tgamble

>"Every individual alive today, the highest as well as the lowest, is derived in an unbroken line from the first and lowest forms." --August Frederick Lopold Weismann, German biologist/geneticist (l834-1914).

Aside from the obvious point that this quote is over 80 years old, it runs counter to my understanding of evolution. Which means either my understanding is wrong or his is wrong.

My understanding is that evolution is NOT a line, but more like a branching bush so that there is no such thing as a higher "individual" or a lower one. This sounds like the great chain of being to me. Also, wouldn't it be slightly more accurate to refer to species rather than individuals?

Thanks for the help.

scigirl

I think the bush, rather than line, analogy is correct. While it is true that complexity increased with time in every system (we talk about 'primitive' immune systems, etc), every organism alive today--from bacteria to humans--is a success story and equally "fit" i.e. adapted to its environment.

I suspect a lot of evolution has more to do with adapting to climate changes, etc, than it does with becoming "better" and more complex.

scigirl

Mageth

I see the truth in his statement. After all, you had two parents, each of them had two parents, and so on, back to the first collection of organic molecules that started replicating.

Look at it another way; it is true that all of your ancestors survived to reproduce. Thus, there is no break in the chain from you (an individual) back to a particular one of the first, "lowest" form (where "low" means further down in the "branching bush").

I do agree with you, however, about the "highest and lowest" bit, if what he meant was that one life form is somehow "better" than another.

tgamble

Looking at it again, I may be reading it wrong. That's the problem with quotes. I think Mageth might be correct through it does remind me (at least, if I understand the terms) the so called "great chain of being."

Peez

The Scala naturae (great chain of being) was certainly a powerful idea, and its vestiges persist today. I actively discourage the use of words like "higher" or "lower" in describing organisms, but many people tend to think in those terms. I think that Mageth is correct about the sense of the "unbroken line", much like many monarchs point to their ancestry in an unbroken line back to some despot... er... king.


Peez

pz

You are trying to read too much into it. It is an entirely true statement: every organism is the product of an unbroken lineage. If you pick any random twig on your branching bush, you can trace it back along a single line to the trunk, correct?

tgamble

Pretty big bush if you have a twig for every individual. But point taken.

KeithHarwood

It's possible here he was talking about "highest" == kings, statesmen etc. and "lowest" == beggars, prostitutes etc. except that doesn't fit with his second use of "lowest". Perhaps something was lost in translation.

pz

But of course -- that's the initial premise. "Every individual alive today, the highest as well as the lowest, is derived in an unbroken line from the first and lowest forms." If you start with every and any individual, you can trace their history back in an unbroken line way, way back.

The only problems with the statement that I see is that the distinction of organisms into "highest" and "lowest" is an unfortunate anachronism, and that I expect that the earliest stock would not have been properly considered discrete individuals -- all that horizontal transfer would have messed up Weissman's pretty picture.

Camaban

Would a nuclear holocaust simplify things?