Post Ac2HOw9YaabW8sefui by ubi@ecoevo.social
(DIR) More posts by ubi@ecoevo.social
(DIR) Post #AbzskrZ3Rbtx6x1IMy by gay_ornithischians@sauropods.win
2023-11-20T07:15:38Z
0 likes, 0 repeats
friends w reading comprehension is this abstract saying that there were 3400 genera of dinosaur if you add up the number of genera that existed troughtout the mesozoic? or is it saying that there were times during the mesozoic in which there were 3400 genera at the same time?https://www.tandfonline.com/doi/abs/10.1080/10292389509380510
(DIR) Post #AbzsksmCwC16s2BJVg by john@sauropods.win
2023-11-20T12:01:06Z
0 likes, 0 repeats
@gay_ornithischians “A total of at least 3,400 genera of dinosaurs have been present on Earth at one time or another through Mesozoic time." - very bad no good sentence, Dale.
(DIR) Post #AbzsnKegFyJNuhpRse by llewelly@sauropods.win
2023-11-20T09:57:22Z
0 likes, 0 repeats
@gay_ornithischians I find that abstract really difficult to read.I think 3400 is meant to be the total number of genera through the whole of the Mesozoic, but not a total of described genera; it includes genera not then (2009) described but whose existence could be reasonably estimated based on material known at the time; "Only eight percent of this number are presently known from taxonomically diagnostic materials."It seems low to me, but it was 14 years ago.
(DIR) Post #AbzsnLl69b2VKtq5WS by alcootatooter@sauropods.win
2023-11-20T10:46:09Z
0 likes, 0 repeats
@llewelly @gay_ornithischians I have trouble accepting that estimated numbers of such ill-defined and arbitrary constructs as genera have any meaning.
(DIR) Post #AbzsnMj0YqxgKhrvu4 by john@sauropods.win
2023-11-20T12:01:35Z
0 likes, 0 repeats
@alcootatooter @llewelly @gay_ornithischians Eh, species in palaeontology are no better.
(DIR) Post #AbztnhzdaPmMFWNHv6 by llewelly@sauropods.win
2023-11-20T12:13:02Z
0 likes, 0 repeats
@john @alcootatooter @gay_ornithischians for mesozoic dinosaurs it often seems they're effectively the same, because most genera have only one well known species (if that), and then 1-4 other species known only from bits. (A few well-studied ceratopsian and hadrosaur genera have more than one well-known species, but those are exceptional.)
(DIR) Post #Ac0etDcY7QHjdNhkQ4 by alcootatooter@sauropods.win
2023-11-20T21:00:35Z
0 likes, 0 repeats
@john @llewelly @gay_ornithischians absolutely true, palaeodiversity should be trying to estimate things like cladogenic events and co-existing lineages (regardless of taxonomic rank).
(DIR) Post #Ac0lP37lHOnc4TrhZo by gay_ornithischians@sauropods.win
2023-11-20T22:13:39Z
0 likes, 0 repeats
@john @alcootatooter @llewelly is that due to the limitations of the fossil record or for other reasons?
(DIR) Post #Ac1wUQ9AP1WfZoFKD2 by alcootatooter@sauropods.win
2023-11-20T22:34:50Z
0 likes, 0 repeats
@gay_ornithischians @john @llewelly I'd say the biggest problem with defining palaeo species is that we don't really know (or agree) on what a species is. Add to that, that all fossils are dead, things such as potential to interbreed and gene flow between populations are nearly always beyond our ability to investigate.
(DIR) Post #Ac1wURBgX98OnuQqm0 by AmyIsCoolz@sauropods.win
2023-11-21T02:03:44Z
0 likes, 0 repeats
@alcootatooter @gay_ornithischians @john @llewelly A concept of species in general is kinda weird and I don't quite understand it. Like it's apparently supposed to be if they can't interbreed then they are separate species but then many species can interbreed (some hybrids can even continue breeding after that)
(DIR) Post #Ac1wUS8sz2UPlW8836 by john@sauropods.win
2023-11-21T11:52:22Z
0 likes, 0 repeats
@AmyIsCoolz @alcootatooter @gay_ornithischians @llewelly Species aren't real, and I will die on this hill. If interbreeding is the definition then most life on earth can't have species. It doesn't work through geologic time, and has all sorts of weird exceptions as you point out. (The notion that we have to make up a category of “hybrids” makes the whole thing a joke.)
(DIR) Post #Ac1wUSECfGk820cNKy by alcootatooter@sauropods.win
2023-11-20T22:36:11Z
0 likes, 0 repeats
@gay_ornithischians @john @llewelly Furthermore we now have the time dimension to contend with, instead of a nice convenient time-slice like the modern day where many (most?) lineages are neatly bundled up into separate recognisable parcels we call species. Once we look down the time dimension all the smeary, gradual changes that link lineages together open up.
