@sfmatheson’s post makes for an excellent thread that should be easy to find! Here’s the list contained within the post:
If you are looking for examples of speciation (or the processes that lead to it) happening rapidly and observably in living species, here is a reading list. These are examples of great scientific investigations, some involving decades of work and some involving experimentation in the wild. All of them examine rapid morphological change. The links go to basic overviews, but there are tons of articles on each of these topics that can keep you transfixed for days.
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Guppies in Trinidad: rapid evolution and experiments involving “transplantation” of populations between habitats http://www.guppyevolution.org/
Anole lizards in the Caribbean: one famous lab at Harvard is led by author of a very recent book on evolution and convergence
Stickleback fish in lakes and rivers all over the continent
Corn and teosinte (my own blog, from 10 years ago, great story)
Darwin’s finches (Peter and Rosemary Grant, two titans of evolutionary biology; the book about them won the Pulitzer almost 25 years ago)
Various populations on the “sky islands” of Southeastern Arizona
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My opinion is that only for very specific religious reasons would anyone even wonder about whether speciation happens or whether living species descend from ancestral species that were different from them. I don’t mean to claim that you are expressing real skepticism, but I do mean to say that there is no reasonable cause for doubt. Mountains form, sometimes slowly, sometimes quickly, by the accumulation of change. So do species. It’s not mysterious.
“It is interesting to contemplate a tangled bank, clothed with many plants of many kinds, with birds singing on the bushes, with various insects flitting about, and with worms crawling through the damp earth, and to reflect that these elaborately constructed forms, so different from each other, and dependent upon each other in so complex a manner, have all been produced by laws acting around us. These laws, taken in the largest sense, being Growth with reproduction; Inheritance which is almost implied by reproduction; Variability from the indirect and direct action of the conditions of life, and from use and disuse; a Ratio of Increase so high as to lead to a Struggle for Life, and as a consequence to Natural Selection, entailing Divergence of Character and the Extinction of less improved forms. Thus, from the war of nature, from famine and death, the most exalted object which we are capable of conceiving, namely, the production of the higher animals, directly follows. There is grandeur in this view of life, with its several powers, having been originally breathed by the Creator into a few forms or into one; and that, whilst this planet has gone circling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being evolved.”–Charles Darwin, “Origin of Species”
Ecology is based on Symbiosis. Natural Selection as Darwinian struggle or survival of the fittest is not Symbiosis or ecology.
Ecology is not “the war of nature” or survival of the fittest. The dinosaurs did not become extinct because struggle with other creatures, but because they lost their ecological niche because of climate change.
Natural selection produces both ecology and symbiosis. Mutations that favor a symbiotic relationship can increase fitness and thereby be selected for.
Umm, yeah it is. If there was no natural selection then we would have an infinite number of deer running around. Obviously, their numbers are limited, and it is limited by resources. Competition for those limited resources is survival of the fittest.
When you have limited resources and imperfect replicators you will have natural selection. It is unavoidable. The results of natural selection is the ecology we see today.
Natural selection in whatever form creates only one thing, different forms of creatures. It determines which flora and fauna will survive and thrive. On the other hand symbiosis and ecology is the way that nature exists. Natural selection does not create symbiosis and ecology, it is created by them. They provide the tools that natural selection uses to determine which forms of flora and fauna will survive and flourish. When we fail to understand the relationship between ecology and natural selection, we have a real scientific problem.
The reason that there are not an infinite number of deer is because deer are mortal. Clearly there is also a limited amount of food and drink also, but if the ecology does not change, the species does not change. It does not matter how many mutations that are, if the habitat does not change, the species does not change. Evolution is about Change, which is triggered by ecological change and not by genetic variation.
The dinosaurs when extinct because they lost their habitat because of climate change. Without climate change natural selection would not have selected them out. Dinosaurs did not lose a struggle against mammals. They lost a struggle against natural change.
Some dinosaurs evolved into birds, because they used natural selection to adapt to and take advantage of a new ecological niche. Again the change of ecology triggered evolutionary change, not a struggle against others for resources.
This is mostly wrong. I know that you are particularly interested in niche construction, and that’s just one window into why statements like these are inaccurate depictions of evolution and ecology. Niche construction (for those unfamiliar with the term) occurs when a population of organisms creates a new sector of an ecosystem. By its very definition, niche construction falsifies the claim that “natural selection does not create symbiosis and ecology.” This one-way view of evolution is simply false.
These statements are flat-out false. Genetic change is known to drive evolutionary change, and so is ecological change. Any view of evolution that asks you to choose between them is deeply wrong. There is no debate here.
It would seem to me that if there is no life there is no ecology. It is life that determines ecology. Furthermore, it is the competition for limited resources between organisms that determines what that life looks like, and hence what ecology looks like.
Simple math shows that this isn’t the case. Even with a limited life expectancy they can still increase their numbers exponentially until the universe is filled with deer. So why don’t we see this?
That’s not clear at all. The introduction of placental mammal species has clearly changed the Australian continent even though the environmental conditions haven’t changed.
But why did mammals survive?
Birds predate the K/T boundary by quite a bit, as do mammals.
Roger, I don’t know why you keep becoming so fixated. Ecologies (aka Ecological Niches) are defined by everything in them … including the arrival of a new predator, or a new rival for food, or for living spaces. And these rivals can be a different species… or a “new and improved” version of the original population!
The arrival of Homo Sapien into Europe is almost certainly the single most important thing in the extinction of Neandertal, wouldn’t you agree?
I have a different definition of niche construction. (Ecological) niche construction is where organisms modify a part of the ecosystem to create a niche which is better adapted to their needs.
For instance earthworms lived in water, but found themselves on land. They modified the ground in which found themselves do the can live in ground water and can be found in water above ground after a rain.
