weaselle:

insomniac-arrest:

Convergent evolution is wild, bc like, crabs keep evolving to look the same but aren’t closely related, nature is just like: BIG MEATY CLAWS, little legs, pincers, head, tiny eyes, let’s do it again!

and trees look the same but oak trees are more closely related to rose bushes than they are pine trees, fucked up

nature just likes these damns shapes:

but on the other hand, mammals flying with powered flight?? That shit only happened ONCE and it had to do some janky shit to get there, especially with bat immune systems

likebat’s immune systems are HYPER-POWERED as well as repress most of their inflammatory reactions because in order to fly they needed a bonkers-high metabolic rate which unfortunately also create waste products from the process called “free radicals” that damage cells

however, despite these free radicals they manage to live up to FORTY YEARS, which is super long for a species their size, because their immune system are basically always ON and in an anti-viral state that make them incubators for disease due to warfare between their jacked immune systems and disease 

bats are so gdamn weird, I love them, no other mammal has been able to copy off their homework and accomplish the same shape, and for that they are the anti-crab of the natural world, God bless

It really worked out for them too, like it’s a hell of a lane and they have it all to themselves, so they’ve really filled their niche.  There are more bats than almost any other kind of mammal. Like, there are a higher number of individual bats, but also the most KINDS of bat.

For example there are about 30 million white-tailed deer alive in the world, whereas there are 15 million Mexican free-tailed bats living in ONE single colony in Texas. But also, there are about 43 species of deer on the whole planet, 38 species of feline, 34 species of canine…  and about 1,300 species of bat.

It is estimated that one out of every five living mammals on Earth is a bat, or, to put it another way, if you took every single mammal on the planet and counted them as individuals, 20% of those animals would be some kind of bat.

South America//Pliocene (~2 million years ago) // Sparassodonta//image source

While it appears to be a sabre-toothed cat like Smilodon, Thylacosmilus was actually a marsupial (or at least a very close relative of them), making it a prime example of convergent evolution.

“I’d like thank grad school for a seemingly limitless supply of terribly qualified henchmen, who are at a point where they unquestionably follow the orders of a possessed shaman’s mask.”

-Uka Uka

I love seeing people learn for the first time just how mind-meltingly vast and ancient the arthropods are.

Grasshoppers as a group are around 250 millions years old. To put that in perspective, the first dinosaurs showed up 230 million years ago. Grass is a relative youngster and has only been around for an estimated 66 million years.

So, yes, dinosaurs are also older than grass.

What were grasshoppers (and herbivorous dinosaurs) eating before there was grass to hop on? Get ready for a very not-exciting answer; they were just eating other older plants that were not grass. Plants first took to land around 700 million years ago.

Luckily grasshoppers are not particularly picky about what they will put in their mouth-holes. Some are perfectly happy to dine on meat when it’s available, even the meat of other grasshoppers. The evolutionary pitch for grasshoppers was basically “make a very hungry wood-chipper and then give it legs to throw itself at food”.

Nowadays most grasshopper species do have a preference for grass though, so this reaction is pretty accurate:

Image Credit: (1)(2) (3)

Sources for relative evolutionary ages: (1) (2) (3)

Supergene turns spider into a ‘macho male’

Biologists from the Royal Belgian Institute of Natural Sciences (@rbins)found in a spider species that ‘macho males’ have an extra set of genes that is lacking in feminized males. The study in Nature Ecology & Evolution explains how individuals of the same species can develop a strikingly different morphology. “We saw that throughout evolution genes may become grouped together and form a 'supergene’. As a result, they are neatly inherited in a single bundle”, says evolutionary biologist Frederik Hendrickx. Having that supergene or not makes the difference between looking very masculine or feminine in the males of this species.

In nature, you sometimes find two drastically different 'types’ within the same species and even within the same sex. For example, a primrose species has specimens with elevated anthers and anthers that are deeper in the stem, or damselfly and butterfly species with individuals having different colour patterns. This is also the case in the sheet-weaving spider Oedothorax gibbosus. There are two distinct types of males: 'flat’ and 'hunched’. The flat males look more like females and mature more quickly, allowing them to be the first to fertilize females. The hunched specimens have a complex head structure with glands and sensory hairs that allow them to seduce already fertilized females: they are 'macho males’.

