Transcript Animals
Chapters 25 and 26 Objectives List the characteristics that all animals share. Differentiate between invertebrates and chordates. Describe some features of animal body plans. Heterotrophic Multi-cellular Eukaryotic No cell walls Invertebrates – 95% of animals Lack a backbone Examples: Jellyfish Seastar Worm Insect Chordates – 5% of animals Characteristics: 1. Dorsal, hollow nerve chord 2. Notochord Long supporting rod running length of body 3. Tail extending past anus 4. Pharyngeal pouches Paired structures in throat region Most are vertebrates (animals with backbones) Examples: fish, amphibians, reptiles, birds, mammals List the characteristics all animals have Multicellular, heterotrophs, eukaryotes, no cell walls What characteristic do all invertebrates share? No backbone What characteristics do all chordates have sometime in their life cycle? Hollow nerve cord, notochord, postanal tail, pharyngeal pouches Cells Tissues Organs Organ systems Organism Asymmetry – no symmetry Radial symmetry – body parts extend from central point Bilateral symmetry – two sides (mirror image) Anterior – front Posterior – back Dorsal – upper Ventral - lower Cells of most animal embryos differentiate into: Endoderm – innermost layer Mesoderm – middle layer Ectoderm – outermost layer Body cavity – fluid filled space between digestive tract and body wall Acoelomate – no body cavity Pseudocoelomate – body cavity partially lined with mesoderm Coelomate – body cavity lined with mesoderm Zygote – fertilized egg Develops into blastula (hollow ball of cells) Blastopore – single opening to outside formed as blastula folds inward Protostome –organism in which blastopore becomes mouth Deuterostome –blastopore becomes anus List the levels of organization Cells Tissues Organs Organ systems Organisms What type of symmetry do each of the following have? Radial Bilateral Asymmetry Radial Identify the sides of the animal that are labeled: dorsal ventral anterior posterior What germ layer is the outermost layer? Ectoderm What germ layer makes up the linings of the digestive tract and respiratory system? Endoderm If an organism has a body cavity partially lined with mesoderm, what is it called? Pseudocoelomate What is a fertilized egg called? Zygote Organism in which blastopore becomes anus: Deuterostome What is an organism with a body cavity partially lined with mesoderm called? Pseudocoelomate Objectives Describe characteristics of invertebrate phyla. “Pore-bearer” Ex. Sponges No tissues or organ systems Asymmetrical Filter feeders “Nettle” or “Stinger” Ex. Hydras, Jellyfish, Sea anemones, Corals Cells organized into tissues Radial symmetry Feed by stinging prey with nematocysts, mouth gastrovascular cavity Arthropods- “Jointed foot” Ex. Insects, crustaceans, spiders Segmented body, exoskeleton of chitin, jointed appendages Ex. pinworms Bilateral symmetry Tissue layers Pseudocoelomate Digestive system with mouth and anus Molt (shed skin) as they grow Ex. planarians, flukes, tapeworms Bilateral symmetry Three tissue layers Acoelomate Ex. earthworms, leeches, bristleworms Bilateral symmetry Tissue layers Coelomate Digestion- mouth and anus, pharynx Circulation- closed system (blood contained in vessels) Respiration- some gills, skin Excretion- Nephridia, anus Nervous- brain and nerve cords Reproduction Sexual: (most), separate sexes, hermaphrodites Mollusks Ex. Gastropods (snails), Bivalves (clams), Cephalopods (squid) Internal or external shell Bilateral symmetry Tissue layers Coelomate Echinoderms- “Spiny skin” Ex. Sea Stars, Sea Urchins, Sand Dollars Internal skeleton Water vascular system (tube feet) Radial symmetry Objectives Describe characteristics of chordate phyla. Two invertebrate subphyla: Cephalochordata: Urochordata: lancelets tunicates No true jaws or teeth Lack vertebrae Skeleton made of cartilage Ex. Lampreys, hagfish Skeleton made of cartilage Paired fins Most have tooth-like scales Ex. Sharks, rays, skates Skeleton of true bone Paired fins, scales, gills Swim bladder Ex. Perch, bass, flounder Means “double life” Young: live in water and breathe with gills Adult: live on land and breathe with lungs and skin Undergo metamorphosis Dramatic change in body form Moist skin with mucous glands Lack scales and claws Ex. Frogs, toads, newts, salamanders Digestive/Excretory: Developed: stomach, intestines, etc. Nervous: Developed: large eyesgreat sight Circulatory: Closed circulatory system Three chamber heart Reproductive: Most lay eggs without shells in water External Fertilization Respiratory: Gills when immature, lungs and skin when mature (skin must stay moist to function) Vertebrates with lungs Scaly skin Leathery shelled amniotic eggs Ex. Lizards, snakes, turtles, crocodiles, dinosaurs Warm-blooded Feathers Strong light-weight bones Hard-shelled amniotic eggs Two scaly legs and wings as fore-limbs Ex. Hawk, eagle, penguin, ostrich, hummingbird, robin Warm-blooded Feed young with milk from mammary glands Hair or fur Breathe air Four-chamber heart Many groups of mammals Insect-eating, Water-dwelling, Hoofed, Gnawing, etc. Monotremes Egg-laying mammals Ex. Platypus Marsupials Give birth to under-developed young Young develop in the pouch of the mother Ex. Kangaroo, koalas, possum Placental mammals: Give birth to young that have developed in the mother’s body Ex. Humans, Dogs, Mice