HOW DID HUMAN ORIGINATE?

HOW DID HUMAN ORIGINATE?

Where we humans come from? Everybody wants to get the answer to this fundamental question. Human evolution is the lengthy process of change by which people originated from apelike ancestors.

Here are the EARLY HOMINIDS –

8 TO 6 MILLION YEARS AGO:-

Last common ancestor of chimpanzees and hominids

8 TO 6 MILLION YEARS AGO:-

Sahelanthropus tchadenis

5.8 MILLION YEARS AGO:-

Ardipithecus ramidus

4.4 MILLION YEARS AGO:-

Australopithecus anamensis

4 MILLION YEARS AGO:-

Australopithecus afarensis

3.5 MILLION YEARS AGO:-

Kenyanthropus platyops

3 MILLION YEARS AGO:-

Australopithecus africans

THE DETAILS OF HUMAN EVOLUTION:

are a subject of continuing study and debate, but the general sequence from an apelike proconsul of 23 to 15 million years ago(far left)through hominid forms to the present- day human posture(far right) is generally accepted by scientists today.

Today only one species, Homo sapiens, exists, but over the course of human prehistory as many as 15 varieties of early human walked the Earth. Though the number of species and their relationships to one another are not settled, it seems clear that the earliest hominids-a term that describes all humans who ever lived-took their first steps in Africa. They were (and still we are) primates, descended from a grouo of apes that also gave rise to gorillas and chimpanzees. Around 4 million yeara ago, something in the environment led the first hominids to leave the trees and walk upright, marking thw official transition to human status. These early homìnids are often grouped under the name Australopiths (from the term “southern ape”) and include the genera Ardipithecus, Australopithecus, and paranthropus. About 3.5 to 5 feet tall, they had apelike faces, with sloping foreheads and prominent jaws, but their canine teeth were small compared with an ape’s and their hands featured long, flexible thumbs. The most famous fossil member of these early humans is the Australopithecus afarensis known fondly as “Lucy”, whose partial skeleton was discovered in 1974. Her species, which lived in eastern Africa between 3 and 4 million yeara ago, is one leading candidate for beiñg a direct ancestor of Homi sapiens.

Australopiths died out about 1.2 million years ago. By that time, their descendants, a new kind of hominid, were already roaming Africa: The genus Homo, which came into existence roughly 2.3 to 2.5 million years ago, marked by a distint increase in brain size. By 1.9 million years ago, these humans had tall skeletons like those of today’s Homo sapiens, although their skulls still featured sloping foreheads, prominent brows, and heavy jaws.

These late species of Homo also demonstrated another similarity to modern humans: the desire to explore new lands. Starting around 1.8 million years ago, the first great wave of human migration occured when adventurous members of Homo erectus trekked out of Africa and into Europe and Asia. However, these hominids eventually died out and were not the direct ancestors of today’s humans. That honor falls to the first members of our own genus, Homo sapiens, who appeared in East Africa about 200,000 years ago.

MITOCHONDRIAL EYE AND Y CHROMOSOME ADAM

The study of human DNA has increased our knowledge of human origins and migration. Although virtually all of our DNA 8s recombined with every generation, two parts of tge genome remain mostly unshuffled. The Y chromosome is passed down virtually unchanged from father to son. DNA in the cell’s mitochondria, on the other hand, is passed down only from mothers to children. Very rarely, but at a steady rate over time, a harmless mutation will occur in the DNA. This genetic marker will be carried through subsequent generations. Genticists have traced the markers to the original pair of Homo sapiens ancestors, “Mitochondrial Eve” and “Y chromosome Adam, “two Africans who lived about 60000 and 150,000 years ago, respectively.

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