When was man evolved

Another, even better way to understand time is to study it in terms of generations. So, keeping in mind that primitive people married and had children early, 20 years will make an average generation.

Keeping this in mind if we calculate generations we find that generations back take us to the time when written history began,. David was king of Israel less than generations ago, Julius Caesar was alive just generations ago, Columbus was there 25 generations ago and the United States is just 10 generations old. So, the current scenario is that there were 49, generations of men before written history began! And another generations back would take us to the time 10, years ago , when cultivation began and man started settled life.

Can the human mind accept this fact that for such a long period of time and for so many generations, man did not make any effort to change either his surrounding or his life style? Why was he only a hunter and a gatherer for thousands and thousands of years?

Why did it take him such a long time to change himself and his way of life? Or would it not be wrong to say here that it was not really man who was roaming the earth at that time, but some other species, with fewer qualities than what man has been blessed with.

According to them, man did not evolve out of any other species: man was born a man with the best of qualities among all living species. Let us briefly review human evolution, in order to understand this concept and to try to find answers to questions that are still confusing us today. Let us begin with the evolution of animals.

Zoologists have classified the members of the animal kingdom according to their differences and similarities. We humans fall under this kingdom because we move and eat with our mouth; we are vertebrates because of our backbone, and we are mammals because we are warm-blooded and we breast-feed our offspring. We are primates because we have grasping hands, flexible limbs, and a highly developed sense of vision. We are also members of the family Hominoidea , the taxonomic group which includes both humans and apes, because of the absence of a tail, swinging arms, and the shape of our teeth.

The term hominoid refers to all present and past apes and humans, while hominid refers specifically to present and past humans Price and Feinman , a , b , c , d , e , f. Hominids are known as walking creatures with comparatively large brains; humans today are the sole living representation of this group. According to some evolutionists, fossil bones and genetic studies indicate that the hominids shared an ancestor with the great African ape.

It is at this point that the record becomes more complex, when the study of primate evolution turns into the study of hominid evolution. According to Richard Klein of Stanford University, determining the genus and species of the fossil bones of early humans is a very difficult task.

The fragmentary pieces of the early fossil finds represent only a few hundred separate individuals. Determining the age of the fossils is also very difficult. He says paleo-anthropology is more like a court of law than a physics laboratory, where we reassess and even redraw the whole family tree on finding a new fragment Price and Feinman , a , b , c , d , e , f.

Although we humans differ considerably from apes, genetically we are closest to them of all hominoids. As far as our genetic composition is concerned we share These statistics show great similarities and suggests that the last ancestor shared by the great ape and human lines was probably a chimpanzee-like creature.

Thus, changes in genetic regulatory mechanism play an important role in the evolution of different lineages. Geography had quite an important influence in shaping the development of humanity.

It was in the middle of the Tertiary period 5—25 million of years ago when the climate was much warmer and wetter than what it is today, and tropical forests grew across much of Africa, Europe and Asia that an increase in the variety of mammals occurred. Many species of apes lived in these forests, including one that is considered by some to be the ancestor of modern humans.

Then sometime around 5 million years ago, towards the end of the Tertiary time, the global temperatures began to cool, ice caps formed at the poles, and the climate grew drier. As a result, the area of the tropical forests grew smaller, giving way to expanses of open woodland and grasslands.

These developments did not occur all at once but evolved slowly. In East Africa the hominoids groups were trapped in shrinking patches of forest. Before this they had lived in the trees and moved on four feet when travelling around the forest bed. Now in order to cross wide stretches of open land quickly, some hominoids began walking on two feet, like modern humans. It was under these conditions that the hominids split from this ape or the hominoid group. It is believed that this whole process of hominization began in Africa, which is the only continent where fossils of early hominids dating back to four - 5 million years are found today.

These early hominids are called australopithecines: specialist believe in addition to walking upright with two feet, they had comparatively larger brains and they depended on tools for their survival Bahn a , b , c , d , e. While studying the fossils we also need to study how these beings modified objects and landscapes, thus creating an archaeological record. It is important to study both, as it helps us to understand how human beings evolved into what they are today. Some new fossil finds from Ethiopia, Kenya and Tanzania have pushed back the age of the earliest known hominids and have modified our understanding of their appearance and behavior Price and Feinman , a , b , c , d , e , f.

