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AP Biology

AP Biology. Lecture #49 Non-Vertebrate Animals. Characteristics of Animals. Animals are: Multicellular Heterotrophs Eukaryotic Have tissues and differentiated cells Eat Reproduce and Develop 1.3 millions species have been identified, estimates of 10 to 200 million exist.

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AP Biology

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  1. AP Biology Lecture #49 Non-Vertebrate Animals

  2. Characteristics of Animals Animals are: Multicellular Heterotrophs Eukaryotic Have tissues and differentiated cells Eat Reproduce and Develop 1.3 millions species have been identified, estimates of 10 to 200 million exist

  3. Early Embryonic Development Sperm and egg meet through fertilization to form a zygote The zygote undergoes mitosis, called cleavage A blastula, or multi-celled hollow ball forms These cells form tissue layers that make up a gastrula

  4. Eras of Animal Life Neoproterozoic Era (1 B  542 mya): First fossilized animals are from this time period. Paleozoic Era (542 251 mya): the Cambrian explosion occurs, huge diversity of animal species, including vertebrates, evolve Mesozoic Era (251  65.5 mya): animal life spreads across the planet Cenozoic Era (65.5 mya present): dinosaurs, birds, and mammals all evolve

  5. Body Plans Animals can have radial symmetry, in which the parts of an animal radiate out from the center (starfish) Or they can have bilateral symmetry, with equal left and right sides (lobsters, humans) Animals with a distinct forward facing head at the top of the body have gone through cephalization.

  6. Tissue Layers The tissue layers of an animal embryo are called germ layers, and form organs. The ectoderm is the outermost layer and forms the skin and nervous system. The endoderm is the inner layer of the embryo and turns into the digestive system. Some animals have a third layer, called the mesoderm, which forms the other body organs.

  7. Body Cavities Some animals have body cavities, a fluid-filled space that separates the digestive tract from the outer body wall, this is called a coelom. Pseudocoelomates have a body cavity that is formed from a different type of tissue. Acoelomates do not have body cavities.

  8. Protostomes and Deuterostomes Protostomes, like worms and bugs, develop a mouth first during fetal development. Deuterostomes, like people and starfish, develop an anus before they develop mouths.

  9. Invertebrates

  10. Invertebrates • Invertebrates are animals without a backbone. • The main phyla we will talk about are: • Porifera • Cnidaria • Platyhelminthes • Nemotodes • Mollusks • Annelids • Arthropods • Echinodermata • Some chordates

  11. Parazoa • Invertebrates: animals without backbones • Closest lineage to protists • Loose federation of cells (unspecialized); no tissues • Phylum.: (only one)Porifera(sponges)

  12. The Sponges – Phylum Porifera

  13. Phylum Porifera • Phylum Porifera are the sponges. • They may have radial symmetry, or no symmetry. • They are non-motile filter feeders. • Individual cells are specialized, but they have no true organs.

  14. General Information Size range – 1 cm to 2 meters in diameter Giant Barrel sponges

  15. Eumetazoa: Animals with true body tissueThe Radiata, I • Diploblastic • Radial symmetry • Phylum:Cnidaria(hydra, jellies, sea anemones, corals) • tissues, but no organs • two cell layers • predators • tentacles surround gut opening • extracellular digestion • release enzymes into gut cavity • absorption by cellslining gut

  16. mouth tentacles sensory cell discharged nematocyst stingingcell undischarged nematocyst hydra trigger stinging cell with nematocyst Stinging cells of Cnidarians

  17. The Radiata, II • Phylum: Ctenophora(comb jellies) • 8 rows of comblike plates of fused cilia (largest animals that use cilia for locomotion) • Tentacles with colloblasts (adhesive structures that capture prey)

  18. ectoderm mesoderm endoderm Eumetazoa: The Acoelomates • Phy: Platyhelminthes(flatworms, flukes, tapeworms) • Bilateral; no body cavity • Predators, scavengers, parasites • Some cephalization~ development of brain concentration of sense organs in head acoelomate

  19. Eumetazoa: Pseudocoelomates, I • Body cavity partially derived from mesodermally derived tissue • Phylum: Rotifera • 1st with a complete digestive tract • Hydrostatic skeleton • Parthenogenesis: type of reproduction in which females produce offspring from unfertilized eggs

  20. Eumetazoa: Pseudocoelomates, II C. elegans • Phylum: Nematoda(roundworms) • Very widespread group of animals (900,000 sp. ?) • Cuticle (tough exoskeleton) • Decomposition and nutrient cycling • Complete digestive track; no circulatory system many are parasitic • hookworm • Trichinella spiralis

  21. The Coelomates: Protostomes, I • Phylogenetics debated…. • Phy: Nemertea (proboscis and ribbon worms) • Complete digestion and closed circulatory system (blood) • Phy: thelophophorates (sea mats, tube worms, lamp shells) • Lophophore: Circular shaped body fold with ciliated tentacles around the mouth

  22. The Coelomates: Protostomes, II • Phylum: Mollusca (snails, slugs, squid, octopus, clams, oysters, chiton) • Soft body most protected by a hard shell of calcium carbonate • Foot (movement), visceral mass (internal organs); mantle (secretes shell); radula (rasp-like scraping organ) true coelem • increases complexity & specialization of internal organs

  23. Phylum Mollusca • There are 3 types of mollusks: • Gastropods: sea slugs, snails and slugs • Bivalves: clams, oysters, mussels, and scallops (2 hinged shells) • Cephalopods: built for speed and motility, include squid and octopi; have sophisticated sense organs.

  24. Class Cephalopoda squids, octopus, cuttlefish, nautilus

  25. The Coelomates: Protostomes, III • Phylum:Annelida(earthworms, leeches, marine worms) • True body segmentation (specialization of body regions) • Closed circulatory system • Metanephridia: excretory tubes • “Brainlike” cerebral ganglia • Hermaphrodites, but cross- fertilize leech fan worm

  26. The Coelomates: Protostomes, IV • Phy: Arthropoda trilobites (extinct); crustaceans (crabs, lobsters, shrimps); spiders, scorpions, ticks (arachnids); insects (entomology) • 2 out of every 3 organisms (most successful of all phyla) • Segmentation, hard exoskeleton (cuticle)~ molting, jointed appendages; open circulatory system (hemolymph); extensive cephalization

  27. Arthropod groups arachnids 8 legs, 2 body parts spiders, ticks, scorpions crustaceans gills, 2 pairs antennae crab, lobster, barnacles, shrmp insects 6 legs, 3 body parts

  28. The Coelomates: Deuterostomes, I • Phylum: Echinodermata(sea stars, sea urchins, sand dollars, sea lilies, sea cucumbers, sea daisies) • Spiny skin; sessile or slow moving • Often pentaradial • Water vascular system • They are radially symmetrical as adults, and bilateral as larvae.

  29. Water Vascular System • Madreporite • stone canal • ring canal • radial canal • lateral canals • Ampulae • tube feet

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