Chapter 23: The Animal Kingdom

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1 Chapter 23: The Animal Kingdom Lecture Outline Enger, E. D., Ross, F. C., & Bailey, D. B. (2012). Concepts in biology (14th ed.). New York: McGraw- Hill

2 What is an animal? 23-2 Eukaryotic Multicellular Have specialized cells Many have sensory cells that detect changes in the environment. Lack cell walls Heterotrophic Most can move Most reproduce sexually

3 Variety of Animals See Figure

4 The Evolution of Animals 23-4 Early animals were all aquatic. The first animals were likely small organisms that floated/swam in the ocean or worms that lived on the ocean floor. These animals didn t need to Deal with rapid or extreme environmental changes Deal with dehydration Expend energy to keep cells in osmotic balance Terrestrial animals appeared relatively recently. Arthropods and vertebrates have been the most successful. 99.9% of all animals are invertebrates. Invertebrates lack a backbone. Vertebrates have a backbone.

5 Animal Evolution See Figure

6 Temperature Regulation Body temperature impacts the rate of metabolic activity. Poikilotherms Body temperature varies with environmental temperature Metabolic rate decreases as temperature decreases Also called ectotherms Regulate body temperature behaviorally (sunning, moving) Insects, worms, reptiles 23-6

7 Temperature Regulation Homeotherms Maintain a constant body temperature Body temperature usually higher than environmental temperature Have high metabolic rates Have higher energy needs than poikilotherms Also called endotherms 23-7

8 Regulating Body Temperature See Figure

9 Body Plans Animal bodies conform to a few basic body plans. 23-9

10 Symmetry Asymmetry No pattern to individual parts Only occurs in sponges Radial symmetry Body constructed across a central axis Dividing the body in any plane along that axis results in two identical parts These animals do not have a head Starfish, jellyfish Bilateral symmetry Both sides of a single plane are mirror images These animals have a head Move head-first (cephalization)

11 Radial and Bilateral Symmetry See Figure

12 Embryonic Cell Layers Animals differ in the number of cell layers of which they are composed. These layers are established and most easily seen in the embryonic stage. Sponges have no body layers. Diploblastic Two body layers Endoderm Gives rise to inner hollow layer involved in processing food Ectoderm Jellyfish Gives rise to outer protective layer

13 Embryonic Cell Layers Triploblastic Have three layers Endoderm Gives rise to lining of digestive tract Mesoderm Gives rise to muscles and connective tissue Ectoderm Gives rise to skin and nervous system All other major groups are triploblastic

14 Embryonic Cell Layers See Figure

15 Body Cavities Many animals have a body cavity that separates the outer body wall from the gut. Called a coelom Acoelomate Contain no body cavity Sponges, jellyfish, and flatworms Pseudocoelomate Located between the lining of the gut and the outer body wall Nematodes 23-15

16 Body Cavities Coelomate This is the cavity that contains the digestive, excretory, and circulatory organs. Organs are held in place by sheets of connective tissue called mesenteries. The presence of the coelom allows for separation of inner organs and body-wall muscles. This allows the organ systems to be more specialized

17 Body Cavities See Figure

18 Segmentation Segmented animals have bodies that are separated into several units. These units run along the anterior to posterior axis of the animal. Associated with specialization of body parts Annelids, arthropods, and chordates Annelid segments are all very similar. Arthropods have specialized head segments. Posterior segments have legs and appendages. Chordate segments are most obvious in the vertebral column and musculature.

19 Segmentation See Figure

20 Skeletons Skeletons are body parts that provide support. Serves as a scaffolding for the attachment of organs Provides a place for muscles to attach Most important in terrestrial animals 23-20

21 Skeletons Types of skeleton Endoskeleton internal Vertebrates Grows as the animal grows Exoskeleton external Arthropods Hard and jointed Shed and regenerated as animal grows Water skeletons Fluid-filled coeloms Compressed by muscles to facilitate movement

22 Skeletons See Figure

23 Marine Lifestyles: Zooplankton A mixture of different kinds of small animals Drift with currents Feed on phytoplankton and other zooplankton 70% are crustaceans Copepods, krill, etc

24 Marine Lifestyles: Nekton Includes many kinds of aquatic animals that can swim against the current Go where they want to Carnivores Feed on plankton or other nekton Jellyfish, squid, cuttlefish, shrimp, sharks, bony fish, turtles, sea snakes, aquatic birds, and mammals 23-24

25 Marine Lifestyles: Benthic Animals Bottom-dwelling animals Includes Segmented worms, clams, snails, lobsters, crabs, shrimp, starfish, sea urchins, several kinds of fish Two types Those that move to find food Filter feeders Attached to objects Are sessile Create currents with cilia or use appendages to draw food to them

