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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
List three main factors responsible for the speciation and briefly describe each one of them
"Natural selection and speciation leads to evolution." Justify this statement.
What do you understand by the term variation?
Name two human traits which show variation.
How does the creation of variation in a species ensure its survival
A plant has two varieties, one with red petals and the other with white petals. When these two varieties are cross-pollinated, all the offsprings have red petals?
(a) Which gene is dominant?
(b) Choose suitable letters to represent the two genes.
Name an animal having rudimentary eyes.
Name five varieties of vegetables which have been produced from 'wild cabbage' by the process of artificial selection.
Give two examples of plant species and two of animals.
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
According to the evolutionary theory, the formation of a new species is generally due to ______
List any two factors that could lead to speciation.
State and define three factors responsible for the rise of a new species.
In the following Question, the Assertion and Reason have been put forward. Read the statements carefully and choose the correct alternative from the following:
Assertion: Speciation is the reproductive isolation amongst once interbreeding population.
Reason: Genetic drift, Natural selection, and Severe DNA change can cause speciation.
Cichlid fishes in Lake Victoria are representatives of ______ type of speciation.
Complete the following chart:
| Animals | Connecting link between | |
| (1) | Balanoglossus | ______ |
| (2) | ______ | Annelida and Arthropoda |
| (3) | Lung fishes | ______ |
| (4) | ______ | Reptiles and mammals |
| (5) | Seymouria | ______ |
| (6) | Fishes and Amphibia |
What is the evolutionary process by which new, distinct species are formed?
