General Biology 1004 Chapter 17 Lecture Handout, Summer 2005 Dr. Frisby

Transcription

1 Slide 1 CHAPTER 17 The Evolution of Animals 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 Slide 2 THE ORIGINS OF ANIMAL DIVERSITY Animal life began in the Precambrian seas with the evolution of multicellular creatures that ate other organisms Slide 3 What Is an Animal? Animals Figure 17.2

2 Slide 4 Most animals reproduce sexually and then proceed through a series of developmental stages Haploid Sperm Egg 2 1 Meio sis Fertiliz ation Zygote (fertilized egg) Adult 3 Diploid Blastula (cross section) 7 Metamorphosis Digestive tract Primitive gut Outer cell layer (ectoderm) Early gastrula Larva Inner cell layer (endoderm) Figure 17.3 Later gastrula Opening Slide 5 Most animals have muscle cells and nerve cells that control the muscles Slide 6 Early Animals and the Cambrian Explosion Animals probably evolved from a colonial protist that lived in the Precambrian seas Digestive cavity Reproductive cells 1 Early colony of protists (aggregate of identical cells) 2 Hollow sphere (shown in cross section) Somatic cells 3 Beginning of cell specialization 4 Infolding 5 Gastrula-like protoanimal Figure 17.4

3 Slide 7 At the beginning of the Cambrian period, 545 million years ago, animals underwent a rapid diversification Figure 17.5 Slide 8 Animal Phylogeny To reconstruct the evolutionary history of animal phyla, researchers must depend on clues from comparative anatomy and embryology Slide 9 Four key evolutionary branch points have been hypothesized

4 Slide 10 Sponges Cnidarians Flatworm s Roundworms Mo llu sks An nelid s Arthropod s Coelom from cell masses Echinoderms Chordates Coelom from digestive tube 4 Pseudocoelom True coelom No body cavity 3 Body cavities Radial symmetry 1 Bilateral 2 symmetry True tissues Multicellularity Figure 17.6 Slide 11 The first branch point is defined by the presence of true tissues Slide 12 The second major evolutionary split is based partly on body symmetry (a) Radial symmetry (b) Bilateral symmetry Figure 17.7

5 Slide 13 Third, the evolution of body cavities led to more complex animals Slide 14 A body cavity Body covering (from ectoderm) Tissue -filled region (from mesoderm) (a) No body cavity (e.g., flatworm) Pseudocoelom Body covering (from ectoderm) Digestive tract (from endoderm) (b) Pseudocoelom (e.g., roundworm) Coelom Figure 17.8 Digestive tract (from endoderm) Muscle layer (from mesoderm) Body covering (from ectoderm) Tissue layer lining coelom and suspending Digestive tract (from Mesentery internal organs endoderm) (from (c) True coelom (e.g., annelid) mesoderm) Slide 15 Fourth, among animals with a true coelom, there are two main evolutionary branches, which differ in embryonic development

6 Slide 16 MAJOR INVERTEBRATE PHYLA Invertebrates Slide 17 Sponges Phylum Porifera Figure 17.9 Slide 18 The body of a sponge

7 Slide 19 Choanocyte in contact with an amoebocyte Pores Water flow Skeleton fiber Central cavity Choanocyte Amoebocyte Flagella Figure Slide 20 Cnidarians Phylum Cnidaria Slide 21 The basic body plan of a cnidarian Mouth/anus Tentacle Gastrovascular cavity Tentacle Mouth/anus Polyp form Medusa form Figure 17.11

8 Slide 22 Examples of polyps are Figure Slide 23 The organisms we call jellies are medusas Slide 24 Cnidarians are carnivores that use tentacles armed with cnidocytes, or stinging cells, to capture prey Coiled thread Tentacle Trigger Capsule Cnidocyte Discharge of thread Prey Figure 17.13

9 Slide 25 Flatworms Phylum Platyhelminthes Digestive tract (gastrovascular cavity) Nerve cords Mouth Eyespots Nervous tissue clusters Figure Slide 26 Some flatworms are parasitic Head Reproductive structures Hooks Sucker Figure Slide 27 Roundworms Phylum Nematoda Figure 17.16

10 Slide 28 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 Slide 29 Mollusks Phylum Mollusca Slide 30 The body of a mollusk has three main parts: a muscular foot, a visceral mass, and a mantle Visceral mass Coelom Mantle Kidney Reproductive organs Heart Digestive tract Mantle cavity Shell Radula Radula Anus Gill Foot Mouth Nerve cords Mouth Figure 17.17

11 Slide 31 The three major classes of mollusks are Figure 17.18a Slide 32 Bivalves, protected by shells divided into two halves Figure 17.18b Slide 33 Cephalopods, which may or may not have a shell Figure 17.18c

