[Polymath20]

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What about selective abortions? This is the ultimate form of Darwinism. Rather than manually crafting babies, why not just abort all the ones with undesirable traits? Never give them a chance to spread their "bad genes" (<-this term is laughable)

[Monte314]

Can anyone here provide a formal definition of the term "speciation"? Absent that, this is all hand-waving.

[vampyroteuthis]

Originally Posted by sunitaishot To view links or images in this forum your post count must be 2 or greater. You currently have 0 posts.

In our species' history, there is only evidence of art and culture from approximately 50,000 years ago. From 200,000 to 50,000, no such evidence has been found. Some anthroplogists believe we became physically modern before we developed behavioural modernity. Early homo sapiens, according to some anthropologists, had similar lifestyle/social behaviour to early species, such as homo erectus and homo heidelbergensis.

I'm not following -- how does "similar lifestyle/social behaviour" indicate that there wasn't species change?

And yeah, for once I find myself agreeing with Monte. How is a change in species defined/identified?

[Polymath20]

	Originally Posted by Monte314 To view links or images in this forum your post count must be 2 or greater. You currently have 0 posts.
	Can anyone here provide a formal definition of the term "speciation"? Absent that, this is all hand-waving.

When two populations of a species can no longer produce fertile offspring. This most often happens through physical separation, but often can happen in a small environment with specialization (Darwin's Finches).

Think of how horses and donkeys can still reproduce, but the species have drifted enough such that they cannot produce fertile offspring. Same with lions and tigers.

Wolves and domestic dogs are technically still the same species, as they can produce fertile offspring*. Domestic cats, I think, do not enjoy this quality with any known wild cats. This is why the origin of domestic cats is somewhat mysterious. Domestic cats have fully speciated (dunno if that's a real word) from their lineage.

*It was recently shown that black wolves have a genetic mutation which came from domestic dogs, so obviously there is still the capacity for genetic communication between the two groups.

[Monte314]

This definition fails for asexual organisms. Try again.
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[Polymath20]

	Originally Posted by Monte314 To view links or images in this forum your post count must be 2 or greater. You currently have 0 posts.
	This definition fails for asexual organisms. Try again.

You can stick your head in the dirt and shout "lallalaallala" or do your own research at this point.

[IslandHead]

	Originally Posted by Monte314 To view links or images in this forum your post count must be 2 or greater. You currently have 0 posts.
	This definition fails for asexual organisms. Try again.

Species can be defined in multiple ways. It is a very hard definition, there is a lot of wiggle room. It is often difficult to define and not all concepts or definitions of a species is always applicable.

I'll give you some definitions

Species - "the most specific level in the taxonomic hierarchy"

Species - "A population or group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring, but do not produce viable fertile offspring with members of other such groups"
(By this definition humans and neanderthals could be the same species, hence why genomics would be used to further define the two species)

Prokaryotic species - "a population of cells with similar characteristics"
In this case you would start looking at the cell's structures, genome, and metabolic functions to help identify what the cell is. This is used on bacteria and some other unicellular, asexual organisms.

Eukaryotic species - "a group closely related organisms that can interbreed"

Morphological species concept - "a species is characterized by body shape and other structural features"

Ecological species concept - "Species is viewed in terms of its ecological niche, the sum of how members of the species interact with the nonliving and living parts of their environment"

Speciation - "an evolutionary process in which one species splits into two or more species"

Phylogenetic species concept - " a species is the smallest group of individuals that share a common ancestor; forming on branch on the tree of life"
This concept of species uses genomes to help define when different species arise.


However the process of speciation is so slow, when you zoom in on the timeline it's just a blur. An organism's progeny aren't a different species. Speciation generally occurs when either populations get split and separated, so that genetic information can't be shared between the two or more groups. Or when ecological niches open up, so that populations splits to specialize in different niches, an example being after the dinosaurs died out, mammals could fill the ecological niches that they held. And finally some molecular events can result in a reproductive barrier, such as cell division errors that create a polyploid organism (an organism with an extra set of chromosomes). This often causes the polyploid organisms to be reproductively isolated from the wild type organisms, allowing for the two populations to evolve into different species.

[Monte314]

Yes, this will all come back to the definition of "species" sooner or later. I must confess that these definitions all seem quite arbitrary to me. In fact, NONE of them passes muster for inclusion in a formal system, and at least two of them are clearly circular.

So... we really aren't discussing anything real here, are we?

[Polymath20]

	Originally Posted by Monte314 To view links or images in this forum your post count must be 2 or greater. You currently have 0 posts.
	So... we really aren't discussing anything real here, are we?

Ability to produce fertile offspring is petty specific, and it's relevant enough for humans, who are sexual reproducers.

As per the OP, which proposes speciation due ongoing evolutionary changes, there is nothing saying this won't or hasn't happened. Every species alive today is the descendent of another species. Sometimes species go extinct, but more often they simply change. Humans will probably not split into two parallel species (as with Neanderthal man and early man), but rather will perform a more linear type of speciation: the humans of today would not be able to reproduce with humans a million years from today.

I know you're smarter than these cheap jibes Monte. I am truly disappointed by your last two posts.

