#speciation

[speciose2]

[Tweet from @/fozmeadows: "human gender and sexuality are very much like animal taxonomy, in that both look structured and simple on the surface, but once you start investigating, it turns out there's actually no such thing as a fish despite the fact that we all know what a fish is, and that's okay"]

[lichenaday]

Angiactis spinicola

Did you know that the diversity of the Galapagos also extends to lichens? A. spinicola is one of several lichen species endemic to the Galápagos Islands, where it grows on the twigs and spines of shrubs and trees near the coast. It has a dense, white, crustose thallus covered in lots of wart-like, elongated or irregular apothecia. The apothecia have a pronounced thalline margin and thin black discs obscured by a thick layer of pale pruina. A. spinicola has a Trentepohlioid photobiont. The genus Angiactis was only described in 2008, with only 4 recognized species thus far. 2 of these species are located in Australia, while another is endemic to the Bahamas. With such a disjunct and unique distribution pattern, this genus must have an interesting history. Gets me thinkin, ya know?

images: source | source

info: source | source | source

[markscherz]

Hello, I was wondering what criteria you personally use to decide if something is a species or a subspecies?

I quite like Kevin de Queiroz's recent take on the matter, so I will refer you to him. There has been quite a bit of subsequent discussion, some of which I agree with, some of which I think is a bit moronic.

TL;DR: They should be treated as a difference of degree, not of kind, and can conveniently be used to capture the grey zone that we know characterises the incipient stages of speciation.

[panicinthestudio]

They Didn't Make Dire Wolves, They Made Something…Else, April 8, 2025

TL;DW: 1. Dire wolves are probably not that closely related to gray wolves, though Colossal says that's not true, they haven't produced anything to back that up. 2. Dire wolf-like animals will never be ecologically important to our current world because they ecosystems they existed inside of do not exist anymore. 3. Collossal's goal isn't de-extinction, is creating new species to fill in niches left behind by extinct species, which is an idea worthy of debate! But it's not what you think of when you hear "de-extinction." 4. There's lots of really cool science here, which does include maybe kinda creating the frist large mammalian synthetic species.

Fixing my Direwolf Mistake, April 11, 2025

This has been an interesting journey...there is obviously something to like about de-extinction hype, which is that we're talking about the biodiversity crisis, which is absolutely great, because usually we do not! Is lying about making direwolves worth that? I dunno, maybe! Probably even!!

[bonefall]

if humanity was wiped out and clan cats were the first species to begin to evolve to take their place, what part of their bodies would be the first to change? what would be the last?

Hmm... Well, I think when discussing evolution, it's good to keep in mind that it is not a process that has a "goal." Humans are an incredibly unique species; there may not ever be anything quite like us ever again.

There are ecological niches; and convergent evolution happens so often because there is an optimal shape to accomplish that task. A social pursuit predator develops long muzzles, and long legs, so hyenas and dogs look similar even though they're barely related at all.

And Clan cats are clearly some kind of subspecies of cat that's finding value in social learning and tool use. If humans were no longer a threat or consideration, and this subspecies kept selecting for traits that value social ability and tool use;

Non-physical changes

Their brains would change. I'm not going to say their skull would get larger though; that's a correlation with species intelligence, but I wouldn't rule out some other change. Feel the back of your skull; that is actually a broken monkey gene at work. OUR brains got larger, but evolution is random change. It's just as likely their brains just get wrinklier, or some protein mutates and makes their synapses fire faster. But the brain would change somehow. Which leads to,

Their diet would change. Brainpower is INTENSE. They would need a lot of food and a more varied diet. for my Clan Culture series I actually gave them a gene that turns their taste for sweetness back on, like lactose tolerance in humans. They may need to eat more fish, or start eating ONLY cooked food to help absorb more nutrients.

Longer lives, longer childhoods, less babies Big brains are INTENSE. We are a cocial species-- that means we have to LEARN as we grow. We are not like precocial, like baby kittens, who are born knowing how to crawl and hiss. This brain takes massive parental investment, both in the womb and after we're born. Even as adults, we're constantly learning, improving our skills, teaching what we know to others. It's not good if your master craftsman dies early or you have generation turnover in less than 5 years. And what good is being a social species if there's no society to support these long, informative childhoods? If you'd waste all that energy pushing out 5 kittens a year only for half of them to die and "waste" so much investment? Smaller litters, longer childhoods.