26 Marine Lifestyles: Benthic animals Reproduction is difficult for sessile animals because they cannot move. Sperm swim to the eggs. Fertilized egg develops into mobile larva Enables sessile animals to disperse Uses a different source of food from adults to minimize competition 23-26

27 The Life Cycle of an Oyster See Figure

28 Primitive Marine Animals: Porifera Similar to colonial protozoa Have two layers of cells All cells come in contact with the environment. Each individual cell gets its nutrition directly from the water. Adults are sessile (non-motile). Most are asymmetrical. Have spicules in a jelly-like material Spicules are made of calcium carbonate, silicon dioxide, or protein. Reproduce asexually by fragmentation or budding Reproduce sexually by external fertilization Sperm and egg unite in the water Fertilized egg develops into free-swimming ciliated larva 23-28

29 Sponge Structure and Function See Figure

30 Primitive Marine Animals: Cnidaria Jellyfish, corals, and sea anemones Have two layers of cells Jelly-like material in between cell layers Show radial symmetry Have a single opening that leads to digestive cavity Opening surrounded by tentacles Contain specialized cells called nematocytes that can sting and paralyze The cells that produce nematocytes are called cnidocytes.

31 Phylum Cnidaria See Figure

32 Cnidaria Exhibit alternation of generations Have both sexual and asexual reproduction Medusa is the freeswimming adult stage that reproduces sexually. Polyp is a sessile larval stage that reproduces asexually. See Figure

33 Ctenophora: The Comb Jellies See figure

34 Platyhelminthes Also called flatworms Bilaterally symmetrical Triploblastic Lack a coelom Have one opening to the gut Have no circulatory or respiratory systems Their flat body allows for the diffusion of gases between environment and all cells

35 Platyhelminthes Three basic types Free-living flatworms (planarians) Bottom-dwellers in aquatic environments Some live in moist terrestrial habitats Carnivores or scavengers that feed on dead organisms Flukes Parasitic Tapeworms Parasitic 23-35

36 Platyhelminthes See figure

37 Flukes All are parasites (some external, most internal). Life cycles usually involve a vertebrate and invertebrate host. Example: Schistosoma mansoni 23-37

38 Life Cycle of Schistosoma mansoni See figure

39 Tapeworms All are parasites. Life cycles involve two hosts an herbivore and a carnivore (both vertebrates)

40 Life Cycle of a Tapeworm See figure

41 Nematoda Also called roundworms Unsegmented Have an outer epidermis covered by a thick, flexible cuticle Triploblastic Have a pseudocoelom Digestive tract is open at two ends Mouth at one end, anus at the other Live in diverse habitats Water, soil, as parasites Examples of parasitic forms Pinworms, heartworms, hookworms

42 Nematode Worms See Figure

43 The Life Cycle of a Hookworm See Figure

44 Annelida Segmented worms Bilaterally symmetrical Have bodies with repeating segments Most segments are similar to one another. Segments containing head, reproductive, and digestive structures are specialized. Each segment has a coelom. Have well-developed muscular, circulatory, digestive, excretory, and nervous systems 23-44

45 Annelida See figure

46 Types of Annelida Polychates Primarily benthic, marine worms Have paddle-like appendages on each segment Have heads with sense organs and a mouth Are filter feeders Have separate sexes that reproduce sexually Produce larva called trochophores 23-46

47 Types of Annelida Oligochates Live in soil or freshwater Earthworms Do not have appendages or a well-defined head Are hermaphroditic Eat dead organic matter, generate air spaces in soil 23-47

48 Types of Annelida Leeches Live in freshwater or moist terrestrial environments Have suckers that allow them to hold on to objects Feed on the blood of vertebrates 23-48

49 Annelids See Figure

50 Mollusca Live in marine, freshwater, or terrestrial environments Majority live in the ocean Have a coelom Reproduce sexually Some are hemaphroditic Have a soft body enclosed by a hard shell 23-50

51 Mollusca Most are slow moving, benthic animals Most are herbivores or saprophytes Have free-living larval forms that aid in dispersal Have three body regions Mantle, foot, and visceral mass Visceral mass contains digestive, circulatory, and reproductive organs. Most have a radula with teeth. Used to scrape surfaces for food 23-51

52 Mollusca See figure

53 Types of Mollusca Chitons Have a series of shells on their backs Live attached to rocks Feed on algae Bivalves Have two shells Filter feeders without a radula Snails Have coiled shells Slugs are snails without shells Octopus and squid No outer shell

54 Types of Mollusca See figure

55 Arthropoda Most successful types of animals Have exoskeletons made of chitin Must shed to grow Have segmented bodies Segments are highly modified. Most segments have paired appendages. Body and appendages are segmented. Have well-developed nervous, muscular, digestive, respiratory, circulatory, and reproductive systems 23-55

