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.
The answer is no, high biological fitness in one environment doesn’t have to be high in another environment.
Biological fitness is a term used in evolutionary biology and it is the quantitative representation of how a genotype (or phenotype) is successful (reproductively) in a certain environment. Fitness depends on environment so it changes if the environment changes. The fitness of a genotype is manifested through its phenotype, which is affected by the environment.
Answer:
zygote, fertilization
(haploid) spores, meiosis
a pollen tube
Biodiversity depends on a species' ability to reproduce itself. If a species cannot reproduce then it will die out. This depends on the climatic conditions of the region. If there is a natural disaster for example, it will affect a species' ability to reproduce. This reduces the number of diverse species on earth. Biodiversity is the recognised variety of different types of life found on the earth. It also measures the variety of number and variety of plants, animals and other organisms found in different ecosystems.
The day before or the day after.
