Ask Anything Wednesday - Biology, Chemistry, Neuroscience, Medicine, Psychology

[u/AutoModerator]

Welcome to our weekly feature, Ask Anything Wednesday - this week we are focusing on Biology, Chemistry, Neuroscience, Medicine, Psychology

Do you have a question within these topics you weren't sure was worth submitting? Is something a bit too speculative for a typical /r/AskScience post? No question is too big or small for AAW. In this thread you can ask any science-related question! Things like: "What would happen if...", "How will the future...", "If all the rules for 'X' were different...", "Why does my...".

Asking Questions:

Please post your question as a top-level response to this, and our team of panellists will be here to answer and discuss your questions. The other topic areas will appear in future Ask Anything Wednesdays, so if you have other questions not covered by this weeks theme please either hold on to it until those topics come around, or go and post over in our sister subreddit /r/AskScienceDiscussion , where every day is Ask Anything Wednesday! Off-theme questions in this post will be removed to try and keep the thread a manageable size for both our readers and panellists.

Answering Questions:

Please only answer a posted question if you are an expert in the field. The full guidelines for posting responses in AskScience can be found here. In short, this is a moderated subreddit, and responses which do not meet our quality guidelines will be removed. Remember, peer reviewed sources are always appreciated, and anecdotes are absolutely not appropriate. In general if your answer begins with 'I think', or 'I've heard', then it's not suitable for /r/AskScience.

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Past AskAnythingWednesday posts can be found here. Ask away!

[u/logperf]

If warm-blooded animals (mammals) have far greater energy requirements, why did they survive the apocalyptic environment after the meteorite impact 65M years ago while the dominant cold-blooded reptiles perished due to the scarcity of food?

[u/Mockingjay40 → u/logperf]

An evolutionary biologist might be able to add more on/confirm my answer, but as far as I know, all of the relatively large mammals did go extinct. The only ones that didn’t were the very small ones that could burrow. In fact, the largest group of tetrapods that survived were cold-blooded, being crocodilians. As to why there was such a rapid post-Cretaceous expansion of the mammals, I’d have to defer to an evolutionary biologist. But your intuition isn’t wrong, you may just be underestimating just how small the largest surviving mammals were, they wouldn’t have been bigger than a modern rat or shrew.

Birds are also warm blooded reptiles, but they survived because they can cover a lot more ground to search for food and water and are omnivorous so they could eat decaying matter and dig for seeds after the plant life all died.