Already have an account? Get multiple benefits of using own account!
Login in your account..!
Remember me
Don't have an account? Create your account in less than a minutes,
Forgot password? how can I recover my password now!
Enter right registered email to receive password!
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.
How can Heart be affect Heart may be affected in two ways. One of the complications of diabetes is autonomic dysfunction which may disturb rhythm of heart beat and may lead to
Normal 0 false false false EN-IN X-NONE X-NONE MicrosoftInternetExplorer4
Locomotion,nutrition and reproduction in ptotozoa
Pulmonary Regurgitation : Most of the clinical cases are after balloon valvotomy or surgical valvotomy using a trans annular patch. It can be quantified by Echocardiography and D
What are the typical features of mammals? The typical features of mammals are: body (more or less) covered with hair; presence of the diaphragm muscle (that divides the thorax
Define drug effects on Carbohydrate metabolism? Carbohydrate metabolism: Hypoglycemic drugs such as insulin and sulphonylureas are prescribed because of their ability to increa
simplest way to learn their classifiction
Define the Classification of Proteins? Proteins vary widely in. their properties. We suggest you look up this unit once again now as the information about proteins and their pr
Q. Do protozoans have asexual or sexual reproduction ? In protozoans reproduction is asexual or sexual. The most frequent form of sexual reproduction is binary scissiparity or d
What is the significance of magnesium for plants? What are the other main biological functions of magnesium? Magnesium is fundamentally significant for plants because it is par
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!
whatsapp: +91-977-207-8620
Phone: +91-977-207-8620
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd