Biology

Influence of Environment on Body Plans of Organisms

The context of this paper aims to confirm that the environment influences the body plans of organisms. In retrospect, it can be argued that the evolutionary success of organisms through tine can be understood to mean the organism adapting the best way it can to survive in the environment in which it lives in. Arthur (2000) confirms this through asserting, “…selection may often favor organisms whose developmental pathways respond to environmental factors in particular ways…” (284). This could loosely translate to mean that an organism’s body plan is in itself an adaptive approach triggered by particular environmental cues. This can best be considered through looking at the following examples: the size of a blue whale and its ocean environment, a salt-water fish in its saline environment and a comparison between a human being living in high and cool environments with one living in low and warm environments.

The blue whale is currently recognized as the world’s largest living animal. Such an organism with a weight exceeding 102 tons would have a problem moving in an environment other than water once this weight is put into consideration. In addition, they are equipped with fins, which have applicatory relevance in the water. Again, the fact that whales often live in cold environments means that its bulk is an added advantage.

Salt-water fish live in saline environments. They are exposed to the risk of dehydration, via osmosis. The aforementioned salt-water fish as other marine fish have developed mechanisms to help purge excess salt out of their bodies. Unlike their fresh-water counterparts, they also have mechanisms to avoid excessive loss of water from the body through diffusion. Their bodies generally have a high tolerance for saline environments.

High and cool environments only support organisms that have body plans accustomed to the cold conditions and lower oxygen concentration levels. Therefore, it will be noted that human beings in such areas often appear more bulky and hairier than human beings living in lower altitudes. Their blood is also noted to have more red blood cells to cater for the lower oxygen concentrations in high altitudes.

Citing the examples provided above, it is noted that the environment an organism lives in structures the body plan of the aforementioned organism. However, one can still argue that a particular body plans do instead influence the environment in which an organism can live in, as can be said about the size of the whale it being unable to live outside water. Despite this though, everything eventually boils down to the fact that the environmental cues distinguish organisms that cannot live in particular settings from those that can through ensuring that the body plans of the latter conform to the environmental requirements. That would explain why water is the only convenient environmental setting that can support the weight of a whale, a fresh-water fish will die of dehydration when exposed to a saline environment and a human being living in cold conditions has a stockier body to retain more heat as compared to their warmer climate colleagues.

Question 1

In aerobic reactions, cells make use of oxygen to produce energy that is in form of ATP while in anaerobic reactions, oxygen is not needed but instead, inorganic compounds are used.

This difference can be illustrated by the following word equation.

Aerobic cellular reaction

Glucose + oxygen                   water + carbon dioxide + 38 ATP

Anaerobic cellular reaction

Glucose     Inorganic materials              Lactic acid + 2 ATP

 

 

Question 2

Human anatomy is made up of water. The blood, plasma and saliva have a high content of water. Water helps in cell physiology by providing the medium through which nutrients are transported in the body (Heymsfield, 2005). It helps in nerve co-ordination and acts as an electrolyte. The ions present in water help in impulse transmissions. Water plays a key role in the excretion system of a body. Water acts as a cooling agent in the body. Other visceral organs like brain and liver need water for their proper functioning (Heymsfield, 2005).

 

References

Arthur, W. (2000). The origin of animal body plans: a study in evolutionary developmental biology. London, UK: Cambridge University Press

Heymsfield, S. (2005). Human Body Composition. Windsor, ON: Human Kinetics