Tag: biology

On his visit to the Galapagos Islands, Charles Darwin found a few types of finches that fluctuated from island to island, which helped him to build up his hypothesis of characteristic selection. Darwin's finches are a traditional case of a versatile radiation. Their regular precursor touched base on the Galapagos around two million years prior. Amid the time that has passed Darwin's finches have advanced into 15 perceived species contrasting in body measure, snout shape, melody and sustaining conduct.

The key aspects of the theory of natural selection are rapid increase in population, struggle for existence resulting from limited food and space, Natural selection or survival of the fittest and elimination of the unfit and origin of new species. Darwinism fails to attribute the reasons for the existence of vestigial organs like vermiform appendix in human beings. These organs should have been eliminated during the progression of evolution because of its no use for long time. Another big limitation is the difference between heritable and non-heritable variations. Theory of natural selection fails to explain the origin of variation. Further, Darwin believed evolution is due to gradual variations. But in many instances, the occurrence of such variations are not of use for the struggle of existence. For example, the eye in the case of animals is functional only in a fully formed condition and all the features of the eye according to Darwin could not have come into existence at one step. It should have been by the collection of several mutations. But then each change by itself is of no advantage. Thus, the correct answer is 'All of the above.'

One of his persuasions was Thomas Robert Malthus, a late-eighteenth-century financial analyst. Malthus stated is "Essay on the Principle of Population" (1798), which Darwin read and was roused.

According to Darwin theory, there is both long and short neck giraffe due variation in the population. when there is a shortage of short tree leaves, short neck giraffe died and long neck giraffe survive.

During the process of reproduction, the DNA is passed from one generation to another. This replication takes place with little or no errors. There is consistency which leads to stability of reproduction. Also, reproduction helps in replacing aging population with new population and thus ensures the survival of the species. In the absence of reproduction, one particular species will disappear with time.
Thus, the correct answer is the option (A).

The Sympathetic Nervous System manifests 'fight or flight' responses. It decreases the tear secretion and saliva secretion but increases sweat secretion. The parasympathetic nervous system increases tear secretion and saliva secretion.