The Animal Kingdom

What is an animal? Heterotrophic, multicellular eukaryotes No cell walls 2 types of tissue that are only found in animals: nervous and muscle tissue most reproduce sexually diploid stage is dominant

Simple Invertebrates First division in animal kingdom is between animals with no nerves and animals with nervous tissue. The only non nervous tissue animals are the Phylum Porifera Porifera are commonly known as sponges Stay in a fixed place, have asymmetric body plan Have specialized types of cells

Phylum Cnidaria The next division is between radially symmetrical animals and bilaterally symmetrical animals. Cnidaria have symmetrical bodies (radial) and have cells that are organized into tissues. Include hydrozoans, jellyfish, sea anemones, sea fans, and corals.

Other Invertebrates The other invertebrates include the phyla: –Platyhelminthes (Flatworms) Unsegmented worms Single opening Parasites usually No circulatory or respiratory systems –Rotifera Aquatic, freshwater No circulatory or respiratory systems –Mollusca Clams, snails, octopus, squid 3 main body parts: foot, mantle (shell) and visceral mass Digestive system, circulatory system, gills

–Annelida (segmented worms) Earthworm Digestive system Bodies are segmented –Nematoda (roundworms) Pinworms, heartworms Unsegmented bodies, complete digestive tract Many are parasites Soil and aquatic

–Arthropoda (have an exoskeleton made of chitin) Most abundant Segmented body parts that are more specialized Jointed legs, body cavity Complete digestive, excretory, circulatory, respiratory Many different classes. Some include: –Arachnida (scorpions, spiders, mites, ticks) –Crustacea (shrimp, lobster, crayfish, crabs) –Insecta –Diplopoda and Chilopoda (millipede)

–Echinodermata Same pattern of embryonic development as the vertebrates Starfish, sea urchins, sea cucumbers Immature stages are free swimming and bilaterally symmetrical but as they grow, they develop radial symmetrical bodies.

Vertebrates Phylum Chordata have at one point in their development a hollow nerve cord and gill slits. Bilaterally symmetrical, tails. Have 7 classes: –Jawless fish Lamprey Skeletons made of cartilage No paired appendages –Cartilaginous fish Shark, ray, skate Skeletons made of cartilage Paired appendages

–Bony Fish Bass, trout, salmon Skeletons are bony Swim bladder (for buoyancy) –Amphibians Frogs, salamanders Adults have 4 limbs for land, aquatic larval stage Breathe through lungs or skin –Reptiles Snakes, lizards, crocodiles, turtles Most are terrestrial tetrapods with dry scaly skin Breathe with lungs

–Class Aves (Birds) 2 legs and 2 arms for wings Most are capable of flight Feathers Warm blooded –Class Mammalia Tetrapods Hair Nurse young with milk Warm blooded Most give birth to live young