The oldest known Australopithecus species is A. Anamensis , which dates approximately 4 million years ago. The remaining early hominid fossils have been assigned to the species A. Afarensis , which includes the famous Lucy from Hadar see Fig. Afarensis, Lucy from Hadar, Ethiopia , Ethiopia. Other direct evidence of hominid bipedalism is a fossilized trail of footprints some 3. Another evolutionary trend that occurred during this time was the change in dental pattern. Fossils of hominids dating back to three to 2 million years from southern and eastern African sites have small front teeth and large cheek teeth.

Some form of gracile australopithecine is thought to have evolved into the first members of the genus homo about 2 million years ago, known as Homo habilis which literally means handyman.

Anthropologists continue to disagree about what caused this complete transition from ape to humans. Whereas many paleontologists believe that more than one species belonging to the genus homo may have co-existed in eastern Africa during the early Pleistocene, along with the robust australopithecines species with massive teeth and jaws.

It is also during this time that we find the oldest undisputed stone tools from Ethiopia, classified under the Oldowan tradition. They were taller than modern humans, but were very much like us in other respects, though their brains were still much smaller. It is assumed that they were capable of using fire and speech to a certain extent, and went, to far areas like Central Asia, Southwest Asia, South Asia, Europe and China.

The Acheulean stone-tool tradition is associated with them. But in recent years archaeologists have concluded that it is quite misleading to associate any Stone Age traditions uniquely to a single hominid species. Traditions can vary due to the availability of particular resources in different areas.

Keeping all the above details in mind, paleoanthropologists consider a logical link between H. They believe that the Acheulean stone — tool making ability was a determinant factor in the migration of early hominids out of Africa into new environments. The earliest handaxes found from outside of Africa are in Ubeidiya, Israel.

While the punctuationists and gradualists continue to debate about the fate of H. Replica of the fossilized trail of footprints some 3. Towards the end of the Tertiary Period the global climate had started to cool down and this continued into the next Quaternary Period, also known as the Ice Age see Fig.

In spite of its name the climate was not cold all the time: there were frequent warm intervals interglacial periods, separate from the cold, dry glacial periods. As these changes were quite rapid, the animals and plants sometimes found it difficult and sometimes impossible to adapt and to survive under the new climatic changes. This meant that greater intelligence was available now for problem solving.

One million years ago the brain of H. But recent studies have shown that stone tools found in association with animal bones were not used for slaughtering animals but for cleaning the skins and cutting up the meat. Plants probably formed a large part of their diet. No ornaments or art work is found and neither is there any evidence of them burying their dead Bahn a , b , c , d , e. So the question remains, was H.

Map of the Last Ice Age. It was sometime between , and , years ago that the fossils of H. Though these fossils differ considerably from one another they collectively are known as archaic H. They are poorly dated and paleoanthropologists find them difficult to classify and to relate specifically to H.

There are two major interpretations of the evidence of these fossil records. Their descendants then later migrated to other regions. According to it H. However, archaeologists have found no record to back the claim that either H.

There is no evidence of personal ornamentation - jewelry, beads, or any kinds of art form, exists, nor are there paintings, sculptures or engravings that show that use of more than basic instincts. The ability to think and reason is still missing Ingold a , b , c. Therefore, whether they were really our ancestor, might be questioned. In Europe a specie known as Neanderthals flourished between , and 35, years ago, they are considered by some to be the descendant of archaic H. A large collection of fossils remains, tells us that they were shorter and more robust than modern H.

But during the s, new evidence revealed that Neanderthals appeared in Europe and western Asia at the same time anatomically modern H. These dates and the new evidence have made paleoanthropologists revise their traditional understanding of the relationship between Neanderthals and modern peoples. The archaic H. Even more puzzling is the fact that both were using tools made in the same way. Mousterian experts disagree whether Neanderthals created a religion and whether hunting was important to them, but there is compelling fossil evidence from many sites and regions that they buried their dead and looked after their sick and old.

Moreover, it seems probable, given the scant evidence for any form of art or ornamentation, that they did not make use of symbols, which is a critical element in the development of human language. Another thing that concerns us today is whether the Neanderthals and the moderns interbred, and whether the modern human populations today contain any Neanderthal genes.

This situation creates a dispute among historians today Schultz and Lavenda a , b , c , d. There are many questions that come to mind. Why did the Neanderthals look after their sick and old?

