Arthropods and Echinoderms

Khang nguyen4

Introduction to the ArthropodsWhat is an Arthropods ?

Arthropods have a segmented body a tough exoskeleton, and joined appendages.Exoskeleton- the exoskeleton is like a suit of armor that protects and sup-ports the body.Appendages are structures such as legs and antennae that extend from the body wall.

http://en.wikipedia.org/wiki/Grasshopper

Evolution of ArthropodsTrilobites, such as the fossilized

one shown above, were marine arthropods that were abundant more than 500 million years ago.

They were divided into many body segments, each with a walking leg.

Trilobites became extinct some 200 million years ago.

Living arthropods generally have fewer body segments and more specialized appendages than ancestral arthropods.

http://en.wikipedia.org/wiki/Trilobite

Form and function in arthropods* Arthropods use complex organ systems to carry out different essential functions.

* Most arthropods use tracheal tubes or other specialized organs for respiration, have an open circulatory system, and excrete wastes through saclike tubules.

* This nut weevil use its mouthparts to bore into and eat nuts.

http://en.wikipedia.org/wiki/Weevil

Work cited

• Levine, Joe and Miller, Ken.• Biology: New Jersey, Prentice Hall,

2002.• Page: 714-719