Presentation on theme: "Chapters 25 and 26. Objectives List the characteristics that all animals share. Differentiate between invertebrates and chordates. Describe some features."— Presentation transcript:
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: SeastarWorm Jellyfish 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? RadialBilateralAsymmetryRadial
Identify the sides of the animal that are labeled: posterior ventral anterior dorsal
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
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
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 Urochordata: tunicates Cephalochordata: lancelets subphyla:
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 eyes great 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)
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