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.
What are the alleles of a gene? The Diploid individuals have paired chromosomes. For instance in humans there are 23 pairs of chromosomes totaling 46 chromosomes. Every pair co
The Amazon rainforest in South America is a biodiverse ecosystem. There are large numbers of plant and animal species making up the food web, including over 350 species of predator
What is the Mendel's second law? The Mendel's second law postulates that two or more different traits are also conditioned by two or more pair of different factors that every i
Q. Explain the types of classification of plants? It is practically impossible for anyone to study all the plants of the world, 'even if one spends whole life. Thus, it is nece
Bone Remodeling Bone remodeling differs from the other means of bone structure alteration in that osteoblasts and Osteoclasts do not act independently but are coupled and bone
Class of Mollusca - Aplacophora Worm-like, no shell, head or excretory organs mantle with chitinous cuticle or scales or spicules mantle cavity posterior. Aplacophorans are a
Lungs - Respiration Lungs can be simple, characterised by air exchange with surrounding environment by diffusion only. These are called the diffusion lungs and are present in
how can explain
Vegetative Development - Development The process of growth and differentiation of cells into organs and organisms is often termed development. For example, the development of
Determine the Types of Exercises Exercises are generally grouped into three types: - Flexibility exercises such as stretching improves the range of motion of muscles and jo
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