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ANIMALS. Chapters 25 and 26. Chapter 25.1 and 25.2. Objectives List the characteristics that all animals share. Differentiate between invertebrates and chordates. Describe some features of animal body plans. Characteristics of Animals. Heterotrophic Multi-cellular Eukaryotic
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ANIMALS Chapters 25 and 26
Chapter 25.1 and 25.2 • Objectives • List the characteristics that all animals share. • Differentiate between invertebrates and chordates. • Describe some features of animal body plans.
Characteristics of Animals • Heterotrophic • Multi-cellular • Eukaryotic • No cell walls
Types of Animals • Invertebrates – 95% of animals • Lack a backbone • Examples: Jellyfish Seastar Worm Insect
Types of Animals • Chordates – 5% of animals • Characteristics: • Dorsal, hollow nerve chord • Notochord • Long supporting rod running length of body • Tail extending past anus • Pharyngeal pouches • Paired structures in throat region • Most are vertebrates (animals with backbones) • Examples: fish, amphibians, reptiles, birds, mammals
Check-in • 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
Levels of Organization • Cells • Tissues • Organs • Organ systems • Organism
Types of Body Symmetry • 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
Differentiation of Germ Layers • Cells of most animal embryos differentiate into: • Endoderm – innermost layer • Mesoderm – middle layer • Ectoderm – outermost layer
Formation of a Body Cavity • 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
Embryological Development • 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
Check-in • 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
Check-in Identify the sides of the animal that are labeled: dorsal ventral posterior anterior
Check-in • 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
Check-in • 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
Chapter 26.1 • Objectives • Describe characteristics of invertebrate phyla.
Phylum Porifera • “Pore-bearer” • Ex. Sponges • No tissues or organ systems • Asymmetrical • Filter feeders
Phylum Cnidaria • “Nettle” or “Stinger” • Ex. Hydras, Jellyfish, Sea anemones, Corals • Cells organized into tissues • Radial symmetry • Feed by stinging prey with nematocysts, mouth gastrovascular cavity
Phylum Arthropoda • Arthropods- “Jointed foot” • Ex. Insects, crustaceans, spiders • Segmented body, exoskeleton of chitin, jointed appendages
Nematoda - Roundworms • Ex. pinworms • Bilateral symmetry • Tissue layers • Pseudocoelomate • Digestive system with mouth and anus • Molt (shed skin) as they grow
Platyhelminthes - Flatworms • Ex. planarians, flukes, tapeworms • Bilateral symmetry • Three tissue layers • Acoelomate
Annelida – Segmented worms • Ex. earthworms, leeches, bristleworms • Bilateral symmetry • Tissue layers • Coelomate
Annelida Systems • 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
Phylum Mollusca • Mollusks • Ex. Gastropods (snails), Bivalves (clams), Cephalopods (squid) • Internal or external shell • Bilateral symmetry • Tissue layers • Coelomate
Phylum Echinodermata • Echinoderms- “Spiny skin” • Ex. Sea Stars, Sea Urchins, Sand Dollars • Internal skeleton • Water vascular system (tube feet) • Radial symmetry
Chapter 26.2 • Objectives • Describe characteristics of chordate phyla.
Nonvertebrate Chordates • Two invertebrate • Urochordata: tunicates • Cephalochordata: lancelets subphyla:
Jawless Fishes • No true jaws or teeth • Lack vertebrae • Skeleton made of cartilage • Ex. Lampreys, hagfish
Cartilaginous Fish • Skeleton made of cartilage • Paired fins • Most have tooth-like scales • Ex. Sharks, rays, skates
Bony Fish • Skeleton of true bone • Paired fins, scales, gills • Swim bladder • Ex. Perch, bass, flounder
Amphibians • 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
Amphibian Systems • 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)
Reptiles • Vertebrates with lungs • Scaly skin • Leathery shelled amniotic eggs • Ex. Lizards, snakes, turtles, crocodiles, dinosaurs
Birds • 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
Mammals • 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.
Groups of Mammals • 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