One's personality is both a composition and reflection, but if I have to choose one of them, I will choose reflection as the "self" is more important to me than "me". One's composition may change, walking across the cultural landscapes and climbing the social ladder but one's self is tied to one's reflections. The fun part is that reflections are not bound to "Time-Space" barriers ( it is not time-space) and respective mental constructs, which have grown so thick over ages, that they had reduced the image of humans to Sisyphus, rolling different sizes of boulders on hills of different heights.… As the name of this Blog indicates, knols are my perspectives on topics of interests, sweet/bitter experiences or just doodling :)

Monday, November 28, 2011

Redox and evolution

Oxidation and reduction is key in transforming energy from one trophic level to next. As any biological activity and expression requires energy so the redox played a key role in giving direction to evolution. Oxygen as a chief oxidant become a dominant element in determining the direction of evolution.

Oxygen and evolution

Oxygen is an important element in evolution of organisms. Due to its high oxidative property it is both a source of energy and inhabitor for organisms.

1. It was absence of oxygen in earlier environments on earth that made abiogenesis possible. If earleir environments were oxygen rich they could oxidize the compounds and prevent developments of organic compounds.
2. Some of organisms like bacteria have evolved to to use alternative oxidative elements, like Nitrogen, Iron, Manganese, etc
3. There is an interesting link between feeding, lungs and heart chambers.
a. Fish respire through gills, have two chambered heart, so it doesnot chew the prey but swallow. It can live only in water.
b. Amphibians on other hand, have three chambered heart with two atria but a single ventricle. As oxygenated blood mix to some extent in ventricle to despite respiring by lungs, it live close to water and its skin is wet to absorb oxygen. It also swallow the prey.
c. We can describe the heart of reptiles in two ways, three chambered and fourth chambere. Because the ventricle is partially divided. Though it has more effective separation of oxygenated and deoxygenated blood but again it also swallow the prey.
d. It is the four chambered heart of mammals that separate the oxygenated blood and deoxygenated blood so the mammals live in diverse environments and can swallow and chew their prey or food.

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