For the identification of insects and other fauna and flora of South Africa: please click on the following links:
Insects and related species: Antlions - Ants - Bees - Beetles - Bugs - Butterflies, Moths and Caterpillars - Centipedes and Millipedes - Cockroaches - Crickets - Dragonflies and Damselflies - Grasshoppers and Katydids - Mantis - Stick Insects - Ticks and Mites - Wasps - Woodlice
Plants, Trees, Flowers: (Note: Unless plants fall into a specific species such as Cacti, they have been classified by their flower colour to make them easier to find) Bonsai - Cacti, Succulents, Aloes, Euplorbia - Ferns and Cycads - Flowers - Fungi, Lichen and Moss - Grass - Trees
Animals, Birds, Reptiles etc.: Animals, Birds, Fish and Crabs - Frogs - Lizards - Scorpions - Snails and Slugs - Snakes - Spiders - Tortoise, Turtles and Terrapins - Whipscorpions
Other photography: Aeroplanes - Cars and Bikes - Travel - Sunrise - Water drops/falls - Sudwala and Sterkfontein Caves etc.

Videos: YouTube

Sunday, May 31, 2009

Cradle of Humankind SA - Part 5

Bipedalism
About 7-million years ago, early hominids began to adapt to a climate that was cooling globally. Before this, Africa had been mostly covered in rainforest. But as the temperature cooled and dried, savannah replaced the forest. This meant tree-climbing apes had to become more adept at walking on land.

Our ancestors who ventured out into the savannah were rewarded with roots, shrubs and occasional animal carcasses, ensuring that those who walked on two legs were more likely to survive.
Bipedalism allowed hominids to free their arms, enabling them to make and use tools well, stretch for fruit in trees and use their hands to communicate. They could also see further over the savannah grass.
But even with these advantages, our ancestors probably spent time in trees as well, which we can tell by studying fossils of hands and feet, and how they were adapted to climbing. Although there is a popular idea that our ancestors slouched and stooped forward, the study of fossil hips, spines and feet suggest they always walked fairly upright.
Development of the jaw and diet
Our ancestors’ diet changed over time. From eating mostly plants, they began to eat a mixture of meat and protein, along with plant matter. This helped their brains to develop, and in turn altered the shapes of their jaws. Over time, their jaws became less heavy or “robust” and more slender or “gracile”. The jaws of Australopithecus, for example, projected far more forward than ours, but as Homo developed, the jaw moved further back, under the growing braincase. Our teeth also became smaller as we developed the capacity to cut and grind food.
Development and growth of the brain
One of the defining characteristics of becoming human has been the growth and development of our brains. Australopithecus had an average cranial (brain) capacity of about 450cc, about the size of an orange. Today, our brains are on average more than three times as big as that, at around 1400cc. But bigger brains don’t necessarily mean a species will survive. Neanderthals had brains on average between about 5% and 10% bigger than ours, and they became extinct about 20,000 years ago.
Stone tools
The oldest stone tools so far dated come from Ethiopia and are about 2.6-million years old. The first technology that our ancestors developed was the Oldowan Industry. These tools were primitive and were mostly just pebbles or broken pebbles. Next, came the Acheulean Industry (pronounced “Eish-oo-lean”). Acheulean tools included large, rough hand-axes and cleavers, probably for chopping and mashing meat. Dozens of Acheulean tools, including hand-axes, have been found right here at Maropeng in an ongoing excavation. The Acheulean was followed by the Middle Stone Age and Later Stone Age, during which tools became much smaller and more refined and were developed for specific tasks, such as skinning an animal, or hafting onto a wooden handle to make a spear. The Later Stone Age in South Africa lasted right up till about 200,000 years ago, and the San people knew how to make these tools right into historical times.
Control and use of fire
The ability to harness and use fire was a major technological step in human development. Our ancestors probably learnt to capture fire from wildfires and keep it burning before they learned to make it. At Swartkrans in the Cradle of Humankind, scientists have found a collection of about 300 bones which have been burnt at a consistent temperature, which is higher than the temperature of the average bushfire. These have been dated to more than 1-million years old.

This is the oldest evidence for controlled use of fire in Southern Africa so far, though there is even slightly older evidence of it in East Africa. So we can say South Africa’s first braai happened right here in the Cradle! The ability to control and use fire helped our ancestors to warm themselves and to cook food, thus helping to expand their diets.
Development of language
Scientists don’t really know much about this, as our voice-boxes are made of soft tissue, and there is no fossil evidence of how they may have developed over time. Some scientists say we may have acquired the ability to speak at the time of Homo habilis, 2-million years ago, while others say it is only modern Homo sapiens that has been able to speak, within the past 200,000 years ago.
Our sophisticated ability to communicate across time and space sets us apart from other animals, and has helped us to populate the Earth and travel to its most inaccessible regions. It has allowed us to gather food better, to live in groups better, and to express ourselves better.
Exhibit SK54 is a juvenile cranium of a Paranthropus robustus dated at 1.5 million years discovered in 1949 at Swartkrans by Dr Robert Broom and J.T. Robinson. This specimen possesses two 6mm puncture wounds. Initially it was thought that these fractures were caused by a pointed weapon. Based on subsequent excavations by C.K. Brain the generally accepted theory is that these puncture wounds were caused by a leopard attack. Using another Swartkrans find a lower mandible from an African leopard, C.K. Brain hypothesized that victims wounds were from a predator/prey scenario. The canines of the leopard matched up to the puncture wounds of the skull. An equal distance of 33mm.

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