Biston betularia, commonly known as the black and white moth or pepper moths, is a good example to show how natural selection influences the features of a species. Natural selection involves four key parts consisting of variation, influence of the environment, survival of the fittest and population changes. All populations have genetic variation which can be passed on. Some variations are more favourable than others, making those individuals better suited to their environment. Individuals with more favourable variations are more likely to survive longer and reproduce and individuals with unfavourable variations are more likely to die. Individuals that survive and reproduce pass on their favourable genes causing the population to change over time.
First of all, pepper moths have variations in their wing colour, with it being either light or dark coloured. The environment influences the wing colour of these moths. The industrial revolution and other pollution blacked birch tree trunks which caused the dark wing moths to have better camouflage and avoid predation. Survival of the fittest is also used in these dark-winged moths because they had more favourable characteristics. This meant that they were more likely to live longer and reproduce compared to light winged moths. Therefore, the population changed to include the favourable genes for the next generation, consequently increasing the number of dark-winged moths and decreasing the number of light winged moths.
Camelus bactrianus (Dromedary), commonly known as the Arabian camel, lives in deserts. Deserts are large, arid and barren areas of land. Deserts also don’t have much rain and are also dry and scorching. Consequently, only certain animals and plants that are specially adapted to this harsh environment can survive in deserts. Deserts have lots of sand that blows around with gusts of winds, blinding any nearby fauna. Deserts also have few sources of water and food with competition for these resources always occurring between other animals and plants. In response to this, camels have adapted by getting fat-filled humps. These humps supply camels with the energy, as well as water formed by fat burning, required to survive long treks through the rough desert. At the end of a difficult trip, camels’ humps may lay over their side since they are drained of all the fat that once filled them. Camels can also quickly drink a large amount of water, but it takes some time for camels to eat enough food to restore their humps. An extra purpose of the hump is to insulate camels since the layers of fat in the hump conducts heat slower than water. This adaptation helps camels to survive their harsh environment for long periods of time without stopping for food or water. It also helps camels to decrease the likelihood of overheating and sweating, saving more water.
Camels may continue to change over time in response to deserts’ sandstorms and lack of food and water. Global warming and pollution will make these selection pressures more severe resulting in violent sandstorms, extremely high temperatures and even less food and water. Camels would use natural selection to find the camels with the best adaptations allowing them to survive longer and reproduce. One adaptation that camels could have to enhance their survival in response to these selection pressures is by producing chloroplasts, allowing camels to photosynthesise. Due to a large amount of time in the sunlight, photosynthesising would help camels to survive long treks in the deserts with limited food. This would also help reduce the competition for food between different species of animals. An enchantment of an existing adaptation is to have thicker and stronger skin. This feature would help camels to withstand brutal sandstorms by ensuring that the sand would only slide across the skin instead of cutting it. Another enhancement is to make camels’ feet larger, padded and stronger. This will ensure that camels will be able to survive long treks on hot rocks and sand without causing significant pain to their feet or other parts of their body.