I like this post for several reasons. As a plant physiologist, I love that you’ve pointed out that bryophytes and vascular species share a common ancestor. So good! I also really like how well you make the point that all extant species have been evolving for an equal amount of time, i.e, none should be viewed as old dysfunctional relicts, untouched from the consequences of recent selection. I know that when you write, “...everyone is equal and just as evolved as everyone else…”, you are making the point that all extant organisms been subject to natural selection for the same amount of time. However, I wonder if the word “equal” here is being asked to do too much work? Just to add to this thought-provoking sentence, I would like to point out to general readers, some of whom may not be scientists, that this does not mean all organisms, even organisms within species, are equal. They are unequal in almost every meaningful sense of the word… and this is a good thing, not a bad thing. Plants differ in structural complexity, in their ecological functions, in their shape and size, even in the genome size. Just because plants have been subject to natural selection for the same amount of time does not mean that they have changed the same amount, nor in the same way. For example, the “basal” (actually, “sister taxon”) Amborella trichopoda, although exhibiting many similarities with other flowering plant families, has retained many features from its more distant and extinct ancestors. This doesn’t mean that other flowering plants are superior to Amborella, but it certainly does give them a fitness advantage in many important contexts. These differences, especially differences within species, are incredibly important. Mutations and variants arising within populations (differences) are the raw material natural selection acts on, i.e., it is how evolution itself works. If all individuals within a population were identical, natural selection would have no heritable variation upon which to act. So, what I would like to add to this wonderful post is that differences are not bad things. They are good and necessary things – wondrous things. I like to think that Charles Darwin had differences in mind when he wrote, “From so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved”.
Well said! I used the word equal as Jefferson did, not in the sense of 'the same'. But you are right, of course, to point out that the word equal carries a lot of weight and could be very misleading if misunderstood. Just as it carried a lot of weight in the Declaration of Independence. And at the same time, it did not carry enough weight back then because it allowed the exclusion of women and enslaved humans. Equal, what a word!
It is not "my theory"; it is the consensus of biological science that all life on Earth stems from only one ancestor. This is based on the fact that there is a universal genetic code in RNA and DNA and that other biomolecules are essentially the same in all organisms, including of course humans. There may have been other life forms in the history of our planet, but if so they did not leave any living descendants. Of course there are many other explanations for the origin of life and of humans in different religions, but none of those explanations are backed by science. I write about science, not religion. Which is not to say that I do not respect religion. I do, but that is not what I write about.
I am biologist and such a thing as a consensus does not exist in science. The one ancestor claim is just a theory. The 'universal genetic code' argument is a fallacy. Live can have originated many times, it's organization depending to great extent to the conditions for self-assemby of life existing on earth.
It’s quite fun to start a 1st year UG lecture. “are there any Opisthonkonts in the room?”
In my experience a lot of ophistokonts skip lecture.
Not our 1st years, still to develop such bad habits.
I like this post for several reasons. As a plant physiologist, I love that you’ve pointed out that bryophytes and vascular species share a common ancestor. So good! I also really like how well you make the point that all extant species have been evolving for an equal amount of time, i.e, none should be viewed as old dysfunctional relicts, untouched from the consequences of recent selection. I know that when you write, “...everyone is equal and just as evolved as everyone else…”, you are making the point that all extant organisms been subject to natural selection for the same amount of time. However, I wonder if the word “equal” here is being asked to do too much work? Just to add to this thought-provoking sentence, I would like to point out to general readers, some of whom may not be scientists, that this does not mean all organisms, even organisms within species, are equal. They are unequal in almost every meaningful sense of the word… and this is a good thing, not a bad thing. Plants differ in structural complexity, in their ecological functions, in their shape and size, even in the genome size. Just because plants have been subject to natural selection for the same amount of time does not mean that they have changed the same amount, nor in the same way. For example, the “basal” (actually, “sister taxon”) Amborella trichopoda, although exhibiting many similarities with other flowering plant families, has retained many features from its more distant and extinct ancestors. This doesn’t mean that other flowering plants are superior to Amborella, but it certainly does give them a fitness advantage in many important contexts. These differences, especially differences within species, are incredibly important. Mutations and variants arising within populations (differences) are the raw material natural selection acts on, i.e., it is how evolution itself works. If all individuals within a population were identical, natural selection would have no heritable variation upon which to act. So, what I would like to add to this wonderful post is that differences are not bad things. They are good and necessary things – wondrous things. I like to think that Charles Darwin had differences in mind when he wrote, “From so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved”.
Thank you. This is the post I'm sharing today.
Not here though, in the real world.
Thanks for sharing! There's a real world?
So I'm constantly reminded.
Well said! I used the word equal as Jefferson did, not in the sense of 'the same'. But you are right, of course, to point out that the word equal carries a lot of weight and could be very misleading if misunderstood. Just as it carried a lot of weight in the Declaration of Independence. And at the same time, it did not carry enough weight back then because it allowed the exclusion of women and enslaved humans. Equal, what a word!
All living organisms had the same time to evolve.
No. Unless we are unicellular, too. Which makes no sense. We do share the same blue marble now with fellow beings much older than us.
We all have the same unicellular ancestor, both Eukaryotes and Prokaryotes. All living organisms had the same time to evolve.
As if there was only one ancestor … Basically this theory sounds like a kind of religious ideology: life only happened once.
Humankind appeared in the holocene … before, they aren't considered human.
But according to your theory ‘the ancestor™’ is the ancestor not only of humankind, but of all living there is … no distinctions.
You won't have other gods beside me.
It is not "my theory"; it is the consensus of biological science that all life on Earth stems from only one ancestor. This is based on the fact that there is a universal genetic code in RNA and DNA and that other biomolecules are essentially the same in all organisms, including of course humans. There may have been other life forms in the history of our planet, but if so they did not leave any living descendants. Of course there are many other explanations for the origin of life and of humans in different religions, but none of those explanations are backed by science. I write about science, not religion. Which is not to say that I do not respect religion. I do, but that is not what I write about.
I am biologist and such a thing as a consensus does not exist in science. The one ancestor claim is just a theory. The 'universal genetic code' argument is a fallacy. Live can have originated many times, it's organization depending to great extent to the conditions for self-assemby of life existing on earth.