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

#aschelminthes, #General characters of Aschelminthes

#General characters of Aschelminthes

Forebrain - diancephalon, DIANCEPHALO N - Less visible. Occupies on...

DIANCEPHALO N - Less visible. Occupies only 1% of brain's volume. Its lumen is diocoel or III ventricle. Roof is epithalamus . On it pineal body is present. Fl

Hypothalamus and pituitary, Hypothalamus and Pituitary The most obviou...

Hypothalamus and Pituitary The most obvious neuroendocrine link is between the hypothalamus and pituitary. The hypothalamus is a part of the brain which is connected to the pi

Amylase stock solution, Assume that you have 1 mL of a solution amylase (an...

Assume that you have 1 mL of a solution amylase (an enzyme) at a concentration of 15 mg protein/mL. Calculate the volume of diluting buffer that you would have to add to 1.0 mL of

What is meant by the peripheral nervous system, Q. What is meant by the per...

Q. What is meant by the peripheral nervous system (PNS)? The peripheral nervous system comprehends the ganglia and nerves of the body.

Proteins Requirement for nutrients, Q. Requirement for nutrients? Ulcer...

Q. Requirement for nutrients? Ulcer is a form of wound which if not healed on time call get perforated and bleed. Adequate protein intake ensures synthesis of new tissues esse

Explain the equilibrium dialysis, Explain the Equilibrium Dialysis? Equ...

Explain the Equilibrium Dialysis? Equilibrium dialysis is a useful technique for studying the binding of a small uncharged solute species (a ligand) to a macromolecule. The mac

What are some things that have algae in them, What are some things that hav...

What are some things that have algae in them? Yeast is considered Algae.

List the benefits of lsm, List the benefits of LSM. Life style modifica...

List the benefits of LSM. Life style modification helps in the following ways: - Reduction of weight - Good sugar control - Good blood pressure control - Reduction

Explain amylase, Amylase The presence of pancreatic amylase brings abou...

Amylase The presence of pancreatic amylase brings about  the breakdown  of starch  and glycogen and  its action is similar to salivary amylase. The hydrolysis of  starch and gl

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