Evolution Debate

[Jackson]

I'm not replying directly to you, Jackson. I just wanted to ask if Bob B agrees with this and finds no problem with the logic.

My reply was in general not to you either. No harm no foul!

 

[Lord Vader]

My reply was in general not to you either. No harm no foul!

Oh no, I didn't mean to argue that I didn't like you replying to me... I mean that I specifically wanted to ask Bob B about your post. So much of communication is non verbal...

 

[fool]

The problem with evolution scientists is that they are searching for an answer and they say that positively under no circumstances can the answers ever be any thing the Bible says! It is like trying to figure out what 2+2 is and saying the answer can never be 4...

Strawman.
Anyone can make an accurate statement at any time.
Even if there reasoning is flawed their statement may be true.
Try again.

 

[bob b]

Hello. I'm not a biologist, so I wanted to ask what was wrong with the highlighted part? Many thanks.

I presume that you are referring to:

The same processes that give us different species also give us different phyla.

In the posting where this quotation appeared, aharvey gave us some examples, or at least some reason to believe that small changes can create new species. This is hard to refute in a situation where the people who are declaring and naming new species are the same ones who are telling us what the mechanism is which is responsible for creating a new species.

A hypothetical simple example may suffice:

Let us suppose for the sake of argument that a canine is born of an Alaskan Malamute father and a Chow mother. The result is like no other dog presently known. The scientists tell us that it is so different it is a new species. They also surmise that its DNA is considerably different (of course everyone's DNA is different from everyone elses so it is a subjective judgment as to how much difference constitutes a new species).

Finally the suggestion is made that the physical appearance plus the DNA difference is sufficient to justify the declaration that this is a new species. Of course the acid test of a new species is whether it can mate with a different species and produce fertile offspring which then can go on and produce more fertile offspring. Or is it?

Wrong. There are exceptions. These exceptions are ignored or else explained away as "not occurring in the wild".

There are always nasty exceptions in biology, but "most of the time" is the ready answer to them.

This is a rather long and drawn out discussion which should lead thoughtful people to realize that even in the "simple" case of small changes and "species" that people do not know everything about even the simplest and best understood area of biology: i.e. small changes.

But then they claim that the same poorly understood process which underlies small changes will eventually result, given unlimited time, to the huge changes which differentiate one phylum (body plan) from another. The process is obviously the same, as any fool can plainly see.

The used car salesman has stated the "hooker" as fact, and many people believe.

 

[aharvey]

I presume that you are referring to:

mined quote from aharvey: The same processes that give us different species also give us different phyla.

In the posting where this quotation appeared, aharvey gave us some examples, or at least some reason to believe that small changes can create new species. This is hard to refute in a situation where the people who are declaring and naming new species are the same ones who are telling us what the mechanism is which is responsible for creating a new species.

A hypothetical simple example may suffice:

Let us suppose for the sake of argument that a canine is born of an Alaskan Malamute father and a Chow mother. The result is like no other dog presently known. The scientists tell us that it is so different it is a new species. They also surmise that its DNA is considerably different (of course everyone's DNA is different from everyone elses so it is a subjective judgment as to how much difference constitutes a new species).

Finally the suggestion is made that the physical appearance plus the DNA difference is sufficient to justify the declaration that this is a new species. Of course the acid test of a new species is whether it can mate with a different species and produce fertile offspring which then can go on and produce more fertile offspring. Or is it?

Wrong. There are exceptions. These exceptions are ignored or else explained away as "not occurring in the wild".

There are always nasty exceptions in biology, but "most of the time" is the ready answer to them.

This is a rather long and drawn out discussion which should lead thoughtful people to realize that even in the "simple" case of small changes and "species" that people do not know everything about even the simplest and best understood area of biology: i.e. small changes.

But then they claim that the same poorly understood process which underlies small changes will eventually result, given unlimited time, to the huge changes which differentiate one phylum (body plan) from another. The process is obviously the same, as any fool can plainly see.

The used car salesman has stated the "hooker" as fact, and many people believe.

Since I have repeatedly observed that, unlike species, higher taxonomic categories like "phyla" are post hoc, largely arbitrary categorizations, it seems disingenuous at best for you to intrepret one sentence of mine to imply otherwise. It may be true that today, organisms in different phyla have been separated for so long that they have accumulated a large number of major differences from each other, but that doesn't mean that those huge changes all appeared at the same time. I don't expect you to understand this, as it's quite similar to the idea that just because sedimentary layers can be found worldwide today doesn't mean they were all laid down at the same time. It's worth noting that the more likely the members of a major taxonomic group are to leave a good fossil record, the less likely we are to see "sudden appearances" of that group, and the more clearly we see the episodic accumulation of those "huge differences." For example, as easy as it is to distinguish a mammal from a reptile today, the distinction becomes more or less arbitrary when you include fossils.

Incidentally, there have been very few attempts to use DNA to delineate species, for exactly the reason you provide: there are no objective criteria as to how different DNA of different species needs to be (see, biologists are already kinda clued into the distinction between intraspecific and interspecific genetic variation). And there probably will never be: speciation is not the same as evolution, and two populations can undergo a great deal of genetic differentiation and still be able to breed quite successfully, and alternatively two populations may have only accumulated changes at a couple of loci that nonetheless essentially prevent subsequent gene flow.