An aspect of biology that interests me is the evolution of humans over many hundreds of years. Human evolution began six million years ago in Africa. This has been proven countless times by evidence such as fossils of human remains which can be dated back to many million years ago.
Our first ever relative was a fish that existed 400-350 MYA. It was called the Notharctus Tenebrosus and its first fossil was discovered in 187in 1870. It is linked with the human species as it shared a unique characteristic which was the opposable thumb, this is because life living in trees caused fingers to grow in length so you could reach the edible fruit. They also had large hind limbs and a tail which helped with weight distribution. It also provides another important characteristic which is coloured vision. Early primates had a limited colour range but then the one group discovered full red, green, and blue vision to tell the difference from the ripe fruits and the green ripe fruits. (3)
First, we have a clear relationship with Apes, and this was discovered as our genetic makeup is quite similar. For example, around about 98.5% of the genes we find in people are also in chimpanzees. This does mean that they are our closest living relative however this does not mean that we have evolved from the chimpanzees. It does suggest that we share a common ancestor with modern apes like chimpanzees, therefore we are related to the primates, but we do descend from them. We have however evolved in numerous ways from chimps as human brains are larger thus more complex. This means that have different varying cultures and languages, people can also walk upright. Humans can also speak and manipulate objects unlike these apes. (1)
Darwin’s natural selection theory can explain why we have differentiated from chimpanzees. The main points of the theory were: struggle for existence, Variation, survival of the fittest and then reproduction of the fittest animals. In the stages of human evolution, the Dryopithecus is generally considered the ancestor to apes and humans but the diverge from the line is still debatable. Dryopithecus lived in Africa, China, India and Europe. The name means oak wood apes as it is believed environmental conditions were dense with trees and they could have been predominantly herbivores.
Next are the Ramapithecus and they were first discovered in Punjab in the Shivalik Hills and then found later in Africa and Saudi Arabia. They had a habit which consisted of not only trees but also grassland. Fossils show that they had a thickened jaw enamel and more robust jaws. Next is the Australopithecus, and they were first found in 1924 at Taung, Africa. They would walk erect and they lived on the ground. They could have also used stone to hunt animals.
Then the Hume Erectus was discovered in Java in 1891, by Eugene Dubois. They had a bigger cranial capacity than the Australopithecus and used fire. Stone tools were made of quartz and evidence suggests of big game hunting and it must have been in collective cooperative groups. They seemed to have lived in caves, thus the use of fire is important.
Homo Sapiens Neanderthals are one of the two sub species of the Homo Sapiens. Most of the fossils found are around 75000 years old. Stone flakes which seem to be spears were also found for the very first time. The caves they dwelled in were also more comfortable as they had fireplaces at the entrance of the cave. They could also hunt elephants and Rhinos.
Then there is the Homo Sapiens Sapiens and the first remains were found in Europe. Here there was a final reduction of the jaw and the chin and rounded skull also made an appearance. Hunting and gathering was the main source of food. Art was also appeared for the first time on caves and shown in the cave walls were animal figures. (2)
Even though we are genetically similar to apes we still have remarkable differences that chimpanzees simply don’t have. For example, evidence from fossils suggests how apes were incapable of running for a long distance, however living humans and fossils show that we can. We also have other minute differences. For example, our saliva is different from the saliva of apes. Human saliva is much waterier, and the concentration of proteins is much lower in human saliva than apes. Also, each primate species had its own unique collection of saliva proteins. (4)
Another mystery is how humans are bipedal which means can walk on two legs. There are many theories but none that are completely satisfactory. As bipedalism leaves the hands free, scientists think that weapons were our reason for the hands to be free. However, early stone artefacts only date to around 3.3mya and this is after hominins became bipedal. This could suggest earlier tools were not of stone but wood and other not so long-lasting material. Other theories are standing in tall grass looking out, presenting sexual displays, following migrant herds on the savanna and conserving energy. Bipedalism conserves energy compared to walking on all fours which is called quardrupedism. Also, there are benefits from standing on all two legs you would have regular exposure to sunlight, they are standing on two legs this means that there is less body surface area would be exposed to sun rays, but also that there would be relief in the cooler air.
Scientists think that originally bipedal primates were terrestrial bipedal and even knuckle-walkers like chimpanzees today. In conclusion, we may have the similar genetics to an ape at is still alive like a chimpanzee but we are still quite varied from them.
We are still experiencing natural selection to this day. For example, the height of Dutch people has increased. In the mid-18th century, the average Dutch soldier was 165 centimetres which was below the average of soldiers from other European countries. Recently, Dutch men have experienced a sudden growth spurt which added an extra 20 centimetres to their average height, which has occurred over the past 150 years. In the same time, American men have only added 6 centimetres to their total average. Another example of human evolution is the milk revolution. 11,000 years ago adult humans were unable to digest lactose. Due to humans in some regions relying on dairy farming as a source of nutrition, over time our bodies adjusted to digest this food more, which was previously only tolerated by infants and toddlers. We can still see this today, humans in areas with a long tradition of dairy farming are more tolerant of lactose than people where dairy farming is not a heritage such as Asia. An estimated 5 percent of people who descend from Northern European are lactose intolerant compared with more than 90 percent of people that are East Asian descent. (6)
In conclusion, humans have evolved in numerous ways to get at the stage in which we are in but we are still evolving and we can even see those evolutions from the people we meet as no two person is the same. This is because as humans we still have evolved to have different skin colours and many other features to adapt to the environment in which we live in.