Arthropods

the original ragin cajun

arthropods

arthropods include: arachnids, insects, and crustaceans

Arthropods are invertebrates that have exoskeletons, segmented bodies, and jointed appendages. They can be characterized by their jointed limbs and cuticles, which are made of chitin. Arthropods' largest internal cavity is a hemocoel, which contains their internal organs. They have open circulatory systems and ladder like nervous systems. There are paired ventral nerve chords running through all segments and forming paired ganglia in each segment.The arthropod brain is formed by fusion of the ganglia of these segments. The respiratory and excretory systems vary upon the ecosystem and sub phylum of the arthropod.

Taxonomy

Kingdom: Animalia

Subkingdom: Eumetazo

Superphylum: Ecdysozoa

Phylum: Arthropoda

Evolution

Arthropods have evolved into many different classes. They have adapted new characteristics for specific functions. The fusion of body regions into segments was one major change in arthropods. The earliest arthropods resembled worms.

Lobster Circulatory System

The circulatory system is located within the cephalothorax, below the carapace. Instead of a four-chambered heart it has a single-chambered sac that consists of muscles and several openings called ostia. The heart sits above the stomach on the upper surface of the lobster. The heart of an adult lobster beats 50-136 beats per minute. This is a closed circulatory system.

Works Cited

"The American Lobster." The American Lobster. N.p., n.d. Web. 10 Apr. 2014.

"American Lobst "Evolutionary History of the Arthropods." Evolutionary History of the Arthropods. N.p., n.d. Web. 10 Apr. 2014.er - Life Cycle." - OGSL. N.p., n.d. Web. 10 Apr. 2014.

"Crustaceans." Crustaceans. N.p., n.d. Web. 10 Apr. 2014.