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You’re Such an Animal!. What is an animal?. Multicellular heterotrophs – take in food, digest it, distribute nutrients to cells Eukaryotes, cells lack cell walls Maintain homeostasis Divided into 2 groups: invertebrates and chordates. Characteristics of Animals. What is an invertebrate?.
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What is an animal? • Multicellular heterotrophs – take in food, digest it, distribute nutrients to cells • Eukaryotes, cells lack cell walls • Maintain homeostasis • Divided into 2 groups: invertebrates and chordates Characteristics of Animals
What is an invertebrate? • No backbone • Have special parts for locomotion • 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 invertebrates can regenerate lost parts or even a complete individual from a broken piece.
Porifera – Sponges! • Simplest animals • 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. • No tissues, different cells perform different functions • 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. http://www.middleschoolscience.com/sponges.htm http://www.ucmp.berkeley.edu/porifera/porifera.html http://www.teaching-biomed.man.ac.uk/bs1999/bs146/biodiversity/porifera.htm
Sponges Phylum Porifera
Cnidaria • Radial symmetry • Hollow gut with a single opening • Tentacles with stingers • Prey is stung and stuffed through opening in the gut. • Gets oxygen, water, and gets rid of waste through diffusion
Cnidarians - Sea anemones, coral, jellyfish http://en.wikipedia.org/wiki/Image:Giant_Green_Anemone.gif http://www.ucmp.berkeley.edu/cnidaria/fungiid.html
Hydra Jellyfish
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 http://www.bionat.unipi.it/deee/idx_arch_img.html
Platyhelminthes (flat worms) • Bilateral symmetry • Most are parasites • Flukes feed on host tissue • Tapeworms feed on materials in the host’s gut.
Nematoda (round worms) • Most are microscopic • Most hunt for their food • Complete digestive system – two openings • 50 species are parasites • transmitted in untreated sewage • live everywhere • Move by long muscles • Sexual reproduction, sperm are amoeboid
Nematoda • Roundworms Guinea worm
Annelida (segmented worms) • Segmented bodies help in crawling and burrowing into dirt and holes • Earthworms are hermaphrodites • Most are filter feeders, carnivores or parasites (ex: Leeches feed on animal’s blood) • Over 12,000 known species of earthworms, leeches, and clamworms
Annelida Ocean tubeworms Earthworm – note segments (2) and Clitellum (1) http://animaldiversity.ummz.umich.edu/site/resources/jeffrey_jeffords/misc.inverts/tubes.jpg/view.html
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 • Unsegmented, usually have a defined head • Main parts include: a muscular foot, a head, and a visceral mass (contains organs) • Live in oceans, freshwater, and on land
Mollusca http://www.medslugs.de/E/Med/Phyllidia_flava_10.htm http://www.medslugs.de/E/Med/Flabellina_pedata_28.htm
Mollusca http://home.planet.nl/~erikveldhuis/index.html
Cone Shell • 400 to 500 species of cone shell mollusks • harmful to humans - deadly nerve poisons • 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