You’ve done a good job at reporting the trends in thought and terminology here. I’m not directing the following at you, but at the trend in the field you’re describing.
I’m an evolutionary biologist and I’m tired of people saying r/K has been discredited. I think what really happened is that people realized r/K was a generalization without realizing that every other useful principle in evolutionary biology is also a generalization.
I use r/K parlance and I never get any complaints from the evolutionary theorists and population geneticists around me. It’s just a heuristic. Would you say the logistic model of population dynamics has been debunked because someone points out that it’s doesn’t capture every variable that affects population growth? No, because it’s just a model, so that was obvious from the start. Hence I don’t see why people pointing out that there are other dimensions to life history somehow invalidates using the r/K spectrum as a knowing simplification. I’m all for clarifying that r/K is just a heuristic and educating people about the fundamentals of life history theory, but I don’t think the fact that there’s more to it invalidates r->K as a useful dimension.
There’s never going to be a life history theory that’s both 100% accurate and can provide generalizations at the gross level at which we typically consider life history traits. In order to make any useful statements about the relationship between offspring number and life span, for example, we’re going to have to allow for exceptions.
Yes, I hope I made it plain that r- and K- classification is still in use, and that there were a variety of critiques, not just the fact there were are exception to the generalization.
I’m curious tho, some of Pianka’s associated traits have opposite relationships to those stated in big taxonomic groups. Notably for insects, reptiles and fish, “generally” reproductive output increases with body size as compared to mammals and birds where it decreases. As an evolutionary biologist what is your take here? I can think of half a dozen explanations, but never found a literature consensus (e.g., Pianka just got the traits wrong for r—and K and now we use...., r and K- not good for these groups, body size relationships within groups not so important etc etc)
You’ve done a good job at reporting the trends in thought and terminology here. I’m not directing the following at you, but at the trend in the field you’re describing.
I’m an evolutionary biologist and I’m tired of people saying r/K has been discredited. I think what really happened is that people realized r/K was a generalization without realizing that every other useful principle in evolutionary biology is also a generalization.
I use r/K parlance and I never get any complaints from the evolutionary theorists and population geneticists around me. It’s just a heuristic. Would you say the logistic model of population dynamics has been debunked because someone points out that it’s doesn’t capture every variable that affects population growth? No, because it’s just a model, so that was obvious from the start. Hence I don’t see why people pointing out that there are other dimensions to life history somehow invalidates using the r/K spectrum as a knowing simplification. I’m all for clarifying that r/K is just a heuristic and educating people about the fundamentals of life history theory, but I don’t think the fact that there’s more to it invalidates r->K as a useful dimension.
There’s never going to be a life history theory that’s both 100% accurate and can provide generalizations at the gross level at which we typically consider life history traits. In order to make any useful statements about the relationship between offspring number and life span, for example, we’re going to have to allow for exceptions.
Yes, I hope I made it plain that r- and K- classification is still in use, and that there were a variety of critiques, not just the fact there were are exception to the generalization.
I’m curious tho, some of Pianka’s associated traits have opposite relationships to those stated in big taxonomic groups. Notably for insects, reptiles and fish, “generally” reproductive output increases with body size as compared to mammals and birds where it decreases. As an evolutionary biologist what is your take here? I can think of half a dozen explanations, but never found a literature consensus (e.g., Pianka just got the traits wrong for r—and K and now we use...., r and K- not good for these groups, body size relationships within groups not so important etc etc)