We must first define these three prominent definitions of species. Biological species concept means that organisms resemble each other because of genes being passed from parent to offspring. Phylogenetic species concept means that organisms resemble each other because they evolved from a common ancestor. Lastly, morphological species concept characterizes species on the structure of their body parts rather than genetic or phylogeny.
In this case, (1) biological species concept is not applicable for extinct species, (2) phylogenetic species concept is based on evolutionary history, (3) morphological species concept relies on similarities in structure, (4) Morphological and phylogenetic species concept accommodates asexual reproduction, and lastly (5) all species concepts are used by scientists in classification.
Well a mutation is like a change in the DNA and so if there was a mutation in the antártica fish, something in their genes would change. If that mutation has a positive effect on it, then that mutation would be passed down to the generations of fish, helping that fish with its survival or something
By meiosis 4 gamets are produced four are functional in males amd only one in female in case of humans