And the DNA evidence doesn’t simply tell us that they are vaguely similar. It is much more specific than that.
This is not mere interpretation. Anyone who tries to portray the DNA evidence as mere similarity is either lying about the evidence or not even examining the evidence.
I thought I would add one more analogy that might help others understand the whole microevolution v. macroevolution debate.
A good analogy is language. As many of you know, the Romance languages descended from Latin. We see different but similar words for the same things shared by these languages, and that is due to their shared common ancestral language. During this development of modern Romance languages there could never be a generation that was not understood by the next generation. There was no time when there was a generation born that spoke modern French, but could not be understood by their parents who spoke primitive French. I doubt many English speaker would completely understand someone speaking middle English, yet there is an unbroken chain of English speakers that could all understand each other from one generation to the next (also noting that English is not a Romance language).
At the same time, these branches of the Romance language tree terminate at languages that are not intelligible to the other branches of the tree. A Spanish speaker is not intelligible to a French speaker, as an example. This is because each language developed separately from the others. Small changes from generation to generation accumulated to the point that when those two groups met each other they could no longer understand each other.
This is analogous to how microevolution accumulates to produce macroevolution. If a population is split into two populations that no longer interbreed, then you will see different mutations accumulating in each population. Over time, those mutations accumulate to the point that those two separated populations are now separate species. Microevolution accumulates into macroevolution when combined with a barrier that prevents interbreeding. The genetic differences between chimps and humans are consistent with the accumulation of microevolutionary events.
Thank you Bill.
dt
Thank you…it’s precisely the DNA evidence I’m trying to understand, so again thank you and BioLogos for this forum.
Thank you T Aquaticus…I like that language analogy.
Now my question was more focused on the idea of on- going stasis. As I understand the phenomenon of stasis, it is the status of a species to maintain itself intact not being substantially changed by evolution into another species. And such stasis in the fossil record was the reason (largely) for Gould’s advancement of the argument for “punctuated equilibrium” …OK, I’m sort of taking off on that idea and asking this question…in my previous post I postulate the idea using horse to hippo asking if such a LIVING example of evolution exists. Here it is again in another formulation. And trust me, I’m not trying to incite or make anyone mad: I’m really trying to get information and if it is non existent … well, it is what it is. So here it is again: Are there any “living” creatures (I’m not asking a fossil question) or plants that can show a gradual change that demonstrate slow change (and are now living) that demonstrate discrete change so that one can identify enough changes in “advanced” individuals, so that the changes cumulatively can be shown to have created a new species? This would require not four or five similar looking individuals and then a jump…I’m wanting to know a stasis question answered…are there living individuals that show a lineage such that a new species can be seen … living… that demonstrates progress from one species to a clearly different species. Given the phenomenon of stasis, I think the question is not absurd. I doubt if an illustration can be shown but I ask here on this forum because the writers are very knowledgeable and understanding of a rather slow guy like me.
Hmmm…Look up studies on the planktonic foraminifera.Their plentitude and ready fossilization seem to allow solid historical data on evolutionary differentiation.
From what I read in “Finding Darwin’s God” Gould’s punctuated equilibrium has been deflated. But I am not a biologist, I only act like one on the internet.
There are several examples on the page I linked in my post above. I like the example of the cichlid fish. The new species might actually be able to interbreed with the parent population but behavior changes prevent the fish from making whoopee. It can be this sort of subtle change that leads to a new species.
This was an interesting story I read a couple of years ago:
https://news.utexas.edu/2014/10/23/anole-lizards-evolution-florida
And another lizard story from a few years prior:
Cichlid fish are a treasure trove of evolution in process. And another story with some guppies:
Deflated is a pretty good word choice, Bill. There are certainly periods of more rapid evolutionary change, but those periods are still measured in millions of years (and not four thousand!)
Your questions are often based on flawed premises, and that explains why they are sometimes hard to answer. In this case, I think I understand you to be asking about examples of rapid speciation that have occurred fast enough to have been observed in over human history. I may be wrong, though: maybe you are asking about currently living species and how they came about over the long stretches of time that is required for “normal” speciation. Either way, stasis is not really relevant. Sometimes there is rapid morphological change (i.e., change in physical form) in a lineage, and sometimes there’s very slow change, and sometimes there’s no change at all, for eons. I don’t see how that makes a question about rapid speciation more or less reasonable. Maybe it would be helpful to think about plate tectonics or the formation of mountains or river deltas. We know these things happen and we know a bit about how, but that doesn’t mean they always happen everywhere, and it doesn’t mean they always happen at the same speed.
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.
Guppies in Trinidad: rapid evolution and experiments involving “transplantation” of populations between habitats
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)
Cichlid fishes in African rift lakes
Nearly instantaneous speciation in plants
Various populations on the “sky islands” of Southeastern Arizona
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.
Regarding existing species that are evolved from one another, it requires a lot of time so it is difficult to see from our limited view, but a fascinating example is perhaps seen with brown (grizzly) bears and polar bears. Polar bears have only separated into a sub species over the past 100k years or so , but given longer in separation might well totally separate into a new species. However with climate change ad melting ice, the subspecies of polar bears may be absorbed back in the population of brown bears and go “extinct” though some of their genes may live on.
Here are a couple of papers from a few years ago on rapid (EXTREMELY rapid) speciation occurring due to intense natural selection (divergent selection; the phenomenon is called ecological speciation).
In plants on Mt. Etna
In fish in the Baltic
This has been seen in sticklebacks too, and recently examined at the genomic level.
Note that guppies, cichlids, and sticklebacks are all different fish.
No, it would be not exhibiting significant changes in allele frequencies.
You’re welcome. Just don’t believe anyone who describes it as mere similarity.
Thank you Argon.
Now please remember, through my posts above, and often misunderstood, I’m not … repeat not… asking a differentiation within “kind” question. I’m asking a transition from one species to another species question.
But I will look at your suggested illustration.
Everyone has been very helpful in helping me understand and answer some of my questions.
Several of us have put forward examples of speciation either in progress or having already occurred. This is not a detailed account, but yet another link for several examples of observed speciation.
http://www.darwinwasright.org/observations_speciation.html
If you are looking for broader speciation events, it will be important for you to define what “kind” means.
I understand, but realize that the differentiation within the made up non scientific “kind” is that it is first step to moving to a new species, with more time required to do so, by which time the original species is likely extinct. We see the leaves and buds, not the stems.
If a species is well adapted to its environment then there are fewer and fewer changes that would increase fitness. This does tend to promote stasis.[quote=“senatorthomas, post:45, topic:36182”]
Are there any “living” creatures (I’m not asking a fossil question) or plants that can show a gradual change that demonstrate slow change (and are now living) that demonstrate discrete change so that one can identify enough changes in “advanced” individuals, so that the changes cumulatively can be shown to have created a new species?
[/quote]
There are many known examples of observed speciation, here and here. We have seen the process of one population dividing and turning into two populations that don’t interbreed or only rarely interbreed. We also have examples of domesticated species, such as horses and donkeys. Due to different mutations accumulating in each branch, the horse and the donkey can no longer produce fertile offspring. They are two different species.
Another interesting example is lab mice. In the past, scientists set up their own inbreeding colonies of mice to use in the lab. Some of these colonies of mice were established decades ago. Some decided to look at their genomes, and they found that those colonies are evolving their own genomes, accumulating different mutations in each colony. Those papers can be found here and here.
Try “Family”. Maybe that narrowing gets me what I’d like to know. Thank you.
You are terrific. Thank you for your insights and links.
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