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

What is contact osteogenesis, Contact Osteogenesis In this the osteoge...

Contact Osteogenesis In this the osteogenic cells attach to the implant surface and the new (de novo) bone is formed on the implant surface first. The developing bone matrix c

Define nutrient and drug interaction, Define Nutrient and Drug Interaction?...

Define Nutrient and Drug Interaction? Modern medicine has given us many useful drugs that not only prolong and save lives but in fact improve the quality of our lives. Have you

Binding site, Binding site  is the place on cellular DNA to which a protein...

Binding site  is the place on cellular DNA to which a protein (like transcription factor) can bind. Typically, binding sites may be found in the vicinity of genes, and would be inv

Explain the sub-clinical protein energy malnutrition, Explain the Sub-clini...

Explain the Sub-clinical Protein Energy Malnutrition? You have already learnt that clinical forms of PEM represent only a small proportion of the total cases of PEM in a commun

What is the virus that causes flu, Q. What is the virus that causes flu? Wh...

Q. What is the virus that causes flu? Why doesn't the body produce permanent immunity against that virus? How does the vaccine against flu work? Flu is a disease caused through

Symptoms and signs of diabetes mellitus, Symptoms refer to the problems exp...

Symptoms refer to the problems expressed by the patients. Signs are obtained by a health professional from the patients by interacting with him, by conducting tests, etc. The sympt

Threshold value of different larval tissues, Threshold Value of Different L...

Threshold Value of Different Larval Tissues Threshold value of dissimilar larval tissues for the thyroid hormone concentration One of the main problems of metamorphosis is

Fungal diseases - aspergillosis, F u n g a l diseases A spergill...

F u n g a l diseases A spergillosis Aspergillosis is mycotic disease of poultry and all other species of birds caused by a fungus known as Aspergillus fumigatus . F

Determine the axon of a nerve cell, In the axon of a nerve cell, A. the...

In the axon of a nerve cell, A. the voltage-dependent conductance of the voltage-gated potassium channel has a faster time course than the voltage-dependent conductance of the

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