The Biology, Agriculture, and Paleontology thread

Dunno. Might have protracted brain fog, but I'm not entirely sure. I don't think I do, but that's never a solid indication.

I tend to play word games when I am, though. With loads and loads more typos than usual.

Playing games with phylum, philology and the squishy nature of classification over time? Might be a sign.

You do sound somewhat more giddy than average, Euo. I took it as a sign that you were in a good mood.

Kind of a weird question, did the lobe finned ancestors of the tetrapods have four fins or six like the coelacanth? or better question, are four limbs more economic compared to six when it comes to vertebrates?

Jawed vertebrates only have 2 pairs of paired fins, which are our actual limbs. But other fins being present seems to be plesiomorphic, due to, well, the approach of "if sharks and teleosts have it, our ancestors likely did as well".

Losing fins is quite common across fish lineages anyway, but only the pectoral and pelvic fins matter for the issue of limbs. They are the most important ones generally speaking.

https://www.sciencedirect.com/science/article/pii/S001216061630029X Give this a read as well.

The Ediacaran and Cambian periods had some weird and wonderful body plans get tried out. Some of which might well have been viable longer term.

Had the critters they had been attached to also had cold-resistance and adaptations to poor lighting conditions, that is. :/

Evolution: it's not necessarily the best at something that wins and gets built upon, but that which doesn't prove to have a critical weakness to any given change.

Viable stuff tends to be selected for repeatedly; look at how many different clades evolved shark-like, or croc-like forms.

Those didn't.

Ask cephalopods, millipedes, centipedes, urchins and starfish how useless going ham on the limbs is. I'll wait.

The key was hitting the bilateral symmetry hard more than anything else, I think.

Pretty much everything that didn't use that back then met the Reaper by the time the iceballing got through with them.

Even microscopic trilateral symmetry tends to run into issues, even though it has a better chance to work at that scale.

Radial symmetry is better for sesile lifestyles, bilateral symmetry is better for movile ones. And cephalopods are not that weird among molluscs anyway, but molluscs are the odd ones among bilaterians.

Ah, molluscs... always good for bulking up the exceptions lists.

My mind went to coneshells very fast, there: nightmares, those. <shudders> [To elaborate: for such a bog-standard, innocent mollusc to look at, that incredibly overcharged venom with such an efficient delivery system is... a little bit of a surprise. Talk about overkill.]

Edited by Euodiachloris on Jan 11th 2020 at 11:50:10 AM

I have a weird question. Can parasites survive in the bodies of drug abusers and alcoholics?

Yup.

In fact, people who don't take good care of themselves because of, say, addiction tend to being open hotels as far as most parasites go.

You'd think all the toxic chemicals would make it a pretty inhospitable environment for them.

Things that are toxic to one species are not necessarily the same for others.

And then there's the whole deal involving tolerances. Otherwise we wouldn't be having insecticide for breakfast.

I'd also add whether not the parasites are being exposed to the active ingredient directly or are only ingesting or being exposed to the metabolites.

What these people said. Sometimes drugs and alcohol will damage parasites but I don't think that's a common occurrence. It's probably best documented in fruit flies - the parasitic wasps that target Drosophila maggots do not tolerate ethanol and female fruit flies who have noticed the presence of parasitic wasps will seek out rotten fruits with more ethanol than fruit flies which didn't notice their presence ([1],[2]).

Edited by SeptimusHeap on Jan 19th 2020 at 10:28:11 AM

And that's how medicine works, particularly antiparasitic medicine, but also chemotherapy.

Don't mobulid rays have six appendages?

Are you refering to their gill plates?

That would be similar to refering to your ears as limbs.

Speaking of mobulid rays, what the hell does the genus name Mobula even mean? Google failed utterly at finding any etymology for the word.

I suspect it has something to do with their generally flat shape, but am not sure.

Well, that or somebody decided to give them the most generic mobile gaming company name in creation.

Edited by Euodiachloris on Feb 15th 2020 at 4:23:07 PM

Considering the name was coined over 200 years ago, that would mean that they're precognitive.

I have a paleontology question, since saurischian dinosaurs had airsacs in their bodies that allowed them to grow as big as they did, how heavy would they have been otherwise? For example, a Tyrannosaurus weighed about 7 tons with airsacs, so how heavy would it have been without them?

Tyrannosaurus is quite wide-boned.◊ Most of the pneumatization is on the head (theropod heads are more air than bone) and vertebrae. It wouldn't be THAT much heavier, but it would be heavier in crucial areas.

Can you estimate by how much?