Speciation: The origin of new species from the exiting ones due to reproductive isolation of a part of its population is called speciation.
A species is defined as a group of interbreeding organisms that produce fertile offspring and are productively isolated from other groups. Reproductive isolation means that sexual reproduction between different species is impossible because of the physical, ecological, behavioral, temporal or developmental reasons.However, inbreeding continues within the isolated populations producing more and more generations. Eventually, the members of these two groups will be incapable of reproducing with each other even if they happen to meet. Over generations, genetic drift accumulates different changes in a sub-population. Also, natural selection may also operate variably in these different geographic locations. e.g. in the territory of one sub-population, crows may get eliminated by eagles.
Different type of barriers causing reproductive isolation are:
. Physical:There may be a sea, mountain or desert between them.
. Behavioural: Populations may have different courtship patterns.
. Temporal (time based) :Plants may be flowering at different times.
. Ecological Species :Inhabit different places and never meet up.
There are four geographic modes of speciation in nature:
Population splits into two geographically isolated regions and each population undergoes genotype or phenotypic divergence is known as ______________. | |||
Right Option : A | |||
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Which of the following are correct ? (a) The reproductive isolation means physical there may be a sea, mountain or desert between them. (b) The reproductive isolation means behavioral populations may have different courtship patterns (c) Sympatric speciation it refers to the formation of two or more descendant species from a single ancestral species all occupying the same geographical location. | |||
Right Option : D | |||
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Which of the following are correct ? (a) The origin of new species from the exiting ones due to reproductive isolation of a part of its population is called speciation. (b) The example of allopatric speciation is Ensoltina salamanders. | |||
Right Option : A | |||
View Explanation |
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