Period 1
AP Biology
8/16/17
Survival of the Sickest
The title of Survival of the Sickest by Dr. Sharon Moalem suggests a notion opposite to both common knowledge and common sense. The basis of evolution-- “survival of the fittest”--means that weak genes, like ones that cause harmful iron buildup, or misshaped and nonfunctional red blood cells, should have been eliminated long ago. Evolutionarily, Moalem sets up, hereditary diseases do not make sense. However, he proves passing down certain seemingly negative traits, in the long run, comes with some sort of benefit and reason.
The first example considered by Moalem is the one of Aran Gordon. A lifetime long distance runner, in good shape, who suddenly shut down due to tiredness, …show more content…
He is primarily of Northern European descent--there may be an evolutionary reason as to why he got it. Malaria is common along the Mediterranean border, and people descending from those places (Italy, Turkey, Greece) grew thicker body hair as a layer of protection.3 People with a background like my uncle’s didn’t have an evolutionary need for protection against malaria. In sub-Saharan Africa, where a thick layer of hair is a disadvantage against the heat, malaria resistance sprouted up in another way. Sickle-cell anemia is a disorder that causes red blood cells to misshape. To simplify Moalem’s thesis, the bacteria causing malaria can’t thrive as well in sickle-shaped cells, and the gene got passed on as a trait. 4
Even aging, the decomposition of the body over time, has an evolutionary advantage. Cancer is a disease based upon abnormal cells multiplying uncontrollably and eating away at healthy body tissue. Leonard Hayflick discovered in the 1960s that human cells only reproduce 50-60 times before essentially dying. This keeps a “check” on uncontrollable reproduction, preventing some cancerous cells from exploding. However, the Hayflick Limit also programs an expiration date, leading to