Evolutionary biologist Frederik Hendrickx (RBINS): “The differences between these two types of males are enormous, at least as large as between two very different species, such as a tiger and a lion. When you mix tigers and lions you obtain an intermediate form – ligers or tigons, with both lion and tiger characteristics - because the genes are mixed up like a deck of cards. But in some species, like this spider, you neatly retain the two separate types. 'How this is possible is a largely unresolved mystery within evolutionary biology. The gibbosusspiders are a great opportunity to figure out how this works genetically.’

Supergene

The researchers screened the genome and found that the hunched males have a package of genes that is missing from the flat males. The package consists of genes that you also find elsewhere in the genome. Natural selection caused those copies to lie neatly next to each other so that offspring receive them as a single package. "The genome appears to be surprisingly dynamic,” says Hendrickx. “The genes responsible for the development of these conspicuous male traits are moved or duplicated and end up grouped together, so that they are inherited as a bundle. This is a huge eye-opener.”

The bundle is called a supergene. The extra piece of genome not only explains the difference between the two types, but also why we find no intermediate forms, no half-half versions. Only the genes necessary for the development of hunched males have grouped together in this supergene. The flat males can perfectly live without them. This explains why the population breaks down into two types: either super-masculine or female-like males.

Chain Reaction

When the evolutionary biologists zoomed into the supergene, they found that one of the genes in the supergene is a copy of the doublesex gene. All animals - including us - have that gene. Doublesex is a transcription factor: it switches other genes on or off. It’s a big on-button for typical male characteristics. “If the doublesex gene is turned off in mice, the males develop something resembling ovaries,” says Hendrickx. The development of male characteristics in gibbosusspiders occurs after a chain reaction: the sex chromosomes activate that doublesex gene, which in turn turns on other genes that provide male traits, both genes that are inside and outside the supergene package. Flat males have no supergene and therefore no extra on-button doublesex. They don’t develop those extra male characteristics: no hump, no extra glands and no hair. “In most species, the development of sexual characteristics depends on much more than the sex chromosomes. It’s a cascade of genes that are switched on or off, and one link more or less can make a big difference.”

Toolbox

Still, flat males do differ markedly from females. They possess male sex organs, produce sperm and can reproduce. That is because there are five more doublesex genes in other places of the genome, which tap into basic male characteristics.

“You could think of the supergene as a toolbox: over the course of evolution, more and more genes have ended up in that toolbox. An extra doublesex gene and other genes for distinct male characteristics were added to the box because they provided a clear advantage. The spiders with the supergene develop extra male characteristics. Those that do not inherit the toolbox only develop the basic male characteristics.”

[: 1. ARABEL-image bank/Gilbert Loos; 2. RBINS]

robotics5:

tenoretofruddigore:

tenoretofruddigore:

#Wait what?#Science dad EXPLAIN
  

Ok, I explain.  So the major categories of vertebrates that we all learned as kids (fish, bird, mammal, reptile, and amphibian…) were first published around the 1750s by a man named Carl Linneas.  He tried to classify all of life based on shared anatomical traits- things like fur, feathers, or scales, methods of reproduction, number of legs, and so forth.  He created the system of Kingdom/Phylum/Class/Order/Family/Genus/Species, grouping increasingly similar organisms into groups that he put in these 7 levels.

Of course, Actual Nature is a continuum and does not care that one man tried to make all of it fit in seven equal boxes.  And we’ve learned a lot since Linneas was working- dinosaurs weren’t scientifically described until decades after Linne’s death, and Darwin’s theory of evolution was published nearly a century later.  Other technology, such as DNA sequencing, has only really become available in the past couple years (DNA hadn’t even been DISCOVERED yet in Linneas’ time.)

Enter phylogeny.  While traditional taxonomy grouped living species based on anatomical traits, phylogeny groups species based on evolutionary relationships.  As we’ve gotten a more complete fossil record, the old model has needed some updates.  

