Anusha De 4/9/14 Vu-PAP Bio- P3
- Kingdom: Animalia - eukaryotic, multicellular
- Phylum: Arthropoda - segmentation, bilateral symmetry, jointed paired appendages, chitinous exoskeleton
- Class: Insecta - 3 main body parts, compound eyes, metamorphosis
- Order: Orthoptera - cylindrical body, hind legs
- Family: Acrididae - short or absent wings, short antennae
- Genus: Melanoplus
- Species: Differentialis
- Class: Crustacea - gills, exoskeleton, filter feeder
- Order: Decapod - chelipeds, 10 legs
- Family: Cambaridae - 2 main body parts, large pincers
- Genus: Cambarus
- Species: Bartonii
Arthropods at a Glance
All organisms in class Insecta have bodies divided into 3 parts (head, thorax, abdomen), 6 legs attached to the thorax, two antennae, and lateral compound eyes. Melanoplus differentialis, otherwise known as grasshoppers, are organisms that have olive green, brown, or yellow cylindrical bodies that can be up to 1.75 inches in length. They have enlarged femora (hind legs) which have distinctive black markings. Grasshoppers eat most types of plants, and have a variety of predators. Grasshopper adaptations include enlarged femora for jumping and the ability to detect moisture in the environment (through antennae).
All organisms in class Crustacea have 2 body regions, 2 pairs of antennae, at least 5 pairs of legs, and are primary aquatic. Cambarus bartonii, otherwise known as crayfish, are organisms that have 10 legs. The front two legs are actually large claws called chellae. Crayfish use their chellae for self-defense and to attack prey.
Anatomy and Dissection
The Respiratory System
- spiracles - let air in
- tracheae - carry oxygen throughout the body
- tracheoles - carry oxygen directly to cells
Grasshoppers are most commonly found in fields, woods, and the edges of water bodies such as ponds, streams, and lakes. In the first food chain below, grasshoppers would be classified as primary consumers because they are consuming grass, the producer. Grasshopper prey includes plants such as grass, weeds, crops, clover, and fruit. Predators of the grasshopper include a variety of animals: birds, frogs, lizards, turtles, raccoons, fish, yellow jackets, snakes, ants, centipedes, dragonflies, and crickets.
Crayfish are most commonly found in wet meadow environments, near farm ponds, in irrigation ditches, and generally any freshwater environment that has heavy soil. Crayfish tend to burrow underneath rocks relative to their size. In the second food web below, crayfish would be classified as secondary consumers because they are consuming honeybees (primary consumers), which are consuming dandelions (producers). Crayfish prey on both plants and animals. Some examples of crayfish prey are worms, insects, fish eggs, frogs, toads, and salamanders. Animals such as raccoons, opossums, snakes, and muskrats are predators of crayfish.
Grasshoppers are classified as agricultural pests because they eat so much plant life that they have the potential to devastate entire farms, especially when in groups. Each grasshopper can consume up to half its body weight in vegetation each day. This has happened many times in history, each with horrible results. An example of this, Grasshopper Plague of 1874, can be seen in the link below. To prevent heavy grasshopper infestations, many farmers and gardeners use a biological control protozoan called Nosema loucustae, or a chitin inhibitor called diflubenzuron.
Contrary to grasshoppers, crayfish are widely sought out by humans because they are so good to eat and are easy to find. Overfishing crayfish is a foreseeable problem because in addition to endangering the crayfish, it could severely disrupt the food chain in the crayfish's habitat.
- Ancestral arthropods were the first land animals.
- Arthropods molt their exoskeleton as they grow.
- All arthropods undergo metamorphosis at some point in their life cycle.
- Arthropods have been on Earth for 428 million years.
- Arthropods do not have blood vessels.
- Arthropods are cold-blooded.
- Arthropod means 'jointed foot' in Greek.
- All arthropods have multiple pairs of limbs.
- Arthropods live in a wide range of habitats, from deserts to oceans.
- Arthropods have been responsible for the most devastated plagues and famines in the history of mankind.