Transcript Phylum Arthropoda

Phylum Arthropoda
Copy this organization down.
Kingdom Animalia
Can you give the common
Phylum Arthropoda
name for each group listed?
Subphylum Crustacea
Class Cirripedia
Class Copepoda
Class Malacostraca
Order Decapoda
Order Euphausiacea
Subphylum Chelicerata
Class Merostomata
Class Pycnogonida
Arthropods
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Largest phylum of
animals
1 million species
(some estimates
say up to 20
million)
Includes mainly
terrestrial bugs
3 out of every 4
animals are
arthropods
General Characteristics of Arthropods
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Segmented body
Bilateral Symmetry
Jointed
appendages
Chitinous
exoskeleton
Sub Phylum Crustacea
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Includes:
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Shrimp
Crabs
Lobsters
Barnacles
General Characteristics of Crustaceans
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Two pairs of
antennae
Mandibles for
chewing
Pair of
appendages on
each body
segment
Gills for oxygen
Molting
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To grow,
arthropods must
molt their
exoskeleton
Digestion
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Smaller crustaceans
are filter feeders,
catching particles in
bristles on their
appendages
Some have
specialized
appendages that push
food towards their
mouths
Nutrients passed to an
open circulatory
system
Nervous System
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Can vary from simple
ladder-like to
centralized nervous
systems
Most have compound
eyes
Keen sense of smell
Communicate with
each other via body
postures
Compound Eyes
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Bundles of up to
14,000 light
sensitive units
grouped together
Reproduction
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Separate sexes
Mating usually takes place
immediately after female molts
Some carry eggs in appendages
under the body
Planktonic larvae (number of stages
varies from group to group
Class Cirripedia
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Filter feeders
Cirri – feathery like
appendages (actually
legs) sweep water
Attached to surfaces
including living ones
Calcareous
plates/shells (look like
mollusks)
Class Copepoda
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Abundant and
important in the
role of plankton
Can use their
antennae to swim
“Sea Monkeys”
Importance of Copepods
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Most numerous
multi-cellular
animals on Earth
Eat the tiniest
plankton and are in
turned eaten by
fish & krill
Nutrient cycling
Order Decapoda
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“ten legs”
Largest
crustaceans in
terms of size
Extended carapace
Shrimp, lobsters,
and crabs
Order Decapoda
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Five pairs of walking legs (pereopods) of
which one is usually heavier (claws)
Carapace encloses the cephlalothorax with
the rest of the body being the abdomen
Order Decapoda
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Shrimp and
lobsters can range
from scavengers to
parasite removers
Crabs tend to be
scavengers
Order Euphausiacea
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Krill
Planktonic
Shrimp-like
Filter feeders (eat diatoms)
Head fused with body pieces to form a
unique carapace
Major food source for larger organisms
(whales, seals, penguins, etc.)
Very common in polar waters
Sub Phylum Chelicerata
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Includes
Horseshoe crabs,
spiders, mites
Chelicerae are the
only small
appendages before
the mouth
Range from small
pinchers to
venomous fangs
Class Merostomata
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Horseshoe Crabs
Not true crabs and
have not evolved for
millions of years
Six pairs of
appendages
No mandible jaw
Chelicerae, Walking
Legs, four pairs of
Pushing Legs
Telson or tail used for
steering and flipping
itself right side up.
Class Pycnogonida
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Sea Spiders
Have four or more pairs of
legs
A large proboscis with a
mouth on the tip allows it to
feed on soft invertebrates
No respiratory system as
gases diffuse through body
Tiny muscles consist of one
cell covered with
connective tissue