There is grandeur in this view of life, with its sev­er­al pow­ers, hav­ing been orig­i­nal­ly breathed into a few forms or into one; and that, whilst this plan­et has gone cycling on accord­ing to the fixed law of grav­i­ty, from so sim­ple a begin­ning end­less forms most beau­ti­ful and most won­der­ful have been, and are being, evolved.” – Charles Dar­win, On the Ori­gin of Species, 1859

The hominid fam­i­ly tree has a large num­ber of branch­es. Although researchers agree on the gen­er­al trends of hominid evo­lu­tion, the rel­a­tive scarci­ty and frag­men­tary nature of fos­sils and time gaps in the fos­sil record leave room for debate. For exam­ple, there are dif­fer­ing views on the rela­tion­ship between hominids and the liv­ing apes. The gen­er­al view is that humans and chim­panzees share a com­mon ances­tor, but some researchers argue that orang­utans are more close­ly relat­ed to humans.

Dif­fer­ences between species occur as a result of muta­tions and recom­bi­na­tions of genes. Although it is not pos­si­ble to study the genes of species rep­re­sent­ed by fos­sils, palaeon­tol­o­gists use the avail­able fos­sil data to try to recon­struct fam­i­ly trees”. With new finds and research, these trees are con­stant­ly being redrawn.

Australopithecus Image

An artist’s impres­sion of Australopithecus

The dis­cov­ery of our ancestors

In the 19th cen­tu­ry, zool­o­gists began to the­o­rise about the evo­lu­tion of humans from ape-like ancestors.

Anatom­i­cal indi­ca­tions which sup­port the con­cept of evo­lu­tion can be seen in hominid fos­sils from the Sterk­fontein Caves and oth­er sites in the Cra­dle of Humankind. Our ear­li­est ances­tors belonged to species now extinct and are known only from fos­sils at sites such as these. They had human-like teeth and could walk on two legs, but they also had sev­er­al ape-like fea­tures, includ­ing much small­er brains than ours.

Humans and apes prob­a­bly had com­mon ances­try rel­a­tive­ly recent­ly, in the Miocene peri­od – per­haps about 8-mil­lion years ago.

It’s only in the past 50 years or so that the con­cept of evo­lu­tion has received wide pub­lic accep­tance. But it’s an idea that’s been accept­ed by zool­o­gists and anthro­pol­o­gists for more than 100 years. Carl Lin­naeus, a Swedish botanist who devised a clas­si­fi­ca­tion sys­tem (see below) for all liv­ing things in 1735, clas­si­fied humans togeth­er with the apes in the zoo­log­i­cal order primates.

In the 19th cen­tu­ry, Charles Dar­win pub­lished his the­o­ry of the evo­lu­tion of species and sug­gest­ed that humans had evolved from old­er, yet to be dis­cov­ered, species.

The first archa­ic fos­sil of a human ances­tor to be recog­nised was the Nean­derthal skull cap found in 1856 in Ger­many. In the same year a Miocene fos­sil ape, Dry­op­ithe­cus, was dis­cov­ered in France. A more archa­ic hominid than the nean­derthal, Pithecan­thro­pus, known as Java Man” and since reclas­si­fied as Homo erec­tus, was found in Java, now Indone­sia, in 1891.

In 1924 the skull of a very ape-like human ances­tor was found at Taung, South Africa. This fos­silised skull of a four-year-old child became known as the Taung Skull” or the Taung Child”. It had an ape-sized brain but human-like teeth. Pro­fes­sor Ray­mond Dart, the anatomist who recog­nised it for what it was, claimed this fos­sil was a link between ape and human and named it Aus­tralo­p­ithe­cus africanus (“south­ern ape of Africa”).

