Question

Question 6 An example of a postzygotic isolating mechanism between closely related species would be which of the following? One species flowers in April, the other in August. The two species are pollinated by different species of bees. A zygote produced by syngamy of sperm and egg of the two species contains an uneven number of chromosomes. The pollen from one species will not germinate on the stigma of the other. One species is terrestrial, the other totally aquatic.

Answer 1

ans correct option is i il produced by syngamy of speam and egg of the two an uneven number of chromosomes. la 10 4 zygote species contains Explanation - • Post-zygotic isolation is a mechanism win which featilisation of egg takes place and even zygote is formed but due to inviability or sterility of offspring, they may not survive long or reproduce next generation. Thus, hybrid produced by such post zygotic isolation will prevent further reproduction of offsprings. • In the given question, option (c) is correct because in this case formation of zygote takes place but due to uneven chromosome number it will not able to form or reproduce offsprings. • All other options given are of prezygotic isolation in which even formation of zygote will not take place as fertilisation cannot occur either due to habitation isolation or mating seasons. other reasons responsible for pre-zygotic isolation are mechanical isolation, gamete isolation and behavioral isolation, number it will ons given are of hot take pladation or mating