Human Evolution

Evolution is a truly magical thing. Over millions of years, species can diverge to become entirely new species with traits specially adapted to their environments. There are two main types of evolution: microevolution and macroevolution. Microevolution can happen in only a few generations - it is simply a change in the frequencies of alleles in a population. For example, in the Galapagos islands, there are many finches. After a drought, only the cacti survived on an island. Cacti have large seeds, so only finches with large beaks could eat them. Over only a couple generations, scientists observed more and more finches with longer beaks. This is microevolution, and it is often caused by natural selection.

Macroevolution is the result of many microevolutions building up to produce an entirely new species. This can happen through natural selection, genetic drift, gene drift, or mutation. Genetic drift is when only a small group of individuals of a population remains, either through a disaster (Bottleneck effect) or accidental isolation (Founder effect). The alleles of these few individuals have an increased effect on future generations, leading to rapid microevolution and eventually macroevolution. Gene drift is simply the intermingling of different populations, leading to new alleles being introduced to the gene pool.

The two common threads of evolution are death and reproduction. Evolution and natural selection work only if individuals with superior alleles live longer or reproduce more. However, in human society, death and reproduction have been artificially flattened. Through advanced medicine, individuals with inherently worse metabolisms can live as long as individuals with great metabolisms. This is something to be celebrated, but it also slows evolution. Furthermore, humans have essentially removed the attractiveness factor from evolution. Lions evolved to have manes and peacocks evolved to have their signature tails because it attracts females. Humans, however, have a good chance of finding a mate no matter their looks or physical prowess. Furthermore, most humans only have one or two mates through their lifetimes due to marriage. In essence, no matter our alleles or phenotypes, each human has a good chance of reproducing at least once. Therefore, good and bad alleles are passed down in equal proportion. This is especially true in very developed countries, like America. In less developed countries with higher death rates before reproduction, humans are more likely to evolve. Of course, humans are still evolving slowly. This is due to random mutations, which can very gradually become more common. This will cause us to very slowly evolve over many generations.

However, we must remember that this only holds true if Earth remains the same as it is for a long time. However, in the case of nuclear fallout or an asteroid hitting Earth, genetic drift and natural selection will ensure that humans swiftly evolve to adapt to their new environment.

#Evolution #ScienceResearch #Biology