Question:

Can natural selection result in the extinction of humans?

Initial Model:

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Claim


I believe that natural selection can not cause the human race to become extinct because of previous events that happened in the history of the earth, such as ice ages and high amounts of volcanic activity that have cause drastic change in the environment but some type of organism prevailed through it, so with all the way we have came to reach where we are today, it would be near impossible for natural selection to cause the human race to become extinct.

Evidence

Mass Extinction Estimations:
Ordovician-60% of all life ended
Devonian- 70 - 80 % of all marine species go extinct.
Permian-80%-95% of all marine life ended
Triassic-50% of marine invertebrate and 80% of quadrapeds
Cretaceous- Almost all life decimated including plants
The reason for these extinctions are unknown, but there are lots of theories.

http://www.theresilientearth.com/?q=content/when-humans-almost-went-extinct
Around 1.2 million years ago, only 18,500 early humans were breeding on the planet. According to researchers, this is evidence that there was a real risk of extinction for our early ancestors. What's more, according to a new study it took at least a million years for humans to come back from the brink. It was not until the emergence of modern humans, Homo sapiens, around 160,000 years ago and their migration out of Africa that humanity's place on Earth was secured. Two factors helped humans to survive: an increasingly carnivorous diet and mastery of fire.
One possible indecent was the eruption of the Toba super-volcano, 70,000 years ago in Indonesia. Some scientists have speculated that the eruption could have triggered a “nuclear” winter that fewer than 15,000 individuals survived. Other genetic studies attributed our low genetic variation to chronically low numbers, with as few as 10,000 breeding humans at different times during the past 2 million years. To this point there have been technical problems with all these studies, making their conclusions uncertain.
external image questforfire1.jpg
http://www.widerscreenings.com/questforfire1.jpg

Final Model

external image zKBqO.jpg

Reasoning

Because of the scientific advances of people and the history of the world, it can be reasoned that people will not die out due to natural selectoin or lack thereof. Many mass extinctions have occured before, but they were due to major global events. For example, a long time ago there was a time where humans in there early form did become almost completely extinct but they managed to survive even with drastically low numbers. Now in present day, we have so much technology and development that if something similar were to happen such as a "nuclear" winter, we would be able to keep a substantial high number of people to survive through it. A factor such as the possibility for the sun to be destroyed in many many years can be one of the greatest theories on the extinction of the human race but with the advances we have made in the last two hundred years, it is unimaginable the advances we can make in thousands of years to come.
Works Used:
http://en.wikipedia.org/wiki/Human_extinction
http://news.discovery.com/human/human-extinction-doomsday.html
http://www.pbs.org/wgbh/evolution/library/03/2/l_032_02.htm
http://www.skepticalscience.com/Earths-five-mass-extinction-events.html