Kingdom Animalia Invertebrates to Vertebrates

General Characteristics Multicellular eukaryotes Heterotrophs that ingest their food Mostly sexual reproduction, some asexual Controlled Movement – response via nerve impulses & muscle coordination

Invertebrates vs. vertebrates

Evolution 800 MYA from motile protists that liked to hang out together –choanoflagellates Movement from water to land –protection from dessication & sun’s rays

Move from water to land determines changes in… Body support & movement Reproduction Circulatory system Respiratory system Digestive and excretory system Nervous system

Common morphology 3 categories of morphology for classification and evolutionary advances –Symmetry –Germ layers –Body cavity

symmetry

Advantages of bilateral symmetry –Allow for cephalization Centralized nervous system in a head –Allows for segmentation Specialization of body parts –Allows for one way digestive system Input (eating) to output (excretion) that flows in one direction vs. a 2-way system

Germ layers Ectoderm - becomes hair, skin, nervous system Mesoderm -becomes skeleton, muscle, inner skin, circulatory system, liver Endoderm –becomes gut and associated organs, lungs, gills, pancreas, and their linings

Body Cavity Acoelomate –Solid organism –restricted movement & function Psuedocoelomate –False body cavity

Body Cavity, cont’d Coelomate –True body cavity – body cavity surrounded by mesoderm –Allows for ease of mobility & function, i.e. digestion, circulation –More room for larger organs (or coiled organs) so processes can take longer/efficiency –Allows for retention of eggs/gametes Internal fertilization (protects young)

Patterns of Development Type of cleavage determines whether or not cells can regenerate and ease of cloning

Patterns of Development Indirect –Metamorphosis through a life cycle vs. Direct -growth & differentiation

Earliest animals - sponges Phylum Porifera Collection of cells, able to communicate with each other No true tissue layers No symmetry or organs Sessile, suspension feeders O&D regeneration

First true animals Phylum Cnidarian –Jellies, anemones, hydra, corals Phylum Ctenophora –Comb jellies –2 (?) true tissue layers but lacking in complex systems –Sexual reproduction –Radial Symmetry

Early Worms Phylum Playthelminthes –flatworms Phylum Nematoda –Round worms

Phylum Mollusca 1 st with true coelum The “head-foods” Radula

Phylum Annelida Earthworms (segmented worms) Hermaphrodites Do NOT regenerate!!

Phylum Arthropoda Largest phylum, essential for evo. Of plants Exoskeleton limits size –Crayfish, insects, lobsters, spiders –Jointed appendages

Phylum Echinodermata First deuterostomes, closely related to us Starfish, sea urchins –“Spiny skin”

Phylum Chordata Dorsal nerve chord Notochord Pharyngeal (gill) slits Post-anal tail –Classes – birds, reptiles, amphibians, mammals