The Evolution of Humans – Out of Africa
This time of year we are busy organising orders of dinosaur toys and games in time for Christmas. As a result we are having more frequent collections by the various mail and delivery companies that we use. We are also visiting various sorting depots and collection points as team members drop off parcels ready for sending onward on their journey to customers. One of the spin-offs from all this increased interaction with post office staff, the Royal Mail and other agencies is that our team members get asked all sorts of questions about prehistoric animals and related subjects.
One of the areas of greatest interest is the origin of our species. This was a contentious issue when considered by Darwin in his ground breaking text of that name, although Darwin chose to skate round the subject in his first edition. He merely noted that “light will be thrown on the origin of man and his history”.
It is difficult to explain how very little scientists know about the origin of human-kind, indeed the fossil record is so poor that very little can actually be established as conclusive, for example, some palaeontologists support the theory that hominids diverged from other higher African apes some 4.5 million years ago, whilst others believe that the split occurred much further back in time, perhaps some 6 million years ago.
Ground dwelling animals of a grassland type environment such as our direct ancestors have a very poor chance of fossilisation. The conditions are all wrong to permit fossilisation and preservation. Usually only teeth (enamel is extremely tough), or knuckle bones and skull fragments are found. This makes the establishment of evolutionary relationships and even the identification of species extremely difficult. The fossil record of other apes, such as those that had an arboreal (tree-living existence), is even worse. Organic material such as the corpse of a dead ape on the floor of a tropical forest, is rapidly broken down and easily scavenged by predators. Decay is normally rapid and complete leaving very little evidence of our primate ancestors.
Experts even argue about what species should be classified as hominid. For example, some scientists believe that the higher apes such as chimpanzees and the Bonobo (pygmy chimp) should be classified as hominids, after all we share something like 98% of the same DNA.
However, the earliest fossils of human-like creatures (about 2.5 million years old) have been found in Eastern and Southern Africa there is strong evidence to suggest that Africa was the cradle of human origins and that indeed we, as a result are “out of Africa”. This information has certainly got the postal workers talking.
Wait until we inform them that according to evolutionary biologists H. sapiens that’s us; are not the pinnacle of evolutionary achievement – we are not the end game of evolution on planet Earth.
This should encourage some lively debate around the mail rooms and sorting office.