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Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings PowerPoint ® Lecture Slides for Essential Biology, Second Edition & Essential.

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Presentation on theme: "Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings PowerPoint ® Lecture Slides for Essential Biology, Second Edition & Essential."— Presentation transcript:

1 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings PowerPoint ® Lecture Slides for Essential Biology, Second Edition & Essential Biology with Physiology Neil Campbell, Jane Reece, and Eric Simon Presentation prepared by Chris C. Romero CHAPTER 17 The Evolution of Animals Figures 17.1 – 17.3

2 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Zoologists estimate that about a billion billion (10 18 ) individual arthropods populate the Earth Tapeworms can reach lengths of 20 meters in the human intestine

3 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings The blue whale, an endangered species that grows to lengths of nearly 30 meters, is the largest animal that has ever existed A reptile can survive on less than 10% of the calories required by a mammal of equivalent size

4 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings The incredible diversity of animals BIOLOGY AND SOCIETY: INVASION OF THE KILLER TOADS –Arose through hundreds of millions of years of evolution –Can be quickly threatened

5 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings The Australian quoll Figure 17.1a –Is a catlike creature that preys on many small animals, such as toads

6 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings A non-native toad –Was introduced from South America in 1935 to fight beetles in sugarcane fields –Caused considerable damage to the ecosystem Figure 17.1b

7 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Animal life began in the Precambrian seas with the evolution of multicellular creatures that ate other organisms THE ORIGINS OF ANIMAL DIVERSITY

8 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Animals What Is an Animal? –Are eukaryotic, multicellular, heterotrophic organisms that obtain nutrients by ingestion –Digest their food within their bodies Figure 17.2

9 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Most animals reproduce sexually and then proceed through a series of developmental stages Figure 17.3 Egg Sperm Fertilization Zygote (fertilized egg) Blastula (cross section) Early gastrula Later gastrula Outer cell layer (ectoderm) Opening Primitive gut Inner cell layer (endoderm) Larva Digestive tract Metamorphosis Adult Meiosis Haploid Diploid 1 2 3 4 5 6 7

10 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Most animals have muscle cells and nerve cells that control the muscles

11 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Early Animals and the Cambrian Explosion Animals probably evolved from a colonial protist that lived in the Precambrian seas Figure 17.4 Reproductive cells Somatic cells Digestive cavity Early colony of protists (aggregate of identical cells) 1 2 3 4 Hollow sphere (shown in cross section) Beginning of cell specialization 5 Gastrula-like “proto- animal” Infolding

12 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings At the beginning of the Cambrian period, 545 million years ago, animals underwent a rapid diversification Figure 17.5

13 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings What ignited the Cambrian explosion? –Many hypotheses exist

14 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings To reconstruct the evolutionary history of animal phyla, researchers must depend on clues from comparative anatomy and embryology Animal Phylogeny

15 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Four key evolutionary branch points have been hypothesized

16 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Multicellularity True tissues Radial symmetry Bilateral symmetry No body cavity Body cavities Pseudocoelom True coelom Coelom from cell masses Coelom from digestive tube Figure 17.6 1 2 3 4 SpongesCnidarians Flatworms Roundworms Mollusks Annelids Arthropods Echinoderms Chordates

17 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings The first branch point is defined by the presence of true tissues

18 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings The second major evolutionary split is based partly on body symmetry Figure 17.7 (a) Radial symmetry (b) Bilateral symmetry

19 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Third, the evolution of body cavities led to more complex animals

20 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings A body cavity –Is a fluid-filled space separating the digestive tract from the outer body wall –May be a pseudocoelom or a true coelom Figure 17.8 (a) No body cavity (e.g., flatworm) Body covering (from ectoderm) Digestive tract (from endoderm) Tissue-filled region (from mesoderm) (b) Pseudocoelom (e.g., roundworm) Pseudocoelom Digestive tract (from endoderm) Body covering (from ectoderm) Muscle layer (from mesoderm) (c) True coelom (e.g., annelid) Coelom Digestive tract (from endoderm) Body covering (from ectoderm) Tissue layer lining coelom and suspending internal organs (from mesoderm) Mesentery

21 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Fourth, among animals with a true coelom, there are two main evolutionary branches, which differ in embryonic development

22 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Invertebrates MAJOR INVERTEBRATE PHYLA –Are animals without backbones –Represent 95% of the animal kingdom

