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1 INTRODUCTION TO ANIMALS •Most diverse kingdom in appearance •More than 1 million species! •Each phylum has its own typical body plan (arrangement) WHAT IS AN ANIMAL? •Animals: •are heterotrophic •are eukaryotic •are multicellular •lack cell walls •95% = invertebrates (do not have backbone) •5% = vertebrates (have a backbone) •Anatomy = the structure of the organism/organs what it is •Physiology = study of the functions of organs how it works •Homeostasis (balance) is maintained by internal feedback mechanisms •Ex: dog panting releases heat, you sweat to release heat FUNCTIONS OF ANIMALS •Feeding animals must obtain energy by eating •Examples of types of feeding: –Herbivore = eats plants –Carnivore = eats animals –Omnivore = eats plants and animals –Scavenger = eats dead organisms –Detritivore = feed on decaying organic material –Filter Feeders = aquatic animals that strain food from water –Parasite = lives in or on another organism (symbiotic relationship) •Respiration animals require oxygen •Take in O2 and give off CO2 •Lungs, gills, through skin, simple diffusion •Circulation animals must move necessary materials within their bodies •Very small animals rely on diffusion •Larger animals have circulatory system 2 •Excretion animals must expel waste •Primary waste product is ammonia Liquid waste •Response animals respond to a stimulus •Receptor cells = sound, light, external stimuli •Nerve cells = nervous system Movement •Most animals are motile (can move) •Muscles usually work with a skeleton •Reproduction animals must reproduce •Most reproduce sexually = genetic diversity •Many invertebrates can also reproduce asexually = to increase their numbers rapidly LEVELS OF ORGANIZATION •Cell Specialization and Levels of Organization: cells tissues organs organ systems EARLY DEVELOPMENT •Zygote = fertilized egg •Blastula = a hollow ball of cells •Blastopore = the blastula folds in creating this opening •Protostome = mouth is formed from blastopore •Deuterostome = anus is formed from blastopore •Anus = opening for solid waste removal from digestive tract •The cells of most animal embryos differentiate into three layers called germ layers: •Endoderm = (innermost) develops into the lining of the digestive tract and respiratory tract •Mesoderm = (middle) muscle, circulatory, reproductive, and excretory systems •Ectoderm = (outermost) sense organs, nerves, outer layer of skin BODY SYMMETRY •Body Symmetry - the body plan of an animal, how its parts are arranged •Asymmetry - no pattern (corals, sponges) •Radial Symmetry - shaped like a wheel (starfish, hydra, jellyfish) •Bilateral Symmetry - has a right and left side (humans, insects, cats, etc) 3 CEPHALIZATION •Cephalization - an anterior concentration of sense organs (to have a head) •The more complex the animals becomes the more pronounced their cephalization BODY PLAN •anterior - toward the head •posterior - toward the tail •dorsal - back side •ventral - belly side SEGMENTATION •Segmentation - "advanced" animals have body segments and specialization of tissue (even humans are segmented, look at the ribs and spine) BODY CAVITY •Body Cavity Formation: A fluid-filled space where internal organs can be suspended TYPES OF ANIMALS •Phylum Porifera •Typically asymmetrical •Lack tissues and organs •Adults are sessile •Mostly marine •Sexual and asexual reproduction •Example: sponges •About 10,000 species •Phylum Cnidaria •Radially symmetrical •Have distinct tissues •Marine and freshwater •Examples: jellyfish, hydra, coral •About 10,000 species •Phylum Ctenophora •Radially symmetrical •Transparent, gelatinous marine animals resembling jellyfishes •Propelled by cilia •Examples: comb jellies •About 100 species 4 •Phylum Platyhelminthes •Bilaterally symmetrical •Acoelomates •Body flat and ribbon-like •Lack true segments •Organs present •Examples: Planaria, Tapeworm, Schistosoma •More than 18,000 species •Phylum Nematoda •Roundworms •Body slender and elongated •Pseudocoelomates •Oneway gut •Examples: Ascaris, pinworms, hookworms, Trichinella, and Wuchereria •More than 80,000 species •Phylum Rotifera •Small, transparent, wormlike or spherical animals •Bilaterally symmetrical •Pseudocoelomates •Almost all live in fresh water •Example: rotifers •About 1,750 species •Phylum Annelida •Bilaterally symmetrical •Serially segmented worms •Protostomes •Examples: earthworms, leeches •About 15,000 species •Phylum Mollusca •Soft-bodied animals •Coelomates •Protostomes •most have a radula •Terrestrial, freshwater, and marine •Examples: clams, octopuses, snails •More than 110,000 species 5 •Phylum Arthropoda •Bilaterally symmetrical •Coelomates •Protostomes •Segmented bodies •Paired , jointed appendages •Chitinous exoskeleton •Aerial, terrestrial, and aquatic forms •Examples: insects, spiders, crustaceans •About 1 million species •Phylum Echinodermata •Adults are radially symmetrical –five-part body plan •Coleomates •Deuterostomes •Most forms have a water vascular system with tube feet for locomotion •Marine •Examples: sea star, sand dollar, sea urchin •About 7,000 species •Phylum Chordata •Bilaterally symmetrical •Deuterostomes •Coelomates •Have –A notochord (early backbone and spinal cord) –A dorsal nerve cord –Pharyngeal slits –A tail at some stage of life •Aquatic and terrestrial •Examples: fishes, amphibians, reptiles, birds, mammals •More than 47,000 species