Crustaceans

 

Phylum Names

Kingdom: Animalia  

Phylum: Arthropoda organisms with segmented bodies, jointed legs or wings, and an external skeleton

Subphylum: Crustacea 

Common Names

Crustaceans include many common seafood such as:

CrabsShrimpLobster

And other common aquatic life such asBarnaclesCrayfish

  Giant Isopod                            Japanese Spider Crab

  

General Characteristics

-Nearly all aquatico  Few can live on land, such as hermit crabs

-Ranges in size from microscopic to very large -All are mainly free-living, some can be parasitic-Many move by swimming

o Some are sessile such as barnacles o Microscopic ones simply move by current such as krill

    

Anatomy and Body Form

• 3 Parts: Head, Thorax, Abdomen. Head + Thorax = Cephalothorax

• Exoskeleton - hard outer covering that protects the organism, molts for growth.o molting - shed previous exoskeleton, new and larger

exoskeleton is formed

Anatomy and Body Form

• Mandible - hard, short, hefty projections on each side of the mouth. used for biting and chewing food

• Maxillae - projections that hold food• Gills - gas exchange because aquatic• Antenna - 2, project out of head for sense and taste• Antenal glands - 2, large, inside head to take out

metabolic wastes from bodily fluids, excreted through base of antenna

• Statocysts- organ that senses gravity

Anatomy and Body Form

• Carapace- shield that covers the entire body, tough chitin• Chelipeds - pinchers• Swimmerets - small paddles on the underside of the

abdomen that are used for movement and holding eggs in females

• Compound Eyes - adults, little eyes inside a larger cavity, important for detecting movement

Gas Exchanges/ Secretions

• Gills for taking oxygen out of water and air• Chitin secreted through epidermis for exoskeleton molting

o  old exoskeleton isn't removed until the new exoskeleton is fully formed

• Simple excretory organs for waste such as urea and ammonia

• Antenal glands for excreting metabolic waste through base of antenna 

Feeding Practices

• many appendages for feedingo  mandible, maxilla, chelipeds, antenna

•  vary widelyo  filter feeders, scavengers, or predators

• Filter feeder - take out organic matter from water• Scavenger - scraps of dead organisms• Predator - mollusks• Parasites - small crustaceans on or inside fish

Super cute!

Response to Stimuli

• Possess a brain, ventral nerve cord, and well developed sense organs.o Can sense and react to a variety of stimuli.

• Capable of feeling pain as well as stress, and will react to negative stimuli. 

Reproduction

• Most reproduce sexually through eggs.o Most are separate sexes, few are hermaphroditeso Some reproduce asexually

• Female eggs are carried on the body. o Eggs will develop and hatch after fertilization

• Larvae undergoes a series of transformations to become an adult.o They grow by molting. 

• Some can change sex during their life