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There are many debates about how Homo sapiens came to be. Different people have different theories or ideas about the evolution of man. There is the Christian belief that a spiritual power put humans onto the earth, this view is shared by many religions throughout the world, this is not strictly evolution but is called the creationism theory. The theory of evolution was first brought to scientists' attention by Charles Darwin one hundred and forty years ago, where he speculated that man evolved from earlier life form. Since then scientists have been trying to solve the mysteries of mans origins. There is a period of time before approximately five million years ago that has no fossil evidence to prove the step from ape like primates to hominids, the theories of evolution all ponder on this period to try and find "the missing link". There are many theories of human evolution, although just two are widely debated by scientists today. The savannah hypothesis is a theory that man evolved from the primates that were forced down from the trees in the African rainforests to the dry African savannah and thereby had to adapt to this new way of life. The other is the aquatic ape theory. This theory says that man evolved some of its distinctive features such as bipedalism and relative hairlessness in an aquatic environment and that ancient human ancestors spent more time in this aquatic environment than its present day descendants. This essay will explore the aquatic ape theory in depth and show the arguments for and against this theory.
The aquatic ape theory was demonstrated by Sir Alistair Hardy in his original paper "Was man more aquatic in the past?". It puts across the idea of a more aquatic primate that lived near water, using it more readily than modern humans do today. This theory followed the proposal by Max Westerhofer's that some modern human physiological features indicate an aquatic type adaptation. Elaine Morgan embraced the aquatic ape theory publishing many articles showing her beliefs and theories about the aquatic ape. The theory had been rejected for many years until Morgan stood up and questioned our origins. The argument supporting the aquatic ape hypothesis grows in strength as new evidence and theories are being discovered.
There are many features that set Homo sapiens apart from the apes and those features appear to relate them to aquatic animals. The absence of fur on mammals only occurs in two types of habitat, a subterranean one and an aquatic one. There are certain types of moles called 'Somalian mole rats' that never venture above ground, the only other hairless mammals are those that live in the water, such as the whales, dolphins and walruses. There are also the waders or wallowers that spend a lot of their time wading in the water, such as the elephants and rhinoceros. The loss of hair in the water makes the body more streamlined and fur was not needed to protect from the sunrays.
The savannah theory says that humans lost their hair in order to "prevent over heating in the savannah" (AAT leaflet), but no other mammal's evolution has ever naturally selected this strategy. The mammals that live on the savannah have a covering of fur to protect them from the harsh sun, a coat of fur reflects a certain amount of sunlight. Another theory for hair loss is that it facilitates sweating, but again most of the mammals on the savannah can sweat quite effectively without having to lose their fur. One theory by a man called Phil Nicholls states "advantageous in mammals because it reduces drag and thereby lowers the energetic cost of locomotion". Nicholls also argues that only extremely large sea creatures lose their fur.
Humans have different sweat glands to most mammals, these glands lose large amounts of water and salt. If humans were evolved on the savannah with these sweat glands they would have dehydrated very quickly, as water and salt are needed within the body in hot conditions. Another way that humans lose salt and water is through the tear ducts. Humans cry tears of emotion and tears in response to a stimulus such as smoke or dust, no other land mammal does this. There are however marine mammals that can do this such as a walrus, they can weep due to excitement when feeding or weep when they have induced too much water and the body tries to expel some of it. The aquatic ape theory argues that in order for the aquatic apes to lose the excess salt ingested in the salty environment these adaptations were necessary. The human body has another type of gland that secretes oil known as sebum. Other primates such as chimpanzees have these glands although theirs are very small whereas the human glands are enormous. The aquatic ape theory leaflet states that "the only known function of sebum is that of waterproofing the skin or fur".
The savannah theorists believe that apes lost their fur as the upright stan
Quotes talked about in this paper
Terminology referenced in this essay
Homo sapiens, genes, energy, DNA,
Names talked about in this paper
Elaine Morgan, Phil Nicholls, Charles Darwin, Max Westerhofer, Sir Alistair Hardy, Washburn, Wheeler,
Organizations mentioned in this term paper
Locations talked about in this essay
‘Danakil Island, Africa, Danakil Island, fertile Danakil island, red sea, Europe,
Keywords referenced in this essay
aquatic ape, aquatic ape theory, the aquatic ape theory, aquatic ape hypothesis, primates, apes, savannah, human, bipedalism, aquatic animals, homo sapiens, sweat glands, water and salt, modern human, brain size, large, babies, great apes, sea creatures, marine mammals, hair, sea mammals, other land, human brain, human evolution, human body, genetic marker, fat cells, subcutaneous fat, bipedal locomotion, upright, human baby, human appearance, small brain, DNA evidence, omega 3 fatty acids, arterial blood pressure, dolphin, body shape, fossil, hair loss, tear ducts, one million, Another way, sex organs, Charles Darwin, Africa, pectoral girdle, missing link, africans,