This is not evolution, this is ecology and symbiosis. Evolution is involved as a side product, so to speak, because evolution is about creating new species. The result of creating a new niche is normally the creation of a new species.
Like @T_aquaticus I so not just take someone’s word of a fact. There is nom need to take someone’s word for a scientific fact that has not been scientifically proven. I have not been able to find a single instance where genetic change drives evolutionary change and many instances , such as @gbrooks9 cited where ecology triggers evolutionary change.
I issue you the same challenge I have issued others. If genetic change does drive evolutionary change, prove it. Then there will be no debate.
I am not asking you to make a choice. The proven facts speak for themselves.
The claim is that genetic change can drive evolutionary change, and this is so well known that I think it should be considered basic evolutionary knowledge. Genetic change can create reproductive isolation overnight. (It’s what this thread is about.) This can result in evolutionary change for the same reason that geographic isolation can. Indeed, anyone who understands evolution at all knows that the isolation of populations can create new evolutionary opportunity. Really basic.
There are hundreds and hundreds of examples of genetic changes that can drive evolution. Some can be inferred(1) by studying examples of adaptation and speciation, some can be observed in (almost) real time in the wild(2), and some have been seen in lab evolution experiments(3).
It is estimated that as many as 4% of angiosperm species came about by the kind of instantaneous “speciation” that can occur in polyploids (angiosperms are famous for polyploidy). See links elsewhere in this thread.
See any of dozens of papers on the Lenski experiments and the many related experiments in bacteria, yeast, and so on.
Our knowledge of evolutionary genetics is always growing. We have a lot of data and hundreds of papers. None of the “facts speak for themselves,” not in biology or in any other science. What we can say with confidence is this: it is obviously false to claim that only ecology drives evolution. There is no debate about that, nor is there any good reason to want to have one.
@sfmatheson,
Do you think that Roger might be trying to get some special use out of the phrase “drive change”? But what could he possibly mean? …
@Relates
Certainly you understand that any life form that perfectly replicated its genetic code 100% of the time would never evolve at all. So I’m really not understanding why you are making such an extreme assertion …
2 studies concerning adaptive radiation which is a new theory. The studies are not specific, but general. The following explains what adaptive radiation is all about.
Adaptive radiation. In evolutionary biology, adaptive radiation is a process in which organisms diversify rapidly from an ancestral species into a multitude of new forms, **particularly when a change in the environment makes new resources available, creates new challenges, or opens new environmental niches.**
You cited the Lenski long term study on a strain of e. coli with which I am familiar. Again it does not back up you claim. Lenski used a long term study to see if a strain of e. coli would adapt to a difficult artificial environment and some of the cultures did. Since the changes were in direct response to the environmental challenge, it is clear that it is the this challenge which triggered the change, not caused it, but encouraged and enabled it.
So you claimed hundreds and hundreds of examples, but 2 of 3 citations provided none. I could not the third citation, even so it would seem to fall short.
How did you determine that these changes were in direct response to the environmental conditions?
If the E. coli did have this response system then they should have produced this change in the very first generation instead of seeing this change emerge after many years in the same environment.
If this is a direct response then every parallel culture should have the same changes. They don’t. Only certain lineages have these changes even though multiple lineages were in the same conditions.
The earliest genetics experiments dealing with mutations in bacteria demonstrated that there is no meaningful connection between the mutations that occur and the mutations the bacteria need. These experiments include the Lederberg’s plate replica experiment and the Luria-Delbruck fluctuation experiment. These are super famous experiments, and ones you should read up on (a Google search should find you all you need). In both experiments they found that beneficial mutations occurred in environments where they weren’t needed. For example, mutations that confer antibiotic resistance occurred in bacteria who weren’t even in contact with antibiotics. Even when the bacteria were put in contact with antibiotics, these beneficial mutations occurred at the same rate as they did in the absence of antibiotic. These experiments and others are what led scientists to conclude that mutations are random with respect to fitness.
So, maybe we are actually making progress on this “hurricane in a bottle”:
You make the more or less un-controversial statement that the direction of evolution is determined by “ecological natural selection”.
And so I surmise that your earlier posts that talked about “driving evolution” is all tied up in your meaning of “the direction” of evolution.
One:
the only way we can use “direction” of evolution as a concept is when we invoke God’s involvement. Otherwise, Evolution-without-God would obviously be directionless.
Two: But notice, Roger, that you are trying to expand this idea to also mean:
a) that rivalry and competition are not part of the process (which seems obviously false);
b) and that mutation is not the point of the discussion (which seems to be more a matter of religion than fact).
Newly arrived competitors for food and nesting or living places are obviously part of any ecological niche.
Roger, is there a reason why you think Ecology can only include plants and geology?
You haven’t commented on the obvious example to show you where you need to adjust your thinking: Neanderthals probably went extinct because of the arrival of Homo Sapiens.
And finally, there is Genetic Drift, which is also able to drive evolution… but without direction if Genetic Drift is not ultimately controlled by God:
I would agree. Mutations are random with respect to fitness, and they are constantly ticking away in the background. It is natural selection that determines which mutations are neutral, beneficial, or detrimental, and therefore natural selection determines which mutations will carry on into the future. Those selective pressures are a direct result of the population interacting with each other, with other species, and with the conditions of the environment around them.
If life only had direct and pre-programmed mutational responses to environmental cues then they would be in just as much trouble as not mutating at all. If their direct response failed then they go extinct. Random mutations, on the other hand, hold the possibility of nearly endless solutions to environmental challenges instead of a single or limited set of directed responses.
I agree with what you write, as long as it acknowledges that perception of “randomness” is from the perspective of human knowledge - - not the non-random actions of God for those scenarios we apply to God-guided evolution.