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As in other mammals, human thermoregulation is an important aspect of homeostasis. In thermoregulation, body heat is generated mostly in the deep organs, especially the liver, brain, and heart, and in contraction of skeletal muscles. [1] Humans have been able to adapt to a great diversity of climates, including hot humid and hot arid.
Humans (species in the genus Homo) are the only animals that cook their food, and Wrangham argues Homo erectus emerged about two million years ago as a result of this unique trait. Cooking had profound evolutionary effects because it increased food efficiency, which allowed human ancestors to spend less time foraging, chewing, and digesting.
Sperm cells were believed to contain complete preformed individuals called "animalcules". Development was therefore a matter of enlarging this into a fully formed being. The term homunculus was later used in the discussion of conception and birth. Nicolas Hartsoeker postulated the existence of animalcules in the semen of humans and other ...
[2] [3] Some of the earliest known traces of controlled fire were found at the Daughters of Jacob Bridge, Israel, and dated to ~790,000 years ago. [4] [5] At the site, archaeologists also found the oldest likely evidence of controlled use of fire to cook food ~780,000 years ago. [6] [7] However, some studies suggest cooking started ~1.8 million ...
Here’s a look at how people and animals around the world are trying to beat the extreme heat. A polar bear cools down in ice that was brought to its enclosure on a hot and sunny day at the zoo ...
Humans adapted to heat early on. In Africa, the climate selected for traits that helped them stay cool. Also, humans had physiological mechanisms that reduced the rate of metabolism and that modified the sensitivity of sweat glands to provide an adequate amount for cooldown without the individual becoming dehydrated. [17] [20]
Human cannibalism is the act or practice of humans eating the flesh or internal organs of other human beings. A person who practices cannibalism is called a cannibal . The meaning of " cannibalism " has been extended into zoology to describe animals consuming parts of individuals of the same species as food.
All organisms metabolize food and other inputs, but some make better use of the output than others. Like all energy conversions, metabolism is rather inefficient, and around 60% of the available energy is converted to heat rather than to ATP. [7] In most organisms, this heat dissipates into the surroundings.