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प्रश्न
Define ‘reproductive isolation’ and explain two types of reproductive isolation.
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उत्तर
Reproductive Isolation: Prevents interbreeding between the populations whether they are geographically isolation or living close together.
Types of Isolating mechanisms :
1. Pre -mating or pre-zygotic isolating mechanisms : In habitat Isolation, members of a population living in the same region occupy different habitat. Thus potential mates do not meet. In seasonal isolation, members of a population attains sexual isolation, members of a population attain sexual maturity at the different times, thus preventing interbreeding.
In ethological isolation, members of two populations have different mating behaviours. This prevents interbreeding.
In mechanical isolation, the members of two populations have differences in the structure of reproductive organs. So interbreeding is not possible.
2. Post-matting or post zygotic isolating mechanisms are : Gamete mortality (Sperms transfer takes place but egg is not fertilized), Zygote mortality (Egg is fertilized but zygote dies) and hybrid sterility (Hybrids are sterile)
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संबंधित प्रश्न
The range of cranial capacities in the following ancestral forms were
Cro-magnon ______.
Given alongside are two figures (A and B) representing the two stages of evolution of human beings.

Answer the following:
- Mention any two contrasting characters between the two stages.
- Write all the stages of human evolution in their correct sequence.
- State any two characteristic features of stage B.
Match the following.
| Column I | Column II | ||
| i. | Homo habilis | p. | 900 cc |
| ii. | Australopithecus | q. | 1350 cc |
| iii. | Homo erectus | r. | 650 - 800 cc |
| iv. | Homo sapiens | s. | 450-600 cc |
Select the correct option.
Character which is closely related to human evolution is:
The brain capacity of Neanderthal man was ______
Who was more intelligent than modem man, cave-dweller, had prominent chin and appeared after Neanderthal man?
Among the human ancestors, the brain size was more than 1000 cc in ______.
Name the following:
Scientific name of Handy man
Which changes to facial features occurred during human evolution?
What was the distinguishing characteristic between Dryopithecus and Ramapithecus?
