Download Subphylum Crustacea

Chapter 38
Arthropods
Subphylum:
Crustacea
Characteristics
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Arthropods have three main
characteristics:
1. A tough exoskeleton, made of chitin
2. Jointed appendages
3. A segmented body
Subphylum Crustacea
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Contains over 40,000 species
Crustaceans are abundant in oceans,
lakes, and rivers
Some crustaceans are
– Sessile (no movement)
– move by walking on legs
– swimming with paddle like appendages
– Drift with currents
Crustaceans
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Includes shrimp,
lobsters, crayfish,
barnacles, isopods,
copepods, and water
fleas.
External Structure
2 Major Sections:
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Cephalothorax:
– Head with 5
segments
– Thorax with 8
segments
– Fused together =
carpace
Abdomen:
– 7 segments
– 7th segment = telson
External Features
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2 pairs of
antennae/feelers
 Mandibles
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Chelipeds-modified claws
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Maxillae
Maxillipeds
Larger claw crushes prey
Smaller claw holds and tears
food
Walking legs
Swimmerets
Uropod- tail flips
Crayfish
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A freshwater crustacean
A decapod: 10 feet composed of 5
pairs of legs. Shrimps and Crabs are
also decapods.
Crayfish parts
Feeding
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Crayfish are bottom dwellers
Eat things such as worms, slugs, bugs
and vegetation
Minimal effort into hunting but will eat
small fish that inhabit the area they
live in
Digestion
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Food  esophagus  stomach intestine
 anus
– teeth made of chitin and calcium carbonate grind
the food into a fine paste
– Paste mixed with enzymes secreted by a
digestive gland
– Move to intestine for digestion and absorption.
– Indigestible material is excreted through the
anus
Crustacean Excretion
H20 constantly
enters tissues
by osmosis
Have green
glands
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–
–
Eliminates
excess water
Through pore
at base of
antennae
Respiration
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Gills:
– Extend from base
of walking leg
into chamber
under carapace
– Legs circulate
H2O across gills
– Permits gas
diffusion
OPEN Circulatory System
Nervous System/Response
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Brain that consist of ganglia
– Receive nerve impulses from eyes &
antennules
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Ventral nerve cord
Sense vibrations and chemical in water
– Small sensory hairs on exoskeleton
Reproduction
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Male deposits sack
filled with sperm on
the underside of the
females belly
Female release eggs
to sperm
Embyro free
swimming naupilus 
molts  adult
– 3 pairs of appendages
– single eye