A Level 3 Biology Quiz About Speciation.

Hybrid inviability is a type of reproductive isolating mechanism that occurs after the formation of a zygote. It refers to the situation where the offspring of two different species fail to develop properly and cannot survive to reproductive age. This mechanism prevents gene flow between species by reducing the fitness of hybrid individuals. Therefore, "post-zygotic," "postzygotic," or "post zygotic" all accurately describe hybrid inviability as a reproductive isolating mechanism.

at the level of DNA all evolution is divergent

Pre-zygotic reproductive isolating mechanisms occur before the formation of a zygote. Mechanical differences refer to physical incompatibilities between reproductive organs, making successful mating impossible. Behavioural differences involve differences in courtship rituals or behaviors that prevent individuals from recognizing or attracting mates of different species. Habitat differences occur when species occupy different habitats, preventing them from coming into contact and mating. Therefore, mechanical differences, behavioural differences, and habitat differences are all examples of pre-zygotic reproductive isolating mechanisms. Hybrid sterility and hybrid breakdown, on the other hand, are post-zygotic mechanisms that occur after fertilization.

Allopolyploidy refers to the condition where an organism has acquired an additional set of chromosomes from a different species. This can occur through hybridization between two species, resulting in a hybrid organism with a doubled chromosome number. The presence of this extra set of chromosomes can lead to genetic variation and potentially new traits in the organism. Therefore, an organism that has gained an extra set of chromosomes from another species is an example of allopolyploidy.

Polyploidy is an example of instantaneous sympatric speciation because it occurs when an organism gains one or more extra sets of chromosomes in a single generation, leading to the formation of a new species. This process can happen suddenly and in the same geographic location, without the need for geographic isolation or gradual genetic changes. Polyploidy can result in reproductive isolation and the formation of a new species, making it an example of instantaneous sympatric speciation.

Ecological speciation refers to the formation of new species due to divergent natural selection pressures in different environments. The Brown and Green Gecko is an example of ecological speciation because these geckos have adapted to different habitats and developed distinct traits to survive in their respective environments. This divergence in traits and adaptation to different ecological niches has led to the formation of separate species.