SPLATS about human evolution
For an explanation, see
the main splats page
All of the humans in the world are of the same species, although some racial groups show a range of adaptations that are useful in their chosen environments.
All living things with a global distribution will show the same sort of variation in different environments, but they won't necessarily become separate species.
Over time periods much greater than our lifetime, living things change in a process called evolution. This also applies to humans. We were once more ape-like.
We are probably not the same species as our direct ancestors of a million years ago, because the species has changed in a variety of ways since that time.
Humans have evolved over a long time: we are arguably the same species as our ancestors of 50,000 or 100,000 years ago, and could probably breed with them.
We probably could not breed with Homo habilis or Homo erectus, if we could travel back in time. We certainly could not breed with the Australopithecines.
In the past, humans have been shaped by natural selection and almost certainly by a variety of chance events, most of which we will never be able to identify.
Human shoulders have a collar-bone, showing they are built for brachiation, indicating that at some time in the past, our ancestors probably lived in trees.
It is likely humans evolved as they did after one or more genetic bottlenecks which saw most of their number wiped out, limiting the available variability.
Bottlenecks can be caused by many things: drought, famine and disease are three likely causes, but floods, fire and volcanoes probably also play a part.
We can learn about human evolution and origins from mitochondrial DNA in human populations, because this offers us an insight into the unbroken female line.
The evidence points to humans being descended from Australopithecus, or animals very like them, based on the fossil evidence we have collected since the 1920s.
As new evidence is found, so we adjust the way we see our hominin 'family tree' in minor ways, but the overall view remains unchanged, most of the time.
In 1974, Donald Johanson and Tom Gray found a 3.5 million-year-old female hominid fossil, 40% complete and named it 'Lucy', Australopithecus afarensis.
In 1771 Johann Friedrich Esper found human bones in a German cave, along with the skeleton of an extinct bear, raising some interesting considerations.
The first Cro-Magnon remains were found at Les Eyzies in 1868, in the Dordogne region of France. There were four skeletons, weapons and flint tools in the find.
We are descendants of the Cro-Magnon people, or else we are descended from people very like them, with a highly developed language system and culture.
The fossils we regard as like us and completely human are all from the Quaternary period, but modern humans evolved over a period of some millions of years.
Humans appear to be paedomorphic apes, shaped by neoteny, so that in effect, we advanced in an evolutionary sense by being retarded in our development.
Human groups may be recognized by the tools they make, but the first tool makers were probably the habilines (or Homo habilis), but this view may change.
One class of human tools is made up of the artefacts we call Acheulian tools, stone tools which reflect a form of manufacture common over a large area.
Almost all of the known and assumed ancestral forms found so far in the fossil record that seem close to humans have been found in Africa, or close to Africa.
Hominin brain size has shown a steady increase over time, but brain size is no more important than brain quality: modern humans have a considerable range.
The shape of a fossil hominin pelvis tells us a great deal about the hominins, about how they walked, and how large a brain they could have had at birth.
Hominins (previously called hominids) are the individuals in the fossil record who are closest to our ancestors. Future researchers will class us as hominins.
It is possible the Neandertals were a different species from us, or that they interbred with early modern humans. There is evidence for each of these views.
Java Man may or may not have been an ancestor of modern humans, mainly because some specimens appear to have coexisted in some areas with modern humans.
Nobody knows why the megafauna died in America and Australia, but it was either human hunting or climate changes which brought the humans in at the same time.
The position of the ramapithecines in human evolution is uncertain, but they are probably not part of the line leading to us, according to most researchers.
The position of the sivapithecines in human evolution is uncertain, but they are probably not part of the line leading to modern humans, just a side branch.
This file is http://members.ozemail.com.au/~macinnis/scifun/splatshumanevol.htm, first created on February 20, 2008. Last
revision (well I get lazy and forget sometimes!) was on February 20, 2008.
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