The Dangers of Heat
Living in hot climates like the
desert or tropical rain forest can negatively affect humans. In the United
States more people die from the heat than the cold. It is more bearable to live in the desert
than a tropical rain forest because of humidity. Hot temperatures and humidity make it very
difficult to sweat and evaporate excess heat. When we sweat we lose precious
salts and water that our bodies need. Heat stroke is a major problem for
humans. It occurs after our core body temperature reaches 104°F or higher and if not treated it can
cause brain, kidney, heart, and muscle damage that can result in death.
Heat stroke symptoms include high body temperature, lack of sweating,
nausea, vomiting, flushed skin, rapid breathing, racing heart rate, headache, confusion,
and muscle cramps or weakness. Two lesser heat related illnesses are heat
cramps and heat exhaustion. Heat cramps are caused by exposure to high
temperatures or physical exertion. Heat exhaustion occurs when the symptoms of
heat stress are ignored and get worse. The symptoms of both illnesses are very
similar to heat stroke.
Humans have adapted in many ways to
live in extreme heat. A short term adaptation humans have is the ability to
sweat when overheated. There are millions of sweat glands on the human body. An
example of a heat related facultative adaptation is the ability to produce more
sweat. The average human who is not adapted to live in an extremely hot
environment sweats about 1 liter per hour. People who live in hot climates like
the American Southwest can lose about 2-3 liters per hour. It can take about
six weeks for a person to adapt to live in hot climates and produce more sweat.
An example of a developmental adaptation is body shape. People who live in hot
climate like East Africans tend to have longer appendages. Having longer arms
and legs increases the body’s surface area. A larger surface area allows more
heat loss and keeps people cooler. The last example is cultural adaptation.
Humans have the power to use tools to create whatever they want. Humans have
created many ways to stay cool. My personal favorite invention is air
conditioning. Air conditioning has allowed humans to live in super-hot climates
and still stay cool by controlling the temperature of their environment.
Short-term
adaptation of what the sweat gland looks like
Facultative
adaptation of a man sweating
Developmental
adaptation of longer limbs in East Africa
Cultural
adaptation of a woman keeping cool with air conditioning
Studying
human evolution from an environmental perspective is very important. It shows
us how humans evolved to similar climates in different ways. This information
can be very useful to us. Knowing it takes about six weeks for the body to adapt
and produce more sweat in hot climates is important. This information can be
very useful to soldiers serving in hot countries like Iraq. They can train
soldiers in the desert for at least six weeks before being deployed to adapt to
the heat. Once they have adapted and produce more sweat they can stay cooler
for longer when resources may not be available.
I would use race to compare a
specific group of people. There is more variation among members within the same
race than outside their race. I could use this information to calculate the surface area of people in East Africa by measuring their arms and legs.This would allow me to calculate how much they sweat
compared to people who live in cooler climates and have less surface area. It
is much easier to use environmental influences to understand human adaptions.
Using race involves categorizing people based on physical traits and has no
genetic basis. No one characteristic or trait can be used to distinguish and
entire race of people and it is a highly subjective process.
