Answer:
Prezygotic barriers:
1. Habitat isolation
2. Behavioral isolation
Explanation:
Pre-zygotic barriers are the barriers which do not allow the formation of the zygote in the organisms.
The two mechanisms of the pre-zygotic barriers are the:
1. Habitat isolation: the Flycatchers do not share the same habitat which is also mentioned in the question that they live on different islands.
2. The behavioural isolation: the Flycatchers could have evolved the different mating rituals as a result of which the could not interbreed.
Thus, Habitat isolation and Behavioral isolation are correct.
Answer:
A dominant trait can be described as the one which masks the effect of a recessive trait. The alleles for a recessive trait gets suppressed by the dominant one.
A punnet square can be described as a diagram which depicts the outcomes of a cross. For single traits, the cross is monohybrid. For studying two traits at a time, a dihybrid cross can be made.
The punnet square for the following Holstein cattle can be shown as:
BP Bp bP bp
BP BBPP BBPp BbPP BbPp
Bp BBPp BBpp BbPp Bbpp
bP BbPP BbPp bbPP bbPp
bp BbPp Bbpp bbPp bbpp
The results show the phenotypic ratio to be 9 black/polled : 3 black/horned : 3 red/polled : 1 red/horned