Increases in Genetic Information

Hi, Jbozz.Welcome to EvC!You bring back memories of when I first started posting on EvC from the PCs at the information commons in the Harold B. Lee library, during my breaks between classes. It was my last semester at BYU, and I was still stressing out about whether or not it was okay for a Mormon to accept evolution. I don't know: can they? To your knowledge, has this ever been subjected to any scientific study at all? In your first 9 posts here at EvC, you've made a big deal about how you won't accept scientific conclusions that aren't verified by multiple, independent research studies. Yet, you didn't even make it through those 9 posts without violating those standards yourself.I submit that the actual criterion you're using to determine the validity of ideas is the degree to which they conform to your pre-existing beliefs. Reproductive isolation between humans and apes works well for your beliefs, so you accept it without looking for scientific verification; but, macroevolution doesn't square with your pre-existing beliefs, so you demand all kinds of scientific rigor there.Maybe I've misjudged you (in which case, I'm terribly sorry), but that's the impression you've given me so far. That's one definition of "species." It isn't perfect. But, it doesn't need to be: classification is really just for our convenience as researchers. There are enough differences between lions and tigers to justify a cataloging system that distinguishes them.If you would be more comfortable thinking of them as subspecies, then go ahead and do so. It wouldn't really change anything, would it? Do you have any idea how difficult it is to confirm that two populations CANNOT interbreed? Think your way through the studies you would conduct to determine that they CANNOT physically or genetically interbreed with each other.Would you put them together in a cage and wait to see if they would mate?
What if their mating seasons don't align? They wouldn't be ready to mate at the same time, so, even if there are no genetic barriers to interbreeding, they wouldn't interbreed.
So, what then? I guess you'd have to collect some sperm and use artificial insemination.
Sometimes, female animals don't take to artificial insemination unless they actually copulate with a male. So, you need a sterile male of her own species to mate with her.
But, you have to check and make sure your sterile male is actually just shooting blanks, so you know that he isn't actually getting her pregnant.
Then, you get to see if any eggs are laid or babies are birthed. And, then, you get to monitor the offspring for any major health problems or infertility issues.
Or, you could develop a "paternity test" to determine that the offspring is, indeed, a hybrid.Good data is hard to come by, and scientific rigor exhausts lots of resources and takes lots of time. In the meantime, science exists precisely so we don't have to wait until we know everything before we can start reasoning, learning and using our data. It's only logical to base our worldview on the little, imperfect evidence that we have.

Hi, Bozz. This is what I was talking about right here: As far as I'm aware, it has never been shown that humans and chimpanzees cannot have fertile offspring (research ethics make it impossible). Yet, you seem to have accepted that humans and chimpanzees are not the same species.So, although you told Dr Adequate that you won't accept scientific ideas that haven't been demonstrated by multiple, independent studies, you did accept one scientific idea that had not been demonstrated in any studies. This is a double standard: you can't demand scientific rigor from your opponents, then throw around untested ideas yourself.In reality, very few (if any) species are described based on reproductive isolation: it's just not practical. Most of the time, we describe things as new species if we think they are distinct enough to be considered different species. It's not a perfect system, but nobody has claimed that it is, and it isn't particularly important for the system to be perfect: it just needs to be good enough that we can use it for our purposes. Let's be a little more cautious here. Nobody "proves" anything in science, because we are always, of necessity, working with imperfect and incomplete information. What we do is show that evolution is a better explanation than anything else we can think of.So, if we see two populations that are very distinct from one another, a likely explanation is that they are distinct species. But, when we look at the diversity of life, we don't always see such clear distinctions. Sometimes, reproductive barriers are complete; but, sometimes, they're "leaky" (hybrid offspring are not fertile, or are sometimes fertile and sometimes not). The Theory of Evolution isn't based on the definition of "species." It doesn't strictly matter what the word "species" means: the idea of a "species" is just a convenient way to sort information so we can use it for research or other purposes.If life evolves, we actually expect our classification system to be messy, because we expect to see that things are still in the process of evolving and speciating. So, our inability to confidently classify species, and the lack of a solid definition for "species" are actually very much in line with our expectations.