For example, Culex mosquitoes, which transmit West Nile and other life-threatening illnesses, are able to detect even minute concentrations of nonanal, a chemical substance given off by humans. Repellency effect of forty-one essential oils against Aedes, Anopheles, and Culex mosquitoes.
There were not many humans at this time, and they were spread out, rather than living close together. Experts think there were no more than one million humans living during any time of the Paleolithic Era. That might sound like a lot of people, but today there are about seven billion people, 7,000 times more people than in the Paleolithic Era. Archaeological evidence points to humans beginning in the continent of Africa, and later migrating to other continents.
Early Transitional Humans. Humans are members of the genus Homo. Modern people are Homo sapiens. However, we are not the only species of humans who have ever lived. There were earlier species of our genus that are now extinct.In the past, it was incorrectly assumed that human evolution was a relatively straightforward sequence of one species evolving into another.all (100-235 cm) and weighed around 70 pounds (32 kg) The evolution of larger bodies occurred later in human evolution. The differences between australopithecines and early humans are most noticeable in the head.