Hello, it's me again.

Thanks for your quick answer on dead zones; it was very informative, and sorry I forgot to express units.  I did in fact intend Fahrenheit, but the answer was clear either way.

A follow up question.  A situation where temperature/rainfall are rapidly changing (like global warming), and possibly the amount of radiation from the sun is increasingly able to reach earth (thinning ozone layer) thereby (I think) enabling more frequent mutations, and an increasing number of new chemical risks in the environment seems to favor K-strategists in reproduction very much. 

Will we then see an overall species population shift toward K-strategy organisms over the next few decades? And do R-strategists ever shift more toward K strategies in unstable times?  Are there any very intelligent K-strategists?  And if amphibians are K-strategists, can they possibly get through the massive die-off that they seem to be experiencing, with a few old and a lot of new species intact?

Thank you.

Hi Jenny,

r-strategists will generally be best suited to any changing environment by virtue of their high reproductive rate, hence their ability to colonise new niches rapidly. K-strategists are at a disadvantage in changing environments and it is not until a niche is stable that K-selected species are able to dominate through their greater ability to compete for resources.

Hypothetically, r-selected species may evolve towards K-strategies in a stable environment where there are niches not filled by existing K-strategists. As an example, some pigeons have a high reproductive rate, varied diet and are able to disperse widely, thus they could be considered r-strategists. The dodo was adapted to a specific environment, had a poor ability to disperse and probably had quite a low reproductive rate (due to large size), thus it can be considered a K-strategist. Dodos evolved from pigeons that colonised Mauritius, demonstrating an evolutionary shift in strategy within the pigeon lineage.

K-strategists, like the dodo, are generally at a disadvantage when it comes to shifting to r-selecting conditions, since their low reproductive rate and low dispersal potential do not provide the key factors needed for the rapid evolution of new adaptations (and as an extension species).

Generally speaking, K-strategists are in trouble in the modern world. The most r-selected members of any group are more likely to survive the next millenia if the changes wrought in the world don't stop soon. I put my money on weeds, mice and cockroaches to make it through and provide the evolutionary material for future diversity.