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Animal Kingdom

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Animal Kingdom ANIMAL KINGDOM Characteristics of Animals Heterotrophic Can’t make their own food Mobile Multicellular Diploid cells Sexual reproduction No cell wall Blastula Fertilized egg cell divides to form a hollow ball of cells Forms 3 layers – ectoderm, endoderm, mesoderm Tissues Group of cells with a common function Characteristics of Animals Body symmetry Asymmetrical – irregular in shape Ex: sponges Radial symmetry – body parts around a central axis Ex: sea anemone Bilateral symmetry – distinct right and left halves Characteristics of Animals Internal body cavity Coelom – fluid-filled space between the body wall and digestive tract Acoelomates – animal with no body cavity Pseudocoelomates – “false coelom” Located between mesoderm and endoderm Coelomates – body cavity located entirely in the mesoderm Kinds of Animals Divided into two groups Invertebrates Animals without a backbone Vertebrates Animals with a backbone Invertebrates Sponges Cnidarians Flatworms and Roundworms SPONGES Phylum – Porifera Asymmetrical body form Not organized into tissues and organs Ostia – openings in the body wall Where water enters the sponge Oscula – large openings Where water exits the sponge Sessile – attached to the sea bottom or a rock or coral reef and don’t move from that place Filter feeders Can reproduce sexually or asexually CNIDARIANS What kinds of animals are these??? Jellyfish, sea anemones 2 different body forms Medusa – free-floating, jellylike, often shaped like an umbrella Polyp – tubelike and usually attached to a rock or other object Cnidarians are organized into tissues Cnidarians are carnivores Flatworms Phylum – Platyhelminthes Bilateral symmetry Acoelomates and have tissues that are organized into organs Many are parasites Ex: tapeworms, flukes Roundworms Phylum: Nematoda Pseudocoelomates Serves as a simple circulatory and gas exchange system Simplest animals to have a one way digestive system Long cylindrical body Thick and flexible epidermis and cuticle Form protective cover and give worm its shape Layer of muscle extend the length of the body Pull against the cuticle and pseudocoelom Whip the body from side to side Annelids Segmented worms Coelomates Range in size from 1mm (.04 in) to 3 m (10 ft.) Divided into segments Each segment contains digestive, excretory, circulatory and motor organs Characteristics of Annelids Coelom Organ systems Closed circulatory system and excretory structures Primitive brain located at the anterior end Attached to a nerve cord that runs along the underside (ventral) of the worm’s body Bristles Setae – 1 pair of setae on each segment Provide traction as the worm crawls Parapodia – fleshy appendages Not present in all Annelids Earthworms Their waste enrich the soil and their tunneling allows air to penetrate the soil They have a hydrostatic skeleton Each segment has muscles that pull against the hydrostatic skeleton Circular muscles wrap around the segment Longitudinal muscles run the length of the segment When the circular muscles contract the segment becomes longer When the longitudinal muscles contract the segment bunches up To crawl they alternate the contractions of these muscles Mollusks Characteristics Body Cavity True Coelom Bilateral symmetry Three-part body plan Visceral mass – central section that contains the organs Mantle – heavy fold of tissue that forms the outer layer of the body Foot – muscular region used for locomotion Organ systems Shell Radula – tongue –like organ in the mouth Phylum Arthropods Insects, crustaceans, arachnids All have jointed appendages Coelomates Body segmentation Head Thorax – midbody region Abdomen Exoskeleton Made of chitin Tough but brittle Muscles attach to it and causes joints to bend Phylum Echinoderm Sea stars, sea urchins, sand dollars 4 Main characteristics Endoskeleton – made of ossicles, calcium-rich plates, most are covered with spines and skin Radial symmetry Water-vascular system – Functions in feeding and gas exchange Coelomic circulation and respiration – body cavity functions as a simple circulatory and respiratory system Vertebrates Animals with a backbone Phylum - Cordates Classes Agnatha Chondrichthyes Osteichthyes Amphibia Reptiles Aves Mammals Agnatha No jaws No paired fins Backbone provided a place for muscles to attach Marine Ex: Hagfish and Lamprey Chondrichthyes Ex: sharks and rays Skeleton made of cartilage Very light but strong skeleton Streamlined for speed in water Various fins to aide in swimming Gills for breathing Large jaws with very sharp teeth Allows for active hunting Osteichthyes Bony Fish Ex: Catfish, Redfish, etc. Skeleton is heavier and less flexible than chondrichthyes Have a swim bladder Gas filled organ to help float Amphibia Ex: Frogs, toads, salamanders Live on Land Legs Support body weight Allow movement Lungs Allow gas exchange without water Heart Pumps blood carrying oxygen to the body Walking on land requires more oxygen Live in moist areas Reptiles Ex: snakes and lizards Skin is almost watertight Very rough and scaly Lay eggs that have leathery coating Keeps moisture in Ectotherms – “coldblooded” Aves Birds – ex: cardinal, blue jay, mockingbird Endotherms “warmblooded” Feathers Hollow bones Keep skeleton light and able to fly Have beaks Help eat small meals of fruits seeds worms or insects Ex: Whales and bats Mammals Covered with hair Can lay eggs or give birth to live young Monotremes Ex: duckbill platypus and spiny anteaters Lay eggs Marsupials Young born at an immature stage and complete development in mother’s pouch Ex: kangaroos, opossums, koalas Placentals Young develop within the mother’s body by the placenta and born more developed Ex: dogs, cats, horses, sheep, gorillas, humans .
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