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

Define the water bath with shaker, Define the Water Bath with Shaker? A...

Define the Water Bath with Shaker? An electric water bath with a shaker that can hold test tubes as well as conical flasks. When on a non-shake mode, it acts as a simple water

What is the function of the flagellum of the sperm cell, What is the functi...

What is the function of the flagellum of the sperm cell? How is it formed? The flagellum of the sperm cell is produced by the centrioles that migrate to the region posterior to

Vitamins, Vitamins Animals cannot sustain a healthy life if they are ...

Vitamins Animals cannot sustain a healthy life if they are fed on a diet having only carbohydrates, fats and proteins. They also require vitamins in small quantities in the r

What is the mechanism of elisa, ELIZA stands for enzyme linked immune diffu...

ELIZA stands for enzyme linked immune diffusion assays. It works on standard of antigen antibody reaction.

How can we determine solutions, How can we determine Solutions Solution...

How can we determine Solutions Solutions are a homogeneous mixture of two or more different substances. This means that the molecules of the dissolved substances (solute) and t

What is polymerase chain reaction, Which of the following is a false statem...

Which of the following is a false statement regarding Polymerase Chain Reaction (PCR)? A. PCR is a modified version of cellular replication that is used to amplify small amount

Draw a diagram of transverse section of the spinal cord, Draw a diagram of ...

Draw a diagram of transverse section of the spinal cord showing reflex are and label the following parts: (i) Afferent nerve fibre (ii) Grey matter (iii) Motor nerve fibre

Explain lyme disease, Explain Lyme disease The disease - About 70-80% o...

Explain Lyme disease The disease - About 70-80% of patients infected by B. burgdorferi develop the characteristic skin lesion, erythema migrans, which occurs at the site of the

Assessment of tricuspid and pulmonary orifice areas, Assessment of Tricusp...

Assessment of Tricuspid and Pulmonary Orifice Areas Due to the rarity of tricuspid stenosis and pulmonary stenosis, no general agreement exists on what constitutes critical o

Explain ventricular septal defects vsd chsude technique, Explain Ventricula...

Explain Ventricular septal defects VSD Chsude Technique ? Ventricular septal defects are closed on cardiopulmonary bypass. Approach is through median stemotomy. Ascending aort

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