Final answer:
The diversity of cichlid species in Lake Malawi can be attributed to adaptive radiation, a process where a common ancestor evolves into many different species adapted to various ecological niches.
Step-by-step explanation:
The origins of 300 or more species of cichlid fish in Lake Malawi are best explained by the biological concept of adaptive radiation. This process involves a common ancestor rapidly diversifying into multiple species, each of which adapts to a unique niche or habitat within a relatively short evolutionary timespan. In the case of the cichlid fish, this diversity resulted from different groups specialized in various feeding strategies—such as eating plankton, scraping algae, consuming insect larvae, or even preying on the eggs of other cichlids—which illustrates a prime example of speciation driven by exploitation of different ecological niches.
Furthermore, in Lake Apoyeque, Nicaragua, we see evidence of sympatric speciation, another form of rapid species diversification. There, thin-lipped and thick-lipped cichlids evolved from a single population into distinct morphologies with different diets, despite living in the same geographic locale. This scenario mirrors the diversity found in Lake Malawi and Victoria cichlids, underlining the incredible rate of cichlid diversification in specific lakes.