What mechanism could explain the diversity of life?

*Note: Throughout, I will utilize Darwin Finch as an example of how diverse life can be, drawing from your question's premise of "diversity of life."

The definition of "survival of the fittest" (also known as evolution) is as follows: the best organism that is more suited to its current environment will prevail.

The definition of speciation is the emergence of diverse organisms through "survival of the fittest," which were formerly able to interbreed but are now too different to; I will go into further detail about this in my example of Darwin Finch.

"Environment" refers to the surrounding area and all of its constituents, including the climate and other living things.

I'll now use Darwin Finch to demonstrate why these three are the most significant.

The Darwin Finch is a bird that is considered 'indigenous' to the Galapagos Islands. It is believed that the birds arrived there a few thousand years ago, when a storm drove their flock off its migratory path and onto the islands.

The flock was split up among these various islands, where they encountered a variety of habitats and food sources, such as fruit, nuts, and insects. The birds in the flock that were better adapted with their beaks to consume the primary food source on each island—fruit or nuts—would fare better in their new environment than those that lacked those desirable traits, and the latter would eventually become extinct or lose their traits as they reproduced.

Because of the physical sea barriers separating these islands, the birds would eventually interbreed more and more on their islands until speciation occurred. As a result, many of these birds are genetically distinct from their ancestors.

Darwin's eventual theory of evolution—survival of the fittest—which produced this wide variety of birds in a comparatively small area (8,010 km2) depended heavily on these finches.

If an organism has good characteristics, it will survive better than its counterparts; hopefully you can see why and how this is replicated elsewhere (e.g., Red Squirrels in Britain with no pox resistance, Grey Squirrels in America with pox resistance).

I hope this is useful.

-Charlie

The mechanism that explains the diversity of life is primarily evolution through natural selection, as proposed by Charles Darwin. This process involves the accumulation of small, random genetic variations within populations over time, which are then selected for or against based on their impact on an organism's ability to survive and reproduce in its environment. Additionally, other mechanisms such as genetic drift, gene flow, and mutations also contribute to the diversity of life.