The mechanisms of reproductive isolation prevent the reproduction of two individuals from different species. The prezygotic mechanisms disrupt the stages of reproduction before the forming of the zygote or prevent the mating at the start, and the postzygotic mechanisms affect the stages of reproduction after the forming of the zygote.
So, the first and the third example (the urchins and the grasshoppers) show the prezygotic mechanism, as the two individuals are not able to mate or form a zygote.
The second and the fourth example ( zonkey and the death of a zygote) show the working of the postzygotic mechanisms, as the zygote is formed, but it seems to be inviable, and the zonkeys are sterile, preventing the individual to reproduce.
Latitude is not a factor in marine life divisions.
In two species of birds, both of which form monogamous pair(one male and one female), In species 1, you find that the eggs in a pair's nest are in fact almost always the offspring of that pair. In species 2, you are surprised to find that many of the eggs in a nest were actually fathered by males of neighboring pairs. Apparently, mating outside of monogamous pairings is widespread in species 2. we would expect that female of species 2 would have sperm from multiple males in their reproductive tracts.
- This is because the species 2 are having many eggs.
- These eggs were formed due to fertilization with multiple male bird partners.
- As a result we can expect eggs with different genotypes.
Thus from the above points we can conclude that two species of birds, both of which form monogamous pairs, female of species 2 would have sperm from multiple males in their reproductive tracts
Learn more about the fertilization in birds:
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Even with treatment, up to 1 in 3 people with necrotizing fasciitis die from the infection. Six out of every 10 people who get both necrotizing fasciitis and streptococcal toxic shock syndrome at the same time die from their infection
Forage crops. pasture crops. Peas, peanuts, or corn is an example of such crops. ... mainly protects other crops during their early days
