CLAW MEETS HOP

Phillip Lu

OBJECTIVES

Students will examine two arthopods - a grasshopper and a crayfish.

They will look for similar traits that these two share in their phylum.

Finally, they will look for differences that may be because of class traits.

THE GRASSHOPPER

The Grasshopper, Chorthippus brunneus, are part of the insect family. Grasshoppers have three pairs of segmented and jointed legs, at least one pair of antennae, multi-faceted eyes, an exoskeleton, and three distinct body segments-the Head, the Abdomen, and the Thorax. Grasshoppers are known for their ability to leap very high up into the air, and are also known for the cricket sounds they make by rubbing their legs against their thoraxes

GRASSHOPPER Pt. 2

Grasshoppers are among the most common of insects, and can be found virtually anywhere. The ideal habitat for a grasshopper is a low-lying area rich in grasses and leaves. Although a grasshopper's diet usually only consists of grasses and leaves, grasshoppers are not known for being finicky, usually just eating about everything. Grasshoppers are herbivores, and eat plant matter. Grasshoppers are not predatory, but rather are prey for other predators. Larger carnivorous insects eat the grasshopper, such as the praying mantis, arachnids such as scorpions and spiders, rodents, snakes, and some frogs. Grasshoppers make their characteristic chirping and cricketing sound by rubbing their hind legs against their thorax, and use it as a mating call. Upon fertilization, the egg will develop and be laid by the female, hatching typically a month after being laid. Larvae, or nymphs, hatch out of the egg and enter the world. Given it survives that long, the average nymph or larvae will mature into an adult grasshopper in about 3 months. All in all, grasshoppers aren't very long lived as organisms go, having an average lifespan of only one year.

RESPIRATORY SYSTEM

The grasshopper breathes using openings on the sides of its body known as spiracles. All in all, the grasshopper possesses ten pairs of spiracles (eight on the abdomen and two on the thorax). To protect the spiracles and ensure a level of homeostasis, valves that line the spiracles open and close in response to environmental changes, and hairs located around the spiracles prevent foreign objects from falling in. The respiratory system of the grasshopper comprises of a series of air sacs, a spiracular trachea, a visceral trachea, and spiracles. The atria are small spaces connected to the spiracles, feeding into larger spaces known as the trachea. Oxygen is taken in by the first 4 spiracles, and the last 6 excrete carbon dioxide.

HOPPING TO EVOLUTION

The grasshopper has developed numerous evolutionary traits that enable it to survive despite the high number of its predators. The grasshopper, like many insects, possess wings and the ability to fly, enabling the grasshopper to get out of threatening positions easily. In addition to wings, the grasshopper has powerful hind legs that it can use to lunge or jump out of harm's way. The grasshopper is always feeling jumpy. Being an insect, the grasshopper has a hard exoskeleton that can protect it to some degree against certain predators.

INTERESTING FACTS

1. Grasshoppers and locusts are the same: when they emigrate in swarms they are called locusts.

2. A grasshopper’s eardrum is on its abdomen, so you could say they hear with their bellies.

3. The fossil record shows that grasshoppers have been around for 200 million years and had evolved before the dinosaurs appeared.

4. Grasshoppers are good at detecting rhythm, but bad at detecting differences in pitch of notes.

5. They make noises by stridulating (rubbing the hind leg against the wing) and crepitating (snapping the wing in flight).

6. The 10,000 or so different species of grasshopper have distinct identifying rhythms.

7. In Japan, grasshoppers are seen as a sign of good luck.

8. Grasshoppers can jump a height of about 25cm and length of a metre.

9. A small cuticle in a grasshopper’s knee acts as a spring and lets it catapult its body into the air.

10. Eating insects is called ‘entomophagy’. Chapulines fundido (grasshopper fondue) consists of crispy fried grasshoppers on a bed of a puree of grasshoppers with shallots, garlic and chilli.

ARTHOPODS Pt. 2: CRAZY CRAYFISH

CRAYFISH

Crayfish are of the order decapoda, and are water-loving crustaceans. The adult crawfish strikingly resembles a miniature lobster, and has a jointed body, usually a mottled brown, light brown, or gray. Crayfish, however turn bright red when cooked, much like shrimp. The eyes of crayfish are on separate stalks, and the cray fish and the lobster are actually, in a way, related. Both organisms are sea crustaceans that belong to the superfamilies Astacoidea and Parastacoidea.

CRAYFISH RESPIRATORY SYSTEM

The grasshopper breathes using openings on the sides of its body known as spiracles. All in all, the grasshopper possesses ten pairs of spiracles (eight on the abdomen and two on the thorax). To protect the spiracles and ensure a level of homeostasis, valves that line the spiracles open and close in response to environmental changes, and hairs located around the spiracles prevent foreign objects from falling in. The respiratory system of the grasshopper comprises of a series of air sacs, a spiracular trachea, a visceral trachea, and spiracles. The atria are small spaces connected to the spiracles, feeding into larger spaces known as the trachea. Oxygen is taken in by the first 4 spiracles, and the last 6 excrete carbon dioxide.

CRAYFISH EVOLUTION

Having evolved from more primitive crustaceans, crayfish have a wide array of defenses against predators. Firstly, most of the crayfish is covered in a thick and hard exoskeleton, making it hard to chew or attack. Secondly, crayfish possess a small set of pincers that can be used in defense. These pincers are not as effective as the massive pincers on lobsters, mind you, but for a crayfish, small pincers do the job. Lastly, Crayfish instinctively choose to hide in rocky outcrops or rocks, camouflaging against the brown or grayish rocks. And, should a predator find a crayfish, it could be hard to get the crayfish out.

DISSECTION PICTURES

INTERESTING FACTS

Someone who studies crayfish (and some other fish) is called a Hydrogeologist .

There is a species that is blue. It is called a Blue Crayfish. There are also red and white crayfish.

The red crayfish is the most common, the blue is the second most common, and the white crayfish is the least common.

With proper care a crayfish can live two years in captivity.

Over 350 species of the 500 crayfish species of the world live in the United States.

The most common crayfish gets 3-4 inches long, but they can get much bigger in the wild in deep lakes.

There is a crayfish that is called a dwarf crayfish that is really tiny.