The Crustacean group includes Barnacles, Crabs, Crayfish, Lobsters, Water fleas, and Pill Bugs. Although crabs and lobsters may look different, they share a common physiology.
Body Anatomy:
Crustaceans can range in sixe from 0.1 mm all the way up to 3.8m. Like other arthropods, crustaceans have an exoskeleton which they molt to grow. They are distinguished from other arthropods such as insects by the possession of biramous (two-parted) limbs. The body of the crustacean is composed into three general regions: the head, thorax, and the abdomen. The head and the thorax may be fused together to create the cephalothorax. Each body segment can bear a pair of appendages: on the segments of the head, these includes two pairs of antennae, the mandibles and the maxillae; the thorax segments bear legs; the abdomen bears pleopods and ends in a telson.
Body Anatomy:
Crustaceans can range in sixe from 0.1 mm all the way up to 3.8m. Like other arthropods, crustaceans have an exoskeleton which they molt to grow. They are distinguished from other arthropods such as insects by the possession of biramous (two-parted) limbs. The body of the crustacean is composed into three general regions: the head, thorax, and the abdomen. The head and the thorax may be fused together to create the cephalothorax. Each body segment can bear a pair of appendages: on the segments of the head, these includes two pairs of antennae, the mandibles and the maxillae; the thorax segments bear legs; the abdomen bears pleopods and ends in a telson.
Habitat:
Crustaceans can be found in a wide range of habitats: most are free-living freshwater or marine animals, but some are terrestrial, some are parasitic, and some do not move.
Diet:
Many crustaceans are scavengers, feeding on scraps and dead creatures. Crabs, shrimp, and prawns search for food mainly at night and hide in crevices by day. Some crabs and lobsters are active predators, seizing prey in their powerful claws. Barnacles filter tiny creatures from the water using their hairy legs.
Reproduction:
The majority of crustaceans have separate sexes, and reproduce sexually. A small number are hermaphrodites. Some may even change sex during the course of their life. In many groups of crustaceans, the fertilised eggs are simply released into the water column, while others have developed a number of mechanisms for holding on to the eggs until they are ready to hatch. Life Cycle: The crustacean life cycle has 5 different stages: The Nauplius stage, Zoea Larval stage, Mysis or Megalopa stage, Post-Larval Stage, and the Adult Growth stage.
|
1.) The Nauplius Stage: This stage of the crustacean's life cycle is perceived as being a defining link among all crustaceans. This is the first larval stage for crustaceans and consists only of the crustacean's head and telson as neither the abdomen nor the thorax has developed. The nauplius has only a single eye located atop the head and three pairs of cephalic appendages that allow them to swim.
2.) The Zoea Larval Stage: When the zoea name was given to the crustacean, naturalists believed that it was an entirely separate species. During this stage, the larvae will swim with thoracic appendages rather than cephalic appendages. 3.) The Mysis or Megalopa Stage: The stage of growth following the zoea stage of growth is either the mysis or megalopa stage dependent on what crustacean group is involved. The megalopa stage is the final stage of growth for most decapod crustaceans including lobster and crabs. 4.) The Post-Larval Stage: During the post-larva growth stages, the maturing crustacean will begin to look more like its adult form. This is also the stage of growth where the crustacean will depend more on foraging and grazing to feed. This is the period of growth where the crustacean will begin to develop its legs for swimming as well as walking. By the time the crustacean has reached the end of its post-larval growth stage, it will be at its full size and its adult appearance. 5.) The Adult Growth Stage: The adult growth stage is reached by one year of age for most crustaceans. After a year has passed, most crustacean varieties will be capable of mating and reproducing. By the adult stage of life, the crustacean has finished growing and is grazing and feeding on its own rather than relying on nutrients from its egg. |
- The giant Spider Crab of Japan measures up to 12 feet
- Lobsters have teeth-like structures in their stomach to grind up food
- There are over 44,000 species of crustaceans
- Live lobsters can be blue, yellow, orange and white, but never red. They turn red after they have been cooked.
- The arrow crab looks more like a spider than a crab
- Rolie-Polies are crustaceans!