Environmental Adaptation

The cold weather can be fun but it can also be dangerous if you're not prepared. In order to preserve heat and protect organs and the body's core temperature from an excessive temperature drop, pores close, hairs stand up, muscles quiver, metabolism speeds up and blood flow is directed away from the extremities by constricting blood vessels in the fingers and toes, even to the point of permanent loss of these appendages. Despite these efforts by the human body, when humans get too cold for a prolonged period of time the normal core body temperature can drop too low causing death.

There are several ways in which humans have adapted to this stressful environment. One developmental adaptation is the metabolic rate. The metabolism get quicker in cold weather in order to create heat in the muscles, and to create excess fatty deposits to help insulate the body more against the cold.  Because of this, people who live in a colder environment eat fattier foods.

Clothing is also much different in cold climates and hot climates and this is a cultural adaptation. This lady won't last too long in this swimsuit!

In colder areas clothing is well insulated to keep minimal air in between clothing and the body. Heavy boots and gloves are used since there is more danger to these parts of the body. Since most of our body heat is lost through the top of the head, hats and hoods are frequently used. 

Fireplaces and other forms of modern heating systems are used to keep humans warm inside their homes. Before modern inventions provided heat, people often huddled together around a fire and slept all together to keep each other warn with body heat.

Many people migrated with the seasons to avoid oncoming cold weather and still do, earning themselves the title of "snowbirds" in the United States.

A short-term adaptation to the cold is shivering. We shiver involuntarily and this is one of the ways in which our body generates heat. When we get back into a warm environment shivering stops. 

An example of a facultative adaptation is one I already mentioned above called vasoconstriction. This is when that blood vessels constrict to direct blood flow to areas that need more heat vital to survival. Signs of vasoconstriction are numbness and tingling When the blood is restricted from the extremities too long, "frost bite" can set in and finger and toes can be lost.



It is important to understand variations among humans across environmental clines because "race" does not provide these answers to human responses. Adaptations to cold occur among the Inuit people in Alaska and the Norwegian descendants in Minnesota. On a vacation to Jamaica one year I went out with a group to go snorkeling. I was surrounded by Europeans and Americans and the Jamaicans driving the ferry. It was about 78 degrees, not too cold and not too hot for the rest of us but for the Jamaicans who were used to temperature not less than 90, it was freezing. While we were all dressed in swimsuits or shorts, the Jamaicans were bundled up in coats and literally shivering. So, I would even say that on a warm day, there are some who react to the "cold" and "race " had nothing to do with it. Environment had everything to do with it! All of the information learned from studying human variations gives us insight into how we as individuals adapt, interact, control health problems and puts it in its proper perspective without the misconception that some adaptations have anything to do with "race".