Time Competition
highly commended
Evolution
- Holly, Lower V
‘change over time’
Our ancestors looked really different about 150 thousand years ago, in fact some scientists considered Neanderthals a subspecies of Homo sapiens while others considered it a separate series of the genus Homo. Later there were Cro-Magnons and they had visible human traits in terms of appearance and physical development, and they quite likely replicate modern day civilisations. We’ve changed and we’re continuing to change, though we don’t feel it. Evolution doesn’t stop for a second.
Charles Darwin was a British naturalist who proposed the theory of biological evolution by natural selection. Darwin defined evolution as “descent with modification,” the idea that species change over time, giving rise to a new species, and share a common ancestor. The mechanism that Darwin proposed for evolution is natural selection. Because resources are limited in nature, organisms with heritable traits that favour survival and reproduction will tend to leave more offspring than their peers, causing the traits to increase in frequency over generations. Natural selection causes populations to become adapted, or increasingly well-suited, to their environments over time. Natural selection depends on the environment and requires existing heritable variation in a group.
The first feature that catches your eye from our ancestors are the thick eyebrows and large brow arcs but this isn’t a coincidence as one of the functions of the eyebrows is to protect the eyes from excess moisture like sweat flowing down the forehead or from rain. However recent studies have shown that human eyebrows have evolved as a means of communication, in fact it seems to be the main function. With the development of intelligence, people got a smooth forehead with visible hairy eyebrows capable of performing various movements. Through these movements we, like our ancestors, can express a variety of emotions including recognition and sympathy.
Although of course this is not the only difference. For example, if you look at monkeys, you will notice that our ears, though similar, are still very different, all because there is no need to constantly listen out for predators. Without it, our ears have noticeably shrunk and pressed harder against the skull. Also the shape of the ear has the greatest influence on how a person hears. The structure of the auricle is individual for each person and the brain is perfectly adapted to it. We have lost the ability to turn the ears in different directions, in which the auricular muscles of the ear help other mammals localise sound and express emotion, but as we got our huge human head, the ears no longer had room to move. The muscles to move our ears become vestigial and in most people, atrophied, but some can still use them to wiggle their ears. Unlike humans, animals such as cats move their ears to hear
well. But, as Dorsa Amir said, since we have flexible necks, we no longer have the need to move our ears toward sounds.
Another feature that has evolved is our teeth. Specialisation progression from small primitive carnivores has gone in two directions, (1) to more efficient carnivores with enlarged cutting teeth, and (2) to herbivores with teeth adapted to grinding harsh grasses. The latter passed through an omnivorous stage with square low-cusped teeth like those of pigs and humans. In addition the modern ‘toothpaste’ was not used which we can only conclude is due to our diet development changing to include things like fatty foods and fizzy drinks. However, the ancient humans ate mostly fibrous foods. These are both beneficial for digestion and helpful to the teeth, since the fibres act as natural toothbrushes and scrub away food particles, bacteria and plaque from the teeth. In conclusion, evolution has changed the way we hear, live and breathe; happening over a long period of time. Now we wonder what we might look like in the future? Will we have smaller ears, thicker eyebrows, curved backs or be taller?