Taung Child

The Taung child fossil

The Taung fos­sil had a num­ber of human-like features:

  • Brain: The brain size was too large to rep­re­sent a fos­sil mon­key, and the brain grooves on the endo­cast, gyri-ele­va­tions and sul­ci-grooves indi­cat­ed human-like or advanced brain function.
  • Facial fea­tures: The degree of prog­nathism or facial pro­jec­tion was not as large as what you would find in an ape.
  • Den­ti­tion: The canine tooth crown was small­er and less pro­ject­ing than that of an ape.
  • Fora­men mag­num: The open­ing at the base of the skull where the spinal cord enters the ver­te­bral col­umn was posi­tioned far for­ward on the base of the skull, which indi­cat­ed that the head would have bal­anced on a ver­ti­cal body. This would mean that the Taung child walked erect and thus was like­ly to be bipedal.

In 1936, the palaeon­tol­o­gist Dr Robert Broom found the first adult Aus­tralo­p­ithe­cus at Sterk­fontein. This and all oth­er human-like fos­sils, includ­ing our own species, Homo sapi­ens, are clas­si­fied in the zoo­log­i­cal fam­i­ly Hominidae. The apes are classed into sev­er­al oth­er fam­i­lies: Hylo­bati­dae (gib­bons), Pongi­dae (orang­utans), and Panidae (chim­panzees and gorillas).

The great apes of the present day are the goril­las, chim­panzee and bono­bos of Africa, and the orang­utan of Asia. Today’s less­er apes – the gib­bons and sia­mangs of Asia – occur only in restrict­ed areas of trop­i­cal forest.

But dur­ing the Miocene peri­od, which last­ed from about 22-mil­lion to 6-mil­lion years ago, there were a great many species of ape that occu­pied forests in Europe and Asia as well as Africa. Some of the gen­era were Pro­con­sul, Afro­p­ithe­cus, Moro­to­p­ithe­cus, Turkanap­ithe­cus, Kenyap­ithe­cus, Den­dropethi­cus, from East Africa; Otavipethi­cus from Namib­ia; Dry­op­ithe­cus; Oura­nop­ithe­cus; Plio­p­ithe­cus and Lufeng­p­ithe­cus from Chi­na. One Asian ape, evolved into the biggest ape ever known, with mas­sive jaws and teeth. Apart from the orang­utan, which has strong sim­i­lar­i­ties to Sivep­ithe­cus, it is not known how the mod­ern apes and humans relate to these fos­sil genera.

It is gen­er­al­ly accept­ed that hominids – the ances­tors of humans – evolved from one of the Miocene apes about 8-mil­lion years ago, as the old­est hominid found so far is the 7-mil­lion-year-old Sahe­lan­thro­pus from Chad. Oth­er ear­ly hominids are the 6-mil­lion-year-old Orror­in tuge­nen­sis from Kenya and the 5.8-million-year-old Ardip­ithe­cus ramidus from Ethiopia.

Mis­lead­ing links

Most sci­en­tists – espe­cial­ly those out­side Africa – dis­missed the impor­tance of the fos­sil dis­cov­er­ies in South Africa in the 1920s and 1930s, and were influ­enced heav­i­ly by the dis­cov­ery of the so-called Pilt­down Man” fos­sil in Sus­sex, Eng­land, in 1912.

The Pilt­down remains were for­mal­ly clas­si­fied as Eoan­thro­pus daw­soni, named after the skull’s dis­cov­er­er, Charles Dawson.

Piltdownexcavation

The exca­va­tion site for the Pilt­down Man

Pilt­down Man reflect­ed the expec­ta­tions of the day, that a dis­tant human ances­tor, found in Europe, should be a crea­ture with a large brain, like that of Homo sapi­ens, while hav­ing an ape-like jaw.

Crit­ics dis­put­ed the claims made by Pro­fes­sor Ray­mond Dart and Dr Robert Broom in South Africa on the grounds that the Aus­tralo­p­ithe­cus africanus spec­i­mens they had found had small brains. How­ev­er, Pilt­down Man” was even­tu­al­ly exposed as a hoax in 1953. The fake was actu­al­ly con­struct­ed from a human skull buried with an orang­utan jaw that had arti­fi­cial­ly abrad­ed teeth to make it look human. The Pilt­down hoax – which had many sci­en­tists fooled for more than 40 years – delayed uni­ver­sal recog­ni­tion of the great sig­nif­i­cance of the South African fos­sils. To this day, it is not known for sure exact­ly who set up the hoax.

