What are some leading hypotheses (informed theories) about how our species emerged? how are humans different?
in relation to "this fleeting world"

1. There is actually only one hypothesis that is widely accepted about the evolution of the humans. It is the hypothesis that suggests that the first hominids evolved in East Africa, with the main reason being the geological activities in the region that sharply changed the environment. Because the environment turned from tropical forest to open savanna, it was advantageous for the initial hominids to be bipedal as they were able to see above the grass and avoid danger. Over time they became exclusively bipedal and abandoned the trees, lived in groups to support and protect each other. Several different types of hominids were evolving and dying out, and they started to gradually spread out across Africa. Because the brain was becoming larger and more complex as a balance for the loss of the physical defense and attack traits, the hominids started to pick up much more things that the other animals, eventually leading to construction of weapons, tools, and taming the fire.

2. The humans are much more close than different, despite the different physical appearances. Several different races have developed over time, and that has been largely because of developing advantageous traits for survival in the environment, as well as the mixing with other hominid species or subspecies. The humans of Europe and the Middle east tend to have small percentage of Neanderthal genes, while the Asian, Amerindian, and Australasian humans tend to have genes from the Denisova man. The sub-Saharan Africans bear a gene of a hominid that still has not been identified. The mixing of the Homo sapiens with other species for sure resulted in some minor differences. The environment though was detrimental, with a general trend of the humans that live closer tot he equator to be darker, while the ones further away to be lighter. The ones that developed in very cold climates have developed fat shortages bellow their eyes in order to avoid freezing, thus giving the almond-eyes of the East Eurasians, and many more physical features that are still only on the surface, while the gene pool is largely the same.