. 1 Patient No. 2 Patient No. 3 Percent of HIV resistant to 3TC Weeks

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure Mammalian forelimbs: Homologous structures HumanCat Whale Bat

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure Anatomical similarities in vertebrate embryos Pharyngeal pouches Post-anal tail Chick embryo Human embryo

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Figure 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