Andres Sanchez/ Pre-ap Biology/ 7th period/ Guzman
Crayfish are Crustaceans, and are closely related to lobsters, crabs, and shrimp. They have ten legs; the front two have developed large claws called "Chellae". Crayfish use their chellae not only to defend themselves, but also to attack prey, move small objects such as stones, and pick things up. Crayfish are omnivores, so they eat both plants and animals. They are also scavengers and will eat dead things, as long as they are relatively fresh.
- Examine two preserved arthropods - a grasshopper and a crayfish.
- Look for similarities in these two animals that may be phylum traits.
- Look for differences in both that may be class traits. Grasshoppers belong to the class Insecta whereas the crayfish belongs to the class Crustacea.
Crayfish Life Cycle
The life cycle of the crayfish starts with the egg. The egg is attached to the tail of the female and when the eggs hatch they are fully formed. The crayfish stays with the mother for one to two weeks and then separate from its mother. It takes about three to four months for it to reach adult size and the lifespan of the crayfish is three to eight years.
Grasshopper Life Cycle
Crayfish can be found in just about any body of fresh water which isn't over-polluted. This includes streams, rivers, lakes, ponds, and sometimes even water-filled ditches.
Evolutionary Relationships of a Crayfish
Evolutionary Relationships of a Grasshopper
External anatomy of Grasshopper
Crayfish Integumentary System
- This crustacean has a hard exoskeleton that protects and supports the body. The crayfish has 8 jointed walking legs, a segmented body, 2 pairs of sensory antennae, and compound eyes. It has 2 large pincers or claws called chelipeds. If a crayfish loses a leg, the leg will regenerate (regrow). The head and thorax are fused, forming the cephalothorax. Using gills, a crayfish breathes oxygen that is dissolved in water. Juvenile crawfish are light tan, but adults are deep red.