Here’s a phylogenetic tree that I shamelessly grabbed from Encyclopedia Brittanica, showing relationships between major groups of vertebrates.  

As different adaptations arose, some groups of organisms have changed very little over time, while others have continued to look quite different.  Some of Linneas’ initial categories still hold up-  Modern amphibians never developed the ability to lay eggs away from water, and resemble many of the early land-dwelling vertebrates.  Likewise, all living mammals are more closely related to each other than to any other vertebrates, and therefore can occupy their own branch of the tree.  “Fish” is an extremely messy term as far as phylogeny is concerned, but that may be the topic for another post.

As you can see, lizards and snakes are close relatives on a shared branch point.  Crocodiles and birds, likewise, share the closest branch point to each other (Dinosaurs have been left off this figure, but are on the branch with crocodiles and birds).  Turtles’ evolutionary branchpoint is a bit more debated, because their skulls have some features that are different than other reptiles, but let’s include them for now.

So, if turtles are reptiles everything from the turtle branchpoint onward is also a reptile.  A valid phylogentic group is a common ancestor (branchpoint) and ALL of its descendents.  Excluding birds, therefore, does not make a valid clade.  

Linneas also didn’t know about dinosaurs, which have some traits more similar to other reptiles, but some types of dinosaurs gradually developed more bird-like traits.  Modern birds are descended from a couple of small, feathery dinosaurs that survived the extinction.  But, because those more transitional anatomical features are lost to the fossil record and not represented in modern species, it can be hard to get used to the idea that small, warm-blooded, beaked, feather-covered things are actually close relatives of scaly, cold-blooded things.  

Hope this makes sense!

Wow you weren’t kidding

I think it’s also cladistically valid to say “all vertebrates are fish”.

Most (~95%) modern animals we would colloquially call a “fish” ( fins, scales, and gills) are a monophyletic clade of ray-finned fishes. But since we also refer to coelocanths, lungfish, and other lobe-finned fishes as “fish”, because they also have fins, scales, and gills, we have to include their direct descendants, tetrapods, too, for the same reason we have to include birds as reptiles.

If we include sharks and rays as fish, which many people do, we’re definitely not monophyletic any more- it’s two very diverged branches. Throw in hagfish, lampreys, lancelets, and a bunch of fossil species and now the term “fish” accounts for basically all vertebrates. (Are we counting sea squirts too? Then it’s all chordates!)

If we include EVERTHING that includes “fish” in its common name (starfish, jellyfish, crayfish)…. Forget about it.

nudityandnerdery:

elfwreck:

alarajrogers:

redshiftsinger:

marlinspirkhall:

cerusee:

mikkeneko:

captainlordauditor:

theredkite:

wongbal:

ieatworm:

wongbal:

notourz:

notourz:

transgenderer:

transhumanoid:

transhumanoid:

might have made this post a couple years ago but how far back along the evolutionary tree do you have to go before it’s bestiality to have sex with early hominids? I think australopithecus is too far but that’s just an upper bound

actually wait since humans are largely differentiated from our ancestors by neotenous traits maybe it would be pedophilia for an australopithecus to have sex with a human. and bestiality the other way. might have just discovered a new kind of crime

i think everyone in the homo erectus group is close enough to not be bestiality, so australopithecus is exactly the most human-like being for whcih it would still be bestiality. i googled some pictures of homo ergaster and like…yeah thats a dude

Yeah, fucking lucy is definitely bestiality. Australopithecines are just upright apes and don’t share many traits with anatomically modern humans. It’s still a point of contention if we really know that Lucy and her kind were actually our ancestors. Additionally, I HAVE to ask my professors this question now and i can already feel their brain doing backflips to answer

@transhumanoid@transgenderer

My prof finally got back to me, a pretty non answer imo

only on tumblr to people ask questions like “would it be ethical to fuck my primate ancestor from 400,000 years ago?”