Why did they start to bury their dead? Why were they using tools? Some believe that all these actions can be related to basic instincts. Tool use is not a distinctive characteristic of humans but; animals too may use or even make simple tools; however, using tools to make other tools does distinguish humans from animals. For example, the sea otter wields a rock to break open the shell of an abalone. And the anthropologist Jane Goodall has observed chimpanzees using a variety of tools in their daily life: thrashing about with branches for display, using clubs and missiles for defense, selecting a twig and stripping its bark to probe the nests of termites and attract them to the stick, then to be eaten by the wise chimp.

West African chimps even use stone and wooden hammers to crack and open nutshells Price and Feinman , a , b , c , d , e , f. Because when it came to something like creating symbols for speech they were unable to do so, since it required more brain capacity, reasoning and intelligence that they unfortunately lacked.

The question whether the Neanderthals and modern humans interbred was recently addressed by paleoanthropologists who claim, that there was no interbreeding between the two. Mitochondrial DNA studies suggest that all humans living today are part of a relatively homogeneous population that originated in Africa within the last few hundred thousand years. In , genetic researchers extracted and decoded a mitochondrial DNA fragment for the original Neander Valley specimen. The analysis revealed significant differences in its DNA from all living humans, suggesting that there was an ancient split between the two lineages, perhaps more than , years ago.

Although, Neanderthals did not disappear from Western Europe until 30, years ago, possibly later, it is a common belief that modern H. This phase is further divided into two phases. During the first phase, there is a general consensus among paleoanthropologists today that modern human H.

Recent studies in genetic evolution also support the view that Africa was the home of the original human population. However, debate continues about the nature of their dispersal. Most believe that a spreading wave of modern humans replaced existing populations of archaic H. This process of dispersal was complex and involved multiple movements of people and genes. In the caves of Qafzeh and Skhul in Israel remains of modern humans similar to found in Ethiopia and Tanzania, ,—, years ago , and in South Africa ,—90, years ago have been found.

This is the first evidence that we have of modern humans if they were outside of Africa. Though, the fossils of these modern humans are still associated with the archaic stone tool traditions like those of the Neanderthals , and like the ones also associated with the race of modern Africans Bahn a , b , c , d , e. But no one can disregard or refute the dramatic changes of many both in anatomy and in behavior, that have taken place over the last 40, years when compared with the previous million years.

Recent evidence from molecular biology has added support to this picture of rapid and recent change, resulting in the current humans that are not only genetically but also behaviorally and anatomically modern. Evidence also points to an African center for the origin of modern humans.

As they moved out of Africa they very soon replaced the variety of other Homo geneses roaming the world Ingold a , b , c. We possess many attributes that differentiate us from other species. Our large brain and intelligence enables us to think rationally and make decisions rather than to follow basic instincts like other species.

Authors of this finding suggested accordingly that A. Homo is the genus group of species that includes modern humans, like us, and our most closely related extinct ancestors. Organisms that belong to the same species produce viable offspring. The famous paleoanthropologist named Louis Leakey, along with his team, discovered Homo habilis meaning handy man in Homo habilis was the most ancient species of Homo ever found [ 2 ]. Homo habilis appeared in Tanzania East Africa over 2.

They were estimated to be about 1. They were different from Australopithecus because of the form of the skull. The shape was not piriform pear-shaped , but spheroid round , like the head of a modern human. Homo habilis made stone tools, a sign of creativity [ 3 ]. In Asia, in , Eugene Dubois also a paleoanthropologist discovered the first fossil of Homo erectus meaning upright man , which appeared 1.

This fossil received several names. The best known are Pithecanthropus ape-man and Sinanthropus Chinese-man. Homo erectus appeared in East Africa and migrated to Asia, where they carved refined tools from stone [ 4 ]. Dubois also brought some shells of the time of H erectus from Java to Europe.

Contemporary scientists studied these shells and found engravings that dated from , and , years ago. They concluded that H.

Several Homo species emerged following H. The best known one is Homo neanderthalensis Figure 3 , usually called Neanderthals and they were known as the European branch originating from two lineages that diverged around , years ago, with the second branch lineage Homo sapiens known as the African branch.

The first Neanderthal fossil, dated from around , years ago, was found in La Sima de los Huesos in Spain and is considered to originate from the common ancestor called Homo heidelbergensis [ 6 ]. Neanderthals used many of the natural resources in their environment: animals, plants, and minerals. Homo neanderthalensis hunted terrestrial and marine ocean animals, requiring a variety of weapons.