The dis­cov­er­ies of sev­er­al spec­i­mens of Aus­tralo­p­ithe­cus africanus from South Africa, and the expo­sure of the Pilt­down scam, encour­aged sci­en­tists from around the world to accept that Africa was, after all, the cra­dle of humankind. One of the first Eng­lish sci­en­tists to recog­nise the impor­tance of South Africa’s fos­sil her­itage was Sir Wil­fred Le Gros Clark.

Sci­en­tif­ic classification

Carl Von Linné

Carl von Lin­né (Source: Wikicommons)

The Swedish botanist Carl von Linne (17071778), also known as Carl Lin­naeus, devised the sci­en­tif­ic clas­si­fi­ca­tion sys­tem which cat­e­goris­es all plants and ani­mals and describes them in a two-part name made up of their genus and species. The basic sys­tem he devised is still in use, though it has been mod­i­fied over the years.

In order to study liv­ing things, sci­en­tists today clas­si­fy each organ­ism accord­ing to its:
King­dom
_​_​_​Phylum
_​_​_​_​_​_​Class
_​_​_​_​_​_​_​_​_​Order
_​_​_​_​_​_​_​_​_​_​_​_​Family
_​_​_​_​_​_​_​_​_​_​_​_​_​_​_​Genus
_​_​_​_​_​_​_​_​_​_​_​_​_​_​_​_​_​_​Species

To give an exam­ple, mod­ern human beings, Homo sapi­ens, are clas­si­fied like this:
King­dom: Ani­mals
Phy­lum: Chor­dates
Class: Mam­mals
Order: Pri­mates
Fam­i­ly: Hominidae
Genus: Homo
Species: sapi­ens

Charles Dar­win

In his clas­sic books, On the Ori­gin of Species (1859) and The Descent of Man (1871), Charles Dar­win (1809 — 1882) argued the case for nat­ur­al selec­tion – that over time crea­tures which are able to adapt bio­log­i­cal­ly to their envi­ron­ments sur­vive, while those that don’t become extinct.

He fur­ther argued that all species of life on Earth are inter­re­lat­ed and have a com­mon ances­try, dat­ing back to the ear­li­est forms of life.

The man who start­ed a revolution

Charles Dar­win was the first per­son to artic­u­late a the­o­ry of evo­lu­tion by descent with modification.

Charles Darwin

Charles Dar­win

As a young man, he sailed around the world on the HMS Bea­gle from 1831 to 1836, vis­it­ing the Gala­pa­gos Islands, among oth­er places, col­lect­ing spec­i­mens and devel­op­ing his the­o­ries of evo­lu­tion and nat­ur­al selec­tion. Dur­ing this jour­ney, he also vis­it­ed the Cape of Good Hope in South Africa.

Although high­ly con­tro­ver­sial at the time, the con­cept has gath­ered wide­spread sup­port, though there is still oppo­si­tion to it.

But Dar­win was not the first to sug­gest that humans and apes may share com­mon ances­try. In 1774, James Bur­net, Lord Mon­bod­do of Scot­land, who was an eccen­tric judge and philoso­pher, sug­gest­ed that humans were relat­ed to orang­utans, and that in Africa all the types of human pro­gres­sion might be traced. Bur­net is now cred­it­ed as being one of the first schol­ars to intro­duce the con­cept of evolution.

Meet the family

Aus­tralo­p­ithe­cus africanus: Taung Child


Taung Child is the type spec­i­men for Aus­tralo­p­ithe­cus africanus. It was col­lect­ed by a quar­ry­man at Taung, in the North West Province of

Taung Plaque P1310673

A plaque mark­ing the site where the Taung child was discovered

South Africa, in Octo­ber, 1924, and tak­en to Pro­fes­sor Ray­mond Dart, an anatomist at the Uni­ver­si­ty of the Wit­wa­ter­srand in Johan­nes­burg. Dart recog­nised, cleaned and described the skull in the sci­en­tif­ic jour­nal, Nature, the fol­low­ing year.

