Inquiry into Life Eleventh Edition Sylvia S Mader

Inquiry into Life Eleventh Edition Sylvia S. Mader Chapter 30 Lecture Outline Prepared by: Wendy Vermillion Columbus State Community College 1 Copyright The Mc. Graw-Hill Companies, Inc. Permission required for reproduction or display.

30. 1 Evolutionary trends among animals • Overview – – – Heterotrophic, acquire food by ingestion Locomotion by means of muscles Multicellular, high degree of cell specialization Adult is diploid Reproduction usually sexual, with embryo undergoing developmental stages • Invertebrates- lack an endoskeleton of bone or cartilage – All but one animal phylum are invertebrates • Vertebrates- have an endoskeleton of bone or cartilage 2

Animal diversity • Fig. 30. 1 3

Evolutionary trends among animals cont’d. • Level of organization – Cellular- no true tissues; sponges – Tissue- cnidarians – Organ- majority of animals • Type of body plan – Sac-plan- incomplete digestive system; cnidarians – Tube-within-a-tube plan-inner tube is digestive system, outer tube is body wall; 4

Evolutionary trends among animals cont’d. • Type of symmetry – Asymmetrical-no particular symmetry – Radial symmetry-circular organization, can be bisected in any plane to produce mirror images – Bilateral symmetry-has definite right and left halves; only a cut down the midline will produce mirror images 5

Evolutionary trends among animals cont’d. • Segmentation – – Repetition of body parts Molluscs and echinoderms are unsegmented Annelids, arthropods, and chordates are segmented Leads to cephalization and specialization of body parts • Jointed appendages – Specialized for locomotion – In arthropods, may be adapted as mouth parts 6

Evolutionary tree • Fig. 30. 2 7

General characteristics of animal phyla • Table 30. 1 8

30. 2 Introducing the invertebrates • Sponges: Phylum Porifera – Multicellular; body a loose aggregate of cells – All aquatic, mostly marine – Body with pores (ostia), canals, and chambers for circulation of water • Epidermis of flat cells, some with contractile fibers • Middle layer is semi-fluid • Inner layer of choanocytes-flagellated to move water – Filter feeders- intracellular digestion • Cells get food from circulating water – Classified based on skeleton-composed of spicules • Chalk sponges-spicules of calcium carbonate • Glass sponges-spicules of silica • Proteinaceous sponges- spongin fibers – Reproduction-asexual by budding, sexual by fusion of gametes 9

Sponge • Fig. 30. 3 10

Evolutionary trends among animals cont’d. • Cnidarians: Phylum Cnidaria – – Multicellular, tubular or bell-shaped animals-radial symmetry All aquatic, mostly marine Cnidocytes-stinging cells unique to cnidarians 2 body types-polyps and medusae • Life cycle alternates between both forms in some; in others one form is reduced or absent – Includes corals, jellyfish, and hydrozoans • Corals- polyps • Jellyfish-medusae • Hydrozoans-may have both forms 11

Cnidarian diversity • Fig. 30. 4 12

Evolutionary trends among animals cont’d. • Cnidarians cont’d. – Hydra – a representative cnidarian (Class Hydrozoa) • Freshwater, attaches to rocks, leaf litter • Small tubular polyp, sac-like body plan with a single opening – Digestion begins in gastrovascular cavity, completed in cells • Can reproduce sexually and asexually (budding) 13

Anatomy of Hydra • Fig. 30. 5 14

Evolutionary trends among animals cont’d. • Flatworms- Phylum Platyhelminthes – Bilateral symmetry, – Muscles, excretory, reproductive, and digestive systems in some • Respiration by diffusion and circulation – Planarians-free-living flatworms (Class Turbellaria) • Live in freshwater, feed on small living and dead organisms • Flame cells- excretion • Ladder-like nervous system- anterior ganglia and eyespots • 3 muscle layers- circular, longitudinal, and diagonal-more complex movements • Cephalization-has an anterior end a posterior end • hermaphroditic 15

Planarian • Fig. 30. 6 16

Evolutionary trends among animals cont’d. • Flatworms cont’d. – Parasitic flatworms-two classes: tapeworms (Cestoda) and flukes (Trematoda) • Tapeworms-internal parasites as adults – Scolex-has hooks for attachment; not a sucker – Body of segments called proglottids » Organs of both sexes in each proglottid » Fertilization is internal- proglottids filled with fertilized eggs are called gravid » Gravid proglottids drop off and pass out in feces 17

Life cycle of a tapeworm, Taenia • Fig. 30. 7 18

Evolutionary trends among animals cont’d. • Parasitic flatworms cont’d. – Flukes • Body covered by a tough tegument • 2 suckers- an oral sucker and another located more posteriorly on the body 19

Evolutionary trends among animals cont’d. • Parasitic roundworms – Ascaris • • Move with whip-like motion Intestinal parasites in many animal species Females are much longer than males and highly prolific Eggs enter host in uncooked vegetables, soil, or feces – Larvae burrow out of intestine and migrate to heart and lungs – Larvae are coughed up and swallowed – Mature to adults in intestines 20

Roundworm anatomy • Fig. 30. 9 21

Evolutionary trends among animals cont’d. • Other roundworms – Trichinella spiralis- the trichina worm • Causes trichinosis • Humans contract the worm by eating undercooked pork • Larvae migrate out of intestines and form painful cysts in the muscles – Wuchereria bancrofti-a filarial worm that causes elephantiasis • Migrates into lymphatic vessels and prevents lymph drainage • Edema occurs – Pinworms and hookworms • Roundworm parasites which cause problems in children • Much more common in U. S. • Pinworms are primarily an annoyance, while hookworks cause skin irritations and in some cases debilitating disease 22

