Chapter Chosen


Book Chosen


Subject Chosen


Book Store

Download books and chapters from book store.
Currently only available for.
CBSE Gujarat Board Haryana Board

Previous Year Papers

Download the PDF Question Papers Free for off line practice and view the Solutions online.
Currently only available for.
Class 10 Class 12
zigya tab
Can we call human evolution as adaptive radiation?

No, human evolution cannot be called adaptive radiation, because adaptive radiation is an evolutionary process that produces new species from a common species, rapidly diversifying lineage, which is not the case with human evolution. Human evolution was a gradual process that took place slowly in time. 

Attempt giving a clear definition of the term species.

Species are that group of organisms which resemble structurally and functionally, are able to interbreed freely and produce fertile offspring of their own kind and share a common gene pool.

Explain antibiotic resistance observed in light of Darwinian selection theory.

According to the Darwinian selection theory.
When the bacteria are grown in culture that have a certain antibiotic, most of the bacteria are killed but some of them develop a mutation which provides resistance against the antibiotic . With time the bacterial population having antibiotic resistance will increase and outgrow the population of the non-resistant bacteria. Thus a new species that has antibiotic resistance will be selected against the original one.

Find out through internet  and popular science articles whether animals other than man has self-consciousness.

There are many animals other than humans, which have self consciousness. An example of an animal being self conscious is dolphins. They are highly intelligent. They have sense of self and they also recognize dolphins within their community and others beings like humans. They communicate with each other by whistles, tail-slapping, and other body movements. Not only dolphins, there are certain other animals such as crow, parrot, chimpanzee, gorilla, orangutan, etc., which exhibit self-consciousness.

Describe one example of adaptive radiation

Adaptive radiation is process of evolution of different species in a given geographical area starting from a point and literally radiating to other areas of geography (habitats). This process occurs due to natural selection. An example of adaptive radiation is Darwin finches, found in Galapagos Island. A large variety of finches is present in Galapagos Island that arose from a single species, which reached this land accidentally. As a result, many new species evolved, diverged, and adapted to occupy new habitats. These finches developed different eating habits and different types of beaks to suit their feeding habits. The insectivorous, blood sucking, and other species of finches with varied dietary habits evolved from a single seed eating finch ancestor.