Arthropod Lab

Andres Sanchez/ Pre-ap Biology/ 7th period/ Guzman

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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.

Scientific Classification

Kingdom: Animalia

Phylum: Arthropods

Class: Crustacean

Order: Decapods

Family: Cambaridae

Genus: Cambarus

Species: Crayfish

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The grasshopper is a medium to large sized insect and the grasshopper is found (close to grass) all over the world. Grasshoppers are best known for their ability to jump incredible heights and distances. Most grasshopper individuals grow to about 2 inches long although larger grasshoppers are found on a fairly regular basis that grow to more than 5 inches in length. The grasshopper has wings meaning it can migrate over long distances when the weather gets too cold. Like all insects, all species of grasshopper have a three-part body that is made up of the grasshopper's head, it's thorax and the abdomen. Grasshoppers also have six legs, two pairs of wings, and two antennae.

Scientific Classification

Kingdom: Animalia

Phylum: Arthropoda

Subphylum: Hexapoda

Class: insecta

Order: Orthoptera

Suborder: Caelifera


Students will:

  • 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.

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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.

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Grasshopper Life Cycle

An adult grasshopper goes through the stages egg, nymph and adult, and has a lifespan of approximately one year.
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Crayfish habitat

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.

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Grasshopper habitat

Most grasshoppers prefer dry open habitats with lots of grass and other low plants, though some species live in forests or jungles. Many of the grassland species invade farmer's fields too.
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Crayfish Predators

The Green Heron are a common species that feed on the crayfish. The Green Heron is relatively small; adult body length is about 44 cm (17 in).
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Grasshoppers' predators

Rodents are typical predators of the insect known as the Grasshopper.

Evolutionary Relationships of a Crayfish

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Evolutionary Relationships of a Grasshopper

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External anatomy

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External anatomy of Grasshopper

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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.
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Grasshopper Integumentary System

Their three part body contains of a head, a thorax, and an abdomen. The exoskeleton is divided into section with flexible joints that allows movement more easily. The joints that the grasshoppers have can be compared to humans because they allow movement but our connect our bones while the grasshoppers needs connection of its three tagmata. That is because humans have an endoskeleton and outer covering is there to protect the organs we have inside.