Comparing Invertibrates

Objective: Pick three invertebrates. Compare them in terms of physical features and systems. Identify at least three similarities and differences.

Mole Crab (Emerita)
Physical Characteristics:
- five pairs of legs
- move backwards
-no pincher
-the strongest pair of legs would be on it's back, allow it to paddle backwards in the sand
-can grow up to 35 mm long and 25 mm wide
-female have a larger carapace(head), 14-35 mm while males have 10-22 mm
- eggs on female would be under the telson, would be bright orange

System:
 -have two pairs of antenna; one for sensing danger, another for feeding
-have eye stalks that reaches above the sand
-crab is divided into two sections, the carapace and abdomen
-carapace contains the head, eye stalks, and the two antennas
- the abdomen includes the telson (tail) and the pleopods (section between tail and head.)

King Crab (Paralithodes Camtschaticus)
Physical Characteristics:
-carapace can measure up to 11 inches
-legs can grow up to 6 feet
-can weight up to 18 pounds
-because of their shell, they are though to have been from the ancestors of the hermit crab
-only crab to have 6 legs instead of 8 legs
- red, blue, brown, and golden is one of the most common crabs caught and sold

System:
- the organs for the digestive tract, respiratory, reproductive and circulatory system are all located in the carapace
-the mouth is located underneath the eyes and antenna
-they have spiny plates that are positioned laterally to grind up the food
- after the food have been processed by the digestive system, they come out as feces called 'bile'
-the liver is the largest organ in the crab

Cockroach (Blattaria)
Physical Characteristics:

-world's heaviest cockroach would be around 30 grams called the giant burrowing cockroach
-they have large compound eyes
- two ocelli
-long flexible antenna
- first pair of wings are hard and act like a shield for the hid wings
-the abdomen have 10 segments
-each leg have five tiny claws
- all four wings have branching longitudinal veins, and multiple cross-veins
 System:
-breath through the treacheae
- the treacheae are attached to the spiracles, meaning that the insect does not depend on the mouth to breath
-treacheae brings air directly to the cells
-uses pheromones to attract mate
-phermones are released from their feces that can lead other roaches to food and water sources
- they carry their young in a capsule called the Ootheca, which is exposed halfway out of their body when the female is matured
- roaches have a incomplete metamorphases