KINGDOM ANIMALIA: 10 PHYLA Porifera Cnidaria Rotifera Platyhelminthes Nematoda Annelida Mollusca Arthropoda Echinodermata 10. Chordata Invertebrates Vertebrates

Ancestral colonial protist No true tissues True tissues Bilateral symmetry Radial symmetry Eumetazoans Bilaterians Protostomes Deuterostomes Sponges Cnidarians Echinoderms Chordates Flatworms Molluscs Annelids Arthropods Nematodes Figure 18.4

Phylum Porifera Sponges Very primitive, no true tissues Supported by spongin (protein fibers) or spicules (mineral crystals) Sessile animals live attached to rocks. Get food/ oxygen from water that is pumped through their hollow bodies by cells with flagella Filter feeders Reproduce through budding and sperm/eggs

Phylum Porifera

Flagellated choanocytes - Filter food / O2 from the water passing through the porous body Pores Amoebocyte Skeletal fiber Central cavity Choanocyte in contact with an amoebocyte Choanocyte Water flow Flagella Figure 18.5D

Phylum Cnidaria Have true tissue; no organs Have a simple skeletal system Excretion through same opening used to pump food/ water through Free-floating or sessile 2 stages of life cycle- medusa/polyp Budding/sexual reproduction

Cnidaria: Corals, Jellyfish, Sea Anemones Polyp stage Medusa stage Cnidaria: Corals, Jellyfish, Sea Anemones

Cnidarians have a gastrovascular cavity and cnidocytes on tentacles that sting prey “Trigger” Coiled thread Capsule (nematocyst) Discharge of thread Cnidocyte Prey Figure 18.6D

PHYLUM ROTIFERA Very small size and mostly soft bodies Microscopic, mostly aquatic-found in many freshwater and moist soil Complete digestive tract with mouth and anus Body cavities that are partially lined by mesoderm- coelomates. Crown of cilia around the mouth of the rotifer that makes them appear to whirl like a wheel Tiny mouths; primarily omnivorous, unicellular algae and other phytoplankton Sexual reproduction

Phylum Rotifera

Phylum Platyhelminthes Flatworms (tapeworms, Planaria) 3 cell layers- Acoelomates Bilaterally symmetrical No respiratory or circulatory systems; gastrovascular cavity and organized response mechanisms Thin flat bodies absorb oxygen and release CO2 and wasted directly in the surrounding water. Reproduce by splitting in 2 Some parasitic, they live in the digestive systems of other animals.

A planarian has a gastrovascular cavity and a simple ner vous system Bilateral symmetry Gastrovascular cavity Nerve cords Mouth Eyespots Nervous tissue clusters Figure 18.7A

Flukes and tapeworms are parasitic flatworms Units with reproductive structures Scolex (anterior end) Hooks Sucker Colorized SEM 80 Figure 18.7B

Phylum Nematoda Roundworms Less than 1 mm long; Live in soil and water. Sexual reproduction- male sperm/female egg Some are decomposers, others are parasites of animals or plants Pseudocoelom; complete digestive system Pinworms and hookworms in soil burrow into the skin of people who go barefoot outdoors; Trichina worms infest people who eat undercooked pork or wild game. (cause “Elephantitis”- swelling of appendages due to blocking of fluid movement in blood vessels by worms)

Phylum Nematoda

Phylum Annelida Earthworms, leeches- segmented worms Each segment is separated from the next by a membrane Closed circulatory system with blood vessels that run the length of the animal. Has a complete excretory and digestive system where food travels through in one direction; from anterior to posterior. Branches of the main nerves and clusters of nerve cells at the anterior end serves as a simple brain. Live in water or damp soil; Bilateral sym Reproduction occurs by splitting or by mutual fertilization (hermaphrodites)

Ear thworms and Their Relatives Eat their way through soil Have a closed circulatory system Giant Australian earthworm Mouth Brain Dorsal vessel Coelom Digestive tract Mucus-secreting organ Segment wall Anus Bristles Blood vessels Nerve cord Pumping segmental vessels Ventral vessel Excretory Segment wall (partition between segments) Epidermis Circular muscle Longitudinal Intestine Figure 18.10A

Phylum Annelida (cont.) Leeches were once used to suck out people’s “excess” blood and reduce harmful high blood pressure Leeches are uses today to produce anti-blood-clotting medicines, to suck blood from bruises, and to stimulate blood circulation in severed limbs that have been surgically reattached..

Phylum Mollusca Includes snails, clams, slugs, squid, and their relatives. Bilateral sym.; coelomates Radula- scrapes up food; complete digestive tract Separate sexes; sexual reprod. Mollusks have soft bodies with 3 parts: A visceral mass that contains most of the organs A muscular “foot” that is used in movement A thick flap called a mantle, which covers the body and in most species produces a heavy shell of calcium compounds.

Phylum Mollusca (cont.) Mollusks pump water through gills- both for oxygen and food for clams and oysters. Squid and octopi use the pump for jet propulsion through the water in search of prey.

Phylum Mollusca

Diverse mollusks are variations on a common body plan All mollusks have a muscular foot and a mantle, which may secrete a shell that encloses the visceral mass Many mollusks feed with a rasping radula Visceral mass Mantle Radula Mouth Nerve cords Foot Digestive tract Shell Digestive tract Reproductive organs Heart Coelom Kidney cavity Anus Gill Figure 18.9A

Gastropods The largest group of mollusks and include the snails and slugs Figure 18.9B, C

Bivalves Have shells divided into 2 halves and include clams, oysters, mussels, and scallops Figure 18.9D

Cephalopods Adapted to be agile predators and include squids and octopi Figure 18.9E, F