56 Arthropoda See figure

57 Types of Arthropods Crustaceans All aquatic Omnivores Millipedes and centipedes Long bodies with many legs Arachnids Spiders, mites, and ticks Insects Have a head, thorax, and abdomen Have 3 pairs of legs Most have wings

58 Arthropods See Figure

59 Echinodermata Are dueterostomates Anus develops before mouth All are marine, benthic animals Most are free-living Most are carnivores or detrivores 23-59

60 Echinodermata Display radial symmetry Have five arms that project from a central axis Larva display bilateral symmetry. Have a water vascular system Water is taken through a pore on the top, then moves through a series of canals. Aids in movement of the animal Have a hard, jointed internal skeleton 23-60

61 Echinoderms See Figure

62 Types of Echinoderms Starfish Some are carnivores that eat clams Sea cucumbers Sausage-shaped organisms Lie on the bottom or burrow in mud Some are detrivores, others are filter-feeders. Crinoids Sessile and stalked Have five arms Called sea lilies Filter feeders Brittlestars Sea urchins 23-62

63 Types of Echinoderms See figure

64 Chordata Have a hollow nerve cord down the back of the body Have a flexible rod just beneath the nerve cord Called the notochord Have a tail that extends beyond the anus Have a pharynx Most are vertebrates Notochord only present during embryonic stage 23-64

65 Invertebrate Chordates See Figure

66 Types of Aquatic Vertebrates: Fishes Hagfish and lampreys are the most primitive fish. Hagfish are marine scavengers. Lampreys are mainly marine (some freshwater). Adults suck blood from larger fish. See Figure

67 Types of Aquatic Vertebrates: Fishes Sharks and rays Have an internal skeleton made of cartilage Have no swim bladder, so must constantly swim or they sink Rays feed along bottom. Sharks are predatory. See Figure

68 Types of Aquatic Vertebrates: Fishes Bony fish Have skeletons composed of bones Have a swim bladder that controls their density Allows them to remain at a given depth without swimming See Figure

69 Adaptations to Terrestrial Life Animals that live on land have to overcome certain problems. A moist membrane for gas exchange Means of support and locomotion on land Methods to conserve water Means of reproduction and embryonic development that doesn t require water Methods to survive rapid and extreme climate changes 23-69

70 Terrestrial Arthropods Exoskeleton Waterproof, which reduces water loss Have an internal respiratory system Tracheal system of thinwalled tubes Provides a large surface area for gas-exchange Have small openings to the outside, reducing water loss See Figure

71 Terrestrial Arthropods Have Malpighian tubules Thin-walled tubes that surround the gut Allows for reabsorption of water Reproduce by internal fertilization Protects sperm and egg from drying out Can reproduce rapidly when conditions become favorable 23-71

72 The Life History of a Monarch Butterfly See Figure

73 Terrestrial Vertebrates Endoskeleton Provides support in the air Provides places for muscle attachment Allows for movement on land Appendages are necessary for movement on land

74 Amphibians Lungs Allow for the exchange of oxygen and carbon dioxide from the air Amphibians also breathe through their skin. Skin must remain moist External reproduction in water Frogs and salamanders 23-74

75 Amphibians See Figure

76 Reptiles Have internal lungs Have waterproof skin Have water-conserving kidneys Reproduce via internal fertilization Fertilized egg is encased in an amniotic egg Protects the young from dehydration and injury Young need water to develop. See Figure 23.34

77 Reptiles See Figure

78 Birds Skin, lungs, and kidneys reduce water loss Reproduction involves internal fertilization. Produces a shelled amniotic egg Are homeothermic and have feathers Have high metabolic rates Feathers insulate and enable flight. Must incubate eggs Flight allows Movement with less expenditure of energy Quick escape from predators Ability to cross barriers

79 Birds See Figure

80 Mammals Homeotherms High, constant body temperature High metabolic rate Have waterproof skin, water-conserving lungs and kidneys Have hair as insulation Provide milk to their young 23-80

81 Types of Mammals Monotremes Egg-laying mammals Young lap milk from mother s fur Marsupials Internal development of young Young complete development in mother s pouch In pouch, young drink milk from nipple Placental Internal development of young Stay in mother longer Embryo attached to uterus via a placenta Young are born in a more advanced stage Still rely on mother s milk

82 Mammals See Figure

Symmetry. Asymmetrical- no shape. Radial- same in half when cut any angle. Bilateral- having a distinct right and left side

Symmetry. Asymmetrical- no shape. Radial- same in half when cut any angle. Bilateral- having a distinct right and left side Symmetry Asymmetrical- no shape Radial- same in half when cut any angle Bilateral- having a distinct right and left side Invertebrates 95% of Animals No Backbone The simplest animals and they do not have