Modern and lean in order to lose heat

Modern humans evolved during a time of rapid climate change in Africa nearly 200,000 years ago. Similar to many of the human-like species alive at the time, homo sapiens gathered and hunted food and evolved behaviors that ultimately helped them survive the challenges that they faced in unstable environments. After they migrated from Africa around 50,000 to 100,000 years ago, the human population was exposed to many environmental changes which lead to new cultural innovations such as farming. Modern humans migrated from Africa to various different parts of the world, all with differing environments—from the frigid climate of arctic Siberia to the high elevations of the Tibetan plateau. Since they had to adapt to different environments physically, they also had to do so culturally in order to survive. Adapting to culture is based off of a biological basis which includes imitativeness, sociability, and inventiveness. Most social species have cultural adaptations but humans are the only ones who have extremely complex ones that build up over a long period of time. Modern humans have adapted through their diets, skin pigmentation, and how their bodies are built—and if they were not able to adapt natural selection would have made them become extinct. Adaptations had helped people adapt to almost every single one of the terrestrial habitats that the earth is home to. For instance, people who are from Tropical descent are built physically strong and lean in order to lose heat from their respective environments while arctic and mountain descendants are short and wide which comes in handy when trying to conserve heat. Those who come from places with dim climates tend to have particularly pale skin which adapted to vitamin D photosynthesis. Many gene-culture co-adaptations include disease resistance genes and diet related genes which can help fight against diseases such as Malaria and the Plague and allow adults to digest lactose and have an active alcoholic metabolism. 
The main idea of evolution is survival of the fittest and an extremely large part of that is being able to survive any diseases contracted before you’ve had children. Malaria is one of the most studied diseases in current times and the human race has evolved so that if you have one copy of a specific gene, you also have the gene that will help protect your red blood cells from the malaria parasite. Along with that gene there are also more than one hundred different genes that are capable of causing shortages in protein which breaks down blood cells which makes it harder for the malaria parasite. Malaria is just one of the many diseases that evolution has helped humans adapt to—leprosy, tuberculosis, and cholera are some of the others and some scientists have even found that living in largely populated cities has helped us adapt quicker. Tuberculosis was once the leading cause of death among Europeans for two centuries, killing large numbers of people and putting many children in orphanages. The decline of tuberculosis came as a surprise to most since many of the medical therapies weren’t working, living conditions were still as bad as the nutrition was at the time. Natural selection is what is thought to have helped with the decline of TB but also a persons genetic history with the Arkansas Department of Health stating “Over decades of research, he found that African-Americans were nearly twice as susceptible to TB infection as whites, and that American Indians were even more susceptible than African-Americans 5. He noted, somewhat more speculatively, that this hierarchy of susceptibility correlates with degree of ancestral historical exposure to TB.”(Dr. Drew Smith, Forbes) While is is incredible that certain people can become almost immune to tuberculosis, many of those who are tend to be more susceptible to contracting rheumatoid arthritis or even having their immune systems to over-react to the body’s own tissues. 
Early humans migrated away from Africa and into different parts of the world, some at higher elevations and some at lower elevations. All around the world people have adapted to living in high elevations from Tibet, the Andes, and Ethiopia by acquiring the ability to adapt to the thin air in extremely high climates. The people of Tibet live in one of the least populated places in the world, better known as the Himalayan mountains. The highest elevation point of the Himalayan mounts stands at 29,000 feet which means that the air is pretty thin once you get passed 10,000 feet. Researchers have discovered that people from Tibet have blood that produces much more oxygen-transporting hemoglobin protein, which is a mutation that is estimated to have occurred only 3,000 years ago. The greater part of the human population would suffer serious health consequences if they were to try and live in these high elevations while the native inhabitants thrive in their respective high elevation climates. 
Humans are considered to be a diurnal species—which means that they are active during the day—and are a rarity among mammals since they possess color vision. That can be attributed to our lack of body hair which leaves our skin bare and capable of showing our emotions through blood flow to our face and upper body. The early humans who were able to develop color vision held an advantage in mating and altercations between one another. Scientists have also found that blushing is a way to help in hostile situations so that one can express that they are ashamed or apologetic. When someone displays those facts, sympathy was granted to the person which would come in handy in early times.
With the planet shifting and climates becoming drastically different, modern humans needed to adapt to the new diets that they had to become accustomed to so that they would not starve to death. Mammals are known for drinking milk, but modern day humans are the only species that have adapted so that they can digest it after infancy. Since humans have adapt, a mutation appeared in their genes on the plains of Hungary nearly 7,500 years ago which then allowed some humans to digest milk as adults. Being able to digest calorie rich food such as dairy products came in handy for people serving through the frigid winters in Europe. As seen in about 36% of Chinese, Japanese, and Korean descendants, ingestion of alcohol can cause facial flushing and nausea which is thought to protect the populations from esophageal cancer. East Asians have a deficiency in the ALDH2 enzyme which is an indicator of serious health problems. Many scientists believe that this mutation occurred after agriculture developed since agriculture is what produced alcohol.