That rabbit/hare post is messing me up. I’d thought they were synonyms. Their development and social behavior are all different. They can’t even interbreed. They don’t have the same number of chromosomes. Dogs, wolves, jackals, and coyotes can mate with each other and have fertile offspring but rabbits and hares cant even make infertile ones bc they just die in the womb. Wack.
These
are more genetically compatible than These
and that’s why morphology-based phylogeny has Issues
The problem is perspective. People always think dogs are the ‘standard’ animal, the metric to use for whether or not two organisms “look like” they’re related. When in fact they’re a massive outlier due to the fact that we fucked up this lineage of wolf beyond recognition with selective breeding. It’s why people always say “breed” when they mean “species”, especially when talking about groups like lizards which can’t even be defined cladistically since some of them are closer to snakes than each other. To say nothing of fish.
I once read an article that emphasized there is no such thing as a fish.Sharks and rays, lamprey, lobe-finned fish like lungfish and coelacanth, bichir and sturgeon, and of course the multiple infraclasses of more “modern” fish groups are all only very distantly related to one another. They’ve maintained semi-similar body structures only because there are limited ways to efficiently move through water as a vertebrate.
This
And this
Are more distantly related from one another than you and I are from a lungfish
Which is absolutely fuckin wild.
Not only that, but all of us air-breathing land vertebrates, all the lizards and chickens and people and frogs, are closer to one another than those three “fish” are to one another as well.
these
are genetically closer than these
and…
these
are genetically closer than these
and my personal favorite, it really fucks with people…
these
are more genetically similar than these
COOL.
Some phylogeny for your evening reading, folks. :)
Is it true that some lizards are more closely related to snakes than to other lizards? Holy crap, I did not know that!
[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”]
As a biologist, that is a fantasticcomparison.
We talk about “fish” (which, cladistically, do not exist, there is no monophyletic group of “fish” that simultaneously includes all organisms we understand to be “fish”-like while also excluding, say, humans) because, despite the utter fiction that is fish, it’s still a useful label when we talk about certain features that “fish” tend to have in common.
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.
God that “ants are wasps!” post drives me crazy. Just total misunderstanding of phylogenetics turned into misinformation. The unqualified bug people on this site really need to stop sometimes.
Technically if you trace every living thing on earth back far enough we’re all zooplankton. ‘Being related on a phylogenetic tree’ does not equal ‘the same thing’.
They do come from the same order as deer; Artiodactyla.Which includes all even-toed ungulates, like camels, goats, cows, sheep, pigs, llamas, antelopes, and cetaceans (as they evolved from ungulates).
Under this is a suborder; Ruminantiawhich includes all the Artiodactylas that use rumination digestion, includes giraffesand deer, as well asgoats, cows, antelopes and so on.
Deer and giraffes then diverge into two separate families; the deer in Cervidae and giraffes into Giraffidae.So it makes giraffes very much not deer. As deer are the family group Cervidae.
It’s sort of like saying that bears are dogs / canines. Bears and canines are both under the same order; Carnivora and the same suborder Caniformia. But they are two seperate family groups; Canidae (dogs) and Ursidae (bears).
Taxonomy can be a bit tricky to wrap your head around so hopefully this helps explain a little about how we order animals based on evolution.