[sunitaishot]

	Originally Posted by vampyroteuthis To view links or images in this forum your post count must be 2 or greater. You currently have 0 posts.
	I'm not following -- how does "similar lifestyle/social behaviour" indicate that there wasn't species change? And yeah, for once I find myself agreeing with Monte. How is a change in species defined/identified?

Because some early humans held similar lifestyles and technology. Homo erectus was believed to be the first true hunter gatherer, and all subsequent human species were also. Species in this context are defined by morphology/anatomy.

[vampyroteuthis]

	Originally Posted by sunitaishot To view links or images in this forum your post count must be 2 or greater. You currently have 0 posts.
	Because some early humans held similar lifestyles and technology. Homo erectus was believed to be the first true hunter gatherer, and all subsequent human species were also. Species in this context are defined by morphology/anatomy.

If species is anatomically defined, then how do "similar lifestyles and technology" indicate sameness? I'm not following.

[Monte314]

Originally Posted by Polymath20 To view links or images in this forum your post count must be 2 or greater. You currently have 0 posts.

Ability to produce fertile offspring is petty specific, and it's relevant enough for humans, who are sexual reproducers. As per the OP, which proposes speciation due ongoing evolutionary changes, there is nothing saying this won't or hasn't happened. Every species alive today is the descendent of another species. Sometimes species go extinct, but more often they simply change. Humans will probably not split into two parallel species (as with Neanderthal man and early man), but rather will perform a more linear type of speciation: the humans of today would not be able to reproduce with humans a million years from today. I know you're smarter than these cheap jibes Monte. I am truly disappointed by your last two posts.

Your "definition" does not cover MOST of the organisms that live on the Earth.

[MrGates]

Speciation is incredibly variable and there are some hefty gray areas as to how this happens. We know reproductive isolation and reduction of gene flow can cause speciation. We know it only takes a few changes on a gene loci to cause significant change. Sympatric speciation is highly debated and some evolutionary biologists don't believe it even occurs. However, it's still up for debate; that two or more species can arise from a single ancestor occupying the same geographic location. We are highly intelligent life forms and could theoretically speciate through assortative mating. The argument to this is interbreeding, which entirely diminishes the point! I don't claim to even begin to know.

[Ravendicon]

	Originally Posted by Monte314 To view links or images in this forum your post count must be 2 or greater. You currently have 0 posts.
	Your "definition" does not cover MOST of the organisms that live on the Earth. Try again... or withdraw in PUBLIC SHAME.

Almost all definitions of speciation do not easily apply to asexual organisms. Even a PhD in evolutionary biology will tell you that. That's why the taxonomy becomes so damn complicated with bacteria. That is also why you rarely see the word speciation used when discussing bacteria.

Many biologists have tried adapting the definition to fit asexuality by defining it as "organisms with a high degree of genetic similarity," but this definition is so nebulous as to be meaningless.

[Monte314]

Thanks, Ravendicon. This is what I thought.

[KonTiki]

It might be worth considering possible mechanisms of speciation that could apply to humans. And I don't mean in the ecological sense already mentioned, such as sympatric vs allopatric (ie, separation) speciation, and hybrid sterility.

Consider a few possibilities:
Genomic incompatibility. The two species can mate, but there are genetic differences that prevent the pairing of parental chromosomes. This could involve either few or many changes including a difference in chromosome number, a transposition of a large block of DNA, etc.

Sperm-egg incompatibility. Sperm and egg surface proteins are evolving rapidly. (Though admittedly much more rapidly in marine creatures that broadcast their sperm into the waves.) It is possible that a human subpopulation could evolve sperm-egg protein recognition that excludes the general population.

Behavioral. This is the easiest to imagine. A subpopulation of humans evolves an elaborate mating ritual (eg, Ivy League educations) that excludes everybody else. Over time, genetic variants are favored that optimize success in different mating paradigms, leading to subpopulations that never mate.

Technological. I think this is the most interesting to consider for humans. Already there are way more premature babies and big babies born that never would have lived in ancient times. Eventually, we may get to the point where some people simply cannot reproduce without technology. (And no, I'm not talking about online dating sites!) I mean, they can't reproduce without artificial insemination, cesaerian births, or other tools I can't even imagine. At that point, you could have "natural" people and "technology-assisted" people. They might or might not be able to interbreed.

Lastly, I'll point out that the biological species concept usually makes a distinction between actually and potentially reproducing groups. This is something else to argue over, but some people would say that just because two groups could mate, they are only a single species if they actually do mate and produce viable offspring.

[sunitaishot]

	Originally Posted by vampyroteuthis To view links or images in this forum your post count must be 2 or greater. You currently have 0 posts.
	If species is anatomically defined, then how do "similar lifestyles and technology" indicate sameness? I'm not following.

When did I mention sameness?

I simply said that it is believed modern humans became anatomically modern before we became behaviourally modern. Homo sapiens who lived from 200,000 to 50,000 years ago are believed to have lived similar lifestyles to earlier species, since there is no evidence of art or culture from this period.

