Kingdom Anamalia Characteristics of Animals Multicelled heterotrophic eukaryotes

Kingdom Anamalia

Characteristics of Animals • Multicelled heterotrophic eukaryotes • Require oxygen for aerobic respiration • Reproduce sexually, and perhaps asexually • Motile at some stage • Develop from embryos

Chordates Major Animal Phyla Echinoderms Arthropods Annelids Coelomate Ancestry Mollusks Rotifers Roundworms Bilateral Ancestry Radial Ancestry Multicelled Ancestry Figure 25. 2 Page 415 Flatworms Cnidarians Sponges Single-celled, protistanlike ancestors

Symmetry r o i r al te s o s r do ior er t an Radial p l ra t n ve Bilateral Figure 25. 3 Page 416

The Gut • Region where food is digested and then absorbed • Saclike gut – One opening for taking in food and expelling waste • Complete digestive system – Opening at both ends; mouth and anus

Body Cavities - Acoelomate epidermis gut cavity no body cavity; region between gut and body wall packed with organs Figure 25. 4 a Page 417

Body Cavities - Pseudocoel epidermis gut cavity unlined body cavity (pseudocoel) around gut Figure 25. 4 b Page 417

Body Cavities - Coelom gut cavity lined body cavity (coelom) peritoneum Figure 25. 4 c Page 417

Body Cavities - Coelom gut cavity lined body cavity (coelom) peritoneum Figure 25. 4 c Page 417

Animal Origins • Originated during the Precambrian (1. 2 billion - 670 million years ago) • From what? Two hypotheses: – Multinucleated ciliate became compartmentalized – Cells in a colonial flagellate became specialized

Kingdom Anamalia • • • Multicellular Heterotrophic Sexual reproduction Produce gametes in sex organs, gonads 95% lack a backbone and are called invertebratees • Vertebrates aare a subphylum within the phylum chordata • Aquatic and terrestrial • tissues organized into organs

Internal Organization

The Protostomes Molluscs (Phylum Mollusca): shellfish such as clams and limpets, snails, slugs, octopus, and squid. segmented worms (Phylum Annelida): earthworms, many marine worms that may be free-swimming or live in tunnels or tubes, and leeches arthropods (Phylum Arthropoda): the most diverse group of animals, which includes insects, spiders, scorpions, ticks, mites, centipedes, millipedes, and crustaceans (aquatic organisms like shrimp and lobster. )

Phylum Mollusca Mollusks have 3 body regions: a head, a visceral mass, and a "foot. “

Mollusks: Phylum Mollusca • Bilateral, soft-bodied, coelomate • Most have a shell or reduced version of one • Mantle drapes over body and secretes shell • Most have a fleshy foot • Many have a radula for shredding food

Molluscan Diversity • Gastropods • Chitins • Bivalves • Cephalopods

Torsion • Twisting of body parts during larval development • Occurs only in gastropods mouth gill anus Figure 25. 18 Page 426

Body Plan of a Snail heart mantle cavity anus gill mantle digestive gland foot radula Figure 25. 18 Page 426

Body Plan of a Clam mouth left mantle retractor muscle foot palps left gill shell Figure 25. 21 Page 429

The coelom is a body cavity, within which internal organs can develop, which is completely lined with a middle layer of tissue in the body called mesoderm and distinct from the outer layer that makes up the skin (the ectoderm tissue) and the inner layer that makes up the digestive tract (the endoderm tissue. )

Class Amphineura “Chitons”

Characteristics • • Eight dorsal plates Reduced head One Foot Radula for scraping rocks

Class Gastropoda “Snails, limpets, abalones, slugs”

Spiraled Shell

Class Bivalvia (Cephalopoda) “clams, oysters and mussels”

Bivalvia • • Shell of two valves Head Reduced Gills No radula and filter feeders

Class Cephalopoda “Squid, octopi, chambered nautilus” • Shell external, internal or absent • Foot modified into eight arms and some with two tentacles • mantle muscular and forms a siphon for “jet” propulsion • radula modified as a beak • excellent vision • All marine

Cuttlefish Body Plan Closed circulatory system with heart and accessory heart esophagus digestive kidney stomach gland Figure 25. 22 Page 429 brain arm jaw tentacle mantle reproductive internal siphon shell ink sac heart accessory organ radula anus gill heart

Annelids: Phylum Annelida Segmented, coelomate worms • Class Polychaeta • Class Oligochaeta • Class Hirudinea

Phylum Annelida “segmented worms”

Class Polycheata “Bristle Worms” • • • Many setae born on parapodia Relatively well devloped head Sedentary (tube dwelling) Errant (Swimmers or crawlers All are marine

Polychaetes • Most are marine • Bristles extend from paired, fleshy parapods on each segment • Head end is specialized “jaws” toothlike structures pharynx (everted) antenna palp (food handling) tentacle eyes chemicalsensing pit parapod Fig. 25. 24 c Page 430

Class Oligochaeta “Earthworms and Freshwater Annelids” • Few setae borne on parapodia • Reduced head • Terrestrial and Fresh water

Earthworm - An Oligochaete No parapodia, few bristles per segment Dorsal blood vessel Circular muscle Coelom Longitudinal muscle Nephridium Nerve cord Figure 25. 25 a Page 431 Nerve cord Seta (retracted)

Earthworm Nephridium bladderlike storage region of nephridium’s thin loop reabsorbs some solutes, relinquishes them to blood vessels body wall funnel (coelomic fluid with waste enters here) external pore (fluid containing wastes discharged here) Figure 25. 25 b Page 431

Earthworm Circulatory System Hearts Figure 25. 25 c Page 431

Earthworm Digestive System Coelomic chambers Esophagus Crop Gizzard Pharynx Mouth Figure 25. 25 d Page 431

Earthworm Nervous System Brain Nerve cord Figure 25. 25 e Page 431

Class Hirudinea “Leeches” • • Body Flattened Anterior and Posterior Suckers Constant number of segments (32 or 33) Predatory or parasitic Anticoagulant No setae Most freshwater, Few terrestrial

Leeches - Class Hirudinea • Predators and parasites • Less obvious body segmentation • Most have sharp jaws