What are the various speculation on the existance of life or how did life form on earth?

In evolutionary biology, abiogenesis, or informally the origin of life (OoL), is the natural process ... For the oldest life forms, see Earliest known life forms. ... There are several principles and hypotheses for how abiogenesis could have occurred. ... In 2017 scientists found possible evidence of early life on land in 3.48 Gyo

Explanation:

Many scientists favor the RNA world hypothesis, in which RNA, not DNA, was the first genetic molecule of life on Earth. Other ideas include the pre-RNA world hypothesis and the metabolism-first hypothesis. Organic compounds could have been delivered to early Earth by meteorites and other celestial objects. We can only speculate about these questions, since we haven't yet found any life forms that hail from off of Earth. But we can think in a more informed way about whether life might exist on other ... When did life appear on Earth? ... For many millions of years, early Earth was pummeled by asteroids and other celestial objects.

1) gene flow

- it is described as the transfer of genes from one population to another population so that frequency of gene is increased.

-a zebra migrates to join a different herd of zebras.

2) natural selection

- a mechanism of evolutionary change in which individuals with advantageous traits survive and reproduce whereas the others ( those that can not adapt) eliminate from the population.

-competition for sunlight leads to taller trees.

3) mutation

- permanent change in the nucleotide sequence of dna ( genetic material) that could have harmful or useful consequences.

-the dna of a snake changes to make its venom stronger.

4) genetic drift - it is a random phenomenon ( that occurs by chance such as fire) that results in change in the gene frequency in a small population.    

-a grassfire randomly sweeps through a population of buffalo and kills most of the animals.

explanation:

you can have just about every answer you can think of