Throughout time humans have become the most dominate mammals on Earth by developing characteristics to better adapt to the changing environment. Some examples include bipedalism and the ability to use tools. One special trait that has allowed the early humans to thrive in the harsh conditions of their environment is the evolutionary development of bare skin. Researchers are looking to fossil record to find any clues to the reason as to how humans become hairless.
All mammals have a dome form of hair or fur on their body. Fur is a key benefactor in protecting against harmful sun rays, cuts, or bacteria. It can also allow animals to blend into their surrounding in order to avoid predators, or in some cases hunt prey. Although hair can be seen to hold many benefits, there have been many animals who evolved to have little amounts of hair for some sort of purpose. Some examples include species that live underground or in the ocean. Mammals such as elephants are prone to get overly hot because their large bodies, so they developed hairless skin in order to combat the onslaught of gaining to much heat.
One theory that points to why humans have developed a hairless body is the need to stay cool by
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sweating. When it comes to animals the need to regulate their body temperature is difficult to procure at times. It is important for animals living in hot environments to remain cool in order to prevent overheating which can cause their internal organs to shut down. Animals such as dogs pant in order to keep their body temperature check. Many animals are more active when the sun begins to go down such as big cats. Humans along with other primates use sweating for their source to keep their body temperature down. Sweating works by causing the skin acquire liquids that will go through the process of evaporation which in turns allows heat to be drawn away from the body. About twelve liters of lightweight sweat is created each day through what is known as eccrine glands. Humans have millions of eccrine glands on the skins allowing humans to form an efficient cooling system by pumping out sweat through pores. The answer to what caused this evolutionary change in humans is the change in the environment and climate. It was discovered through the observation of fossils that the world began to cool down and dry out. This caused rain to subside which in turn led to plant, fruit, and water to dissipate. This lead our early ancestors to turn to other sources to find food and during this time our ancestors began hunting for meat to gain other source of food. A lot of energy was needed to hunt down prey so humans had to better adapt. This evolutionary change is believed to occur about 1.6 million years ago when the Homo ergaster began to exhibit human features which allow for running and walking for long periods of time. The color of skin is also an indication of when humans began to develop a hairless body. For example, it was found that humans develop a darker skin tone to protect against harmful sun rays in place of fur. It was found that this specified gene in Africans developed about 1.2 million years ago. Evidence pointing to how humans developed a hairless body is more challenging for researchers to obtain.
Conclusions can be made by comparing human DNA to the DNA of chimps. A Significant difference between the two can be found in the genes create the proteins that control some of the elements found in the skin. This allows our skin to dorm a shield better known as the stratum cornea, so it can stay intact. The keratein found in hair is also an indicator of how people became hairless. Keratin is what cause hairs to be thin and nearly vacant on the human body. Researchers found that keratin causes hair to weaken and break off much more than other primates. It was determined that keratein was no longer need for humans to thrive in their environment so it began to
deteriorate. As it can be seen humans do in fact still have hair throughout the body. The hair under the armpits sustain the underarms when actively moving. The hair that grows on top of head is needed to reduce the amount of heat aimed towards the scalp. It was found people with smaller amounts of hair reside in tropical environments. The hair found on people who do not live in the tropics do not necessarily allow them to keep warm any easier. It is possible that the of level the testosterone is what can determine the development of hair in different groups of people. The evolution of a hairless body relates to the material discussed in class because it is an important factor in how humans survived in changing environment. Getting rid of fur allowed humans to gain the upper hand when it comes to hunting prey. Humans could better regulate their body temperature through sweating which in in turn allowed to gain more stamina and continually track their prey. Once their prey begins to overheat and slow because they need to pant to cool off, humans could take them down. Although humans are not the fastest, they make up for it through endurance. The development of sweat allowed the humans to acquire another source of food more effectively which allowed to climb to the top of the food chain.
Jablonsky and Chaplin states in their article that when it comes to us not having as much hair, we have looked a...
...ct that humans do not have fur, unlike other primates, as the fur would have made underwater motion highly inconvenient.
gorillas and the ancestors of humans and chimpanzees) (Reed, 2007). The ‘recent host switch’ hypothesis, would explain the genetic similarities between the lice acquired by modern humans and the lice acquired by gorillas, chimps, and other primates (Reed, 2007). Because of the evidence of these genetic similarities and differences in Pediculus and Pthirus, the evolutionary divergence of humans, gorillas, and chimps appears to be directly correlated with the evolutionary divergence of different species of lice (Reed, 2007). This evidence allows us to conclude that in order for modern human head lice to have evolved from its ancestral form, humans first had to evolve into a less hairy, less neanderthalian versions of themselves. The evolved trait for hairlessness, then, must have occurred through some form of natural selection. Who would have thought that head lice, the natural enemy and nightmare of second-graders and their parents, could be the key to unlocking the--quite literal--naked
Animals differ in their abilities to regulate body temperature (thermoregulation). We sometimes use the terms "cold-blooded" or "warm-blooded." Most reptiles feel cold to the touch, while mammals and birds often feel warm.
