By competing theories I mean actual scientific theories that have been published in scientific journals, peer reviewed and all that jazz. I am not considering Intelligent Design in that crowd.
I do not mean for this to be a debate on ID versus Evolution versus whatever. I am merely interested in other theories that have been put forward and have some merit to them.
My guess is that by definition - that is, by the way you have excluded Intelligent Design from the “crowd” - there are no other directions to go in. However, you may have overlooked the idea that Evolution itself is NOT a single theory. There are many competing theories within the whole concept. For example, some will theorize that Species X evolved from this, while others hold that it evolved from that. And so on.
I excluded Intelligent Design because it is not a scientific theory (despite attempts to window dress it as such). Certainly it is an opposing explanation for the origins of life but down that road you could pretty much make anything up you like and call it a worthwhile competitor to evolution.
The most famous is Lamarkcian evolution, but that hasnt been taken seriously in some time.
For the most part evolution just means changing over time. No one really disputes that, scientifically, but how that happens was a dispute. Darwin’s natural selection ended that dispute. Of course thats a little simplified. For instance, Im not sure Darwin addressed genetic drift and he certainly did not understand modern genetics.
For instance this cavefish and its regressive evolution would have dumbfounded Darwin.
It may be worth noting a couple points that, strictly speaking, fall outside of your question.
Evolution employs natural selection to explain the origin of species; evolution does not explain the origin of life. There are several competing theories on the origin of life, including panspermia: the idea that life was seeded on earth from space as opposed to having emerged spontaneously from Earth’s primordial soup.
There are various theories that attempt to explain the emergence of specific species that all count evolutionists among their supporters. For example, the origin of modern humans may be explained by the out-of-Africa theory, which holds that humans evolved in one place, Africa, who then migrated around the globe. Alternately there is the multiregional theory that holds that pre-modern humans migrated out of Africa first, and only later evolved into modern humans independently and in different locales.
I’ve said this before, over in GD – ID could be a valid scientific theory, properly addressing all the data from nature, ignoring tribal writings deemed by some to be inspired, setting up falsifiable hypotheses and testing them… If even one biological phenomenon could be shown to be incapable of being explainable by evolutionary processes, but explainable by the minimal assumption of an intelligent designer behind nature, it could get my vote.
The problem is that it isn’t – not as presently presented. It’s Stealth Creationism, and not even the “theistic evolution” that many devout Christians hold to be true, but the way to cherry-pick evidence and set up strawmen that has typified the so-called CrevO “debate”. When what you infer from a random verse in Jeremiah is more important than thousands of hours painstakingly accumulating data on the relative ages and characteristics of a given family of invertebrates, you’re not even pretending to advance a scientific theory. (That “you” of course, was apostrophic, not directed at Whack-a-Mole.)
There’s spontaneous generation, though this has rather largely been discredited.
Punctuated equilibrium vs. gradualism. Sexual selection has been much disputed in the past.
I’m not a scientist by any stretch, but I thought I read recently that studies in epigenetics were making scientists reconsider parts of Lamarckism for small populations.
Found it (but not smart enough to know what to make of it): http://www.sciencedaily.com/releases/2008/10/081030110959.htm
Panspermia is not a theory on the origin of life: It’s a theory of the origin of life on Earth. Life still needed to originate somewhere, and panspermia doesn’t say anything about how that occurred.
You mean it doesn’t have anything to do with pan-fried semen?
The answer to the OP is no. There are none out there that any scientist would take at all seriously. Evolution does a beautiful job of explaining every observed fact in relation to the development of life. Let that sink in. There are, simply, no observed facts that cause anyone to seriously question the theory. Does that mean we know everything? No, of course not. There are a myriad of details yet to be worked out, and debate continues, as is healthy with any scientific theory. The examples mentioned so far in this thread would fall into one of three categories, I think: (A) an old theory that’s been debunked; (B) debate over theories within the overall evolutionary framework; or © debates that surround evolution without actually being part of it.
Darwinian evolution had a struggle in Japan for a while, one of the key opponents was Kinji Imanishi.
Sure there is. For example; we could all be simulations in the computers of an advanced civilization, which was started a year ago. In that case, evolution never happened; it’s just faked. That’s certainly another direction to explaining the origin of species; it just suffers from the problems of having zero evidence, and being unnecessary to explain anything. So the “We’re in a simulation” idea never gets above the “interesting speculation” level. Evolution is THE scientifically accepted theory for the origin of species not because there are no alternatives, but because all of the ( massive amounts of ) evidence is in evolution’s favor, and none against, as Smeghead points out.
That’s the thing about ID; they want to be treated like an actual rival to standard evolution, and being presented in textbooks as such, without actually providing any evidence for their claims. They are demanding that they be respected and taken seriously, not trying to earn it.
Sorry for the minor hijack but this interested me. Why would Darwin have been dumbfounded by the adaptions of the cavefish in that study? The article says that he did not believe species of fish with eyes that start living in an environment of perpetual darkness would lose their eyes (‘regress’ in terms of their traits) because he could not see any way in which they’d be injurious to the fish. Later in the article, having discovered the fish do eventually adapt away from having eyes if they live in darkness, the scientists suggest that there’s a high metabolic cost involved in maintaining retinas which aren’t even being put to use. The writers of that study themselves conclude that for this reason such regression is entirely compatible with evolution.
Edit: Sorry, Darwin said that the fish might lose their eyes, but that if they did it would be a result of random mutation and not natural selection.
There is Endosymbiotic theory, popularized by Carl Sagan’s ex-wife Lynn Margulis, she has been working on it for decades.
Point taken. Thanks.
I’m missing something. You make this sound like random mutation and natural selection are incompatible. My understanding is that evolution and natural selection are dependent on random mutation. That is, a mutation will occur randomly (is there any other way?), and will result in an individual who is more likely to survive and breed, and eventually its descendants will overtake those who do not have that mutation. Isn’t that what natural selection is all about?
For example, fish originally got eyes by random mutation, and then prospered better than the fish who didn’t have that mutation. Am I mistaken?
Not exactly. Here’s the passage in question. If you go back to page 110 and read the section on effects of use and disuse, you can see that Darwin has this nebulous notion of “gradual reduction from disuse” that doesn’t include a mechanism. Remember, Darwin was working before the establishment of modern genetics, (in fact, his attempt to explain heritable variation was the almost-Lamarckian pangenesis theory), so he was really saying it that fish might lose their eyes, but if they did it would be a result of disuse and not natural selection.
Is that an alternative to evolution (or even evolution by natural selection in particular); or just an example of evolution (by natural selection) in action?
I believe the difference is that the random mutation (obviously many mutations in reality) which led to eyes was selected for–as you say, the fish with eyes prospered better than fish without. In the case of losing eyes, the question is, is eyelessness (or blindness with stunted or vestigial eyes) actually selected for–is it itself beneficial in some way? Or is it simply a question that a random mutation comes along and puts a spanner in the eyeworks, which normally would be highly deleterious and strongly selected against–the fish would likely not survive long enough to reproduce–but in a lightless cave just doesn’t make any difference one way or another, so that eventually most fish have had an ancestor with a random mutation in their eye-producing genes somewhere along the line and are consequently blind, not because being blind actually helps, but just because it doesn’t matter either way?