23 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Phylum Porifera Sponges –Includes sessile animals once believed to be plants –Lack true tissues Figure 17.9

24 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings The body of a sponge –Resembles a sac perforated with holes –Draws water into a central cavity, where food is collected

25 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 17.10 Pores Water flow Skeleton fiber Central cavity Choanocyte Amoebocyte Choanocyte in contact with an amoebocyte Flagella

26 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Cnidarians Phylum Cnidaria –Is characterized by organisms with radial symmetry and tentacles with stinging cells

27 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings The basic body plan of a cnidarian –Is a sac with a gastrovascular cavity –Has two variations: the sessile polyp and the floating medusa Mouth/anus Tentacle Gastrovascular cavity Tentacle Mouth/anus Medusa form Polyp form Figure 17.11

28 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Examples of polyps are –Hydras, sea anemones, and coral animals Figure 17.12

29 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings The organisms we call jellies are medusas

30 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Cnidarians are carnivores that use tentacles armed with cnidocytes, or “stinging cells,” to capture prey Figure 17.13 Tentacle Coiled thread Capsule “Trigger” Discharge of thread Cnidocyte Prey

31 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Phylum Platyhelminthes Flatworms –Is represented by the simplest bilateral animals –Includes free-living forms such as planarians Figure 17.14 Digestive tract (gastrovascular cavity) Nerve cords Mouth Eyespots Nervous tissue clusters

32 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Some flatworms are parasitic –Blood flukes are an example –Tapeworms parasitize many vertebrates, including humans Figure 17.15 Reproductive structures Head Hooks Sucker

33 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Phylum Nematoda Roundworms –Includes the most diverse and widespread of all animals –Occurs in aquatic and moist terrestrial habitats Figure 17.16

34 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Roundworms exhibit an important evolutionary adaptation, a digestive tube with two openings, a mouth and an anus A complete digestive tract can process food and absorb nutrients efficiently

35 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Phylum Mollusca Mollusks –Is represented by soft-bodied animals, but most are protected by a hard shell –Includes snails, slugs, clams, octopuses, and squids, to name a few

36 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings The body of a mollusk has three main parts: a muscular foot, a visceral mass, and a mantle Figure 17.17 Mantle Mantle cavity Shell Anus Gill Foot Nerve cords Visceral mass Kidney Coelom Heart Reproductive organs Digestive tract Radula Mouth

37 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings The three major classes of mollusks are –Gastropods, which are protected by a single, spiraled shell Figure 17.18a

38 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings –Bivalves, protected by shells divided into two halves Figure 17.18b

39 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings –Cephalopods, which may or may not have a shell Figure 17.18c

40 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Phylum Annelida Annelids –Includes worms with body segmentation Figure 17.19 Mouth Brain Accessory hearts Main heart Coelom Nerve cord Digestive tract Blood vessels Segment walls Excretory organ Anus

41 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings There are three main classes of annelids –Earthworms, which eat their way through soil Figure 17.20a

42 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings –Polychaetes, which burrow in the sea floor Figure 17.20b

43 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings –Leeches, some of which are parasitic Figure 17.20c

44 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Phylum Arthropoda Arthropods –Contains organisms named for their jointed appendages –Includes crustaceans, arachnids, and insects

45 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Arthropods are segmented animals with specialized segments and appendages General Characteristics of Arthropods Figure 17.21 Antennae (sensory reception) Pincer (defense) Cephalothorax Head Thorax Mouthparts (feeding) Walking legs Abdomen Swimming appendages

46 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings The body of an arthropod is completely covered by an exoskeleton

47 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings There are four main groups of arthropods Arthropod Diversity –Arachnids, such as spiders, scorpions, ticks, and mites Figure 17.22

48 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings –Crustaceans, such as crabs, lobsters, crayfish, shrimps, and barnacles Figure 17.23

49 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings –Millipedes and centipedes Figure 17.24

50 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Hawk moth Mosquito Paper wasp Damselfly Water strider Ground beetle Antenna Eye Head Mouthparts Thorax Forewing Abdomen Hindwing Grasshopper –Insects, most of which have a three-part body Figure 17.25

51 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Many insects undergo metamorphosis in their development Figure 17.26 (a) Larva (caterpillar) (b) Pupa (c) Pupa (d) Emerging adult (e) Adult

