Biological evolution, Biology

Assignment Help:

Natural selection is a process which directs all biological evolution. It is a process that directs genetic changes which when proved to be adapted to the environment are retained in the genome. In other words, man like any other organism may have to passively adapt lo changing ecological circumstances through a slow, generation by generation change in gene complexes. The question is, does natural selection act in the same way in man as it is acting on other organisms. The major difference between man and other organisin is that man is capable of steering his own evolution whereas the other organisms cannot. Teilhard de Chardin, an eminent human paleontologist and anthropologist says "the evoluton of life on earth, far from having come to a stop, is on the contrary now entering a new phase. The Darwinian era of survival by natural selection is thus succeeded by a Lamarkian era of super life brought about by calculated invention". Such a statement gives credence to the hypothesis that man can monitor his own evolution in future.

There is evidence to suggest that man through the technological revolution has modified the role of natural selection. As an example one may mention the cancer of the eye, the retinoblastolna caused by a dominant mutation. The disease develops as a tumor in one of the eyes of the affected child, spreads to the other eye and then extends to the brain causing the death before the individual reaches the adulthood. Today, if the condition is detected sufficiently early, it is possible to remove the tumor surgically despite the loss of one eye. The child can grow into a near normal adult, marry and give birth to children. But there is a 50% chance for his children to be born with retinoblastoma. And inturn they have to be treated for the disease. Here is an instance where, through a surgical treatment a lethal gene is permitted to be preserved and passed on to the subsequent generations. Natural selection in normal course would have aimed to eliminate the gene from the population. But if the lethal condition were to be completely cured in every patient the frequency of the gene would increase slowly in the population.


Related Discussions:- Biological evolution

Flying fish pisces, the characteristics of flying fish belong to pisces

the characteristics of flying fish belong to pisces

Australopithecines, The first ever australopithecine fossil was found in 19...

The first ever australopithecine fossil was found in 1924 at Taung, South Africa. It was the skull of a 6 year old child showing a mixture of human and ape like features. This a

Concentration gradient and passive and active transport, Q. What is the rel...

Q. What is the relationship between concentration gradient and passive and active transport? Passive transport is the movement of substances across membranes in favour of their

Culturing, ime day 0 day 1 day 3 day 4 day 5 day 7 count ...

ime day 0 day 1 day 3 day 4 day 5 day 7 count blank 7 10 5 14 9 8 low 45&49 64&70 62&69 75&79 80&82 68&72

Phosphorus cycle, Phosphorus cycle is sedimentary cycle because it does not...

Phosphorus cycle is sedimentary cycle because it does not enter into atmosphere. It can be found on earth in water, soil and sediments. The phosphorus cycle is the biogeochemical c

What are the possible phenotypes of the progeny, A (w+/ w+) red-eyed Drosop...

A (w+/ w+) red-eyed Drosophila female is crossed with a white-eyed male. Assuming the trait for eye colour is sex-linked, what are the possible phenotypes of the progeny?

Mycoplasmosis, Contagious bovine pleuropneumonia (CBPP) This is a highl...

Contagious bovine pleuropneumonia (CBPP) This is a highly fatal disease of cattle and of major economic importance in certain tropical countries. It also affects buffaloes, bis

Explain procedure for isolation of pure culture, Explain Procedure for Isol...

Explain Procedure for Isolation of Pure Culture? Now carry out the exercise following the steps enumerated herewith. 1. Label the name of the organism on the bottom of the p

Protozoa , lest the characteristics of Protozoa

lest the characteristics of Protozoa

Microscopy, describe the importance,principles,techniques and uses of micro...

describe the importance,principles,techniques and uses of microscopy

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd