Question

Hybrids formed by mating two different species are often incapable of reproducing successfully with each other or with the members of their parent populations. Explain why this is the case. (Hint: Consider what you know about chromosome numbers and meiosis.)

Answer 1

Hybrids formed by mating different species are often unable to reproduce successfully due to factors such as differences in chromosome numbers and the presence of postzygotic barriers. These factors can lead to the hybrids being sterile and unable to produce viable offspring.

Step-by-step explanation:

Hybrids formed by mating two different species are often incapable of reproducing successfully with each other or with the members of their parent populations due to a number of factors. One major factor is the difference in chromosome numbers between the two species. In order for successful reproduction to occur, the parents need to have the same chromosome number and the chromosomes need to be similar enough to pair during meiosis. Since hybrids between different species have different chromosome numbers and the chromosomes are not similar enough to pair during meiosis, they are generally sterile and unable to produce viable offspring. Another factor is the presence of postzygotic barriers, such as hybrid inviability and hybrid sterility, which prevent successful reproduction. These barriers can prevent the hybrid individuals from developing normally or from reproducing offspring of their own.

Answer 2

Because of presence of different sets of chromosomes in hybrids

Step-by-step explanation:

In normal animals the body cells have two sets of chromosomes out of which one comes from mother and the other from father. During the gamete formation, when meiosis occurs, these two sets of chromosomes are duplicated and then only one set of chromosome is transferred to each of the four formed gametes. Now each of these cells have only one set of chromosomes which is a mixture of mother and father chromosomes. This is possible because the parents have same sets of chromosomes.

But, as the hybrids are formed by mating of two different species parents, the chromosomes of hybrids don't match up with others in the order and during meiosis and thus the pairing between the chromosomes become difficult. This is why hybrids are incapable in reproducing sexually.