52 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Phylum Echinodermata Echinoderms –Is named for the spiny surfaces of the organisms –Includes sea stars, sand dollars, sea urchins, and sea cucumbers Figure 17.27

53 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Echinoderms –Are all marine –Lack body segments –Usually have an endoskeleton –Have a water vascular system that facilitates gas exchange and waste disposal

54 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Vertebrates THE VERTEBRATE GENEALOGY –Are represented by mammals, birds, reptiles, amphibians, and fishes –Have unique features, including the cranium and backbone Figure 17.28

55 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Phylum Chordata Characteristics of Chordates –Includes the subphylum of vertebrates

56 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Other subphyla include the lancelets and tunicates, which share four key chordate characteristics Figure 17.29

57 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings The four chordate hallmarks are –A dorsal, hollow nerve cord –A notochord –Pharyngeal slits –A post-anal tail

58 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 17.30 Muscle segments Post-anal tail Notochord Anus Dorsal, hollow nerve cord Pharyngeal slits Brain Mouth

59 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings An overview of chordate and vertebrate evolution

60 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 17.31 Eras Cenozoic Mesozoic Paleozoic Precambrian Tertiary Cretaceous Jurassic Triassic Permian Carboniferous Devonian Silurian Ordovician Cambrian Tunicates Lancelets Agnatha (jawless vertebrates, such as lampreys) Chondrichthyes (sharks and rays) Osteichthyes (bony fishes) Amphibia (frogs and salamanders) Reptilia (reptiles) Aves (birds) Mammalia (mammals) Ancestral chordate Vertebrae Jaws Lungs or lung derivatives Legs Amniotic egg Hair Feathers Chordates Vertebrates Tetrapods Amniotes Periods

61 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings The first vertebrates probably evolved during the early Cambrian period, about 540 million years ago Fishes

62 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings These early vertebrates, the agnathans, lacked jaws Agnathans are represented today by lampreys

63 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings The two major groups of living fishes are the classes –Chondrichthyes –Osteichthyes

64 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Cartilaginous fishes have a flexible skeleton made of cartilage –Sharks have a lateral line system sensitive to vibrations in the water Figure 17.32a

65 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Bony fishes –Have a skeleton reinforced by hard calcium salts –Have a lateral line system, a keen sense of smell, and excellent eyesight Figure 17.32b

66 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Most bony fishes are ray-finned fishes A second evolutionary branch includes lungfishes and lobe-finned fishes

67 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Members of the class Amphibia Amphibians –Exhibit a mixture of aquatic and terrestrial adaptations –Usually need water to reproduce Figure 17.33

68 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Amphibians –Were the first vertebrates to colonize land –Descended from fishes that had lungs and fins with muscles Figure 17.34 Lobe-finned fish Early amphibian

69 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Terrestrial vertebrates are collectively called tetrapods, which means “four legs”

70 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Class Reptilia Reptiles –Includes snakes, lizards, turtles, crocodiles, and alligators –Can live totally on land

71 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Adaptations for living on land include –Scales to prevent dehydration –Lungs for breathing –The amniotic egg Figure 17.35

72 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Reptiles are ectotherms, which obtain their body heat from the environment

73 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Reptiles diversified extensively during the Mesozoic Era Dinosaurs included the largest animals ever to live on land Figure 17.36

74 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Class Aves Birds –Evolved during the great reptilian radiation of the Mesozoic era –Evolved the ability to fly

75 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Bird anatomy and physiology are modified for flight –Bones are honeycombed, which makes them lighter –Some specific organs are absent, which reduces weight –A warm, constant body temperature is maintained through endothermy

76 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings A bird’s wings –Illustrate the same principles of aerodynamics as the wings of an airplane Figure 17.37 Airfoil

77 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Class Mammalia Mammals –Evolved from reptiles about 225 million years ago –Includes mostly terrestrial organisms

78 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Two features are mammalian hallmarks –Hair –Mammary glands that produce milk and nourish the young

79 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings There are three major groups of mammals –Monotremes, the egg-laying mammals, constitute the first group Figure 17.38a

80 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Most mammals are born rather than hatched and are nurtured inside the mother by an organ called a placenta

81 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings The second group of mammals, marsupials, are the so-called pouched mammals Figure 17.38b

82 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Eutherians are also called placental mammals –Their placentas provide more intimate and long- lasting association between the mother and her developing young than do marsupial placentas Figure 17.38c

