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Animal Diversity [Molluscs and Arthropods]


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what are the 3 layers that make up a mollusc shell
periostracum, prismatic, nacreous
how is their reproduction? internal or external (gastropoda)
internal, reproductive system is paired
describe picnogonida
sea spiders. (all marine) enlongated cephalothorax, reduced abdomen
describe nervous system in arthropods
highly developed. large brain to coordinate movement. ventral nerve cords w/ segmental ganglia. many forms of sensory organs. chemosensory: hair, pits, light/ sight- ocelli and compound eyes
what is the class of crustacea that contains crabs?
class gastropoda, describe. give example
radula well developed, tentacles, eyes, osphradia. shell: conical, spiral, tubular, snails, slugs, limpets
what are 3 other organs seen in molluscs
statocysts (orientation), eyes (light) osphradia on gills (chemosensory)
describe crustacea
mostly marine w/ biramous appendages. pairs 1-2: antennae pair 3: mandibles for feeding. pairs 4-5: maxillae handling. remaining- locomotion. respiration- protopodie. endo/exopod. circulatory system open. nervous system
which sub-class of gastropodahas see slugs w/ no shell and secretes defense substances
what are the 3 sub-classes of gastropoda
prosobranchia, opistobranchia, nudibranchia
what is nervous system like in molluscs
nerve ring around esophagus. two nerve cords through the body
describe trilobita
3 lobes vertically. all marine. all extinct by permian periods. biramous appendages. 3 body regions/tagmata: cephlon/head, trunk, pygidium
class cephalopda- describe reproduction and classification and nervous system
seperate sexes- external and internal fertilization. classification- w/ and w/ out shells. well developed nervous system. ganglia grouped in head. giant axons. eyes highly developed
two types of bivalvia feeders. describe
deposit feeders, head or mouth facing down w/ no radula, mantle cavity facing up (protruding out) suspension feeder- food filtered from the water/ gill- gill become longer to handle food
what is respiration like in molluscs
by gills or lungs. there are respiratory pigments
what is the digestive system like in a mollusc
open and complex. includes radula- a toothed structure for scraping
describe class monoplacophora
similar to ancestor. limpet-like, single dorsal shell. low diversity
What is excretion like in molluscs
metanephridia. blood collects wastes, they diffuse into coelom. metanephridia collect them and dispose them in the mantle cavity
what type of excretory system in arthropods
same problem- need specialized structures. insects-malpighian tubules, spiders- coaxal glands, crustaceans- green glands.
what type of circulatory system in arthropods? describe
open circulatory system. long dorsal heart w/ 1 way valves (hostia) blood sinus/hemocoel
what type of fertilization is seen in bivalves
most external. larva veliger
what is the unusual way to grow. how?
molting or ecdysis. 2 ways (1) old cuticle seperates from epidermis. epidermal cells divide new cuticle is secreted, old one absorbed. (2)old cuticle splits and sheds- new cuticle hardens
what are the 3 sub classes of chelicerata
merostomata, picnogonida, arachnida
cephalapoda- describe locomotion and feeding
jet propulsion by muscles in mantle. longitudinal- draw water in, circular - push water out
What are the 3 regions of arthropoda.
head, thorax, abdomen
Describe malacostraca. how many segments are the tagmata divided into
most diverse. ~75% of all crustaceans. thorax 8 segments, 6 segments abdomen. This class includes the decapods (crabs and shrimp).
what type of respiratory system - arthropods
hard cuticle reduces permeability- need gills, trachea, etc.
what are the 4 classes of arthropods? eg of each
trilobites(trilobites, all fossils), chelicerata (spiders, mites, horseshoe crabs), crustacea (crabs, barnacles, copepods), uniramea (insects, centi and millipedes)
what are the 3 main innovations
appendages (flexible and jointed, uniramous or biramous) reduced coelom (no need for h.s. skeleton. surrounds gonads & excretory organs), exoskeleton (hardened plates, flexible joints. chitin and protein cuticle)
describe merostomata
primitive, all marine, large carapace, abdomen w/ telson. feeding: scavengers on small invertebrates. excretion: coxal glands collect NH3.
class bivalvia. describe give example
burrowing or sedentary. soft or hard bottoms. clams, mussels and scallops
describe class aplacophora
no plates or shells. lost shell- mantle rolled. deep sea habitat. carnivores and scavengers.
describe arachnida
mostly terrestrial, wax on cuticle, trachea, spiracles. feeding: predators or scavengers. Poision glands. digestion starts outside (they liquify food and then suck it into mouth). spiders, scorpions, mites, ticks.
open or closed circulatory system ? (molluscs)
open. heart inside coelom
what is the basic body plan for molluscs?
mantle (&shell), mantle cavity, head foot, and visceral mass
describe cephalopoda feeding
catch prey with tentacles. chitinous, jaws and radula. ink sac or "smoke screen"
describe chelicerata
spiders, ticks, mites, horseshoe crabs. mostly terrestrial. six pairs of appendages. pair 1: chelicerae. Pair 2: pedipalps. pair 3-6-
describe reproduction
most groups are dioecious, eggs brooded (in most) Different larvae: nauplis, zoea, megalopore
describe class polyplacophora
chitons. shell w/ 8 overlapping plates. flexible to bend over rocks. have radula to scrape kelps. marine, large foot, diecious. mantle cavity w/ grooves and gills
radula is seen in all classes of molluscs except
digestive system- 3 parts
foregut- ingestion, breakdown. midgut- digestion, and absorption . hindgut - absorption water and feces
what's another word for region

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