(DIR) Post #Ac1wVHNAVhDYeaCktM by john@sauropods.win
2023-11-21T11:52:46Z
0 likes, 0 repeats
@AmyIsCoolz @alcootatooter @gay_ornithischians @llewelly I will accept that the notion of a breeding population is a useful concept for people studying living, interbreeding things. To make that a generalisable concept and a basic biological unit is a mistake.
(DIR) Post #Ac1y84VONtqHzh73my by john@sauropods.win
2023-11-21T12:10:53Z
0 likes, 0 repeats
@u0421793 @AmyIsCoolz @alcootatooter @gay_ornithischians @llewelly Yeah, I think that’s a good way to think about whether things are real: would aliens come up with the same concepts?
(DIR) Post #Ac21lFf18vvJkPzNZ2 by llewelly@sauropods.win
2023-11-21T12:51:37Z
0 likes, 0 repeats
@john @u0421793 @AmyIsCoolz @alcootatooter @gay_ornithischians 1/2I think there are relatively few concepts in any area of science that pass an "alien test"; even in physics messy complexities like wave/particle duality bring the universality of dependent concepts into question. But biology is particularly bereft of concepts that pass; probably natural selection does, and if it does, maths would be needed to maniplate it, but the resemblance of that maths to cladistics seems questionable.
(DIR) Post #Ac226G9AWvfRKy6qK8 by llewelly@sauropods.win
2023-11-21T12:52:00Z
0 likes, 0 repeats
@john @u0421793 @AmyIsCoolz @alcootatooter @gay_ornithischians 2/2Species is right out; species concepts vary so much across different scientists, and across different groups, it's highly unlikely aliens would have any reasonable equivalent. If Linnaeus had died of a severe allergic reaction before publishing his system (something that nearly happened), it's possible the whole history of species concepts would be very different.
(DIR) Post #Ac226GrpqrOdZV0Vwe by john@sauropods.win
2023-11-21T12:55:22Z
0 likes, 0 repeats
@llewelly @u0421793 @AmyIsCoolz @alcootatooter @gay_ornithischians I agree to a certain extent, but when I imagine aliens for this thought experiment, I imagine them being cognitively pretty similar to us, just with a completely separate cultural path.You actually don't need aliens, you can just find out what other human traditions think.
(DIR) Post #Ac26FT8rz1rA41cHM8 by dinogami@sauropods.win
2023-11-21T13:41:51Z
0 likes, 0 repeats
@john @AmyIsCoolz @alcootatooter @gay_ornithischians @llewelly I think biologists need a "fundamental unit" of biology because they need a point at which to say "evolution happens here." Individuals do not evolve. _Populations_ evolve, but then it's a question of "populations of a _what_?" I'm not saying that breeding makes for the best definition of "species," & of course there's a reason why ~150 definitions of "species" are argued! (Not claiming I have a solution here!)
(DIR) Post #Ac27CX11E3TNA86iX2 by john@sauropods.win
2023-11-21T13:52:22Z
0 likes, 0 repeats
@dinogami @AmyIsCoolz @alcootatooter @gay_ornithischians @llewelly It might be actually clarifying in this respect to get rid of the concept. The creative aspect of evolution (mutation) happens in lineages, population changes are part of selection. The “population" part can be variously defined, but any level of clade would do.
(DIR) Post #Ac2CmLw4OgNgzjh14i by ubi@ecoevo.social
2023-11-21T14:55:04Z
0 likes, 0 repeats
@john @llewelly @u0421793 @AmyIsCoolz @alcootatooter @gay_ornithischians Non-western traditions also have concepts of grouping animals into different types based on observed characteristics or behaviour. It's a very important skill for hunting or foraging.Higher level classifications also exist in indigenous cultures. Although it's not as systematic as our current biological classification.
(DIR) Post #Ac2GmUBE8zPQNh6LXE by ubi@ecoevo.social
2023-11-21T15:37:00Z
0 likes, 0 repeats
@AmyIsCoolz @alcootatooter @gay_ornithischians @john @llewelly Biologists don't talk about species concepts in polite company, otherwise it always ends up in the philosophical equivalent of a bar fight. There are no winners and there's just a huge mess on the floor.There are plenty of species concepts available, but I'd argue that the idea is so enduring because the concept of species is very useful for communicating about a set group of living things.
(DIR) Post #Ac2GmV0z2YoEyDJgCu by john@sauropods.win
2023-11-21T15:39:56Z
0 likes, 0 repeats
@ubi @AmyIsCoolz @alcootatooter @gay_ornithischians @llewelly I have no problem talking about clades, and that is my solution, stop pretending there's a special level that is even close to universally applicable. It's actually closer to how people talk about organisms is normal life.