Despite nam­ing it Aus­tralo­p­ithe­cus africanus or south­ern ape of Africa”, he not­ed the infant’s dis­tinct human-like fea­tures, includ­ing a smooth brow region with no trace of brow ridges, small canine teeth, and a for­ward-placed fora­men mag­num (where the spine joins the base of the skull) that indi­cat­ed it was bipedal. The Taung Child was the first aus­tralo­p­ithecine ever found, lend­ing weight to the idea that humankind was born in Africa.

Homo ergaster: KMN-ER3733

One of the best pre­served Homo ergaster fos­sils yet dis­cov­ered, this skull belonged to a mature adult that lived about 1.75-million years ago in Koobi Fora, Kenya. It was

Homoergaster

Homo ergaster

dis­cov­ered by fos­sil hunter Bernard Ngeneo in 1975, who saw just the top of its dou­ble-arched browridge peek­ing out above the ground.

Although its brain size (850 cc) and low cra­nial vault are com­pa­ra­ble with the Asian Homo erec­tus, KMN-ER3733 has enough dif­fer­ences, includ­ing a thin­ner cra­nial (skull) wall, for many palaeoan­thro­pol­o­gists to place it in a dif­fer­ent species – Homo ergaster.

Homo erec­tus: S17”, Indonesia

The 800,000 year-old San­gi­ran 17 cra­ni­um is the best pre­served Java Man” (as fos­sils from this area are known) found so far. Its long cra­ni­um, low fore­head and thick cra­nial bones are typ­i­cal of the Asian Homo erec­tus from the region.

Homoerectus

Homo erec­tus

Homo nean­derthalen­sis: La Fer­rassie 1

This adult male was found in the La Fer­rassie rock shel­ter in France, by Louis Cap­i­tan and Denis Pey­rony in 1909. La Fer­rassie 1, dat­ed to about 50,000 years ago, is con­sid­ered one of the clas­sic exam­ples of Nean­derthal anato­my, as it con­tains all the defin­ing char­ac­ter­is­tics of the species, includ­ing a reced­ing fore­head, low-vault­ed brain­case, large dou­ble-arched browridge, big nose and a huge brain­case (1600 cc). It also has heav­i­ly worn front teeth, which may have been used as clamps for hold­ing skins.

The skele­ton of the spec­i­men is also very impor­tant – it helped to dis­pel the mis­con­cep­tion that Nean­derthals walked with a stooped, slouch­ing stance. In fact, La Fer­rassie 1 and sub­se­quent skele­ton finds show that Nean­derthals had a pos­ture sim­i­lar to mod­ern humans. This skele­ton was inten­tion­al­ly buried, like the oth­er sev­en spec­i­mens found at the site.

Homo sapi­ens

Homo sapi­ens emerged about 200,000 years ago. Mod­ern humans have a large brain (1300 cc aver­age), encased in a high-vault­ed cra­ni­um. They also have a browridge that is very reduced or non-exis­tent com­pared to oth­er Homo species, a near-ver­ti­cal fore­head, ver­ti­cal sides to the brain­case and a promi­nent chin.

Although pop­u­la­tions around the world do look dif­fer­ent – with skin colour being per­haps the most defin­i­tive char­ac­ter­is­tic – we are all alike and share the same species name, Homo sapi­ens.

