Table of Contents

Question:Do humans cheat evolution?


Initial Models:

evolution_map.JPG






Claim: Yes, humans cheat evolution. Humans can manipulate the genetic traits of humans, plants and animals. Humans also manipulate their environment to suit them
better, exempting them, to a degree, from natural selection by environmental factors. Innovation in medicine from antibiotics to surgery has improved to the extent that many humans who would not normally live to reproduce are now able to do so. Genetic engineering allows humans to detect traits and change them to be more favorable, therefore the parentage of an offspring becomes less relevant. Although not stopping their evolution, humans are slowing and evading it.








Evidence: In the pre-industrial world, mortality rates were much higher and although fertility rates were considerably higher as well, the number of children who survived to reproduce themselves was significantly lower. By the nineteenth century new innovation in medicine, technology and ecological development boomed, leading to much lower mortality rates for both adults and children. In addition, even in the past half century, infant mortality rates have declined drastically, 30 percent in just ten years as new medical technology becomes available to the wider population. Artificial selection is another way humans manipulate evolution. In plants and animals, humans can breed, deciding which traits they want. For example, humans have created dwarf wheat in order to increase production. This in turn has allowed more humans to survive to reproduce, an example of how he environment is manipulated. This form of genetic engineering is also applicable to humans. Medicine has allowed humans to artificially change traits of conceived offspring.

Links:
http://www.cdc.gov/nchs/data/hus/hus10.pdf

http://www.econ.ucdavis.edu/faculty/gclark/papers/clark%20-%20jeea.pdf





Final Model:


Cheating_Evolution.JPG
Reasoning:To conclude, humans are manipulating evolution through the use of medicine and technology, including genetic engineering and through manipulating their environment so that it has less control over survival. The use of medicine to improve life expectancy and decrease mortality is evident in statistics that show a steady increase in the number of people who live to a reproductive age, and the number of children that survive to reproduce. Frequently those who would not have been naturally selected are able to pass on injurious traits. A time goes on and technology grows, more and more people survive and reproduce, meaning human evolution is slowing exponentially. Humans are also able to change traits in offspring through the use of genetic engineering, so the relative fitness of an offspring depends less on genetics. Lastly, humans more so than any other species control and manipulate their environment, so nature has less power to select as can be seen with trend of higher survival rates as humans increasingly dominate the environment, from the invention of agriculture to the industrial revolution. Humans have also created artificial selection, with which it is possible to control the genetics of plants and animals.