A few connected topics & thoughts:
In a nutshell: has our evolution led us to bend the laws of natural selection to our long term detriment.
A few heuristics :
- our own human weak genes can survive thks to medical progress,
- which has led us to clearly exceed the earth’s carrying capacity,
- etc

All of the above rolls up into the topic our our species leading the charge of the Sixth Mass Extinction.

Despite the trends and signs of increasing human population, scientists believe that we are in the sixth mass extinction wave. As opposed to the previous mass extinctions that have happened in the past, this one is the first mass extinction triggered by a species.

The five mass extinctions
First mass extinction : (c. 440 mya): End-Ordovician mass extinction
Due to climate change (relatively severe and sudden global cooling)
Caused pronounced change in marine life (little or no life existed on land at that time).

Second mass extinction : (c. 370 mya): End of the Devonian Period
May or may not have been the result of global climate change.
Marine species disappeared (eg brachiopods)

Third mass Extinction (c. 245 mya): End of the Permian Period
Could be due to complex amalgams of climate change perhaps rooted in plate tectonics movements.
Some evidence suggests that a bolide impact may have been the cause.
90% of species were lost.

Fourth mass extinction (c. 210 mya): End of the Triassic Period, shortly after dinosaurs and mammals had first evolved.Precise causes remains difficult to explain. The extinction affected reptiles and amphibians.

Fifth mass extinction (c. 65 mya): End of Cretaceous.
The most famous mass extinction
It wiped out the remaining terrestrial dinosaurs, molluscs and marine reptiles.
Consensus has emerged that this event was caused by one (possibly multiple) collisions between Earth and an extraterrestrial bolide (probably cometary).
Some geologists, however, point to a great volcanic event as part of the chain of physical events that disrupted ecosystems so severely that many species on land and sea rapidly succumbed to extinction.

Scientists argue that the sixth mass extinction began when the first modern humans dispersed to different parts of the world about 100,000 years ago. This process accelerated when humans turned to agriculture. Agriculture represents the single most profound ecological change in the entire 3.5 billion-year history of life. With its invention, humans no longer needed to interact with other species for survival, instead manipulated other species for their own use. They also did not have to adhere to the ecosystem’s carrying capacity, and so could overpopulate.

Humankind is using up almost half of all the energy available to sustain life on Earth, and this figure will only grow as our population leaps from 5.7 billion to 10 billion inside the next half-century.

The scientific community has reached consensus that 30,000 to 50,000 species are disappearing each year. This means that fifty per cent of the Earth’s species will have vanished in the next 100 years.
Such a dramatic and overwhelming mass extinction threatens the entire complex fabric of life on Earth, including the species responsible for it: Homo sapiens.

Bogans/trailer trash/plebeians in general have nothing better to do than have babies, and people duped into following a religion are often instructed by their church to have many babies, or at least not to use contraception.

The end result of this is that to whatever extent traits such as intelligence, rationality, work ethic etc are genetic, we are currently selecting for those who lack, rather than those with an abundance of, these traits.

(See http://en.wikipedia.org/wiki/Idiocracy )

This post is meant mainly in jest, but the point remains – does it matter that people with “better” genes seem to, under our current system of resource allocation, have few babies, rather than many? Or does it not matter at all? Are humans all genetically similar enough that what really determines our eventual phenotype is nurture, rather than nature?