Phylum Arthropodaomarascience.weebly.com/.../2/7/7/4/2774881/arthropoda.pdfPhylum Arthropoda Largest...
Transcript of Phylum Arthropodaomarascience.weebly.com/.../2/7/7/4/2774881/arthropoda.pdfPhylum Arthropoda Largest...
Phylum Arthropoda
Phylum Arthropoda
Largest of all phyla (1,000,000+ species)
Segmented bodies
Jointed appendages
Tough exoskeleton made of chitin
Many have specialized appendages
One-way digestion, bilateral symmetry
Class Crustacea
Two body segments—cephalothorax and abdomen
Carapace: exoskeleton that covers cephalothorax
Also have calcium carbonate within exoskeletons, giving them a “crusty” texture (named for)
Cephalothorax
Abdomen
Order Decapoda—10 legs!
Most of the larger crustaceans
Five pairs of legs under carapace
1 pair claws—for feeding, 4 pairs walking legs
Head—two eyes, two pairs antennae
Thorax—legs
Abdomen—swimmerets
Examples: lobster, crab, shrimp
Lobsters
Aggressive predators
Regenerates appendages
Open circulatory system (hemocyanin)
Breathe with gills attached to walking legs
Well-developed nervous system
Lobster Anatomy
Lobster Reproduction
Internal fert., external develop.
Male stores sperm in female’s seminal receptacle
Eggs are fert. as released
Female carries eggs on abdomen up to 1 year
Hatch into planktonic larvae
Molt and grow into adult
American Lobster
Bottom-dweller, cold waters
Eats mollusks
Swimmerets not as useful as in shrimp, but can propel backwards using tail fan
Crabs
Two body segments, abdomen—small, flat, folded between walking legs
Shape of abdomen determines sex:
U shaped=female
V shaped=male
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♂
Crabs
Scavengers, algae eaters, predators
Claws to tear and shred food
Mouthparts to cut into smaller pieces
Large # of offspring—female carries between abdomen and thorax
Open circulation, well-developed nervous system
Mole (Sand) Crab
Follows tide
Burrows often
Feather-like antennae for feeding
Fiddler & Hermit Crabs
Fiddler—digs tunnels in sand, plugs up hole at low tide, claw for defense or show
Hermit—soft abdomen lacking exoskeleton, finds empty shell (gastropods), lives in shallow, coastal waters
https://www.youtube.com/watch?v=ExV4b77qfww
Spider Crab
Slow, no paddling appendages, algae and barnacles grow on shell
Shrimp
Planktonic swimmers
Cleaner: coral reefs, eats parasites
Mantis: Largest shrimp, burrow in sand or mud, spears prey with jackknife front legs
Pink-Gulf Shrimp: Carolinas and the Gulf of Mexico
Bycatch
Brown shrimp
Copepods and Krill
Copepods: less than 1 cm, most abundant crustacean, elongated antennae, single eye
Krill: less than 5 cm, cold water
Base of ocean food chain
Isopods
aka sea roach
Evolution to land?
Coastal waters, nocturnal
Some parasitic
Barnacles
Sessile crustaceans
Attach to substrates, “glue” secreted by gland
Body folded in shell
6 pairs of cirri protrude from shell, filter-feeders
Breathe by diffusion
Hermaphrodites
“Fouling”
Class Merostomata
Horseshoe crabs
Atlantic and Gulf coasts
4 eyes
1 pair of chelicerae (pinching claws)
5 pairs walking legs
Book gills—breathing and locomotion
Telson (tail) used for locomotion
Marine Insects (Class Insecta)
3 pairs legs, 3 body segments, 1 set antennae, 1 pair eyes
Rarely in open ocean
Common in marsh and bay areas
Examples: marsh mosquito, greenhead fly, sand fly