The evolution of man is constantly in question. While we are reasonably sure that modern humans and primates are both related to the same common ancestor, there is constant debate over what initially caused the two species to split into early hominids and apes. According to some, our longest and most popular theory on the division of man and ape is profoundly wrong. However, those same individuals usually offer an equally controversial theory as a substitute, one that is almost impossible to scientifically test or prove. Both the Savanna Theory and the Aquatic Ape Theory offer solutions to how and why humans evolved into bipedal toolmakers. But with enough questioning, each loses its accountability to rhetorical science.
Growing thick feathers/fur- therefore stopping heat loss by convection as fur and feathers trap air which then acts as an insulator, fat/blubber which as an insulator, oily or greasy skin which would make the animal waterproof and stops water from entering layers of air therefore maintaining insulation layers, dark skin to absorb more light and heat (black absorbs light, white reflects light, th...
They had similar features to today’s apes, such as a hairy body. The purpose of the vast amount of hair is to protect the body from the sun’s ultraviolet (UV) rays and to prevent overheating, mainly by acting as a barrier for the skin underneath the hair (Jablonski, 598). Some parts of the body, such as palms, were not covered with hair, but with sweat glands. Sweat glands allowed the body to cool off via evaporation at the surface of the skin; sweat glands were more efficient at thermoregulation. Over time, early humans with a high amount of sweat glands were selected since they had the best method at the time to keep themselves cool in warm environments (Kirchweger).
In conclusion, the question of how hair texture among an ethnicity is determined has yet to be answered. However, new developments such as the evidence that all humans have the same single origin in Africa and mutations in the P2RY5 gene can determine the hair texture of a human, have shown that researchers are quite close in determining the hair texture of an ethnicity. These developments have the possibility of leading to new hair removal and hair growth treatments. The future looks bright for hair research and hopefully in the next 20-50 years the question is answered.
In conclusion, melanin production has played a considerably important role in human evolution. Not only does it influence color pigmentation through its protective role of defending against harmful UV rays, but also determines detrimental features such as eye-sight and hearing. Furthermore, melanin production and its evolutionary adaptions mark an important presence upon our biological systems to this day. Therefore, in the process of furthering human evolution, melanin production has played an enormous role in human evolution by selecting for several features that allow for particular adaptions according to the human's geographical location and environment.
Paleoanthropology: Pliocene and Pleistocene Human Evolution. Paleobiology, 7:3:298-305. Frayer, David W. and Milford Walpoff 1985 Sexual Dimorphism. Annual Review of Anthropology, 14:429-473 Key, Catherine A. 2000 The Evolution of Human Life History.
hair, this tells us nothing as a whole of the human. This is the same
The members of the Homo genus possess a combination of unique features that distinguish them from other related species. At the time that each respective species was alive, they were able to walk upright on two legs, use their large brains for the benefit of their species, and could thrive in many geographically and climatically diverse areas of the world. One of the most mysterious quandaries in science is how the lineage of the Homo genus became so different from their primate relatives. Bipedalism, brain size, and location diversity all have a common link that may explain this difference – dietary evolution allowed humans to adapt to their surroundings, and in turn, become a more advanced species. The Homo diet evolved in relation to food availability and nutritional necessity. With the ability to maintain a proper diet, the species of the Homo genus were able to flourish and advance toward the development of modern Homo sapiens.
Early mammals were different from early reptiles in that they had developed a bigger brain and they used keratin not only for claws but also hair. Eventually certain mammals developed into early primates and developed the ability to climb branches. One defining characteristic of early primates that set them apart from just about every other creature is their eyes eventually moved from the sides of the face to being in the front of the face, this development was another key point in evolution. Eventually primates split into two groups, the first one being old world monkeys and the other being Great Apes which are also called Hominidae. Some key characteristics of great apes that set them apart from old world monkeys is that they lost their tails, began to walk on two feet, and gained flexible wrists. The development of flexible wrists and becoming bipedal was another key point in evolution, this is because being bipedal allowed for greater movement and flexible wrists allowed weapons and tools to be used once they were
...d cats to have certain characteristics and physical features that that they desired, such as long hair, no hair, and different length noses and other physicalities. Some of these breeding traits have altered the natural capabilities of the cat to be able to hunt and survive in the wild. Breeding cats that have short noses has affected their ability to hunt but not the instinct. Cats that are bred to be hairless, if exposed to the elements would not be able to survive long at all outdoors.
Furthermore, the sensitivity of the human brain to temperature changes supports that a stable internal temperature is vital for the central nervous system. (1) There have been claims that the actual body sizes seen in the fossil record support this theory, because physiologically small ectotherms were represented by basal amniotes and large homeotherms were represented by large bodied carboniferous. Animals were using small surface-volume ratios to buffer against temperature fluctuations in ambient temperature. These claims were however not widely accepted, because they were based on pre-cladistic evidence, and the modern calidistic analysis does not support the claims.