Adaptation does not "make" small changes - it is small changes of particular consequence.saquist said:In this case. It doesn't follow that adaptation which makes small changes also transforms across Orders of animals.
DNA is a limitation.
Experiments show mutations have limitations as well.
Adaptation does not "make" small changes - it is small changes of particular consequence.
DNA is infinitely modifiable - there is no lengh or sequence of DNA which has been demonstrated to be unavailable to a series of small changes in a random walk from any given sequence of codons.
Experiments do not show any limitations in the possible mutations available within a given sequence of DNA - all sixteen point mutations are always available, for example. RNA likewise.
The distinction of "Order" is completely arbitrary - the name refers to a completely arbitrary classification scheme which is invented by humans for their own convenience, and has no other reality outside of evolutionary theory. No mutation is made impossible because its effects would result in a different classification for the resulting organism. Classification schemes do not impose restrictions on living beings - it's the other way around. The map is not the territory.
Given enough time and enough individuals to express varied genotypes for selection, yes. That's the guts of evolutionary theory.Saquist said:do those small changes lead to larger leaps?
Have a look at how infectious bacteria evolve, and develop new "weapons", by adapting old ones.Saquist said:Experimentation did show mutation through irradiation which was forced. If the mutations were not exponetial and the same mutations recurred it implies a limit on DNA alteration through mutation.
Given enough time and enough individuals to express varied genotypes for selection, yes. That's the guts of evolutionary theory.
Have a look at how infectious bacteria evolve, and develop new "weapons", by adapting old ones.
You could say that the prokaryotes evolved motility because it's just too efficient, it was an inevitable outcome.
Enough of them are large leaps - the difference between a frog and a dog, say.saquist said:but do those small changes lead to larger leaps?
I've been chastised for calling the development of an embryo "evolution" since it all happens to the body of a single individual. It is just "gestation." Evolution is a (very long) series of individuals passing their genes on to the next generation and having mutations or selections cause tiny changes from one generation to the next.But you evolved from what was essentially a single-cell organism, a protozoan, into a vertebrate, then a mammal, before you got to human. It only took 9 months, because of the billion or so years that protozoans have been practising, at evolving into invertebrates, then vertebrates, then reptiles, then mammals, then humans.
The large leaps were merely concatenations of millions of small jumps.Enough of them are large leaps - the difference between a frog and a dog, say.
Not entirely, by chance and circumstance, it plays a part, and it's important.Hipparchia said:Evolutionary changes take directions dictated by chance and circumstance.
Right. I was trying to make the point that we're really just specialised protozoans.Fraggle Rocker said:properly speaking it is not evolution. Stop calling it that before you get nailed for it too.
I have not forgotten it at all. They are part of the circumstance.Not entirely, by chance and circumstance, it plays a part, and it's important.
You keep forgetting that organisms are agents,
How come life can be adaptive, but not purposeful?
Can anyone explain this? I don't understand how adaptation can be without adaptivity.
There are one or two contributors who seem assured of their understanding of the tricky subject of Life and its evolution. Maybe one can point to the logic problem here.
If lifeforms can use things, is life purposeless - i.e. it doesn't use things just because it uses them...this must make sense to someone here.
You still haven't explained how life and the way it evolves is without purpose.
Adaptation is not adaptive...
Use is not purposeful...
There is no planning, no strategy involved...
Is that right? Adaptation doesn't involve planning, or use, or purpose?
I was under the impression that adapt means use, and that adaptation means purpose. Obviously this is incorrect. But why is adaptation adaptationless? When an organism uses something, it isn't using it?
Evolutionary theory obviates the need for an external agency?But evolutionary theory obviates the need for such an agency.
Evolutionary theory obviates the need for an external agency?
So Evolution is the "external agency"?
Life just sits back, and evolves because of "Evolution"?
Life doesn't use anything, or adapt anything, evolution does it all?
Evolution must be like something that stirs a big pot. Life is just a bunch of passive chemicals, that would dissipate, if Evolution wasn't there, stirring away.
Evolution is process that has no goals. You seem determined to find an agency where there is none.
If, during replication, a mistake occurs-say an organism axquires a new gene- it is not planned or controlled; it just happens. If you want to insist that the evolutionary process is an agent in some sense, so be it. But is it a blind, purposeless agent. So, insisting that there is an agent at work adds nothing to the explanation.
Evolution is not "an agency". Selection is an agency, so is adaptation, and variation of genotypes. Life is active, life therefore can't be any agency...??Myles said:If you want to insist that the evolutionary process is an agent in some sense, so be it.
Natural selection is blind. Evolution is blind the way a roulette croupier is blind, or a casino is blind.Myles said:But is it a blind, purposeless agent. So, insisting that there is an agent at work adds nothing to the explanation.