Journey of man Essay Example | Topics and Well Written Essays - 750 words

Journey of man - Essay Example This essay will expound on this thesis. In this most compelling story of natural history, the pivotal moment was the great Ice Age that set in 50 thousand years ago. Up until this point, the entire human population (technically of the species Homo sapiens) were confined to just the African continent. This is understandable, for most of the early hominids evolved in this landmass, with the evolution of our species being a natural progression. With the onset of the Ice Age, the rich and diverse ecology of central and southern Africa began to change. With the substantial drop in temperatures, the erstwhile green and fertile regions began to dry up. The early human populations that depended on this ecosystem for survival faced drought like conditions. To illustrate the depth of the problem, the sea-shore caves of South Africa, which were used as shelter by primitive people, became ever more distant from the shore line – nearly 40 kilometers at the peak of the Ice Age. Such radical changes to the ecology forced people to move toward he north-east of the continent, where the climate was somewhat more temperate. And this crisis for survival is perhaps the most important event in anthropology. For, without it, Homo sapiens might not have ever left Africa. In consequence, the richness, diversity and reach of human species might have been limited. There are many interesting subplots within the epic narrative of Journey of Man. What each of these subplots tells us is that there is a shared sense of adventure and enterprise inherent in our species. To begin with, the populating of the Australian continent was a tantalizing story of adventure and chance. Scientists were first confounded by the 6000 mile of ocean that separated the East African coast from the nearest shore in Australia. Later it came to light that the radically new geological conditions created by the Ice Age provided an easy passage wherever the sea had receded. In geological timescales, usually popu lations within a species only gradually expand their habitat. But the speed with which our species moved out of Africa was unprecedented in the history of evolution. This is underscored by the astounding fact that in Australia there was not even a single primate species when humans arrived there. Likewise the crossing of the arctic inhabiting Chikchu people into the New World is another historical achievement of our species. The Americans who are newly native to this expansive continent nearly covered its entire breadth and width in less than a millennia of its advent. Instances such as these highlight how all groups within our species shared the same spirit of adventure and tenacity for survival. It is these qualities that unites us as humans and makes us the most intelligent and successful species on the planet. Another interesting information presented in the documentary is how modern Europeans took a complex migratory route to arrive at Western Europe. The lore of the Cro-Magnon man is very prescient to the mind as they conquered the temperate and cold climes of Europe with a physiology that was ill suited to these conditions. In other words, the early inhabitants of Europe were dark skinned people, who quickly acquired a paler complexion. They were also very imaginative and creative in finding the means to adapt and survive in conditions that are alien to those found in the Central

Psychology, Sleep Theories Research Paper Example | Topics and Well Written Essays - 500 words

Psychology, Sleep Theories - Research Paper Example While asleep, most physiological functions of an individual such as blood pressure, heartbeat and rate of breathing decrease. It has been proved that in human beings, mammals, and a majority of other animals regular sleep is necessary in order to survive. Sleep is not a uniform process. Sleep happens in progressive stages, referred to as the sleep cycle (Tami Port, 2009).These stages show characteristic changes in the activity of brain. The cycle begins with light sleep, followed by deep sleep. Sleep is divided into two main stages, REM sleep and non-REM sleep. Here REM stands for "rapid eye movement". Non-REM sleep can be again divided into four stages. As sleep progresses from stage one to stage four, sleep becomes deeper. The third and fourth stages are often grouped together and are called slow wave sleep (SWS). When an individual is in SWS muscle and eye movements become less. Even though human beings spend almost one-third of their lives sleeping, one does not know exactly the functions of sleep. One of the major theories of sleep says that sleep is necessary for repair and restoration of the body as well as the mind. According to this theory sleep helps the body recover after an active day and gives the body the chance to restore substances that are lost while performing our daily duties. Another theory suggests that sleep has an adaptive function. According to this theory animals sleep because they need to protect themselves. However it is a known fact that sleep is a time to rest and rejuvenate and that it benefits us in many ways. When a person does not get the required amount of sleep he feels drowsy all the time, is not able to concentrate and is irritable .It has been proved that REM sleep is important for learning and memory. Many individuals complain of lack of or insufficient sleep. All of us at some time or the other have experienced this. However for many this problem is severe and