Elephantiasis 23

30. 3 Molluscs: coelomates • Molluscs are a large and diverse group – 3 body parts • Visceral mass-includes most organs • Foot-muscular portion used for locomotion • Mantle-covering that envelopes visceral mass – Mantle may secrete a shell – Radula-rasping organ for feeding 24

Diversity of molluscs • Fig. 30. 10 25

Molluscs: • Gastropods-snails, conchs, nudibranchs – Foot is flattened ventrally – Nudibranchs-sea slugs, lack shell – Conchs, snails have a shell • Protection, prevents dessication in land snails – Aquatic gastropods have gills, terrestrial gastropods-mantle has lung-like function • Cephalopods-squid, octopus, chambered nautilus – – Foot forms tentacles Powerful beak and radula for feeding Extremely well-developed eyes; complex behaviors Ink glands- secrete “ink”as defense mechanism 26

Gastropod and cephalopod anatomy • Fig. 30. 11 27

Molluscs: • Bivalves-clams, oysters, scallops – Two-part shells (valves) – Filter-feeders- water enters through incurrent siphon • Sexes separate 28

30. 4 Annelids: segmented worms • Annelids – Segmented worms • Tube-within-a-tube body plan-segmentation allows specialization of systems – Pharynx, esophagus, crop, gizzard, intestine, accessory glands – Closed circulatory system with pumping hearts – Nervous system consists of brain, ventral nerve cord, and ganglia in each segment – Excretory system consists of nephridia in most segments 29

Annelids: segmented worms cont’d. • Marine worms – Class Polychaeta- largest class – Have setae-bristles for anchoring worm or helping in locomotion • Arranged in bundles on parapodia – Swimming, gas exchange – Tube worms • Tentacles that form a funnel-shaped fan • Sessile filter feeders 30

Polychaete diversity • Fig. 30. 13 31

Annelids: segmented worms cont’d. • Earthworms-Class Oligochaeta – Gas exchange across body wall – Feed on leaves and other organic matter • Food is drawn into mouth by muscular movements 32

Earthworm, Lumbricus • Fig. 30. 14 33

Annelids: segmented worms cont’d. • Segmentation in earthworms – External segmentation evident by body rings – Internal segmentation by septa – Paired nephridia in each segment 34

Annelids: segmented worms cont’d. • Leeches- Class Hirudinea – Most live in freshwater – Most are ectoparasites- have suckers for feeding • Saliva contains hirudin-anticoagulant 35

30. 5 Arthropod diversity • Arthropods- Phylum Arthropoda – Jointed appendages • Walking, swimming, reproduction, eating, sensory reception – Exoskeleton of chitin • Must undergo molting to allow growth – 3 body regions • Head, thorax, abdomen – Well-developed nervous system • Brain • Sense organs-compound eyes, antennae 36

Arthropod diversity • Fig. 30. 15 37

Arthropod diversity cont’d. • Crustaceans- Subphylum Crustacea – Barnacles, shrimps, lobsters, crabs, crayfish, sowbug – Generalized structure-fused cephalothorax • Head has compound eyes and 5 pairs of apendages – First 2 pairs are antennae – Other 3 pair are mouth parts • Thorax has 5 pair of appendages-walking legs – Gills are situated above the walking legs • Abdomen- has swimmerets – Last 2 segments have uropods and telson 38

Arthropod diversity cont’d. • Crayfish cont’d. – Internal organs • Vascular system-heart pumps blood with hemocyanin – Hemocyanin has blue pigment – Hemolymph flows around organs • Sexes separate- sperm transfer by first pair of swimmerets – Ovaries open at base of third walking legs – After fertilization, eggs attach to swimmerets of female 39

Male crayfish, Cambarus • Fig. 30. 16 40

Arthropod diversity cont’d. • Insects- Subphylum Uniramia – Largest and most diverse group – General structure • Head-a pair of compound eyes, several simple eyes, a pair of antennae, mouthparts adapted to specific way of life • Thorax- 3 pairs of legs and wings if present • Abdomen-contains internal organs – Grasshopper • • 3 rd pair of legs is adapted for jumping 2 pairs of wings Tympanum on side of first segment of abdomen Ovipositor of females- for digging a hole to lay eggs in 41

Arthropod diversity cont’d. • Grasshopper cont’d. – Internal organs • Excretory system-Malpighian tubules – Uric acid-nitrogenous waste • Respiratory system-spiracles lead into trachae – Air pumped by contraction and relaxation of body wall 42

Arthropod diversity cont’d. • Grasshopper cont’d. – Reproduction-adapted to terrestrial life • • Male has a penis which is inserted into female Female has seminal receptacles which store sperm Internal fertilization protects zygotes and gametes from drying Female deposits fertilized eggs into ground – Metamorphosis-change in form and physiology that occurs as a larva becomes and adult • Immature grasshopper- nymph 43

Female grasshoppers • Fig. 30. 18 44

Arthropod diversity cont’d. • Arachnids- Subphylum Chelicerata – Spiders, ticks, scorpions, mites – Cephalothorax has 6 pairs of appendages • Chelicerae, pedipalps, and 4 pairs of walking legs – Abdomen contains internal organs – Ticks and mites are ectoparasites – Spiders- narrow waste separates cephalothorax from abdomen • Chelicerae have fangs that deliver poison to prey • Pedipalps sense and hold prey • Digestive juices from mouth are released into prey and digestion begins; digested “broth” then is sucked into stomach • Silk glands for web-spinning 45

Arachnid diversity • Fig. 30. 19 46