Time­line

  • Aus­tralo­p­ithe­cus afaren­sis lived in East Africa between about 3.6-million and 3-mil­lion years ago
  • The ape-like but upright-walk­ing Aus­tralo­p­ithe­cus africanus lived between about 3-mil­lion and 2-mil­lion years ago in South­ern Africa
  • Handy man”, Homo habilis, is com­mon­ly regard­ed as the first tool­mak­er, emerg­ing about 2-mil­lion years ago in East Africa
  • Homo ergaster was about as tall as mod­ern humans and lived between about 1.7-million and 1.4-million years ago in East and South­ern Africa
  • Homo hei­del­ber­gen­sis lived from about 600,000 years ago until 300,000 years ago and was prob­a­bly an ances­tor of Neanderthals
  • Homo nean­derthalen­sis lived from about 200,000 years ago until about 20,000 years ago in Europe
  • Homo sapi­ens emerged about 200,000 years ago, prob­a­bly in Africa

Aus­tralo­p­ithe­cus


Aus­tralo­p­ithe­cus
– Aus­tralo­p­ithecines were some of our most ancient ances­tors, liv­ing in Africa between about 4-mil­lion and 2-mil­lion years ago.

They were small­er than us, with human-like teeth and hands, a flat­tened nose region and for­ward-pro­ject­ing jaws. Their brain was a lit­tle larg­er than that of a mod­ern chimpanzee’s – about a third the size of ours today.

Aus­tralo­p­ithe­cus walked upright, but still used trees – per­haps climb­ing them for pro­tec­tion from preda­tors or to seek food.

Dif­fer­ent species of Aus­tralo­p­ithe­cus lived in East­ern and South­ern Africa. The old­est found thus far, Aus­tralo­p­ithe­cus ana­men­sis, was the most ape-like of the aus­tralo­p­ithecines and lived between 4.2-million and 3.9-million years ago in East Africa.

Oth­er species include Aus­tralo­p­ithe­cus afaren­sis which lived between 3.6-million and 2.9-million years ago in East Africa and Aus­tralo­p­ithe­cus africanus, which lived between 3-mil­lion and 2-mil­lion years ago in South­ern Africa.

The famous South African fos­sils Mrs Ples and the Taung Child are both Aus­tralo­p­ithe­cus africanus.

Homo

Homo – The ear­li­est species of the genus Homo, our most direct ances­tors, appeared about 2.3-million years ago. There were many species of Homo; the first was Homo habilis, known from fos­sils dat­ing to 1.9-million years ago.

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Humans are the only sur­viv­ing Homo species

Homo had a larg­er brain than its aus­tralo­p­ithecine pre­de­ces­sors. It was the first hominid to have the men­tal capac­i­ty in addi­tion to the phys­i­cal abil­i­ty to fash­ion prim­i­tive stone tools.

It was fol­lowed by Homo ergaster about 1.7-million years ago, whose advanced tool use and abil­i­ty to har­ness fire for cook­ing and warmth allowed their descen­dants to even­tu­al­ly leave Africa for cold­er cli­mates. Homo erec­tus emerged soon after, pop­u­lat­ing Asia for over a mil­lion years.

As Homo devel­oped and spe­ci­at­ed, their brains grew larger.

Mod­ern Homo sapi­ens emerged about 200,000 years ago in Africa. Some of the ear­li­est fos­sils of our species have been found in Ethiopia and South Africa.

Mod­ern Humans – Mod­ern humans, Homo sapi­ens, are the only species of Homo that have sur­vived up until this day. The ear­li­est mod­ern humans appeared in Africa about 200,000 years ago. By at least 70,000 years ago, humans were show­ing mod­ern behav­iour­al traits such as adorn­ment and artwork.

Ancient civil­i­sa­tions began to appear about 10,000 years ago, with writ­ing forms fol­low­ing soon after­wards. And the rest… is history.

The human pop­u­la­tion has explod­ed from about 200-mil­lion peo­ple 2000 years ago to over 6-bil­lion. Today we’re able to trav­el from one side of the world to the oth­er faster than the speed of sound, we’ve pop­u­lat­ed almost every dry part of the plan­et, from moun­tain­tops to islands, and we’ve even ven­tured into space.

But we’ve also endan­gered our sur­vival on Earth by pol­lut­ing the atmos­phere, destroy­ing nat­ur­al habi­tats and wag­ing war.

Will the inge­nu­ity that has helped us thus far even­tu­al­ly destroy us or ensure our sur­vival long into the future?