Animal APBio

Slide 1: Chapter 22 The Animal Kingdom

Slide 2: Chapter 22 2 What Is an Animal? Multicellular heterotrophs Lack a cell wall Motile during some stage in life Able to respond rapidly to external stimuli Able to reproduce sexually

Slide 3: Chapter 22 3 Animal Evolution Most animal phyla currently populating the Earth were present by the Cambrian period (544 million years ago) The scarcity of pre-Cambrian fossils led systematists to search for clues about the evolutionary history of animals by examining features of • Anatomy • Embryological development • DNA sequences

Slide 4: Chapter 22 4 Animal Evolution Certain features represent evolutionary milestones • The appearance of tissues • The appearance of body symmetry • Protostome and deuterostome development These features mark major branching points on the animal evolutionary tree

Slide 5: Chapter 22 5 The Appearance of Body Symmetry Symmetrical animals have an upper (dorsal) surface and a lower (ventral) surface Animals with tissues exhibit either radial or bilateral symmetry Animals with radial symmetry can be divided into roughly equal halves by any plane that passes through the central axis

Slide 6: Chapter 22 6 Body Symmetry and Cephalization (a) Radial Central Axis A Radial Plane Sagittal Plane Symmetry Anterior (b) Bilateral Posterior Another Radial Plane Symmetry

Slide 7: Chapter 22 7 Body Cavities Acoelomate animals lack a body cavity • e.g. flatworms

Slide 8: Body Cavities: Chapter 22 8 The Acoelomates No cavity between Cnidaria body wall & digestive tract Digestive Cavity Digestive Lining Solid Tissue Body Wall

Slide 9: Chapter 22 9 Body Cavities Pseudocoelomate animals possess a pseudocoelom (a fluid-filled body cavity that is not completely lined with mesoderm) • e.g. nematodes (roundworms)

Slide 10: Body Cavities: Chapter 22 10 The Pseudocoelomates Body cavity Nematoda partially lined with mesoderm Digestive Cavity Digestive Tract Pseudocoelom Partial Lining Body Wall

Slide 11: Chapter 22 11 Body Cavities Coelomate animals possess a coelom (a fluid-filled body cavity that is completely lined with mesoderm) • e.g. annelids, arthropods, mollusks, echinoderms, chordates

Slide 12: Body Cavities: Chapter 22 12 The True Coelomates Body cavity Annelida completely lined with mesoderm Digestive Cavity Digestive Tract Coelom Complete Lining Body Wall

Slide 13: Chapter 22 13 Embryological Development Bilateral animals can be divided into two main groups based on embryological development Protostomes • Body cavity forms within a space between the body wall and the digestive cavity • e.g. nematodes, arthropods, flatworms, annelids, mollusks Deuterostomes • Body cavity forms as an outgrowth of the digestive cavity • e.g. echinoderms, chordates

Slide 14: 14 a tife es Chapter 22 elm ra Ma ata - rm no ali Mo da en ria Cn ra a An sca Ne r a tyh ho R o int h ct a lid mm r ife d e ch i to ida op llu ne ma se E Po In Ct P la Deuterostome development Protostome development Coelom No body Pseudocoel No true cavity Body cavity tissues 3 tissue layers; bilateral True symmetry tissues 2 tissue Evolutionary Tree layers; radial symmetry of Major Animal Phyla

Slide 15: The Invertebrate Phyla: Chapter 22 15 Porifera Phylum Porifera: the sponges • Simple single-celled organisms living together • Low specialization of cells; no tissue level • Asymmetrical ::::: Reproduce by budding Three major types of cells • Epithelial cells (cover outer body surface) – Some are modified into pore cells (regulate flow of water through pores) • Collar cells (flagellated cells that maintain water flow through the sponge) • Amoeboid cells (motile cells that digest and distribute nutrients, produce reproductive cells, and secrete spicules)

Slide 16: Epithelial Chapter 22 16 Cell Osculum Spicules Pore Amoeboid The Body Cells Water Flow Plan of Sponges Pore Cell Collar Cell

Slide 17: Chapter 22 17 The Invertebrate Phyla: Cnidaria Phylum Cnidaria: the hydra, anemones, & jellyfish – Radial symmetry • Cells organized into distinct tissues • Rudimentary nerve network and contractile tissue • No true organs • Two distinct body plans: – Polyp, attached – Medusa, free swimming • One digestive opening • Reproduce sexually and asexually

Slide 18: Cnidarian Body: Chapter 22 18 The Polyp Mouth Tentacle Body Wall Column Mesoglea Gastrovascular Lining Gastrovascular Cavity Foot

Slide 19: Cnidarian Body: Chapter 22 19 The Medusa Body Wall Mesoglea Gastrovascular Cavity Tentacle Gastrovascular Lining Mouth

