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

Explain the sedimentation - air sampling, Explain the Sedimentation - Air S...

Explain the Sedimentation - Air Sampling? It is the simplest method, which involves exposing agar plates in air for specified time at a location to be sampled.  Microorganisms

Explain adverse effects of valacyclovir, Adverse Effects of Valacyclovir  ...

Adverse Effects of Valacyclovir  Valacyclovir is generally well tolerated; adverse effects are similar to those with acyclovir. GI disturbance, headache, rash, CNS effects such

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

Clinical reasoning , Upon admission the DPU nurse notes: Fasting sta...

Upon admission the DPU nurse notes: Fasting status - fasted from 12 midnight, no morning medication taken. Consent - signed Pre anaesthetic check Test results

Complete the diagram by dragging the correct label, For the cross in Part B...

For the cross in Part B, predict the frequencies of each of the phenotypes in the F1 progeny, and determine the genotype(s) present in each phenotypic class. Complete the diagram b

Single stranded conformation polymorphism analysis, This is a broadly used ...

This is a broadly used screening technique that find several genomic mutations in wide number of samples, this technique finds sequence variations because of point mutations or oth

Which hormone influence maturation of the ovarian follicles, Q. After mense...

Q. After menses what is the hormone that influences the maturation of the ovarian follicles? The maturation of the ovarian follicles after menses is stimulated by the action of

Diarrhoea, Diarrhoea   Diarrhoea refers to frequent passage of loose wa...

Diarrhoea   Diarrhoea refers to frequent passage of loose watery stools. Acute diarrhoea often called as acute gastroenteritis  is particularly a leading cause of mortality in

Environmental accounting, Valuation of biological resources includes the pr...

Valuation of biological resources includes the process of deriving a monetary value to the things that are not sold in the market. Examples are the value given to fuelwood gathere

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