Question

1) Animals vary in size, which is largely due to surface area-to-volume ratios. Explain what surface area to volume ratios are and why this is important for animals. Give three examples from three different phyla of structures that were gained or lost due to surface area volume ratio.

2) Flight has evolved independently three times in the animal kingdom. Compare and contrast the three different evolved forms of flight in the animal kingdom. Discuss the groups they evolved in and the specific structural differences and similarities.

3)Echinoderms have unique body plans considering their closest relationships. Identify and describe three unique characteristics of echinoderms’ body plan.

Answer 1

(1)the ratio between the surface area and volume of cells and organisms has an enormous impact on their biology for example many aquatic microorganisms have increased surface area to increase the drag in the water.this reduces the rate of savings and allows them to remain near the surface with less energy expenditure. An increased surface area to volume ratio also means increased exposure to the environment .The finally branch appendages of filter feeders such as krill provide a large surface area to sift the water for food. Cells can achieve a high surface area to volume ratio with an elaborately convoluted surface like the micro villai lining the small intestine . Small organisms have relatively large surface area : volume ratio and there for efficient exchange of gases. (2) A number ofoanimals hove evolved aerial locomotion . It has evolved at least four times in the insects, pterosaurs, birds and bats.animal aerial locomotion can be divided into two categories powered and unpowered. (3) echinoderms are members of the phylum echinodermata from the Greek word for spinyskin .echinoderms are marine animals include starfish, sea urchin,sand dollars and sea cucumber. They are founded at every Ocean depth. Firstly they all posses five part radial symmetry around a central disc ,a second they all bosses a very unique water ( vascular system system based on water).they are triploblastic. Echinoderms office remarkable ability to regrow lost limbs or other body parts even internal organs.