It is claimed that whales evolved from an ancient rodent-like creature. If scientists know how macroevolution occurs and how whales evolved, I can’t see any reason why humans couldn’t (hypothetically) breed these “rodents” (given enough time) to eventually produce a whale. So can you explain how you would breed these rodents to get them on the path to whale-ness? What would you do first? Select rodents that like water? How would you bred them to live in the ocean permanently? Moving their nostrils to the top of their heads sounds tricky - how would you achieve that feat? And which breeding technique would you use to produce hind-legs fused together to form a tail?
"In just 26 generations, we managed to create relationships between the shape and size of (fruit) fly wings that were more extreme than those resulting from more than 50 million years of evolution." - Geir H. Bolstad, researcher at the Norwegian for Nature Research. (sciencedaily.com, "58,000 fruit flies shed light on 100-year old evolutionary question", 2015)
When breeders started inbreeding dogs, do you think they knew what the results would be? Of course not - they were stepping out into the dark, exploring the limits of the genome.
“Health and welfare problems in pedigree dogs can arise as a result of the deliberate selection for exaggerated physical features or as a result of inherited disease. While some of the following problems can occur in any breed, cross breed or mixed breed dogs, purebred pedigree dogs are at greater risk and appear to be over-represented clinically. This is mainly due to traditional breeding practices.
Difficulty breathing
Difficulty giving birth
Difficulty walking
Serious eye problems
Serious skin problems”
https://www.rspca.org.au/campaigns/pedigree-dogs/five-common-problems-pedigree-dogs
Most of that breeding was based on the desire to get more of a quality exhibited by an individual dog. Lets cross our most protective dogs, or herders or ratters or pointers and so on. Until the last 100 years I doubt if any dog breeder considered that they were involved in anything so abstract as exploring the limits of the genome.
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Edgar, there is no debate as to whether many species go extinct, in fact, all have except those still alive today. Agreed?
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And there is your problem. It takes nature millions of years to do this and humans have only been around for thousands. Given the current gene editing capability it is probably actually doable given, as you say, “enough” time. But what is your point? If humans can’t do it then God did? Not a very good argument. At one time people believed humans would never be able to fly, only the birds God created and look at how well that argument turned out.
You really don’t know anything about dog breeding. Breeders have a goal in mind when they selecte pairs to mate. They keep the offspring that have the characteristics they desired and discard the rest. Do you really think all of the different breeds are just the accidental result of “exploring the limits of the genome?”
An excellent example of why dog breeding doesn’t resemble evolution so why don’t you drop the subject?
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I also can’t see any reason why humans should be able to breed to produce a particular outcome. Breeding for a particular trait is quite different than evolution taking in a species in any of many possible directions. But if I did want to carry on that kind of breeding program, I might create an environment for the ancestral species that had a mixture of land and shallow water regions and provide more food in the water parts, then let the rodents go and then wait a couple million years to see what happened. Do you want to try to get that experiment funded?
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@jpm , @MarkD, @pevaquark
I think @Edgar has an excellent question here. Science has documented the fact that evolution has happened, but science involves more than this.
We have known for some time that gravity exists, but it took Einstein to show us how it works by bending time and space. We have known for some time that natural selection works, but survival of the fittest is not a verifieable explanation of how it works.
The evolution of some dinosaurs to birds is a most dramatic example of evolution, but science has not yet explained how and why it happened. Darwin likened natural selection to artificial selection, but that does not answer the question.
As it happens I posted an article on this forum about 2 years ago that addresses this issue. It was based on an article in Scientific American Jan 2017 issue entitled From Dinosaur to Bird.
Please resurrect my article so we can address the implied question of Edgar.
And what is his “implied” question?
What do you mean how and why it happened? It’s not really a question anyone can possibly answer. From our perspective changes to genomes are random and certain parts of the genome are under very selection pressure due to the environment. That’s it. There’s not really much that one can necessarily predict beyond rather simple things like Darwin did in predicting there should be some kind of insect that could possibly get pollen from the following flower:
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I agree with the way you put it. I’m not sure what the why question would be about that makes it different from the how question. Surely no intention is required.
