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Re: [dinosaur] Dinosaur nest ecology and predation during Late Cretaceous



> Hm...this seems like a new version of the old 'mammals ate all the dinosaur 
> eggs!' scenario.

Worse: the old "mammals ate all the dinosaur eggs _precisely when_ the 
Chicxulub impact happened and apparently Deccan was going on, too!" scenario. I 
promise to read the paper soon.

> the whole argument seems to ignore the fact that dinosaurs in general appear 
> to have been K-strategists to some extent; large numbers of offspring to 
> offset serious losses. Nest failure was probably a feature and not a bug so 
> we are definitely not looking at the loss of numerous eggs being something 
> new to the later Cretaceous.

That's r-strategy, named after r for "reproductive rate", not K-strategy, named 
after K for "carrying capacity".

In the absence of predators or other causes of death, a population of 
r-strategists will grow as fast as its r lets it until or suchlike famine sets 
in; as a population of K-strategists grows under the same conditions, its r 
will decrease as K is approached, because K-strategists, unlike r-strategists, 
are sensitive to stress from overcrowding. In short, exponential increase for 
r-strategists, a sigmoid curve for K-strategists.

Usually, r-strategists have a lot of offspring that they use "as Darwinian 
ammunition" in the immortal words of our own Tom Holtz, while K-strategists 
have fewer offspring that they care for better. But that is not the definition. 
Specifically, it seems like humans are actually r-strategists: there are 
factors other than death that are decreasing our population growth, but a 
fertility decrease caused by population density doesn't seem to be one of them.