Humans are, of course, primates, who shared a common ancestor with Old World monkeys, then with Gibbons and other lesser apes, then with orangutans, followed by the gorilla and eventually with the common ancestor of the chimpanzee and bonobo, the so-called pygmy chimpanzee. In reality we are more similar at the genomic level to chimpanzees and bonobos than these two species are to gorillas.
Thus, from a genomic perspective, humans are nothing more than one kind of “Great Ape”; the correct term encompassing all these groups is “Hominid.” Monkeys, lemurs and apes are our cousins, and we all have evolved from a common ancestor over the last 60 million years. Chimpanzees are genetically closest to humans, and in fact, chimpanzees share about 98.6% of our DNA.
Via Mind the GRAPH
We share more of our DNA with chimpanzees than with monkeys or other groups, or even with other great apes! We also both play, have complex emotions and intelligence, and a very similar physical makeup.
What do most living primates have in common?
Large brains (in relation to body size)
Vision more important than sense of smell
Hands adapted for grasping
Long life spans and slow growth
Few offspring, usually one at a time
Complex social groups
Many of the similarities between humans and apes derive simply from the structural similarity of their skeletons. Given any animal that is partially upright, with grasping hands on its forelimbs, there may just be one optimal way to design the rest of the organs. For example, such an animal will need extra intelligence to control its hands. It will also tend to be flexible and adaptable, and not so tied to the seasons as other animals are; thus, it is more reasonable to have a reproductive cycle that permits offspring at any time of year, rather than only at certain seasons.
Paradoxically, the living apes, even though their populations are under very intense threat from deforestation and direct hunting, still contain more genetic variability than all seven billion humans on the planet today.
Human minds are effective copying machines. Somebody comes up with a good idea, and then everybody in the group maintains that idea. We develop a diminishing culture, in which we build upon each other’s ideas.
Copy-Paste Syndrome
The benefit of belonging to a social group might outweigh the benefits of maximizing individual efficiency. The differences in nutcracking efficiency between chimpanzee groups add to the ever-growing body of cultural variants in wild chimpanzees and expand our knowledge of the importance of group belonging and conformity in wild chimpanzees. Similarly, humans often try to blend with people who may not be as efficient as them for the sake of socializing.
Human and Chimpanzee Disease Profile
So, the question arises: are there human-specific diseases? There are a few criteria for human-specific diseases: they are very common in humans but rarely reported in great apes, even in captivity; and they cannot be experimentally reproduced in apes (in the days when such studies were allowed). The warning, of course, is that reliable information is limited to data on a few thousand Great Apes in captivity.
We can draw several conclusions: 1) The disease profiles of humans and chimpanzees are rather different. 2) Chimpanzees are actually poor models of many human diseases. We should pay more attention to that. 3) Humans are likely to be poor models of many chimpanzee diseases.