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edyong | August 5, 2009You wouldn't think it to look at our skyrocketing global population, but many parts of the world are experiencing serious falls in fertility. A country's fertility rate is the average number of children born to a woman over her lifetime. In most developed countries, it needs to be 2.1 or higher if the number of newborns is to compensate for citizens who die. In developing countries, where death is a more frequent visitor, this replacement threshold is even higher.
The problem is that declining fertility is intimately linked with a country's economic and social development. As a result, more…
edyong | March 4, 2009Earlier this year, I wrote about how the human obsession with size is reshaping the bodies of other species at an incredible pace. Unlike natural predators that cull the sick, weak and unfit, human fishermen prize the biggest catches and throw the smallest ones back in.
As a result, fish and other species harvested by humans are shrinking, often within a few generations, and are becoming sexually mature at an earlier stage. These changes are bad news for populations as a whole, for smaller individuals often have lower odds of survival and produce fewer offspring.
But David Conover from…