MattofVA

As you are all probably aware, almost any given group of morphologically similar organisms comes from one divergence form the ancestral group. Something of an exception to this that I am aware of is the fact that wings/flight have evolved on at least three separate occasion-insects diverging from other arthropod ancestors, birds diverging from reptiles, and bats diverging from other mammals. These examples apply at the level of classes and orders. So, would it be possible for, say a new separate animal kingdom to evolve from protozoans or plants in the future, or could a new kingdom of plants or fungi evolve once again from protozoans? Could it even be happening now? of course, if it is possible,then we would never get to find out, since it would take at least a few million years to be visible(this is why I don't like my mortality). Could another intelligent species, or another primate-like order arise from a non-mammal lineage or as part of another kingdom? If anyone needs clarification on what the hell I just aksed-then ask for clarification. I think it's clear, but I need to know what if any particualr point is not clear.

faust

I need some clarification most certainly.

There are a few issues i had with the statements you made and the presumptions involved.

These two sentences embody 2 different ideas. In the first sentence you are correct in saying that on a morphology basis those with closer morphology are likely to be related (species of beetle, species of hominid, etc). In the second sentence you discuss a different issue altogether, "convergent evolution". This is not an exception to the first idea, it is a different idea. Convergent evolution is the case when two -unrelated- organisms share a similar morphology, i.e. organisms whose ancestors did not possess an adaptation in common, but through speciation and natural selection, arrived at the same solution to the same problem.
That is, there is no common ancestor of birds and bats that ever flew. This is the important phrase "no common ancestor". No species along the road to speciation, that gave rise to both birds and bats, ever had the function of flight. Flightless mammals evolved, some solved the problem of flight in various ways, bats, squirrels, etc. Flightless dinosaurs evolved into reptiles and other groups. One of those groups solved the problem of flight by adapting existing structures into wings and feathers. Insects are in the same boat.

I'm not sure what you're getting at here, so i'll need some clarification. My guess is that are you wondering if it's possible that convergent evolution may, eventually, adapt a plant or protozoan, through natural selection, to exhibit similar morphology to an existing animal or animals. It is possible but highly unlikely. A plant put under selective pressure by its environment might eventually adapt to movement, some exhibit phototaxis, some adapt to lack of nitrogen by catching insects, etc. It is entirely possible that eventually a plant could end up as a photosynthetic type movable creature that ran around supplementing its diet of CO2 with predatory (against stationary plants, and moving animals) aspects. It would more than likely look like existing animals, since convergent evolution tends to solve the same problems in a similar fashion (eyes evolved at least three times. All different, insects very different.).

This is unlikely because that niche (moving, hunting/grazing) is already well filled, thus leaving little room for competition from a not-so-good plant/predator. In the cases of convergent evolution that we see already, due to environment, there is little overlap between two different convergent adaptations. Squids rarely run into wolves, and both can see. Insects evolved eyes first, but they are quite removed from vertebrates, not much competition.

Absolutely! The main issues to think about are, intelligence similar to ours would likely arise from closely related critters (apes, etc.) Except that we are direct competition for them. We'd outcompete them.
You would need a species that we would not compete with very often. It would need to evolve sophisticated neural networks for an unrelated task, and then make that (small) leap to co-opting that existing sophisticated neural network (brain) to be used to construct abstract thought. Accordingly, ocean creatures under such pressure, actually exhibit profound intelligence, dolphins, whales.

Could it happen with plants? Maybe, if conditions were right, for long enough, and no other avenue of advantage was taken by chance, and the selective environmental pressures hit just right.

You must ask yourself, would you end up with a hot, blue skinned female plant, that liked to get naked often? Well, we can always hope

Doubting Didymus

Mmm, almost. There are actually many exceptions to that 'rule', wherethe same trait has evolved many times without being derived from a common ancestor. The eye is one such example, being present in a number of forms, and not all derived from the same eyebearing ancestor.