Should I take your response to mean that the moderators of this forum are unwilling or unable to locate the article that I wrote previously and post it as part of this discussiob or tell us where to find it?
The most important thing they had was the hollow bones. Hard to tell which had feathers, but it is known this does precede flight. Oh and by the way… new evidence suggests that dinosaurs were warm blooded… or in between… and this whole idea of warm blooded versus cold blooded is a bit misleading anyway. The evolution of flight isn’t all that extraordinary considering it happened at least 3 times… among insects and mammals as well as from the dinosaurs… 4 time if you include flying fish which considering the difficulties involved is perhaps a more extra-ordinary feat than the other cases.
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You don’t have to be a moderator to search but the only thing I could find that you posted was this
Is this what you meant?
Excellent response. There are more groups which fly than you might think: Flying and gliding animals - Wikipedia
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This is what I meant. Thank you for your effort.
A very interesting study published in September, 2014 in Current Biology depicts how dinosaurs made the transition to birds is a long series of changes before they were able to fly. This summary was taken from a report in the National Geographic on the web.
The first step was the development of feathers. It has been suggested that many dinosaurs developed feathers, not for flight, but for warmth. They provide excellent insolation.
The next step was to get smaller and the evidence indicates that these fauna get smaller just as other dinosaurs were getting larger. While there is no clear reason for this, I would suggest that this could be based on warmth also. If the warmth problem was solved by feathers, just as mammals used fur, dinosaurs could get smaller. Gigantism of the Mammoths and the Saber Tooth Tiger is tied to cold.
When dinosaurs became small enough to be supported by their wings in the air they were ready to conquer the air.
Why do birds fly? There is an old saying, “Nature abhors a vacuum.” This means that when there is an imbalance in nature, nature3 seeks to restore that balance.
Let us imagine a world where there is no birds. Billions of insects would exist without any predators to keep them in check. Billions of meals would go uneaten. The God of nature found a natural way to populate an important ecological niche by the creation of birds.
The new study supports the views of George G. Simpson published in 1941 that suggested that “evolutionary innovation can lead to rapid diversification among species exploiting new environmental niches.”
Opening the air as a biological niche in a new way through flight undoubtedly saved bird/dinosaurs from the extinction suffered by other dinosaurs 66 million years ago.
This important example amply proves the power of ecology and the environment to shape and guide evolution through Natural Selection.
The first thing I would do is recognize that for large changes in a population, I would need a lot of genetic diversity. So I’d get my population of rodents as big as I can—hopefully a few million—and then let a thousand or so generations go by, so that lots of variation has time to build. Then I’d introduce selection for the animals that do best in the water, and after we got as much change from the population as we could, if diversity had gotten low again, we could repeat the whole process as many times as we wanted, or until the food ran out.
This is also why comparisons of evolution to human domestication is of limited use. Humans can increase selection pressure, and we could even increase mutation rate, but evolution requires vast populations and numbers of generations in order to get truly dramatic results. Think about the process of creating any truly complex piece of technology: nobody schemes anything up from scratch, you always see generations of ideas and trying different things to see what works.
(Note that rather than rodents, whales evolved from small, primitive ungulates, and their closest living relatives are hippos.)
Matthew @pevaquark, most people know that the dinosaurs went extinct because the climate of the earth grew colder. Are you claiming that this is false? Of course there is some disagreement as to the causes of this change.
However now we know that some descendants of dinosaurs did not go extinct, the avian dinosaurs who became birds. Can you say that the evolutionary changes that they went through were not related the to the ecological changes that killed off the other dinosaurs?
Yes, it is an educated guess, but isn’t that what science is about, guesses confirmed by the observed facts? To say that we cannot know something because of some theory is not science.
That’s not what that means.
Also the average density of the universe is one single proton per cubic meter.
Did you read my posts? Or maybe you did and misunderstood what I was saying which is entirely possible. Because the part right after that I said:
That’s pretty much all someone can possibly answer as to how and why we ended up with birds in the modern sense. That seems to be kind of like you were saying as well though I’m prepared to see several posts on ecology and evolution now.