Evolutionary Trends in the Genus Homo

Homo is a genus name given to a group of advanced apes which includes man.  They are at least 1.5 million years old. Some anthropologists believe that the genus originated from australopithecines. Most of these were discovered in the East African region. In 1758, Linneaus classified Homo was as shown in the table below.

Kingdom:

Animalia

Phylum:

Chordata

Class:

Synapsida

Class:

Mammalia

Order:

Primates

Family:

Hominidae

Tribe:

Hominini

Subtribe:

Hominina

Genus:

Homo

The genus is subdivided into several stages according to their period of existence. The best confirmed earliest of these were the Homo habilis, which was believed to be a direct ancestor to the Australopithecus. However, unconfirmed studies claim that there was an intermediary homo, before Homo habilis which is known as  Homo gautengesis. Fossils of this genus were discovered in Africa, which led to a hypothesis that Africa was the cradle for human race. Some of the members of this genus drifted to Asia and were named Homo erectus and others moved to Europe where they were named Homo georgicus. The Homo ergaster and Homo erectus advanced separately for approximately two million years with the former being in Africa and the latter in Eurasia apparently separating into two different species. From Homo ergaster descended the Homo rhodesiensis who migrated to Europe from Africa, they developed into Homo heidelbergensis and later became Homo neanderthalensis and in Asia Denisova Hominin (Thompson, 2003). The name Homo habilis is derived from Latin to mean the “handy man”. The second was the Homo erectus, while the latest was the Homo sapiens.. Homo sapiens or “thinking man”are among the latest discovered fossils and date to about 1.5 million years ago. Here has however been a new development with anthropologists deciding to include another species of modern man, in a species called Homo sapiens sapiens.

Fossils for the Homo habilis were discovered in Tanzania by Leakeys between the year 1962 and 1964. From the studies on the Homo habilis, it was determined that he was shorter than the modern man was. However, they had long arms that were un- proportional to the rest of the body, as compared to man today. In comparison to their predecessors, the Australopithecines, Homo habilis had a less protruding face, which resulted to development of the jaw to have smaller jaws and smaller molar teeth. Its cranial capacity is believed to have ranged between 510 and 660 cm3. This was less than half of what modern man possesses (Campbell, 1998).

Homo habilis used tools for their daily activities that included hunting. They are linked with the Oldowan tool industry which used rounded hammer stones, crude stone flakes and bones that were used for digging. Due to the finding of tools next to dismembered animal remains it is believed that they fed on meat and they used stones in getting marrow from bones that were too large to be broken. They are also believed to have moved in larger groups for security reasons (Thompson, 2003).

After the Homo habilis, there emerged the second species within the genus, known as Homo erectus. Homo erectus was derived from Latin to mean “the upright man” Its fossils have been found in African and Asia continent, with China, Java, India and Caucasus having been among the areas where many of them were discovered. During the early era of Homo erectus, the descendants had a brain capacity of about 800 cm3 but the laterstages had about 1100 cm3. They were more similar to the modern man especially their limb bones, with respect to size and form. They had shallow foreheads and their heads had some special and conspicuous muscles behind their necks. This made them have very strong necks as they carried their loads on their heads (Thompson, 2003).

They adapted to new ecological breaks by generating cultural technologies. They successfully expanded their territories approximately 1.8 million years ago. They migrated from Africa to populate the tropical and subtropical zones in the Old World. This made them pioneer the human culture development. This expansion was in line with the cooler global temperatures which was gradual. Through this expansion they got the ability to move into zones of Asia and Europe which had seasonal cold temperatures. Their intelligence was better and they had created newer cultural technologies like hunting skills and could create fire (Campbell, 1998. p.93). Louis and Mary Leakey found a partial Homo erectus cranium in 1960 at Olduvai Gorge. A nearly complete skeleton of this species was found on the Western side of Lake Turkana in 1984 and was estimated to be of an 8-12 year old boy and is referred to as the “Turkana Boy.”

The other species of Homo was the Homo neanderthalensis, which was named after the valley it was discovered, Neander in Germany. These fossils were mainly found in Europe and Asia and possessed a cranial capacity of between 1200 and 1900 cm3. Their main difference from modern man is the development of the brain, because they have anequal brain apacity as modern man at birth. Howeve, as modern man develops and develops the brain to more sophisticated network and lperception of different things that eventually lead to intelligence, Homo neanderthalensis, grew slowly leading to being surpassed by modern man. Morphologically, they were different from the modern man by the fact that they had strong limbs and were shorter. Their barrel chests and stocky limbs helped them adapt to the highly varying weather patterns that ranged from season to season, and from very cold to very hot(Campbell, 1998).