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प्रश्न
Read the following statement and justify the same in your own words with the help of a suitable example.
Geographical and reproductive isolation of organisms gradually leads to speciation.
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उत्तर
- Every species survives in specific geographical conditions, as the food and habitat requirements are specific for each species.
- Their reproductive ability and period are also different, so the individuals from one species cannot reproduce with individuals from other species.
- When they are separated by a distance or geographical barriers, they are said to be isolated geographically.
- When they cannot reproduce with each other, they are said to be isolated reproductively.
- The ancestor species of both these groups may be the same, but due to isolation over a very long-time duration, there is genetic variation between them. Therefore, this continuous isolation ultimately leads to speciation.
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संबंधित प्रश्न
What is meant by speciation?
Will geographical isolation be a major factor in the speciation of a self-pollinating plant species? Why or why not?
Will geographical isolation be a major factor in the speciation of an organism that reproduces asexually? Why or why not?
Only variations that confer an advantage to an individual organism will survive in a population. Do you agree with this statement? Why or why not?
List four factors responsible for speciation.
The palisade cells of a species of plant contain 28 chromosomes. How many chromosomes will there be in each gamete produced by the plant?
In peas, a pure tall plant (TT) is crossed with a pure short plant (tt). The ratio of pure tall plants to pure short plants in F2 generation will be ______.
Choose the one term from the following which includes the other three :
broccoli, wild cabbage, cauliflower, cabbage
Give an example of characteristics being used to determine how close two species are in evolutionary terms.
Give two examples of plant species and two of animals.
Does geographical isolation of individuals of a species lead to the formation of a new species? Provide a suitable explanation for your answer.
How are those species which are now 'extinct' studied?
Define 'natural selection'.
Which of the following statement is incorrect with respect to variations?
(a) all variations in a species have equal chance of survival
(b) change in genetic composition results in variations
(c) selection of variations by environmental factors forms the basis of evolutionary process
(d) variations are the minimum in asexual reproduction
New species may be formed if:
- DNA undergoes significant changes in germ cells
- chromosome number changes in the gamete
- there is no change in the genetic material
- mating does not take place
List any two factors that could lead to speciation.
State and define three factors responsible for the rise of a new species.
The process by which new species develop from the existing species is known as ______
The theory of evolution of species by natural selection was given by