[gestalt]

The word "evolution" is abused really badly. Evolution is the brainless, mindless optimization process responsible for the production of all biological life on Earth, including human beings.

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All humans are adapting or not to selectional pressures, with various degrees of success.

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[MrGates]

	Originally Posted by KonTiki To view links or images in this forum your post count must be 2 or greater. You currently have 0 posts.
	It might be worth considering possible mechanisms of speciation that could apply to humans. And I don't mean in the ecological sense already mentioned, such as sympatric vs allopatric (ie, separation) speciation, and hybrid sterility.

Yeah, kind of like the mechanisms of evolution but specific to human speciation. The behavioral and technological mechanisms you mentioned is kind of the direction I was inclining toward. It seems most likely. I need to learn more, however, about the ways this can happen. It's an important question to ask I think. How exactly are we evolving and at what pace?

[Monte314]

If this undefinable "speciation" event/process actually occurs, then "we" are no longer "we", right? "We" will have become "them" (*).

If so, then it seems it would be less accurate to speak of the "evolution" of a species than the "evolution" of a .... je ne sais quoi... genus? Biological meme? Genre? And if "evolution" breaches the boundaries of higher taxa, (as in Goldschmidt's "Hopeful Monster" hypothesis), even this is too restrictive.

At some point, shifting from a gradualistic hypothesis to an hypothesis relying heavily upon macromutation begins looking like Catastrophism, which is philosophically unpalatable to the scientific community (despite the appearance of being more consistent with the fossil record than classical Darwinism) (**).

Of course, the observed examples of putative "speciation" people cite are in asexual organisms, for which the notion of species is so different from what it is for so-called "higher forms" that they are of questionable relevance. >HUMBUG<

(*) Hey, look: I used the Future Perfect in a natural way! *Dog is proud*

(**) Immanuel Velikovsky is grinning in his grave!

[Zsych]

	Originally Posted by Shadizar To view links or images in this forum your post count must be 2 or greater. You currently have 0 posts.
	Ready for a mind fuck. We're still close enough to chimps, that we can theoretically produce sterile offspring.

Through invitro? Has someone tried it?

Edit: It didn't work.

We probably are approaching the point where we could create eggs with specific pieces of animal DNA rather than just try to create a straight hybird (which may not be viable).

Oddly, this would be research I would oppose (unless the things weren't going to have any rights and were going to be killed at some point). I don't trust people to have the sense to not pollute the gene pool, given the chance.

[MrGates]

I remember reading somewhere that a humanzee was going to be attempted in the 20's or 30's but met a lot of resistance from society. Sure, we could reproduce with chimpanzee's. I was talking to a friend about this and we came to the conclusion that it is likely some government program has already tried this. Talk about planet of the apes!

[sunitaishot]

	Originally Posted by MrGates To view links or images in this forum your post count must be 2 or greater. You currently have 0 posts.
	I remember reading somewhere that a humanzee was going to be attempted in the 20's or 30's but met a lot of resistance from society. Sure, we could reproduce with chimpanzee's. I was talking to a friend about this and we came to the conclusion that it is likely some government program has already tried this. Talk about planet of the apes!

The Soviets under Stalin supposedly attempted this.

[Vagrant]

	Are we evolving?

Yes, but not observably.

At the moment, human society is not under strong selective pressures.

First world countries are usually only under sexual selection. Third world countries are more subject to selective pressures, but not as strongly as when humans were nomadic.

	Edit: It didn't work.

Not surprising. Humans and chimps have been separate for quite a while.

	At some point, shifting from a gradualistic hypothesis to an hypothesis relying heavily upon macromutation begins looking like Catastrophism, which is philosophically unpalatable to the scientific community (despite the appearance of being more consistent with the fossil record than classical Darwinism) (**).

We don't follow classical Darwinism very much any more.


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In case you guys didn't know, there is a way to prove that a species is not evolving. It's called
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In order to qualify as a non-evolving species, you must be subject to the following:

• Completely random mating. (Not true for humans)
• No migration. (Populations and countries around the globe are genetically different, and migration occurs. Again, not true for humans.)
• No selective pressures. (Excluding sexual selection, there are weak natural selection pressures on all of humanity. Even first world countries have people who starve or die from other causes. Not true for humans)
• Must have a large population (which we do! Congratulations, we meet this criterion.)
• Mutation does not occur. (Not true for humans)

We only meet 1 out of the 5 criteria for non-evolution. We, therefore, are evolving.

And yes, Hardy-Weinberg equilibrium means that all current living organisms are evolving. It does not specify the rate at which organisms evolve, but merely states that an organism is, or is not, evolving.

[NiTe Visor]

There are instances we have observed of microevolution occurring in humankind already. I cannot name the source, but we discussed one example in a phil science course that I took. Apparently, a socioeconomically diverse group of people was studied. Some of the people were wealthy and others had to strive to survive. These lower class people, being more challenged to survive, somehow produced offspring that generally outlived the wealthy class's offspring. There was an apparent correlation. We don't know the mechanism for this, but there are theories suggesting evolution can be caused, not only by natural selection, but also by genetic inheritance concering the parents' own unique course of life. It's called neo-Lamarckian theory.