Loss of biodiversity affects the ecosystem in many ways. For example, if a species disappears, the animals/plants that it fed on will suddenly increase in population due to loss of predators. The predators of the lost species, however, will go down in population because its main source of food has disappeared.
<span>the ability of matter to be self organizing</span>
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.
