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Animals Invertebrate Diversity & Evolution Animal Characteristics • Multicellular • Heterotrophic (can be classified by their feeding strategies) • Classified by feeding strategies • Filter feeders (suspension feeders) • Deposit feeders • Fluid feeders • Mass feeders Animal Characteristics • Heterotrophic (can be classified by their feeding strategies) • Classified by what they eat • Herbivores • Carnivores • Omnivores • Detrivores • Classified by what happens to the other organism • Predator • Parasites • Endoparasite • Ectoparasite Animal Characteristics • Lack a cell wall • Motile at some point in life • Reproduce sexually • Most are diploid • Fertilization is internal or external • Respond quickly to a stimulus Animal Evolution Trends • Greater level of cellular organization & specialization • Tissue to organs to organ systems • Embryo development • Blastula with blastocoel • Gastrula (3 germ layers) • Endoderm • Ectoderm • Mesoderm • Diploblastic vs. triploblastic • Cephalization (head & tail ends) Tissue Layers • Animal Evolution Trends Development of a body cavity • Acoelomate • Pseudocoelomate • Coelom • Provides a hydrostatic skeleton • Protostome- coelom forms within the space between the body wall & digestive cavity • Blastopore & spiral cleavage • Deuterostome- coelom forms as outgrowth of digestive cavity • Radial cleavage • Greater development of digestive system • Incomplete digestion- waste leaves same opening as food goes in • Complete digestion- special regions to breakdown & process food • Body symmetry • Asymmetry • Radial symmetry • Bilateral symmetry • Brain size increases & becomes more sophisticated (seen in vertebrates) Body Cavities Body Cavities Protostomes vs. Deuterostomes Symmetry Symmetry Endoskeleton vs. Exoskeleton Phylum - Porifera • • • • • • • • • • • Asymmetrical – free form to definite shape aquatic- salt and freshwater varieties Variety of shapes and colors Invertebrates Sessile- they are anchored to a substrate (rock, etc.) Filter feeders = as the water passes through the organism it filters food from the water • Tiny pores allow water to enter the ostia (interior cavity) • Expels waste through a large center hole called the osculum (oscula) Asexual reproduction by budding and fragmentation Sexual reproduction- sponges release eggs and sperm in large amounts to increase the chance of fertilization Colonies of independent cells to multicellular Lack true organs and tissues 4 cell types • Pinacocytes- flattened cells that cover the body surface • Choanocytes- have flagella; maintain water flow through the sponge • Amoebocytes- digest & distribute nutrients; produce reproductive cells • Secrete spicules • Porocytes- cells curl end to end to form the ostia pores Sponges Phylum - Porifera Sponges Phylum - Porifera Sponges Phylum - Porifera Sponges Phylum - Cnidaria • • • • • • • • • marine invertebrates radial symmetry 1 body opening, gastrovascular cavity 2 body forms • polyp- tube shaped body and a mouth surrounded by tentacles • medusa- body shaped like an umbrella poison their prey by cnidocytes (tiny stinging cells) located on their tentacles • darts called nematocysts contain specialized tissues • contain a nerve net (a simple nervous system) • contractile tissue asexual reproduction by budding sexual reproduction by external fertilization 2 body layers – endoderm & ectoderm with mesoglea between layers Jellyfish, Anemone, Corals Phylum - Cnidaria Class Hydrozoa- primitive polyps; hydra, physalia & obelia Class Scyphozoa- medusa forms; aurelia Class Anthozoa- advanced polyps; sea anemones & corals Jellyfish, Anemone, Corals Phylum - Cnidaria Jellyfish, Anemone, Corals Phylum - Cnidaria Jellyfish, Anemone, Corals Phylum - Cnidaria Jellyfish, Anemone, Corals Phylum - Cnidaria Jellyfish, Anemone, Corals Phylum - Platyhelminthes • Acoelomates • Bilaterally symmetrical with some cephalization • Some have a nerve net & nerve cords • Some have the beginnings of a central nervous system (the ganglion) • Eyespot • Specialized sense cells • Size: 1 mm to several meters • Most are hermaphroditic • 1 body opening • Planarians extend a muscular organ called the pharynx that releases enzymes to begin digesting food (the mouth is in the center of its body) • Protonephridia transport wastes with the help of flame cells to exit through excretory pores • Sexual reproduction by internal fertilization • Hermaphroditic – cross or self fertilization • Asexual reproduction by regeneration • Parasitic worms have hooks to keep the worm firmly attached to the host (tapeworms) – can form cyst Tapeworms, Flukes, Planaria Phylum - Platyhelminthes • Class Turbellaria- free living flatworms; planaria • Class Trematoda- parasites; flukes • Class Cestoda- parasites; tapeworms Phylum - Platyhelminthes Planaria Phylum - Platyhelminthes Tapeworms, Flukes, Planaria Phylum - Platyhelminthes Tapeworms Phylum Nematoda • • • • • • • • • Tapered at both ends Most are microscopic Free living C. elegans, Rhabditis, vinegar eels Parasitic varieties hookworms, heartworms, Trichinella Cuticle secreted by the hypodermis, thick outer covering for protection from the host organism Pseudocoelomate • Provides a hydrostatic skeleton for muscle movement Tubelike, one-way digestive