Physical Changes

Tool Tooth Evolution works with what the organism has. Caledonian crows haven't evolved thumbs just because they use tools; they use their beak and their feet. Clan cats have two paws and a mouth; Hands and a pair of portable scissors. A top-and-bottom pair of teeth might become adapted to be stronger so they stop breaking their teeth while toolmaking.

More dexterous paws Specifically, the pad would be LOWER on the paw, leaving a "dip" between the beans and pad. It would be like that dip in your palm; that is an adaptation for tool use. You don't see that beautiful square-shape in chimpanzees or our relatives. I'd reckon an animal using its hands as toolmakers would develop a shape very similar RIGHT there.

Wrist mobility Turn your palm towards the ceiling right now. That movement is called supination. Now flip your hand and aim it towards the ground. That's pronation. Cats currently can't move their wrists like that. They would be able to, if the species started adapting towards tool use. (Don't do this if it would hurt your wrist of course!! You get the idea.)

Dewclaw would beef up And I say this because every time I see a cat actually needing to manipulate something, the dewclaw is actively used. I think it's likely that it would slide back down the paw over many generations and become a two-knuckle thumb, but with the claw being permanently extended. Speaking of claws,

Index claw would become long and straighter. And it would stick upright like a velociraptor, so that it doesn't dull over time. A very long index claw would be helpful for fine manipulation. Claws evolved for catching prey but becoming useful for tool use instead is called exaptation, when a structure that evolved for one purpose becomes useful for another.

Tails would become even more expressive. Cats do communicate with sound as well; but they say a LOT more with their tails. I think it would actually follow that they would naturally speak a sort of tail-sign, if they were evolving into an extremely social species, especially since they are hunters (and not apex predators at that) and silence is a virtue. To accommodate the complexity of language, that thing would be like a bendy straw.

Tails would have a light tip. Because it makes it easier to see. A cat with out a tip is harder to understand when they're tail-speaking, let ALONE in dark conditions. If it's not white, any lighter color would start being selected for.

And that's all I can remember off the top of my head. I'd considered this heavily before but, there you have it.

[ravewing]

hi tumblr. can someone help me name these fellas please .. its for a biology project and im blanking out rn😭

[a-dinosaur-a-day]

Years ago I talked to a science coat clad museum person who was going to a palentological talk in isle of wight.

I hadn't talked to someone who listened that closely and excitedly for years. Its a treasured memory. They even invited me to the talk, unfortunately I was going home next day as was only on holiday.

I was talking about how speciation is difficult to classify now, so I can only imagine dinosaurs.

I talked about gull and duck ring species and freaks of nature, hybridisation.

I knew for years of the nanotyrannus being juvenile trex thing.

I now know of the stygimoloc/dracorex being juvenile pachycephalosaur thing and the torosaur/triceratops debate.

I wondered if some dinosaurs that were found once could of been some of this (like beckalspinax, although they may actually be altispinax). But I understand majority is just due to rarity of fossilisation.

What do you think of all that? I'm not a paleontologist or a biologist (both have been a passion though).

There are probably a lot of species that are just ontogenetic stages of one another. But there are probably a lot that are legitimate! Luckily ontogeny we can determine with histological studies, if we're able to do them. And stuff like sexual dimorphism we can find by looking at populations and seeing there are two distinct peaks or morphs of differentiation. Since there are ways to determine of things are different sexes of the same species, or different growth stages, a lot of other variation is probably at least somewhat reflective of actual species and diversity. But, when it comes to fragmentary fossils, it gets a bit murkier.

[academicelephant]

A common misconseption people tend to have is that humans evolved from apes. We didn't. We are apes. Homo sapiens is one of the great ape species alongside bonobos, chimpanzees, gorillas and orangutans. These species share a common ancestor. As far as I know, there is no generally agreed view as to when this common ancestor lived. I myself have seen estimates ranging from 9 to 25 million years. This study, for example, suggests it was 12-16 million years ago. Be that as it may, that ancestor is the one all great ape species evolved from. As for later speciation, it still is not the case that, for example, humans evolved from chimpanzees, but that humans and chimpanzees both evolved from a common ancestral species.