(DIR) Post #Ac2HOw9YaabW8sefui by ubi@ecoevo.social
2023-11-21T15:43:43Z
0 likes, 0 repeats
@AmyIsCoolz @alcootatooter @gay_ornithischians @john @llewelly But it's good to keep in mind that each species is a testable hypothesis. New techniques, evidence and assumptions can be used to support or re-evaluate the hypothesis that it is a discrete category.(This is all from a biologist perspective since we have more to work with than bones.)
(DIR) Post #Ac2HOx7SzqWh8ggWIK by john@sauropods.win
2023-11-21T15:46:53Z
0 likes, 0 repeats
@ubi @AmyIsCoolz @alcootatooter @gay_ornithischians @llewelly I'm not sure what you mean, but I think you're talking about whether set of organism can interbreed with another set... right?
(DIR) Post #Ac2IIBIrxk813aLyRE by ubi@ecoevo.social
2023-11-21T15:56:52Z
0 likes, 0 repeats
@john @AmyIsCoolz @alcootatooter @gay_ornithischians @llewelly No. There are multiple species definitions. So there are many sets of assumptions in which you can define a species. Morphospecies have the assumption that similar morphology belong to a distinct group. Genetic species have the assumption that a distinct group has a common gene pool. Biospecies is about interbreeding. But all of these can be tested in living organisms. A lot of species can be redefined as we learn more about them.
(DIR) Post #Ac2JBKI2FhyGr5G5JY by ubi@ecoevo.social
2023-11-21T16:01:13Z
0 likes, 0 repeats
@john @AmyIsCoolz @alcootatooter @gay_ornithischians @llewelly And in some cases using multiple techniques show similar results, leading us to conclude that all these are detecting a signal of some sort of unique discreet lineage or gene pool or collection of characteristics.And in other cases it's not as well supported and whether the species is real is put into question. Like any scientific hypothesis, a species can be tested and evidence on whether it is real or not can be obtained.
(DIR) Post #Ac2JBLCOs93dftd6Aa by john@sauropods.win
2023-11-21T16:06:35Z
0 likes, 0 repeats
@ubi @AmyIsCoolz @alcootatooter @gay_ornithischians @llewelly See, this is what I'm not understanding, yes, you can test for relatedness or shared characteristics, or any number of measures, but which level is special?
(DIR) Post #Ac2JFsyfE7d5axN6uW by ubi@ecoevo.social
2023-11-21T16:07:40Z
0 likes, 0 repeats
@john @AmyIsCoolz @alcootatooter @gay_ornithischians @llewelly There is the pragmatic use of species for communication. Yes, species are subjective definitions of a natural phenomenon and in the case of paleontology it might not be describing an actual group of extinct animals.But it's useful to have a name to use when talking about something. It's an agreed upon way of talking to each other so we know we are talking about the same thing.
(DIR) Post #Ac2KBh7nS8U7d9D0jI by john@sauropods.win
2023-11-21T16:17:53Z
0 likes, 0 repeats
@ubi @AmyIsCoolz @alcootatooter @gay_ornithischians @llewelly My solution is to use clades for this. There is no special level, but people settle on the most useful ones.
(DIR) Post #Ac2KF6XdPVWdKNv7nU by ubi@ecoevo.social
2023-11-21T16:18:43Z
0 likes, 0 repeats
@john @AmyIsCoolz @alcootatooter @gay_ornithischians @llewelly That's a good question. Honestly, where we draw the line is subjective and based on human judgement rather than a hard criteria.I'll sleep on it and see if I can come up with a better answer, but that's all I got for now.Thanks for a really interesting discussion.
(DIR) Post #Ac2P7TAnsjOyyOQ6Rk by llewelly@sauropods.win
2023-11-21T17:13:18Z
0 likes, 0 repeats
@john @ubi @AmyIsCoolz @alcootatooter @gay_ornithischians in some ways clades are closer to how normal people talk about organisms, but in other ways they're very different; try explaining each of the following to a normal person: (a) vertebrates and some invertebrates like echinoderms are part of the Deuterostome clade, but molluscs and arthropods are not, (b) mammals are part of the bony fish clade, but sharks and rays are not, (c) humans are part of the monkey clade, but lemurs are not.
(DIR) Post #Ac2PrOzFmKOXJIv5qS by john@sauropods.win
2023-11-21T17:21:40Z
0 likes, 0 repeats
@llewelly @ubi @AmyIsCoolz @alcootatooter @gay_ornithischians Indeed, clades are sometimes surprising, but most people feel at least somewhat enlightened when you explain the fairy simple concept behind them, and why we say this is x not y, because it's not completely arbitrary.
(DIR) Post #Ac2dkoQ8DYOpWRFAzQ by gay_ornithischians@sauropods.win
2023-11-21T19:57:17Z
0 likes, 0 repeats
@john @AmyIsCoolz @alcootatooter @llewelly does binomial nomenclature improve or worsen the situation in your view? speaking naively when i hear for example Homo whateverensis it lets me know the organism in question is more closely related to Homo species than it is to non Homo species