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

Phospholipids exhibit important biological functions, Phospholipids exhibi...

Phospholipids exhibit  important biological functions. They are: a)  increase  the rate of fatty acid oxidation b)  act as inorganic ion carrier across the membrane c) hel

State the swinging flashlight test, State the Swinging Flashlight Test ...

State the Swinging Flashlight Test The patient looks into the distance while the examiner shines a bright light first into one eye for a few seconds and then the other. As the

Minerals and reproduction, Minerals and reproduction The mechanism of mine...

Minerals and reproduction The mechanism of mineral-reproduction interactions is not fully understood because  of the complexity of neuro-hormonal dialogue. Some minerals act direc

Define glass photo-emissive tubes, Define Glass photo-emissive tubes? G...

Define Glass photo-emissive tubes? Glass photoemissive tubes are those which consist of a curved metal cathode, coated with a photosensitive material. While light strikes its s

Define principle for simple staining of bacterial cultures, Define Principl...

Define Principle for Simple Staining of Bacterial Cultures? In simple staining, a single staining agent preferably a basic dye is used. Commonly used basic stains are carbol fu

Blood group, when the father and the mother of a newborn baby possesses blo...

when the father and the mother of a newborn baby possesses blood group ''O'' +ve,is it possible that the baby can have a blood group ''A'' +ve or ''B''+ve ? Conventionally it shoul

Why did it not drop more give reason, Mr. Smith read that cholesterol was b...

Mr. Smith read that cholesterol was bad for his health so he eliminated all foods and food products containing this molecule. He later found that his cholesterol level dropped only

What are dimorphic fungi, Question 1 What are dimorphic fungi? List the cl...

Question 1 What are dimorphic fungi? List the clinical manifestations produced by various dimorphic fungi. Add a note on isolation and identification of various dimorphic fungi

What do you understand by carcinogens, Q. What are carcinogens? The Car...

Q. What are carcinogens? The Carcinogens are factors capable of producing neoplasias and any mutagen, a substance that can induce DNA mutation, is a potential carcinogen. Insta

Explain about the glycoproteins, Explain about the Glycoproteins? Most...

Explain about the Glycoproteins? Most of the naturally occurring conjugated proteins are glycoproteins. Sugar molecules are covalently bound to them, especially those secreted

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