12 Slide 34 Annelids Phylum Annelida Anus Brain Main heart Coelom Digestive tract Segment walls Mouth Accessory hearts Nerve cord Blood vessels Excretory organ Figure Slide 35 There are three main classes of annelids Figure 17.20a Slide 36 Polychaetes, which burrow in the sea floor Figure 17.20b

13 Slide 37 Leeches, some of which are parasitic Figure 17.20c Slide 38 Arthropods Phylum Arthropoda Slide 39 General Characteristics of Arthropods Arthropods are segmented animals with specialized segments and appendages Cephalothorax Abdomen Thorax Antennae (sensory reception) Head Swimming appendages Pincer (defense) Walking legs Mouthparts (feeding) Figure 17.21

14 Slide 40 The body of an arthropod is completely covered by an exoskeleton Slide 41 Arthropod Diversity There are four main groups of arthropods Figure Slide 42 Crustaceans, such as crabs, lobsters, crayfish, shrimps, and barnacles Figure 17.23

15 Slide 43 Millipedes and centipedes Figure Slide 44 Insects, most of which have a three -part body Head Thorax Hawk moth Antenna Abdomen Forewing Eye Mosquito Paper wasp Mouthparts Hindwing Grasshopper Damselfly Water strider Ground beetle Figure Slide 45 Many insects undergo metamorphosis in their development (a) Larva (caterpillar) (b) Pupa (c) Pupa (d) Emerging adult (e) Adult Figure 17.26

16 Slide 46 Echinoderms Phylum Echinodermata Figure Slide 47 Echinoderms Slide 48 THE VERTEBRATE GENEALOGY Vertebrates Figure 17.28

17 Slide 49 Characteristics of Chordates Phylum Chordata Slide 50 Other subphyla include the lancelets and tunicates, which share four key chordate characteristics Figure Slide 51 The four chordate hallmarks are

18 Slide 52 Dorsal, hollow nerve cord Notochord Brain Muscle segments Mouth Anus Pharyngeal slits Post-anal tail Figure Slide 53 An overview of chordate and vertebrate evolution Slide 54 Chordates Vertebrates Aves (birds) Mammalia (mammals) Reptilia (reptiles) Amphibia (frogs and salamanders) Feathers Hair De vonia n Amniotic egg Silu ri an Legs Lungs or lung derivatives Cambr ian Ordovician Paleozoi c Osteichthyes (bony fishes) Chondrichthyes (sharks and rays) Lancelets Agnatha (jawless vertebrates, such as lampreys) Ter tiar y Tunicates Cretaceous M esozoi c Amniotes Ca rbonife rous Perm ian Tria ss i c Jurassic Cenozoic Eras Periods Tetrapods Jaws Precam brian Vertebrae Ancestral chordate Figure 17.31

19 Slide 55 Fishes The first vertebrates probably evolved during the early Cambrian period, about 540 million years ago Slide 56 These early vertebrates, the agnathans, lacked jaws Agnathans are represented today by lampreys Slide 57 The two major groups of living fishes are the classes

20 Slide 58 Cartilaginous fishes have a flexible skeleton made of cartilage Figure 17.32a Slide 59 Bony fishes Figure 17.32b Slide 60 Amphibians Members of the class Amphibia Figure 17.33

21 Slide 61 Amphibians Lobe-finned fish Early amphibian Figure Slide 62 Terrestrial vertebrates are collectively called tetrapods, which means four legs Slide 63 Reptiles Class Reptilia

22 Slide 64 Adaptations for living on land include Figure Slide 65 Reptiles are ectotherms, which obtain their body heat from the environment Slide 66 Reptiles diversified extensively during the Mesozoic Era Dinosaurs included the largest animals ever to live on land Figure 17.36

23 Slide 67 Birds Class Aves Slide 68 Bird anatomy and physiology are modified for flight Slide 69 A bird s wings Air fo il Figure 17.37

24 Slide 70 Mammals Class Mammalia Slide 71 Two features are mammalian hallmarks Slide 72 There are three major groups of mammals Figure 17.38a

25 Slide 73 Most mammals are born rather than hatched and are nurtured inside the mother by an organ called a placenta Slide 74 The second group of mammals, marsupials, are the so-called pouched mammals Figure 17.38b Slide 75 Eutherians are also called placental mammals Figure 17.38c

26 Slide 76 THE HUMAN ANCESTRY Humans are primates Slide 77 The Evolution of Primates Primate evolution Slide 78 Primates Early primates

27 Slide 79 The distinguishing characteristics of primates were shaped by the demands of living in trees Slide 80 Primate characteristics include Figure Slide 81 Taxonomists divide primates into two main groups

28 Slide 82 Prosimians include Figure 17.40a Slide 83 Anthropoids include Figure 17.40b, c Slide 84 Apes, the closest relatives to humans Figure 17.40d g

