Which hominoids are the closest living relatives to humans

Learn More Deep Time. Life began more than 3 billion years before the Cambrian, and gradually diversified into a wide variety of single-celled organisms. Toward the end of the Precambrian, about million years ago, a number of multicelled forms began to appear in the fossil record, including invertebrates resembling sponges and jellyfish, and some as-yet-unknown burrowing forms of life. As the Cambrian began, most of the basic body plans of invertebrates emerged from these Precambrian forms.

They emerged relatively rapidly, in the geological sense -- over 10 million to 25 million years. These Cambrian forms were not identical to modern invertebrates, but were their early ancestors.

Major groups of living organisms, such as fish, amphibians, reptiles, birds, and mammals, did not appear until millions of years after the end of the Cambrian Period. Web Activities. About the Project. Site Map. All rights reserved. There are about 14 species of relatively small-bodied apes known as Lesser Apes. These are the gibbons, which live in trees, rarely descend to the ground and are active during the day.

Gibbons are found in the forests of South-east Asia. The Great Apes are named for their large bodies. They also have larger brains than other primates. Like Lesser Apes, the Great Apes are active during the day.

There are four types of Great Apes — the orang-utans, gorillas, chimpanzees and humans. There are two living species of orang-utan — the Bornean Orang-utan, Pongo pygmaeus , and the Sumatran Orang-utan, Pongo abelii. Orang-utans live in dense rainforests of Borneo and Sumatra in South-east Asia. Gorillas live in dense forests in western and central tropical Africa.

Gorillas are the largest of all primates. How do the monkeys stack up? Geneticists have come up with a variety of ways of calculating the percentages, which give different impressions about how similar chimpanzees and humans are. The 1. A comparison of the entire genome, however, indicates that segments of DNA have also been deleted, duplicated over and over, or inserted from one part of the genome into another. No matter how the calculation is done, the big point still holds: humans, chimpanzees, and bonobos are more closely related to one another than either is to gorillas or any other primate.

From the perspective of this powerful test of biological kinship, humans are not only related to the great apes — we are one. The DNA evidence leaves us with one of the greatest surprises in biology: the wall between human, on the one hand, and ape or animal, on the other, has been breached.

The human evolutionary tree is embedded within the great apes. The strong similarities between humans and the African great apes led Charles Darwin in to predict that Africa was the likely place where the human lineage branched off from other animals — that is, the place where the common ancestor of chimpanzees, humans, and gorillas once lived.

The DNA evidence shows an amazing confirmation of this daring prediction. The African great apes, including humans, have a closer kinship bond with one another than the African apes have with orangutans or other primates. The DNA evidence informs this conclusion, and the fossils do, too. The Australopithecus foot may even have had a human-like arch, based on analysis of the metatarsals and the fossilized Laetoli footprints Ward et al.

Nonetheless, compared to modern humans, the forearms were long and the fingers and toes were long and somewhat curved, suggesting that Australopithecus regularly used the trees to forage and perhaps as a refuge from predators at night. Brain size in Australopithecus ranged between and cc, similar to chimpanzees and gorillas Falk et al.

Body size in Australopithecus was rather small and sexually dimorphic, about 30kg for females and 40kg for males McHenry, This level of dimorphism is not reflected in the canines, which were small, blunt, and monomorphic as in earlier hominins. Unlike the canines, molar teeth in Australopithecus were much larger than those of earlier hominins, and had thicker enamel. This suggests their diet included hard, low quality plant foods that required powerful chewing to process.

A subgroup of Australopithecus , known as the "robust" australopiths often labeled by a separate genus Paranthropus because of their enormous teeth and chewing muscles, took this adaptation to the extreme. Most Australopithecus species were extinct by 2 mya, but some robust forms persisted until about 1.

The earliest fossils of our own genus, Homo , are found in East Africa and dated to 2. These early specimens are similar in brain and body size to Australopithecus , but show differences in their molar teeth, suggesting a change in diet. Indeed, by at least 1. The oldest member of the genus Homo , H. Its more formidable and widespread descendant, H. Like modern humans, H.

Its global expansion suggests H. Not surprisingly, it is with H. Molar size is reduced in H. Around kya, and perhaps earlier, H. Neanderthals H. Fossil and DNA evidence suggest our own species, H.

The increased behavioral sophistication of H. By kya, our species spilled into Eurasia, eventually expanding across the entire globe into Australia and the Americas DiGiorgio et al.

Along the way our species displaced other hominins they encountered, including Neanderthals in Europe and similar forms in Asia. Note that not all agree with this interpretation of the data, see Tryon and Bailey. Studies of ancient DNA extracted from Neanderthal fossils suggest our species may have occasionally interbred with them Green et al.

Our increasing global impact continues today, as cultural innovations such as agriculture and urbanization shape the landscape and species around us. Anton, S. Natural history of Homo erectus. American Journal of Physical Anthropology S37 , Blumenschine, R. Science , Brunet, M. New material of the earliest hominid from the Upper Miocene of Chad.

Nature , Dart, R. Australopithecus africanus : the southern ape-man of Africa. DeGiorgio, M. Out of Africa: modern human origins special feature: explaining worldwide patterns of human genetic variation using a coalescent-based serial founder model of migration outward from Africa. Falk, D. Early hominid brain evolution: a new look at old endocasts. Journal of Human Evolution 38 , Harcourt-Smith, W. Fossils, feet and the evolution of human bipedal locomotion.

Journal of Anatomy , Kimbel, W. Systematic assessment of a maxilla of Homo from Hadar, Ethiopia. American Journal of Physical Anthropology , Kunimatsu, Y.

A new Late Miocene great ape from Kenya and its implications for the origins of African great apes and humans. McHenry, H. Body size and proportions in early hominids.