system • 2 body openings: mouth and anus Well developed sense organs in free living species Sexual reproduction with separate sexes C. elegans Phylum Nematoda Roundworms Phylum Nematoda Roundworms • • • • • • • • • • • • Phylum Annelida Coelomates Invertebrates Exhibit metamerism Bilaterally symmetrical Digestive track with 2 body openings • Contains a pharynx, esophagus, crop, gizzard and intestine Bristled setae on each segment used for movement Simple nervous system with a brain in some species Gas exchange occurs through moist skin 2 nephridia (waste removal organs) per segment Hermaphroditic Closed circulatory system (blood contained in vessels) with a heart Nephridia remove & excrete wastes Segmented Worms Phylum Annelida Class Oligochaetes- earthworms * hermaphroditic Class Polychaetes- marine dwelling worms * separate sexes that shed gametes in water * have parapodia Class Hirudinea- leeches * NO setae or parapodia Segmented Worms Phylum Annelida Segmented Worms Phylum Annelida Parapodia Phylum Annelida Segmented Worms • • • • • • • • • • • • • Phylum Mollusca bilaterally symmetrical coelomates supported by a hydrostatic skeleton digestive system with 2 body openings muscular foot for movement contain a mantle- a thin membrane that surrounds the internal organsthe mantle secretes the shell contain a radula- a tonguelike organ with rows of teeth sexual reproduction by external fertilization land mollusks tend to be hermaphroditic to increase chances of fertilization; most mollusks are separate sexes simple nervous systems with a brain and associated nerves 3 chambered hearts with an open circulatory system- blood moves through vessels and into open spaces around body organ larger mollusks have a closed circulatory system- blood moves through the body enclosed entirely in a series of blood vessels contain nephridia- waste removal organs gills for respiration - land snails and slugs have primitive lungs Squid, Octopus, Snails, Slugs, Shelled Animals Phylum Mollusca Class Gastropoda- snails, slugs * use their radula * moist skin supplements gills or primitive lungs Snails & Slugs Phylum Mollusca Class Bivalvia- clams, scallops, mussels & oysters * have 2 part shell attached at a hinge * have a muscular foot for movement or for anchoring the organism * have gills to aide in respiration & filter feeding Clams Phylum Mollusca Class Polyplacophora- chitons * 8 calcium carbonate plates on the dorsal surface Chitons Phylum Mollusca Class Cephalopoda- octopus & squid * predatory & marine dwelling * intelligent * grasping tentacles with chemosensory abilities * complex eye * capable of jet propulsion * have a closed circulatory system Squid & Octopus Phylum Mollusca Squid, Octopus, Snails, Slugs, Shelled Animals Phylum Arthropoda • Have an exoskeleton • Flexible appendages • Watertight • Must go through molting to grow • Largest live in water • Segmented • Head • Thorax • Cephalothorax • Abdomen • Have respiratory system • Gills • Trachea • Book lungs Insects, Arachnids, Crustaceans Phylum Arthropoda • Have open circulatory system • Blood is called hemolymph & empties to the hemocoel • Excretion through malpighian tubules • Sensory organs • Eyes • Antennae for chemical & tactile sense Insects, Arachnids, Crustaceans Phylum Arthropoda Subphylum Chelicerata- horseshoe crabs & arachnids * have chelicerae Arachnids (spiders, scorpions, ticks, mites) * pair of pedipalps & 8 walking legs * carnivorous * multiple pairs of simple eyes Spiders, scorpions, ticks, mites Phylum Arthropoda Subphylum Crustacea- crustaceans (crabs, shrimp, crayfish) * have mandibulae * usually 2 pairs of antennae * compound eyes & gills Crabs, shrimp, crayfish Phylum Arthropoda Subphylum Uniramia- insects, centipedes, milipedes * unbranched appendages * have mandibulae * can be divided into two subphyla: Insecta & Myriapoda Milipedes, centipedes Phylum Arthropoda Insects * 3 pairs of legs & 2 pairs of wings * undergo metamorphosis * holometabolous- complete change in form * larvae to pupa to adult * hemimetabolous- incomplete change * nymphs resemble parents but do not have wings or reproductive organs Phylum Arthropoda • • • • • • • • • • Phylum Echinodermata All aquatic species Hard, spiny, bumpy endoskeletons Radial symmetry (pentaradial symmetry) Coelomates • Coelomic fluid acts as circulatory system Water vascular system • Move by hundreds of suction cup tipped appendages, tube feet • Helps with respiration & feeding • Water enters through the madreporite into the central canal • Radial canals extend out from the central canal All have a mouth, stomach and intestines Central nerve ring Slow paced or sessile Able to regenerate Sexual reproduction with separate sexes • Sheds gametes into the water Spiny Skinned Animals – Starfish, Urchins, Sand Dollars Phylum Echinodermata Class Asteroidea- sea stars Class Ophiuroidea- brittle stars & basket stars Class Echinoidea- sea urchins & sand dollars Class Holothuroidea- sea cucumbers Class Crinoidea- sea lilies & feather stars Spiny Skinned Animals – Starfish, Urchins, Sand Dollars Phylum Echinodermata Spiny Skinned Animals – Starfish, Urchins, Sand Dollars Phylum Echinodermata Spiny Skinned Animals – Starfish, Urchins, Sand Dollars Phylum Echinodermata Spiny Skinned Animals – Starfish, Urchins, Sand Dollars