Slide 20: Cnidarian Weaponry: Chapter 22 20 The Cnidocyte Trigger Filament Nuclei Water Armed Body Cnidocyte Spent Wall Cnidocyt

Slide 21: The Invertebrate Phyla: Chapter 22 21 Platyhelminthes The flatworms • Development of bilateral symmetry • Ability to move forward using aggregations of nerve cells, ganglia • True organs begin to evolve • Most are hermaphroditic (can self-fertilize) • Many are free living—planarians • Some are parasitic—tapeworm and fluke

Slide 22: Chapter 22 22 Flatworm Organ Systems (a) Digestive System Pharynx Gastrovascular Cavity Excretory Canal Excretory Pore (b1) Excretory System (b2) Nervous System Nerve Cord Brain

Slide 23: Egg-filled Human eats poorly Larval tapeworm Life Cycle Chapter 22 23 segments are pork with cooked Tapeworm matures in of liberated by digestion shed from worm human intestine, &live cysts.tohooks Head with human attaches producing a series of & passed in& suckers intestine. reproductive segments. human feces. migrate through Larvae Human vessels to pig muscles & Pork encyst there. Adult tapeworm Tapeworm Larvae hatch in pig intestine Measly pork marketed for Pig eats food human consumption. contaminated by infected feces

Slide 24: The Invertebrate Phyla: Chapter 22 24 Nematoda (Round Worms) Advanced gastrovascular cavity (are bilateral) • Tubular • Two openings Advanced sensory "ganglionic brain" Lack circulatory and respiratory systems Depend on diffusion for gas exchange Sexual reprouction Most are harmless - Some parasitic

Slide 25: Heartworms in the Chapter 22 25 Heart of a Dog Open heart of dog Female heartworms

Slide 26: The Invertebrate Phyla: Chapter 22 26 Annelida (Segmented Worms) Bilateral symm. Repeating rings identical nerve ganglia Excretory structures Advanced locomotion ability Fluid-filled body cavity—coelom; involved in locomotion (hydrostatic skeleton) Sexual Repro. Some hermaphrodites Closed circulatory system Evolved many rudimentary organ systems • Nervous, excretory, circulatory, muscular • Compartmentalized digestive tract

Slide 27: Coelom Intestine ChapterNephridia 22 27 Ventral An Annelid: Nerve Cord the Earthworm Excretory Pore Coelo Anus m Gizzard Ventral Brain Nerve Cord Ventral Mouth Pharynx Vessel Hearts Esophagus Crop Intestine

Slide 28: The Invertebrate Phyla: Chapter 22 28 Arthropoda The most numerous in numbers & species Evolutionary adaptations allow them to reside in diverse environments • Paired, Jointed legs • Exoskeleton for water conservation and support • Segmentation • Well-developed sensory and nervous systems • Efficient gas-exchange (gills, trachea, book lungs) • Well-developed (open) circulatory systems • Sense organs – compound eyes Reside in both aquatic and terrestrial habitats

Slide 29: Major Arthropod Classes: Chapter 22 29 Insecta 800,000 species Have three pairs of legs • Usually two pairs of wings • Make escape from predators easier Metamorphosis eliminates competition for food between generations The importance of insects

Slide 30: Major Arthropod Classes: Chapter 22 30 Arachnida 50,000 species • Spiders • Mites • Ticks • Scorpions Eight walking legs Carnivorous Simple eyes with a single lens

Slide 31: Major Arthropod Classes: Chapter 22 31 Crustacea 30,000 aquatic species • Crabs • Crayfish • Lobster • Shrimp • Barnacles Size varies from microscopic to 12 feet (3.7 m) Vary in number of appendages Have two pairs of antennae Generally with compound eyes Exchange gases using gills

Slide 32: Chapter 22 32 Insect Body Plan Head Antennae Thorax Abdomen Compound Eyes Wing Mouth Parts

Slide 33: The Invertebrate Phyla: Chapter 22 33 Mollusca (Snails & Clams) Bilateral Symmetry Coelomate Moist muscular body without a skeleton Found in aquatic or moist terrestrial habitats Body protected by limy shell or obnoxious taste Complex, concentrated, ganglionic brain Open circulatory system Classes • Gastropoda—snails and sea slugs • Pelecypoda— scallops, oysters, mussels, & clams • Cephalopoda—octopuses, squid, nautiluses

Slide 34: Chapter 22 34 A Generalized Mollusk Tentacle Gonad Heart Coelom Ganglia Digestive Tract (brain) Eye Shell Mantle Anus Radula Gill Mouth Foot Nerve Cords

Slide 35: The Invertebrate Phyla: Chapter 22 35 Echinodermata (Sea Stars, Urchins) Bilateral as larvae – Radial as adult Deuterostome development Coelomate Possesses an endoskeleton of CaCO3 Lack a head and circulatory system Simple nervous system; no distinct brain Water-vascular system for slow movement Can regenerate lost parts