Tens of thousands of stone tools from Neanderthal sites are exhibited in many museums. Neanderthals created paintings in the La Pasiega cave in the South of Spain and decorated their bodies with jewels and colored paint. Graves were found, which meant they held burial ceremonies. Denisovans are a recent addition to the human tree. In , the first specimen was discovered in the Denisova cave in south-western Siberia. Very little information is known on their behavior.

They deserve further studies due to their interactions with Neandertals and other Homo species see below [ 7 ]. Fossils recently discovered in Morocco North Africa have added to the intense debate on the spread of H. The location of these fossils could mean that Homo sapiens had visited the whole of Africa.

In the same way, the scattering of fossils out of Africa indicated their migrations to various continents [ 9 ]. While intensely debated, hypotheses focus on either a single dispersal or multiple dispersals out of the African continent [ 10 , 11 ]. Nevertheless, even if the origin of the migration to Europe is still a matter of debate [ 12 ], it appears that H. Therefore, it could be that migration to Europe was not directly from Africa but indirectly through a stay in Israel-Asia.

They arrived about 45, years ago into Europe [ 14 ] where the Neanderthals were already present see above.

Studies of ancient DNA show that H. Several thousand years ago H. The quality of the paintings shows great artistic ability and intellectual development. Homo sapiens continued to prospect the Earth. They crossed the Bering Land Bridge, connecting Siberia and Alaska and moved south 12, years ago, to what is now called Chile. Homo sapiens gradually colonized our entire planet Figure 5. Neolithic Period means New Stone Age, due to the new stone technology that was developed during that time.

The Neolithic Period started at the end of the glacial period 11, years ago. Once a sperm merges with an egg, all the sperm mitochondria are destroyed. Mitochondrial DNA has been extensively used by evolutionary biologists, as it is easier to extract than DNA found in the nucleus and there are many copies to work with. She was simply the point from which all modern generations of human appear to have grown. This is when the majority of a species suddenly dies out, perhaps due to a sudden catastrophe, bringing it to the brink of extinction.

After studying the genetics and skull measurements of 53 human populations from around the world, scientists found that as you move further away from Africa, populations are less varied in their genetic makeup. This may be because human populations became smaller as they spread out from their original settlements in Africa and so genetic diversity within these populations was less.

As a result the scientists stated that modern humans could not have emerged in different places, but instead had to have come from one region, Africa. These were found in in Omo National Park in south-western Ethiopia. The skulls have been dated to , years ago, highlighting how humans have evolved relatively recently. Evidence shows that the first wave of humans to move out of Africa did not have too much success on their travels. At times it appears they were on the brink of extinction, dwindling to as few as 10, The eruption of a super volcano, Mount Toba, in Sumatra 70, years ago may have led to a 'nuclear winter', followed by a 1,year ice age.

This sort of event would have put immense pressure on humans. It may be that humans were only able to survive these extreme conditions through cooperating with each other. This may have led to the formation of close family groups or tribes and the development of some of the modern human behaviours we are familiar with today, such as cooperation. Between 80, and 50, years ago another wave of humans migrated out of Africa.

Due to their newly cooperative behaviour they were more successful at surviving and covered the whole world in a relatively short period of time. As they migrated they would have encountered earlier, primitive humans, eventually replacing them. A map showing human migration out of Africa. Image credit: Genome Research Limited. Homo neanderthalis , or Neanderthals as they are more often known, are an extinct species of human that was widely distributed in ice-age Europe and Western Asia between , and 28, years ago.

They were characterised as having a receding forehead and prominent brow ridges. Since then, researchers have been striving to uncover the position of Homo neanderthalis in modern human evolution.

Homo neanderthalis appeared in Europe about , years ago and spread into the Near East and Central Asia. They disappeared from the fossil record about 28, years ago. Their disappearance has been put down to competition from modern humans, who expanded out of Africa at least , years ago ,year-old remains of modern humans have been found in Israel , suggesting that there would have been a period of co-existence. Did the two species interbreed? Have Neanderthal genes therefore contributed to the modern human genome?

Initial studies of DNA from the mitochondria of Neanderthals showed that their mitochondrial DNA looks quite different to that of modern humans, suggesting that Homo neanderthalis and Homo sapiens did not interbreed.

They also identified another archaic human group called 'Denisovan', named after the Siberian cave in which the fossil finger, from which the DNA was obtained, was discovered. In they obtained a more refined Neanderthal genome sequence from a 50,year-old Neanderthal toe bone, found in the same cave in southern Siberia. The genome sequence suggested that early modern non-African humans interbred with their now extinct ancient human cousins.