Depending on how you define "flight", there are a couple of others as well (Nonbat mammals, fish, snakes, frogs), though they are usually just glorified gliders. (thats what we call an 'extant transitional form')

I'm not sure what you mean by that. I'm going to have to ask for some of that clarification you promised.

We-eeelll. Sort of. There are three qualifyers to that 'sort of'.

1) the taxonomic classifications as far back as kingdom are largely concerned by how far back in time the group shares its common ancestor. By our current arbitrary taxonomic guidelines, it is certain that the new "kingdom" would first be classified as a simple new species. As time went on , and the new species has founded many other species, we might eventually call it a family. As the species diverge more and more, and into distinct monophyletic groups sharing distinct morphological features, we might call the whole lot an order.

2) the new multicellular group would certainly NOT be identifiable as a 'fungus', 'plant', or 'animal'. It would be an entirely distinct and unique group of metazoans, which might have any number of distinct features. It's possible it would be similar to one of the three current kingdoms, but probability is against it.

3) it is not likely that a new multicellular lineage could arise from protozoans because all the good niches are already taken. To evolve into a decent metazoan with organs and tissues and everything would take a VERY long time, and if it has to compete with already developed organisms with a several billion year headstart, and which already have teeth, its luck is looking grim. A catastrophic mass extinction that knocks a good proportion of all multicellular lineages out would be a great help.

Primate-like? Its possible I guess, but I can't see why evolution would favour specifically primate form creatures. Another intelligent species? It's entirely possible. However, knowing what we do about the energy costs of a complex brain, it's unlikely that fungi or plants will manage it any time soon, without some very large scale alterations in the energy generating areas. Amongst the existing brainy fellers, all thats needed is for high intelligence to be a significant fitness benifit, which seems fairly likely to me, but far from a certainty.

MattofVA

Your replies were quite lengthy(duh-I should have anticipated this-lengthy queries call for lengthy replies). I"ll try to reply to as much of both your posts as I can in one post of my own.
First, off I am a layperson. I work in broadcasting. I have always been interested in biology and physics, but only in the last few years did I shake my absurd childhood religious indoctrination to an extent that allows me to indulge my interests in areas that supposedly could send me to H_E_Double hockey sticks. This was after I chose my (second choice interests, more or less) major and minor in college(Communication and TESOL, respectively). I wish I would indulged more science earlier though, somehow. I have familiarized myself with the evidences for and to some extent the mechanisms behind evolution. I just enjoy now indulging the unanswered hypotheticals. Unfortunately, I suppose it must all be mental masturbation, I am 25 and can no longer afford to go back to school or anything while paying off the debt from my first round of higher education as well as a car, and while still having a religious family that I otherwise get along quite well with.

Now-to the actual matter at hand.

faust-I think you interpreted my query correctly. I was aware that organisms with similar morphology don't always have a common ancestor. I don't understand though why you say that convergent evolution is an entirely different issue-it still seems to be an exception to the rule(or more correctly could we say "general principle") of phylogeny/morphology being indicative of one another. unless there are many many more examples than I am aware.

Your interpretation of my question about a possible future new kingdom was correct. Yes, I meant convergent evolution producing a whole new lineage of multicellular organisms similar to plants or animals. It was a good point you brought up about these new creatures having a hard time finding a long-term niche. Maybe that is why we have never observed such a phenomenon-even in the fossil record.
I guess the overall probabilities are against another intelligent species arising-even from amongst the primates while we are still around, or anytime in the next four billion years until our sun goes nova. Didymus would seem to agree.

Didymus-a lot of what you said was very akin to faust's points. You mentioned that the eye evolved three separate times like flight(I don't count the flying squirrel as actually flying, I would agree that it is just a glider.). What were those three separate occasions that the eye evolved? Was it mollusks, arthropods, vertebrates?

