11–20 of 36 posts
It's certainly a tree of individuals, though with single-celled division even that is not clear. Things get tricky when you talk about species, because species are (arbitrary?) equivalency classes of individuals.
I've always said it's not the Tree of Life , but rather the DAG of Life .
I'd go full mad and say the space continuum of life. Context is what drives life. Similar context breed similar forces and genes.
Flight is so useful, it evolved 4 times independently. With very similar solutions. https://en.wikipedia.org/wiki/Flying_and_gliding_animals
And crustaceans keep evolving into crabs. https://www.popsci.com/story/animals/why-everything-becomes-...
And who even knows how many different times high level intelligence has evolved. I think octopi, birds, and mammals are all good examples of separate intelligence tracks with similar results.
I've always said it's not the Tree of Life , but rather the DAG of Life .
It may not even be acyclic. For example it appears fetal DNA is permanently detectable in mothers and may even have health benefits that conceivably increase the mother’s evolutionary fitness.
If there were Schema.org/Animal and/or schema:AnimalInstance classes, what do you list under a :breed property to indicate that e.g. one parent is breed X and another is breed Y?! That's definitely not a DAG; that looks like a feature clustering dendrogram.
DNA barcoding > Mismatches between conventional (morphological) and barcode based identification https://en.wikipedia.org/wiki/DNA_barcoding#Mismatches_betwe...
Taxonomy (biology) https://en.wikipedia.org/wiki/Taxonomy_(biology)
FWIU, there's at least one DNA-based organism naming system; IDK how much that helps resolve :Animal and :AnimalInstance if at all?
Evolutionary biology is sincerely beautiful, the biological history of our species is a meta-history to human history. On a grander scale, the biological history of life itself weaves the career of the human race into a context of profound interconnectivity. It's natural to contemplate your origins, the place and culture you come from, your ancestors and the history of your family. It's even more profound to contempl…
Be awed by the beauty but also be wary of the horror that is existence.
Awe, beauty and horror are human concepts. Do not let that bias cloud your logic. When something is beautiful to you, you become blind to the horror. When something is horrible to you, you become blind to the beauty. Best way to view something, is to ignore both, and judge it dispassionately.
Nothing is beautiful, nothing is horrible. That is true understanding.
Darwin believed that each successive generation of a species had increasing mutations leading to a gradual divergence. Another school of thought believes that a species remains at equilibrium until some environmental stressor activates a rapid divergence. If this "punctuated equilibrium" is true, climate change will give rise to many new species, as would all mass extinctions.
What Darwin knew about biology is incommensurate with a modern understanding of the word "mutation". A generation later than him, biologists still believed cells were formless blobs of jelly, so to speak. Punctuated equilibrium is even less defensible given our present understanding of the molecular basis of genetics.
Evolutionary biology is sincerely beautiful, the biological history of our species is a meta-history to human history. On a grander scale, the biological history of life itself weaves the career of the human race into a context of profound interconnectivity. It's natural to contemplate your origins, the place and culture you come from, your ancestors and the history of your family. It's even more profound to contempl…
It's certainly a tree of individuals, though with single-celled division even that is not clear. Things get tricky when you talk about species, because species are (arbitrary?) equivalency classes of individuals.
Species are approximations that can be useful to discuss populations but they are very fuzzy at the edges. There is not single definition of species that applies in all cases. In that sense they are somewhat arbitrary but terms can be arbitrary and useful at the same time.
To summarize the article (using a more familiar animal):
Polar Bears and Grizzly Bears are different species… Yet they can reproduce! Good god, that means they were once the same species, then different species, and now the same species again! My minds blown!
Silly…
Earlier quoted context omitted.
Species are approximations that can be useful to discuss populations but they are very fuzzy at the edges. There is not single definition of species that applies in all cases. In that sense they are somewhat arbitrary but terms can be arbitrary and useful at the same time.
It seems the article is merely about the ‘wonder’ and ‘Eureka’ moment of realizing one’s definition of species is over or under inclusive. To summarize the article (using a more familiar animal): Polar Bears and Grizzly Bears are different species… Yet they can reproduce! Good god, that means they were once the same species, then different species, and now the same species again! My minds blown! Silly…
what's surprising is that it took so long to realize that.
we only need to look at dogs to see an immense variety that is still interbreedable.
and if dogs can, why not sharks or bears?
i think the only reason we don't don't see that more often is because they each live in different habitats and opportunities for interbreeding are rare.
i expect genetics will be able to give a better answer as to how much variety is needed before interbreeding no longer works.
I'm not a biologist, but I found this paper (Podani, 2019) about the "Coral of Life" metaphor interesting: https://link.springer.com/content/pdf/10.1007/s11692-019-094...
Earlier quoted context omitted.
It seems the article is merely about the ‘wonder’ and ‘Eureka’ moment of realizing one’s definition of species is over or under inclusive. To summarize the article (using a more familiar animal): Polar Bears and Grizzly Bears are different species… Yet they can reproduce! Good god, that means they were once the same species, then different species, and now the same species again! My minds blown! Silly…
that was my thought too. the general principle hasn't changed, just the understanding of how much divergence is necessary before the branches are truly separate. what's surprising is that it took so long to realize that. we only need to look at dogs to see an immense variety that is still interbreedable. and if dogs can, why not sharks or bears? i think the only reason we don't don't see that more often is because th…
In general, the babies that are born have already passed through a nightmarishly difficult biological gauntlet to survive. If they fail at any stage, the pregnancy is simply terminated. The majority of fertilizations never lead to births as a result.