A Scientific Response to Creationist on: Kinds

[Duke Guilmon]

[quote='ThePaleolithicFreethinker' pid='657560'] Its bad to see that I already put the defenition there.

And? I didn't say that no definition exists. I said that the definitions are vague and "there's no single definition suitable for all purposes." Your own sources support me on this. You're arguing against a straw man.

A. It does not say failing in indication. Did you read the source from Berkeley I gave you? Also it means failing to reproduce.

Yes, I did. Did you read past the first paragraph? That source also agrees with me that the BSC has ambiguities and isn't suitable for all purposes.:

That definition of a species might seem cut and dried, but it is not—in nature, there are lots of places where it is difficult to apply this definition. For example, many bacteria reproduce mainly asexually. The bacterium shown at right is reproducing asexually, by binary fission. The definition of a species as a group of interbreeding individuals cannot be easily applied to organisms that reproduce only or mainly asexually. a dividing streptococcus bacterium

Also, many plants, and some animals, form hybrids in nature. Hooded crows and carrion crows look different, and largely mate within their own groups—but in some areas, they hybridize. Should they be considered the same species or separate species?[quote]
[quote]B. So what? A female liger is fertile, some species can interbreed some can't. Are you suggesting tigers and lions are the same species? If so source the paper

Is a liger a species?

C. we can tell different species in paleontology. There is more than just DNA. Anatomical structures are another way. This is sad to see that on your part.

We apparently don't classify fossils by their reproductive capabilities, so give me the definition of species used in paleontology. If you can do this, you'll further support my claim that "there's no single definition suitable for all purposes."
[/quote]

The word species isnt vauge then. We can define it, that is the point. Yet no one defines the word kind, because when you do you end up making it easier to debunk.

also.

A. We are talking about the definition of species, not how to separate different species. Never did I say reproductive capabilities are the only way, there are many others.

B. Yes the liger is a species. We can tell it is a different species.

C. The part you put in bold explains the difficulty of apply species, not that they can't do it. There a certain things a animal most have from its relatives to make it a different species.

D. http://www.theguardian.com/science/lost-...rs-fossils

Also let me do the quote mining for you.

The real question of course though is how can species be recognised and identified? This is where things get complex and disagreements can arise between biologists, since species are more fluid than elements or atoms. By definition, species evolve and over time populations change, diverge and lineages split into new species. Humans now might be considered the same species as humans ten thousand years ago, but it's also undeniable that we have changed in that time. You might well be familiar with the definition of a species that runs roughly as "a group of animals that can reproduce and have fertile offspring", and that's all well and good, but it's also profoundly limited.

Plenty of species don't have sex (bacteria, some lizards and sharks, many plants) so this definition is irrelevant for these cases (and there's tons of them). We can't separate out fossil species by this definition either, and some things can produce fertile offspring despite being very different in appearance, or being separated by another non-genetic barrier (behaviour, geography etc.).

Thats what you were going to point out be here is the rest that destroys that notion that we can't tell different species in paleontology.

To account for these and other issues, biologists and palaeontologists use a whole raft of different 'species concepts' that can help separate species from one another and also identify new species. We might recognise them as separate because they can't interbreed with close relatives, but also on their anatomy, behaviour, genetics or evolutionary history. This can naturally lead to disagreement with which definition is best for a given putative species, or just how much difference is required to identify a separate species, but in general agreements are quite broad, and quibbling comes down to certain problematic specimens or populations. It's also worth noting of course that many of these definitions line up – tigers can't produce fertile offspring with leopards, but they also have anatomical, behavioural and genetic differences, and the leopards in Africa at least can't physically mate with tigers and so on.

The task however is vast, the number of taxonomists is shrinking and while new techniques make it easier to identify possible new species, it also means we are finding new species long hidden and some species classified as being a single entity apparently consist of multiple species. Even large mammals and birds are turning up with some regularity, so what hope have we of identifying every kind of parasitic worm, fungus or bacterium? Identifying a new species is only the first step, as then it needs to be formally classified and named, and yes, that's the cliffhanger to the next post.