You’re Such an Animal!

What is an animal? Multicellular heterotrophs – take in food, digest it, distribute nutrients to cells Multicellular heterotrophs – take in food, digest it, distribute nutrients to cells Eukaryotes, cells lack cell walls Eukaryotes, cells lack cell walls Maintain homeostasis Maintain homeostasis Divided into 2 groups: invertebrates and chordates Divided into 2 groups: invertebrates and chordates Characteristics of Animals

What is an invertebrate? No backbone No backbone Have special parts for locomotion Have special parts for locomotion Some are sessile (permanently attached or fixed; not free moving) Some are sessile (permanently attached or fixed; not free moving) Some reproduce by budding, some with sperm and egg, some by parthenogenesis (unfertilized egg becomes an individual) Some reproduce by budding, some with sperm and egg, some by parthenogenesis (unfertilized egg becomes an individual) some invertebrates can regenerate lost parts or even a complete individual from a broken piece. some invertebrates can regenerate lost parts or even a complete individual from a broken piece.

Porifera – Sponges! Simplest animals Simplest animals Sac-like bodies – hole in the top leading to open body cavity Sac-like bodies – hole in the top leading to open body cavity Filter feeders - water flows out through top hole and in through pores in body wall. Filter feeders - water flows out through top hole and in through pores in body wall. No tissues, different cells perform different functions No tissues, different cells perform different functions Both sexual and asexual, motile larvae Both sexual and asexual, motile larvae

Porifera - sponges The two pictures on left show living sponges, the two pictures on right show the skeletons – used commercially

Sponges Phylum Porifera

Cnidaria Radial symmetry Radial symmetry Hollow gut with a single opening Hollow gut with a single opening Tentacles with stingers Tentacles with stingers Prey is stung and stuffed through opening in the gut. Prey is stung and stuffed through opening in the gut. Gets oxygen, water, and gets rid of waste through diffusion Gets oxygen, water, and gets rid of waste through diffusion

Cnidarians - Sea anemones, coral, jellyfish

Jellyfish Hydra

Coral Sea anemones

Sea anemone movement Between two cells layers the sea anemone has a jellylike layer with nerve cells and contractile fibers – this is how it moves. Stinging Animals

Bilateral symmetry Bilateral symmetry Most are parasites Most are parasites Flukes feed on host tissue Flukes feed on host tissue Tapeworms feed on materials in the host’s gut. Tapeworms feed on materials in the host’s gut. Platyhelminthes (flat worms)

Planarians

Tapeworms

Flukes

Nematoda (round worms) Most are microscopic Most are microscopic Most hunt for their food Most hunt for their food Complete digestive system – two openings Complete digestive system – two openings 50 species are parasites 50 species are parasites transmitted in untreated sewage transmitted in untreated sewage live everywhere live everywhere Move by long muscles Move by long muscles Sexual reproduction, sperm are amoeboid Sexual reproduction, sperm are amoeboid

Nematoda Roundworms Roundworms Guinea worm

Ascaris (intestinal worms)

Necator (hookworm)

Annelida (segmented worms) Segmented bodies help in crawling and burrowing into dirt and holes Segmented bodies help in crawling and burrowing into dirt and holes Earthworms are hermaphrodites Earthworms are hermaphrodites Most are filter feeders, carnivores or parasites (ex: Leeches feed on animal’s blood) Most are filter feeders, carnivores or parasites (ex: Leeches feed on animal’s blood) Over 12,000 known species of earthworms, leeches, and clamworms Over 12,000 known species of earthworms, leeches, and clamworms

Earthworms and Leeches

Annelida Ocean tubeworms Earthworm – note segments (2) and Clitellum (1)

Annelida Diagram of earthworm anatomy- note development of organs.

Annelida This shows a worm’s five pairs of beating hearts Phylum of Worms

Mollusca Bilateral symmetry Bilateral symmetry Unsegmented, usually have a defined head Unsegmented, usually have a defined head Main parts include: a muscular foot, a head, and a visceral mass (contains organs) Main parts include: a muscular foot, a head, and a visceral mass (contains organs) Live in oceans, freshwater, and on land Live in oceans, freshwater, and on land

Snails

Mollusca

Clams

Mollusca

Cone Shell 400 to 500 species of cone shell mollusks 400 to 500 species of cone shell mollusks harmful to humans - deadly nerve poisons harmful to humans - deadly nerve poisons Hunt prey with a muscular, retractable proboscis that has a mouth, a salivary gland, and teeth. Hunt prey with a muscular, retractable proboscis that has a mouth, a salivary gland, and teeth.

Chambered Nautilus The Chambered Nautilus is a “living fossil” – a member of the cephalopods which includes octopus and squid. Close relatives date back 100’s of millions of years. It propels itself close to the sea floor by shooting water from its movable siphon. Picture taken by Judy Jones

Squid & Octopus Phylum Mollusca