The answer is no, mainly because you’re almost defiantly related

the unexpected answer we all ignored: it’s not bestiality, but it isincest

So this post travelled from “is sex with homo habilis bestiality” to “sex with homo heidlebergensis is incest” and I’m now curious as to where it can go next. Presumably “sex with homo sapiens is SIN” which… does seem to be where a lot of tumblr posts go, come to think of it.

I’m not sure if fucking an australopithicus would necessarily be bestiality. I feel like it might be monsterfucking.

Great post everyone

I have some real bad news for anybody here whose criteria for “is it incest if I fuck them” is like “we share any genetic material” because oh boy, well

I heard that modern humans are all, at most, 50th cousins- there was a genetic bottleneck in human history because they think there was a mass extinction event which left only 10,000 of us alive. So, good job, humans.

So what you’re saying is it’s LESS incestuous to fuck an australopithicus than a homo sapiens

Guys, the important consideration is the one we cannot know without a time machine. if you ask an australopithecine if they want to fuck, do they say “Yes” in a language that some kind of universal translator can comprehend? Or do they say “EEEE eee eeee ooo eee?”

If they have language and can and do say yes, it’s monsterfucking. If they don’t, it’s bestiality.

Tumblr: As usual, tackling the important ethical issues of the day.

Can we just at least agree that, in this day and age, fucking most of them would be necrophilia?

I haven’t written anything for a while since I’ve been so busy recently (been working a lot on the typology of relative clauses - perhaps I’ll post something about that soon). This evening I watched an interview (on YouTube) from the late 1970’s (1977, I think) with Chomsky. The interview is from a series called “Men of Ideas” produced by the BBC.

It’s a great interview - stimulating and perceptive questions and, of course, stimulating and perceptive answers! Many things caught my attention, one of which being that Chomsky spoke of two factors playing a role in language design, namely the biological endowment (i.e. Universal Grammar (UG) - the species- and domain-specific cognitive ‘organ’ dealing with language) and linguistic experience (i.e. the primary linguistic data from which we acquire our native language(s)). The idea was that all humans are born with a capacity for language, i.e. UG is innate in humans, provided by our genetic makeup. The data we encounter as children is so scant and degenerate (full of false starts, sentence fragments, etc.) that it would be virtually impossible to acquire a grammar in the short amount of time that it takes any normal child to do so the world over…unless we came pre-programmed for such a task. The idea was that UG was this pre-programming. UG was thought to be richly specified with linguistic principles (all genetically encoded) that would help children in the task of language acquisition by severely constraining the possible hypotheses that any child would postulate when acquiring a grammar to generate the data the child was exposed to. That was then.

Nowadays, Chomsky speaks not of two factors, but of three factors of language design. UG and the primary linguistic data are the first and second factors respectively. The third factor is made up of general principles of data analysis and efficient computation. The idea is that children can bring these domain-general (i.e. not exclusively related to language) tools to language acquisition. The third factor allows the first factor, i.e. UG, to be made much smaller. In other words, UG is no longer thought to be as richly specified as it once was. In fact, the aim is to make UG as small as possible. This is desirable for a number of reasons, but a particularly pertinent reason concerns the evolution of language, i.e. the evolution of the capacity for language in humans. As an 'organ’ of the mind, UG is a biological entity, and as such it must have evolved (though not necessarily through direct selection, as Chomsky points out in the interview!). Given that chimpanzees do not have UG, UG must have evolved some time in the last 5-7 million years or so. It is therefore unlikely that something as rich and complex as UG as it was originally conceived could have evolved in such an evolutionarily short space of time. The third factors, however, need not be specific to language, nor do they need to be specific to humans. Therefore, it is conceptually desirable if we can explain the design of language in terms of third factors. This is, in fact, viewed as the only source of principled explanation in Chomskyan syntax nowadays.

Importantly, although UG is far smaller than it was and may only consist of very few things (a recursive structure building operation at the very least), it is nevertheless still thought to exist. The UG hypothesis in its modern incarnation is thus still very different from approaches which deny the existence of UG altogether.

Anyway, if you’re interested, I suggest reading Chomsky’s (2005) paper:

Chomsky, N. (2005). Three Factors in Language Design. Linguistic Inquiry 36: 1, 1-22.