Slide 36: Water-Vascular Chapter 22 36 System of Echinoderms Sieve Plate Ampulla Canals Plates of Endoskeleton Photo (ventral) A Mussel (clam) Tube Feet

Slide 37: Chapter 22 37 Key Features of Chordates Notochord • Stiff flexible rod extending the length of the body Dorsal, hollow nerve cord • Expands anteriorly to form brain Pharyngeal gill slits • May form respiratory organs or may appear as grooves Post-anal tail • Extends past the anus

Slide 38: Chapter 22 38 Are Humans Chordates? Only one chordate characteristic, the nerve cord, is present in adult humans; however, human embryos exhibit all four… • Tail will disappear completely • Notochord is replaced by the backbone • Gill slits (grooves) contribute to the formation of the lower jaw

Slide 39: Chapter 22 39

Slide 40: The Vertebrates: Chapter 22 40 Chordata, Vertebrata Subphyla • Invertebrates—lancelets and tunicates – Lack a head and backbone – marine habitat • Vertebrates – Only 2.5% of extant animals – Backbone – Seven Major Classes

Slide 41: The Lancelet: Chapter 22 41 An Invertebrate Chordate Muscle Nerve Cord Notochord Segments Tail Gut Gill Slits Mouth Anus

Slide 42: The Tunicate: Chapter 22 42 An Invertebrate Chordate Brain Mouth Water Exit ADULT Gill Slits LARVA Heart Gut Nerve Cord Notochord

Slide 43: The Vertebrate Classes: Chapter 22 43 Agnatha & Chondrichthyes Agnatha—jawless fish • Skeleton of cartilage and eellike shape • Unpaired fins, lack scales • Slimy skin perforated by circular gill openings Chondrichthyes • “Cartilaginous fishes”—sharks, skates, & rays • Leathery skin • Respire by gills • Two-chamber heart

Slide 44: Chapter 22 44 A Hagfish

Slide 45: Chapter 22 45 Lobe-Finned Fishes Lungfish are found in freshwater habitats Have both gills and lungs Tend to live in stagnant waters low in oxygen Lungs allow them to supplement their supply of oxygen by breathing air directly

Slide 46: Chapter 22 46 Lobe-Finned Fishes Some species can survive even if the water dries up • Burrow into mud, Seal themselves in a mucous-lined chamber and breathe through lungs as metabolic rate slows, Resume underwater life when rains return and pool refills

Slide 48: The Vertebrate Classes: Chapter 22 48 Osteichthyes “Bony fishes” Varied forms Supplemental lungs for freshwater living Fleshy fins

Slide 49: The Vertebrate Classes: Chapter 22 49 Amphibia Bony support for the body Waterproofing for the skin and eggs Moist protection of respiratory membranes Development of adult lungs Cold Blooded --- External Fertilization Still need aquatic habitat for reproduction 3 chambered heart

Slide 50: Chapter 22 50 Amphibians Live a Double Life Include frogs, toads, and salamanders “Double life” of amphibians • Begin life adapted to aquatic environment (eg tadpoles have gills) • Mature into semiterrestrial adult with lungs

Slide 52: The Vertebrate Classes: Chapter 22 52 Reptilia Turtles, alligators, crocodiles, dinosaurs, birds Respire through Lungs Internal fertilization Shelled amniotic egg (encapsulates embryo in a liquid filled membrane, the amnion) Skeleton modified for better support and locomotion

Slide 53: Chapter 22 53 Birds Appeared in the fossil record about 150 million years ago Considered by modern systematists to be feathered reptiles • The earliest known bird, Archaeopteryx

Slide 55: Chapter 22 55 Birds Distinctive group of “reptiles” adapted for flight • Feathers (provide lift and control as well as insulation) • Hollow bones (reduce weight of skeleton) • Females have a single ovary • Shelled egg (frees female from carrying developing offspring) Maintain a constant body temperature (warm-blooded)

Slide 56: The Vertebrate Classes: Chapter 22 56 Mammalia Warm-blooded Four-chambered heart Fur for insulation and protection Legs for running fast to avoid predators Mammary glands to nurse live-born young Complex cerebral cortex—increased learning ability Includes • Egg-laying monotremes (platypus) • Marsupials (opossums, koalas, kangaroos) • Placental mammals (most other mammals)

Slide 57: Chapter 22 57 Mammals Appeared in the fossil record about 250 million years ago Did not diversify and dominate terrestrial habitats until the dinosaurs became extinct (65 million years ago)

Slide 58: Bats, Chapter 22 58 the Only Flying Mammals

Slide 59: Chapter 22 The End

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