83 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Humans are primates THE HUMAN ANCESTRY

84 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Primate evolution The Evolution of Primates –Provides a context for understanding human origins

85 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Primates –Evolved from insect-eating mammals during the late Cretaceous period Early primates –Were small, arboreal mammals

86 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings The distinguishing characteristics of primates were shaped by the demands of living in trees

87 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Primate characteristics include –Limber shoulder joints –Eyes in front of the face –Excellent eye-hand coordination –Extensive parental care Figure 17.39

88 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Taxonomists divide primates into two main groups –Prosimians –Anthropoids

89 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Prosimians include –Lemurs, lorises, pottos, and tarsiers Figure 17.40a

90 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Anthropoids include –Monkeys Figure 17.40b, c

91 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings –Apes, the closest relatives to humans Figure 17.40d–g

92 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings –Humans Figure 17.40h

93 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Humans and apes have shared a common ancestry for all but the last 5–7 million years The Emergence of Humankind

94 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 17.41 Prosimians Anthropoids Monkeys Apes Prosimians (lemurs, lorises, pottos, and tarsiers) New World monkeys Old World monkeys Gibbons Orangutans Gorillas Chim- panzees Humans Ancestral primate

95 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Our ancestors were not chimpanzees or any other modern apes Some Common Misconceptions Chimpanzees and humans represent two divergent branches of the anthropoid tree

96 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Human evolution –Is not a ladder with a series of steps leading directly to Homo sapiens –Is more like a multibranched bush than a ladder

97 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 17.42 Ardipithecus ramidus Australopithecus afarensis Australopithecus africanus Australopithecus boisei Australopithecus robustus Homo habilis Homo erectus Homo sapiens neanderthalensis Homo sapiens sapiens

98 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Upright posture and an enlarged brain appeared at separate times during human evolution

99 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Before there was the genus Homo, several hominid species of the genus Australopithecus walked the African savanna Australopithecus and the Antiquity of Bipedalism

100 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Fossil evidence pushes bipedalism in A. afarensis back to at least 4 million years ago Figure 17.43

101 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings All Australopithecus species were extinct by about 1.4 million years

102 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Homo habilis, “handy-man” Homo habilis and the Evolution of Inventive Minds –Had a larger brain –Probably made stone tools

103 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Homo erectus was the first species to extend humanity’s range from Africa to other continents Homo erectus and the Global Diversity of Humanity The global dispersal began about 1.8 million years ago

104 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Homo erectus –Was taller than H. habilis –Had a larger brain –Gave rise to Neanderthals

105 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings The oldest known post–H. erectus fossils The Origin of Homo sapiens –Date back more than 300,000 years –Are found in Africa

106 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Many paleoanthropologists consider these fossils as the earliest forms of our species, Homo sapiens The famous fossils of modern humans from the Cro-Magnon caves of France date back about 35,000 years

107 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Two hypotheses regarding the origins of modern humans exist –The multiregional hypothesis –The “Out of Africa” hypothesis (also called the replacement hypothesis)

108 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings The multiregional hypothesis –States that modern humans evolved simultaneously in different parts of the world –States that Homo erectus spread from Africa into other continents between 1 and 2 million years ago

109 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 17.44a Interbreeding 1–2 million years ago Homo sapiens AfricanEuropeanAsian Austral- asian Homo erectus in Africa (a) Multiregional hypothesis

110 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings The “Out of Africa” hypothesis –States that modern humans spread out from Africa about 100,000 years ago

111 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 17.44b 100,000 years ago Homo sapiens in Africa African European Asian Austral- asian Homo erectus in Africa (b) “Out of Africa” hypothesis Homo sapiens

112 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Culture Cultural Evolution –Is the transmission of accumulated knowledge over generations

113 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Cultural evolution has had three major stages

114 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings First, nomads who were hunter-gatherers –Made tools –Created art Figure 17.45

115 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Second, the development of agriculture Third, the Industrial Revolution

116 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Cultural evolution EVOLUTION CONNECTION: EARTH’S NEW CRISIS –Made Homo sapiens a new force in the history of life Humans are changing the world faster than many species can adapt –The rate of extinction in the twentieth century was 50 times greater than the average for the past 100,000 years

117 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings This rapid rate of extinction is mainly a result of habitat destruction The exploding human population now threatens Earth’s ecosystems


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