Drought Reveals Rare American Lion Fossil in Dried Up Mississippi River

Post by Tagbert » Wed, Nov 23, 2022, 9:26 PM UTC

chrisco255 wrote: post #29

Xixi wrote: post #16

Earlier quoted context omitted.

On the other hand, the planet was only 4~4.5ºC cooler than at the beginning of the industrial area, so it was not that much cooler. For those who think that warming up the planet by 3 or 4ºC is not a big deal...

We are nowhere close to that kind of pace for temperature change. But it was that much warmer during several eras in the past, including the age of dinosaurs. Life arguably thrived even more under such conditions.

And, as always, the devil is in the rate of change. Living during slow changes is not hard but if the rate of change exceeds your ability to adapt, you are screwed.

Post by EdwardDiego » Wed, Nov 23, 2022, 9:49 PM UTC

chrisco255 wrote: post #30

EdwardDiego wrote: post #14

Earlier quoted context omitted.

Larger animals retain heat better. The square-cube law in action. Hence why dragonflies in the lowlands of my country are quite small, but the ones in sub-alpine regions are fricking massive. (Ditto the hares). https://en.wikipedia.org/wiki/Square–cube_law

The earth was much warmer during the era of dinosaurs, and yet they still grew to such sizes. I'm not sure that body heat retention is a great explanation, especially given the thick fur coats of most modern mammals that were evolved for the cold. I'm mostly curious how the ecosystem was able to support so many large animals, from the base layer of the food chain up. If there was an ice sheet a mile thick covering al…

Fair comment. :)

I was referencing Bergmann's Rule [0], which really only applies to warm blooded animals but there's also a theory that evolving a larger size helps ectotherms maintain a stable temperature also. [1], and relating to your question on carrying capacity of the food available - the Jarman-Bell Principle [2] that larger herbivores can subsist better on low quality food than smaller herbivores.

And, for interest, Allen's Rule on body appendages for temperature regulation. [3] There's also Cope's Rule - that animals just tend to evolve to get larger, until that's no longer viable. [4]

I can't comment on how valid any of them are, as I'm just an armchair biologist :D

[0]: https://en.wikipedia.org/wiki/Bergmann%27s_rule

[1]: https://en.wikipedia.org/wiki/Gigantothermy

[2]: https://en.wikipedia.org/wiki/Jarman-Bell_principle

[3]: https://en.wikipedia.org/wiki/Allen%27s_rule

[4]: https://en.wikipedia.org/wiki/Cope%27s_rule

Re: Drought Reveals Rare American Lion Fossil in Dried Up Mississippi River

Re: Drought Reveals Rare American Lion Fossil in Dried Up Mississippi River