The biblical quotation seems to have been fulfilled for some creatures , particularly Homo-Sapiens. One of the main desires for most creatures is a ready supply of food, even reproduction relies on well fed and fit parents and when a constant food source is secured one holds on to that source, that is until a more powerful creature, tribe, clan, pride, pack decide to take over your territory and food source, then your only course is to move on to find a new source, usually from someone who is even weaker than you or your group. It is instinctive of most creatures do not want to move from their home territory, it is only the constant search for food that drives the weaker groups to move on. This is particular true with primates, if they have a constant supply of food in their home territory and the mutations in their bodies are benign they will remain as a distinct species, chimps will remain as chimps, gorillas will remain as gorillas but the weakest primate, protohumans were the smallest and weakest primate and therefore on the constant move as nomads, living in one area for one or two seasons before moving on. Earliest human ancestors, Homo Erectus, Australopithecus and other hominins were only about 3ft 6 inches tall, the largest, Neanderthals, were not much over 4 ft. , no match for big cats and carnivores of the savannah or forests. So how did they survive?
All living organisms have genetic information encoded in DNA that are divided into genes, there are about 20,000 mammalian genes encoded with similar proteins. As earlier pointed out, if mutations to these genes are of benefit to an organism that organism will flourish, if harmful the organism will become extinct, however right from the beginning of life on earth many genes have continued hardly interrupted and still continue in their basic form. For example, Neil Shubin of the University of Chicago in his book “Your Inner Fish” describes how he and his colleagues Fred Mullison and Bob Masek on analysing the fossil of a 375 million year old fish which they named Tiktaalik discovered that the fish’s forearm fins had shoulder bones, an elbow and a wrist, a wrist that consisted of an upper arm, and a forearm, all with mutations and enlargements as in humans and most mammals. Shubin and his colleagues were fortunate to observe evolutionary changes in fish bones . Unfortunately the cells that make up all of the soft parts of bodies do not fossilise, all past palaeontologists had to work with was bones, they might have guessed, but could not prove what internal organs a fossil had. When comparing the closeness of Tiktaalik’s fins and the bones of a human foot a contributor to “Your Inner Fish” declared that “These feet were made for swimming, not walking”
At over 4 mya Australopithecus Anamensis discovered near Lake Turkana was believed to be the oldest pre Homo-Sapien and being the smallest and presumably the weakest of the hominids A. Anamensis would have been the first to have been dispelled from their homes around Lake Turkana in what is now Kenya. However, in 2000 a team led by Brigitte Senut and Martin Pickford from the Muséum national d’histoire naturelle discovered A. Orrorin Tugenensis which are dated to being over 6 million years old and were also found in the Lake Turkana area. It has not been fully decided if they are separate species who lived along side of each other. If either species had to migrate food and water would have been their first concern making movement to the west not advisable as that is the Dida Galgalu Desert, a vast expanse of arid , inhospitable lava desert, the safest route for the nomads would have been north or south along the Rift Valley. Australopithecus have been found in the Sterkfontein Caves just north of Johannesburg, South Africa, but most headed north because in the periods 195,000, 102,00, 11,000 years ago and from 7 to 4, 000 years ago Lake Turkana flowed directly into the River Nile thus opening a way north for the hominins.
Both A. Anamensis and A. Tugenensis were bipedal, indicating that bipedalism must have started well before six million years ago.
BIPEDALISM
So how did humans become bipedal? As we have seen, if a species obtains a niche in its environment that has a constant supply of food there is not any need to migrate unless it is invaded by a more aggressive species. However, if a species has to migrate the creature will have to adapt to its new environment. Occasional mutations are happening to all creatures and if they are harmful that creature will become extinct, usually in one generation, but if the mutation is helpful the creature will prosper as a sub species like giraffes and okapis or sea otters and river otters.
Sub species are also formed by separation due to changes in the environment such as deserts, mountains, lakes or rivers. After hominins mutated from chimpanzees, chimps had another mutation about two million years ago when communities of chimpanzees were separated by the Congo River, formally the Zaire River. However around about the period of the mutation south of the River Congo suffered from a lengthy drought which wiped out the preferred food of resident creatures. When there is limited supply of food larger animals will move out or die out. This is what happened to Zaires chimpanzees, but fortunately some learnt and mutated/evolved to be able to survive with less food, the side effect was their bodies became smaller until they became a sub species of chimpanzee… Bonobos.
The reduction of size in isolated creatures is a process in which a breed of animals or plants is changed to become significantly smaller than standard members of their interest species. The effect can be induced through human intervention or non-human processes, and can include genetic, nutritional or hormonal means. Hominins isolated on the island of Flores were so much reduced in size that they were nicknamed “The Hobbits”. The thing about Bonobos was not only were they smaller and slimmer but their legs were longer, this could indicate that certain parts of their skeleton, muscles, tendons and body tissue and were prone to mutation. Whats more you’ll rarely see a chimp wading in deep water, they don’t like to swim. Their low body fat ratio causes them to sink and their top heavy body composition makes it difficult for them to keep their heads above water. However, some chimpanzees do enjoy a good splash around in shallow water. Bonobos are more comfortable in water and have often been observed in deep water. One is not suggesting that humans evolved from Bonobos, Homo sapiens were bipedal over 6 million years before bonobos diverged from chimpanzees, Homo sapiens and chimpanzees had a common ancestor but humans did not evolve from chimps.
Up until 1950s the predominate theory of bipedalism was that apes descended from trees to live on open plains. This savannah theory is a theory that human bipedalism evolved as a direct result of human ancestors transition from an arboreal lifestyle to one on the savannahs. According to this hypothesis, millions of years ago hominins left the woodlands that had previously been their natural habitat, and adapted to their new habitat by walking upright. The idea that a climate-driven retraction of tropical forests forced early hominini into bipedalism has been around for a long time, often implicitly. Some early authors saw savannahs as open grasslands, while others saw a mosaic of environments from woodlands to grasslands. The hypothesis has seen rising criticism since at least the late 1960s. The open grasslands version is mostly dismissed, while the mosaic version still has relatively wide support, although the transition from forest to savannah probably was more gradual than previously thought.
The fundamental ideas behind it date back to Darwin, Wallace and also Gustav Steinmann, the eminent German geologist and paleontologist who saw reducing rain forest due to climate change as important driver for bipedalism. The hypothesis first came to prominence however with the discovery of Australopithecus africanus by Raymond Dart in 1924. In an article on the discovery, published in the journal Nature, Dart wrote: “For the production of man a different apprenticeship was needed to sharpen the wits and quicken the higher manifestations of intellect – a more open veldt country where competition was keener between swiftness and stealth, and where adroitness of thinking and movement played a preponderating role in the preservation of the species. Darwin has said, “no country in the world abounds in a greater degree with dangerous beasts than Southern Africa.” and, in my opinion, Southern Africa, by providing a vast open country with occasional wooded belts and a relative scarcity of water, together with a fierce and bitter mammalian competition, furnished a laboratory such as was essential to this penultimate phase of human evolution.”
If Darwin, Wallace and Steinmann had the benefits of modern DNA sequencing and knowledge of plate tectonics and past climate, whilst their basic theories transformed our understanding of evolution they might have arrived at different conclusions. Sadly the derision that greeted Darwin’s theory of evolution prevails today regarding Alister Hardy’s theory that we had an aquatic past.