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प्रश्न
Read the following statement and justify same in your own words with the help of suitable example.
Geographical and reproductive isolation of organisms gradually leads to speciation.
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उत्तर
- Every species survives in specific geographical conditions. The requirements of food and habitat, is specific for each species. Their reproductive ability and period is also different.
- Therefore, 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 subspecies may be the same but due to isolation over a very long time duration, there is genetic variation between the two. Therefore, the isolation leads to speciation.
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संबंधित प्रश्न
Explain the following:- Speciation
Will geographical isolation be a major factor in the speciation of an organism that reproduces asexually? Why or why not?
List four factors that could lead to speciation. Which of them cannot be a major factor in the speciation of a self-pollinating plant species?. Give reason to justify your answer.
List four factors responsible for speciation.
Which of the following represent tall plants and which represent short plants (or dwarf plants)?
(a) Tt
(b) tt
(c) TT
Give reason for your choice (The symbols have their usual meaning).
State one advantage of variation to a species.
Which of the following may be used to obtain an F2 generation?
(a) allowing flowers on a parent plant to be self-pollinated
(b) allowing flowers on an F1 plant to be self-pollinated
(c) cross-pollinating an F1 plant with a parent plant
(d) cross-pollinating two parent plants
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.
What name is given to the sequence of gradual changes over millions of years in which new species are produced?
Name the ancestor of the following :
Broccoli, Kohlrabi, Kale
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 'speciation'. Explain how speciation occurs.
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
What is species and speciation?
Define speciation according to A.E. Emerson.
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.
Add a note on allopatric 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 |
