Bio 1AL Study Guide - Bio 1AL Study Guide Invertebrates I Porifera a Sponges b Contains about 6000 species c Features i Multicellular ii Sessile

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Bio 1AL Study Guide Invertebrates I. Porifera a. Sponges b. Contains about 6000 species c. Features: i. Multicellular ii. Sessile iii. Lack true tissues iv. Suspension feeders v. Chanocytes contain flagella that beat and create a current of water vi. Amoebocytes help distribute food throughout the sponge II. Cnidaria a. Contains about 10,000 species b. Four classes: i. Anthozoa- corals and anemones ii. Hydrazoa- hydras and a few corals iii. Cubozoa- box jellyfish and sea wasps iv. Scyphozoa- jellyfish and sea nettles c. Features: i. Multicellular ii. Radially symmetric iii. Primarily lack organs iv. Possess true tissue (metozoans) v. Contain specialized cells called cnidocytes 1. Contain stinging organelles called nematocysts vi. Possess a gastrovascular body plan and gastrovascular cavity 1. One opening for mouth/anus vii. Two germ layers 1. Outer epidermis (ectoderm) 2. Inner gastrodermis (endoderm) a. Note: have space in-between these two layers called mesoglea viii. Two body plans 1. Sessile- immobile 2. Medusa- free swimming ix. Primitive nervous system arranged in the form of an irregular net 1. No cephalization x. Dioecious or monoecious 1. Some are dioecious, others monoecious III. Platyhelminthes a. Contains about 15,000 species b. Classes: i. Turbellaria- free-living
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ii. Trematoda- flukes iii. Cestoda- tapeworms c. Features i. Three germ layers 1. Ectoderm 2. Mesoderm 3. Endoderm ii. Organ level of organization iii. Bilateral symmetry iv. Some cephalization v. Acoelomate vi. Digestive System 1. Gastrovascular cavity with a mouth, pharynx and three-branched gastrovascular cavity vii. Nervous system 1. Arranged like a ladder 2. Cephalization observed at anterior end 3. Eyespots are light sensitive and allow the planaria to respond to varying light intensities but no imaging viii. Excretory system 1. Nitrogenous waste freely diffuse across surface 2. Protonephridia: regulate ion balance (osmoregulation) a. Similar to a contractile vacuole in protozoans ix. Reproductive System 1. Undergo asexual or sexual reproduction a. Asexual occurs via regeneration 2. Monoecious a. Cross-fertilization IV. Annelida a. Contains about 15,000 species b. Classes Included: i. Polychaetes- Segmented bristleworms ii. Oligochaetes- Earthworms iii. Hirudinea- leeches c. Features i. True coelomic cavity ii. Metamerism 1. Repetition of body parts iii. Complete digestive system with mouth and anus iv. External Appearance 1. Each segment is known as a somite 2. Setae a. Hair like projections used for traction as earthworm moves 3. Clitellum a. Conspicuous swelling that extends over several somites i. Secretes mucus used during reproduction
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4. Dorsal blood vessel v. Locomotion: occurs by a series of synchronized contractions of longitudinal and circular muscles vi. Digestive System 1. Pharynx, esophagus, crop, gizzard, intestine, anus 2. Calciferous glands a. Swellings near the crop vii. Circulatory System 1. Closed circulatory system 2. Dorsal blood vessel and pseudohearts
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This note was uploaded on 09/25/2008 for the course BIO 1al taught by Professor Pederson during the Spring '08 term at University of California, Berkeley.

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Bio 1AL Study Guide - Bio 1AL Study Guide Invertebrates I Porifera a Sponges b Contains about 6000 species c Features i Multicellular ii Sessile

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