In some plants, the sperm can not reach the egg because the stigma prevents formation of the pollen tubes. This is an example of
A) temporal isolation.
B) behavioral isolation.
C) gametic isolation.
D) mechanical isolation.

Question

Quizplus · Accepted Answer

Gametic isolation occurs when the gametes (e.g., sperm and egg) of two different species or in some cases, different genotypes within a species, are unable to fuse or recognize each other, preventing fertilization. In this case, the stigma's prevention of pollen tube formation directly impacts the gametes' ability to unite, fitting the definition of gametic isolation.

In Some Plants, the Sperm Can Not Reach the Egg