Animal Evolution The Invertebrates. Chapter 25 Part 3

Transcription

1 Animal Evolution The Invertebrates Chapter 25 Part 3

2 25.11 Roundworms Unsegmented Worms That Molt Roundworms (phylum Nematoda) are unsegmented, pseudocoelomate worms with a secreted cuticle that is molted Most are decomposers, some are parasites Parasitic roundworms include Trichinella, Ascaris, hookworms, Wuchereria, and pinworms

3 Roundworm Body Plan

4 pharynx intestine eggs in uterus gonad false coelom (unlined body cavity) muscular body wall anus Fig a, p. 420

5 Animation: Roundworm body plan

6 Roundworms

7 25.12 Arthropods Animals With Jointed Legs Arthropods (phylum Arthropoda) are the most diverse animal phylum with more than a million species Trilobites are an extinct group Modern arthropods include horseshoe crabs, spiders, ticks, crabs, lobsters, centipedes, and insects

8 Living Arthropod Subgroups

9 Key Arthropod Adaptations A hardened exoskeleton (cuticle) Hormones control molting Jointed appendages for movement Some legs are modified for special tasks Highly modified segments Example: wings

10 Key Arthropod Adaptations Sensory specializations Compound eyes Antennae that detect touch and chemicals Specialized developmental stages Body plans may change by metamorphosis Example: Caterpillar and butterfly

11 Key Arthropod Adaptations

12 Fig a, p. 421

13 Fig b, p. 421

14 Fig c, p. 421

15 Fig d, p. 421

16 25.13 Chelicerates Spiders and Their Relatives Chelicerates are arthropods without antennae Marine chelicerates include the oldest living arthropod lineage (horseshoe crabs) All land chelicerates are arachnids, including spiders, scorpions, ticks, and mites

17 Chelicerates

18 telson Fig a, p. 422

19 telson (with stinger) pedipalp cephalothorax abdomen Fig b, p. 422

20 Fig c, p. 422

21 Fig d, p. 422

22 Fig e, p. 422

23 Fig f, p. 422

24 Chelicerates: The Spiders Spiders bite with fanglike chelicerae that deliver venom from poison glands Paired spinners in the abdomen eject silk Open circulatory system mingles blood with tissue fluids; Malpighian tubules move excess water and wastes to gut for disposal

25 Body Plan of a Spider

26 digestive gland eye brain heart Malpighian tubules poison gland anus pedipalp chelicera mouth book lung ovary spinners sperm receptacle silk gland Fig , p. 422

27 25.14 The Mostly Marine Crustaceans Crustaceans are mostly marine arthropods with two pairs of antennae Small crustaceans include krill, copepods, and barnacles Decapod crustaceans include lobsters, crayfish, crabs and shrimps

28 Crustaceans

29 Fig a, p. 423

30 Fig b, p. 423

31 Fig c, p. 423

32 Fig d, p. 423

33 Body Plan of a Lobster

34 abdomen segments cephalothorax (fused segments) eyes (two) antennae (two pairs) food-handling appendages (three pairs) tail fan swimmerets first leg walking legs (five pairs) Fig , p. 423

35 Crab Life Cycle

36 juvenile adult female egg larva Fig , p. 423

37 juvenile adult female egg larva Stepped Art Fig , p. 423

38 Animation: Crab life cycle

39 25.15 Myriapods Lots of Legs Myriapods ( many feet ) are arthropods with two antennae and many body segments Centipedes are predators Millipedes are scavengers

40 Myriapods Centipede and millipede

41 25.16 The Insects Insects have a three-part body plan The head has compound eyes, a pair of antennae, and specialized mouthparts The thorax has three pairs of legs; some lineages have wings Malpighian tubules in the abdomen eliminate wastes and save water

42 Insect Body Plan: Bedbug

43 abdomen thorax with six legs head with two eyes, and two antennae Fig , p. 424

44 Specialized Mouthparts

45 liplike antenna labrum compound eye mandible maxilla a maxilla liplike labrum palps c b labium d Fig , p. 425

46 Animation: Insect head parts

47 Insects Arthropods are the most successful animals, and insects are the most successful arthropods Insects are adapted to life on land; a system of tracheal tubes delivers air to their tissues Development may be direct, or through incomplete or complete metamorphosis

48 Insect Development

49 a Direct development: Growth in size between molts but no change in body form egg young adult b Incomplete metamorphosis: gradual change with each molt until the nymph becomes adult egg nymphs adult c Complete metamorphosis: larvae grow, then molt into a pupa, which is remodeled into the adult form egg larvae pupa adult Fig , p. 425

50 25.17 Insect Diversity and Importance It would be hard to overestimate the importance of insects, for either good or ill Insects help provide us with food crops, are food for animals, and help dispose of wastes The four most diverse groups of insects all include pollinators of flowering plants A few insects eat our crops or carry pathogens

51 Insect Diversity

52 Fig a, p. 427

53 Fig b, p. 427

54 Fig c, p. 427

55 Fig d, p. 427

56 Fig e, p. 427

57 Fig f, p. 427

58 Fig g, p. 427

59 Fig h, p. 427

60 Fig i, p. 427

61 Fig j, p. 427

62 Fig k, p. 427

63 Fig l, p. 427

64 Key Concepts The Major Invertebrate Lineages One major lineage of animals with tissues includes the flatworms, annelids, mollusks, nematodes, and arthropods All are bilaterally symmetrical The arthropods, which include the insects, are the most diverse of all animal groups

65 The Protostome-Deuterostome Split So far, all of the animals with a three-layered embryo from flatworms to arthropods have been protostomes All of the following animals from echinoderms to vertebrates are deuterostomes

66 25.18 The Spiny-Skinned Echinoderms Echinoderms (phylum Echinodermata) have spiny skins embedded with interlocking spines and plates of calcium carbonate They begin life as bilateral larvae and develop into spiny-skinned, radial adults They are brainless and have a unique watervascular system for locomotion

67 Echinoderm Body Plan: Sea Star

68 upper stomach gonad anus spine lower stomach coelom digestive gland eyespot ampulla of a tube foot canal of watervascular system a spine ossicle (tiny skeletal structure) tube feet c Fig , p. 428

69 Animation: Body plan of a sea star

70 Echinoderm Diversity Echinoderms include about 6,000 marine invertebrates such as sea stars, brittle stars, sea urchins, and sea cucumbers Echinoderms can regenerate lost body parts; any portion of a sea star with some of the central disc can regrow missing parts

71 Echinoderms

72 25.18 Key Concepts On the Road to Vertebrates Echinoderms are on the same branch of the animal family tree as the vertebrates They are invertebrates with bilateral ancestors, but adults now have a decidedly radial body plan

73 Animation: Chelicerates

74 Animation: Crustaceans

75 Animation: Insect development

76 Video: Old genes, new drugs

77 Video: Water vascular system

78 Video: Rotifers

79 Video: Beetle

80 Video: Brittle star

81 Video: Giant clam, octopus

82 Video: Nudibranch

83 Video: Otter eating

84 Video: Sea anemones