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प्रश्न
List four factors responsible for speciation.
उत्तर १
Following are the factors responsible for speciation:-
1. Genetic drift
2. Natural selection
3. Reproductive isolation
4. Geographical isolation
उत्तर २
The factors which could lead to speciation are
1. The geographical isolation of population caused by various types of barriers such as mountain ranges, rivers, and seas. This leads to reproductive isolation because of which there is no flow of genes between separated groups of the population.
2. Genetic drift caused by drastic changes in the frequencies of particular genes by chance alone.
3. Variations caused in individuals because of natural selection.
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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?
The palisade cells of a species of plant contain 28 chromosomes. How many chromosomes will there be in each gamete produced by the plant?
(a) 56
(b) 28
(c) 14
(d) 4
Name five varieties of vegetables which have been produced from 'wild cabbage' by the process of artificial selection.
What is meant by a species?
Will geographical isolation be a major factor in the speciation of a self-pollinating plant species? Give reason for your answer.
One of the following has not been produced from wild cabbage by the process of artificial selection. This one is :
(a) kohlrabi
(b) cabbage
(c) spinach
(d) kale
State and define three factors responsible for the rise of a new species.
Add a note on sympatric speciation.
Arrange the major events as per geological time scale:
(Origin of conifers, Abundance of trilobites, Diversification of fishes, All types of marine algae, Formation of Forests, Rise of dinosaurs, Extinction of seed ferns, Rise of modern insects.)
| Geological time period |
Major events | |
| 1. | Cambrian | ______ |
| 2. | Devonian | ______ |
| 3. | Permian | ______ |
| 4. | Triassic | ______ |