Do most of the people in this particular forum have an occupation or more than incidental interest in biology? Are you mostly well-informed individuals working/studying other fields. probably a mixture of both-perhaps it's time for a poll

faust

By the convergent evolution being a separate issue, i just meant that it's a separate mechanism that leads two species to have similar morphology. (birds have beaks - common ancestor, flies and squids have eyes - convergent evolution.) But I think from your reply that you seem quite comfortable in your understanding.
Looks like you're dead on with your thinking on the whole question.

Nah!!! Look at hominids for example, intelligence arose several times out of fundamentalism
I'm still holding out for the dolphins myself. Any creature that has sex for pleasure only is a species I can relate to.

You got the big three separate eye evolutions exactly right. Although I be if I thought about it long enough I could come up with a few more examples of independant eye-like organs in other things...

Ok, i give you the squirrel glider as a non-flyer, but i'll raise you a pterydactyl! So, true birds, insects, mammals, -and- dinos (twice from the same group, nifty.) There is speculation that arthropodia may have independantly developed flight more than once, but it hasn't been shown yet (so far as i know).

I myself am sort of a layman as far as traditional ed. goes. I'm 24, and my degree is in English Lit. with a minor in french, thus I was well grounded in science
I learned mah biologilatin' on da streets y0! I graduated with my BA in english lit and noticed that I couldn't get a job anywhere, so I had to fall back on my skills. I got a job working in a molecular genetics lab and doing bioinformatics. (Hey, why not? I demonstrated the required knowlege and skill, and i did have a degree heheheh ) Of course i'm dirt poor too, but i'm just a random guy who likes to learn about everything. So you could say my incidental interest in biology (and computers) got me my occupation.
I wouldn't consider myself a "proffessional", I'm younger than you!
I'm just the guy in the corner of the coffee shop with the laptop laughing to himself from time to time and checking out the hotties.

Doubting Didymus

I hate the fact that education is such a luxury in america. The prices you pay are absolutely disgusting, and this from the wealthiest government in the world to boot. Your government could easily afford to subsidise higher education, and it would reap nothing but benefits from doing so. Heck, If my meazly country can kick the price of a degree down to under ten grand, so can your bloated juggernaught of an administration. (what really pisses me off is that my country is going down the same abominable road.)

Well, if we pull our act together and stop obliterating every species we come across just on reflex action, there's nothing to stop a second comparably intelligent species from appearing. it only took us three or four million years to evolve from the chimp-brained australopithecus, given the right conditions. The only qualifyer is that high intelligence like ours IS a selection benefit under a number of different circumstances, which is not certain. Things like eyes, wings and especially heads, we can say are likely to arise because they have all evolved separately a number of times. High intelligence, on the other hand, has a sample size of a big fat one, so its quite impossible to say. There is a theory, championed by one Geoffrey F. Miller, that suggests that human brains are the result of runaway sexual selection that overpowered run-of-the-mill organism vs environment survival. Thats just an example to show that just because something has evolved once, doesn't neccesarily mean we can assign any reliable probabilities to its evolving again, neither high nor low probability.

Yes I know. We cross-posted, as it happens.

Well, I don't remember ever specifying the number three, but those are the most famous examples. I remember reading that the common ancestor of crustacians and insects posessed eyes of a sort, but that they were only a few lonely photocells. (I really should write my references down). That means that al the features of eyes that we consider important, the cup shape, the iris, any lenslike apparatus, are not derived from the common ancestor in insects and crustaceans, so you could point to that as a possible fourth. As for the gliding squirrel, just give it time.

'm a stoodent o' biology. I beat you both for youthfulness, too.

Claudia

Faust, I think that pterosaurs were not dinos. A separate group of reptils (but I have no idea of their relationships).

ps418

I think the systematics are a little fluid, but you're correct that pterosaurs are not members of the dinosauria. Both the dinosaurs and the pterosaurs, as well as crocodiles, are members of the archosauria.

Patrick