The lopsided tendency of evolution to produce many species in one group while preserving just a few in other groups applies quite well to birds. I called this tendency Haldane’s Rule. Is there something special about groups, like the perching (or Passerine) birds, that dominate our biodiversity? Or is their diversity a natural outcome from a… (read more)
Fixing medicare
Canadians are obsessed with health care. Our publicly-funded system is one of a very few cultural differences (along with the length of our football fields) between ourselves and our great neighbours to the south. As such, medicare is a source of pride and identity. Jeffrey Simpson has recently pointed out that this pride is… (read more)
Caring for the Boomers
Those born between 1910 and 1930 saw fit to raise a generation which could care for them in their old age. Their children, the “Baby Boomers”, were not so far-sighted. Though the Earth has benefitted from the decrease in population growth in Western countries in the last 50 years and though we boomers have had less burdensome… (read more)
Predicting cannibalism
Ecosystems are messy places. The number of possible relationships between species grows exponentially with every species that enters the system. A fairly typical foodweb (see image below) of 70 species has 4900 possible predator-prey interactions. Despite that, food webs are suprisingly predictable. For one thing, most foodwebs have only 10-30% of the possible feeding relationships. This… (read more)
Wearing out the fabric
The fourth of five fundamental theories in ecology that I outlined in my last post states that landscapes – and the services they offer us -will wear out if too much natural habitat is removed. The actual percentage of the landscape that qualifies as “too much” is up for debate. The original “percolation theory” simulations… (read more)
What ecology does tell us
Ecology, like chemistry and physics, can be explained as the interaction of particles. The particles in this case are individual plants and animals ( and I do include fungi and microbes ). True, they do not look or act like billiard balls but they do have measurable properties that allow us to predict their behaviour… (read more)
What ecology does not tell us
I mentioned earlier that ecology is the science that looks at the sustainability of natural resources. So far in this blog, I have mostly ignored ecology in favor of economics and evolution. I mean to address that gap over the next couple of blog entries. Specifically, I want to give you a shorthand version of… (read more)
On sexual selection
The peacock’s tail presented a problem for Charles Darwin. It clearly could not have arisen by natural selection. Its beauty, extravagance, and most of all, its impracticality seemed to argue against the gradual increase, generation after generation, of such a structure within a population. Darwin introduced a separate process, sexual selection, to explain the origin… (read more)
A Source Law for Fitness
Dr. Pangloss in Voltaire’s Candide is famous for seeing how everything fit perfectly together. Everything is for the best in the best of all possible worlds! Most of us have more difficulty in seeing the relationships between living individuals and their environment. This is especially true when many biological traits or environmental measures are involved. To… (read more)
Limits of natural selection
Natural selection describes how small variations in plants and animals lead to the remarkable fit between their traits and the environments they live in. It does not, however, always work. The limits to natural selection receive less attention than the potential it has to explain all manner of adaptation and diversity. I argue here that… (read more)