29 Slide 85 Humans Figure 17.40h Slide 86 The Emergence of Humankind Humans and apes have shared a common ancestry for all but the last 5 7 million years Slide 87 Anthropoids Prosimians Humans Gorillas Gibbons Orangutans Old World monkeys New World monkeys Prosimians (lemurs, lorises, pottos, and tarsiers) Ancestral primate Chimpanzees Apes Monkeys Figure 17.41

30 Slide 88 Some Common Misconceptions Our ancestors were not chimpanzees or any other modern apes Chimpanzees and humans represent two divergent branches of the anthropoid tree Slide 89 Human evolution Slide 90 Homo sapiens Homo sapiens sapiens neanderthalensis Homo erectus Australopithecus boisei Australopithecus robustus Homo habilis Australopithecus africanus Ardipithecus ramidus Australopithecus afarensis Figure 17.42

31 Slide 91 Upright posture and an enlarged brain appeared at separate times during human evolution Slide 92 Australopithecus and the Antiquity of Bipedalism Before there was the genus Homo, several hominid species of the genus Australopithecus walked the African savanna Slide 93 Fossil evidence pushes bipedalism in A. afarensis back to at least 4 million years ago Figure 17.43

32 Slide 94 All Australopithecus species were extinct by about 1.4 million years Slide 95 Homo habilis and the Evolution of Inventive Minds Homo habilis, handy-man Slide 96 Homo erectus and the Global Diversity of Humanity Homo erectus was the first species to extend humanity s range from Africa to other continents The global dispersal began about 1.8 million years ago

33 Slide 97 Homo erectus Slide 98 The Origin of Homo sapiens The oldest known post H. erectus fossils Slide 99 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

34 Slide 100 Two hypotheses regarding the origins of modern humans exist Slide 101 The multiregional hypothesis Slide 102 Homo sapiens African European Asian Australasian Interbreeding 1 2 million years ago (a) Multiregional hypothesis Homo erectus in Africa Figure 17.44a

35 Slide 103 The Out of Africa hypothesis Slide 104 Homo sapiens African European Asian Australasian 100,000 years ago Homo sapiens in Africa (b) Out of Africa hypothesis Homo erectusin Africa Slide 105 Cultural Evolution Culture Figure 17.44b

36 Slide 106 Cultural evolution has had three major stages Slide 107 First, nomads who were hunter-gatherers Figure Slide 108 Second, the development of agriculture Third, the Industrial Revolution

37 Slide 109 EVOLUTION CONNECTION: EARTH S NEW CRISIS Cultural evolution Humans are changing the world faster than many species can adapt Slide 110 This rapid rate of extinction is mainly a result of habitat destruction The exploding human population now threatens Earth s ecosystems

38 Chapter 17 Study Objectives 1. Explain why cane toads were introduced into Australia and the resulting consequences. 2. Define animal, and describe common aspects of animal development. 3. Describe the significance of the Cambrian explosion. Describe two hypotheses that attempt to explain this phenomenon. 4. Distinguish among the nine major animal phyla according to the presence or type of tissues, body symmetry, and body cavities. 5. Describe the body structure of sponges, cnidarians, flatworms, and roundworms, and explain how each group feeds. 6. Describe two roundworm traits that were not found in previous animal phyla. 7. Describe the structure and function of the three parts of a mollusk body. Distinguish among gastropods, bivalves, and cephalopods, and provide examples of each. 8. Describe the general structure of annelids. Distinguish among earthworms, polychaetes, and leeches, and provide examples of each. 9. Describe the general structure of arthropods, and discuss the advantages and disadvantages of an exoskeleton. Also distinguish among arachnids, crustaceans, millipedes, centipedes, and insects, and provide examples of each. 10. Describe the general structure of echinoderms, and explain the significance of the water vascular system. 11. Describe the four characteristics of the phylum chordate. 12. Distinguish among the following aquatic groups: agnathans, Chondrichthyes, ray-finned fishes, lungfishes, and lobe-finned fishes. Describe the significance of the swim bladder. 13. Describe the dual life of amphibians. 14. Describe the adaptations of reptiles to living on land. 15. Describe three adaptations for flight found in birds. Compare birds to reptiles, noting their similarities and differences. 16. Distinguish among monotremes, marsupials, and eutherian mammals, and provide examples of each. Describe the characteristics common to all mammals. 17. Describe the primate adaptations for living in trees. Compare the prosimians and anthropoids, providing examples of each. 18. Compare the multiregional and monogenesis models of human evolution. Describe the traits of each of the following groups: Australopithecus afarensis, Homo habalis, Neanderthals, Homo erectus, and Homo sapiens. 19. Explain how modern humans are impacting the biological world.