Posted on 03/31/2018 10:01:45 AM PDT by Simon Green
Martha Jones: It's like in those films: if you step on a butterfly, you change the future of the human race.
The Doctor: Then don't step on any butterflies. What have butterflies ever done to you?
Science fiction writers can't seem to agree on the rules of time travel. Sometimes, as in Doctor Who (above), characters can travel in time and affect small events without appearing to alter the grand course of history. In other stories, such as Back To The Future, even the tiniest of the time travellers' actions in the past produce major ripples that unpredictably change the future.
Evolutionary biologists have been holding a similar debate about how evolution works for decades. In 1989 (the year of Back To The Future Part II), the American palaeontologist Stephen Jay Gould published his timeless book Wonderful Life, named after the classic movie that also involves time travel of sorts. In it, he proposed a thought experiment: what would happen if you could replay life's tape, rewinding the history of evolution and running it again? Would you still see the same movie with all the evolutionary events playing out as before? Or would it be more like a reboot, with species evolving in different ways?
Gould's answer was the latter. In his view, unpredictable events played a major role in natural history. If you were to travel back in time and step on the first butterfly (reminiscent of the 1952 short story A Sound of Thunder by Ray Bradbury), then butterflies wouldn't evolve ever again.
This is supposedly because the variation we see in nature—the many different physical features and forms of behaviour that lifeforms can have – is caused by random genetic events, such as genetic mutations and recombination. Natural selection filters this variation, preserving and spreading the features that give organisms the best reproductive advantage. In Gould's view, because the series of mutations that led to the first butterfly were random, they would be unlikely to occur a second time.
Convergent evolution
But not everyone agrees with this picture. Some scientists defend the idea of "convergent evolution". This is when organisms that aren't related to each other independently evolve similar features in response to their environment. For example, bats and whales are very different animals, but both have evolved the ability to "see" by listening to how sound echoes around them (echolocation). Both pandas and humans have evolved opposable thumbs. Powered flying has evolved at least four times, in birds, bats, pterosaurs, and insects like butterflies. And eyes have independently evolved at least 50 times in animal history.
Even intelligence has evolved multiple times. The famous palaeontologist Simon Conway-Morris was once asked if dinosaurs would have become intelligent if they were still here. His answer was that "the experiment has been done and we call them crows", referring to the fact that birds, including the very intelligent crow species, evolved from a group of dinosaurs.
Convergent evolution suggests that there are a few optimal ways in which species can adapt to their environment, which means that (if you have enough information) you could predict how a species is likely to evolve over a long time. If you were to step on the first butterfly, another butterfly-like insect will eventually evolve because other mutations will eventually produce the same features that will be favoured by natural selection.
A recent study in the journal Current Biology seems to tip the scale in favour of convergent evolution. This study investigates how stick spiders have evolved in the Hawaiian Islands and provides evidence for different, isolated groups of animals evolving the same features independently.
Islands are often referred to as natural laboratories because they are effectively closed environments. Every time a species colonises a new island, a new independent experiment on adaptation takes place. An iconic example is the finches that have adapted to the various food sources on each island of the Galapagos, a fact that helped Charles Darwin develop his theory of natural selection. Some of these populations have even been caught in the act of becoming new species of finch.
Most of the stick spiders on the Hawaiian Islands have gold, dark or white body colouring as camouflage to hide from predators, such as birds. The scientists used the DNA of the various spider species to reconstruct the history of how they evolved. They showed that the dark spiders and the white spiders have repeatedly evolved from ancestral gold spiders, six times in the case of the dark spiders and twice in the case of the white ones.
Chance or necessity?
This study is a remarkable example of convergent evolution taking place in the same geographical area. It's reminiscent of the classic studies on Anolis lizards by evolutionary ecologist Jonathan Losos, who noticed lizards on different Caribbean islands had independently evolved the same adaptations multiple times. All this suggests that lifeforms living in a specific environment over a long enough time period are likely to evolve certain features.
But the evidence for convergent evolution doesn't rule out the role of chance. There is no doubt that mutations and the biological variations they create are random. Organisms are a mosaic of multiple traits, each with different evolutionary histories. And that means whatever evolved in the butterfly's place might well not look exactly the same.
The evidence isn't conclusive either way, but maybe both chance and necessity play a role in evolution. If we were to run the tape of life again, I think we would end up with the same types of organisms we have today. There would probably be primary producers extracting nutrients from the soil and energy from the sun, and other organisms that move around and eat the primary producers. Many of these would have eyes, some would fly, and some would be intelligent. But they might look quite different from the plants and animals we know today. There might not even be any intelligent two-legged mammals.
So just in case you ever find yourself travelling back in time, don't step on any butterflies.
Party on Dudes!
I have heard this claim repeated hundreds of times, mainly by Christian conservatives and such (e.g. Ken Ham). Is there a publicly accepted citation of this fact?
Since I am obviously not as educated as you, I will have to take the word of other genetic scientists, who say that the process you are talking about still depends on the original assumptions that were made when the process was first figured out.
However, there will come a day when we will know the truth.
Most all of those examples have been shown to be fake just like Global Warming. You have far more faith than me in a dying theory.
https://pterosaurheresies.wordpress.com/category/pelycosaur/page/2/
Please show one that has not been shown to be a fraud.
None that you would accept. Even science is giving up on evolution since it has so many trains size holes in it.
Here is a scientific discussion of those holes:
http://www.wnd.com/2001/02/8220/
http://darwins-god.blogspot.com/2012/07/evolutionists-are-losing-ground-badly.html
You have to admit to respecting the absolute fundamental belief in evolution and its twin Marxism.
First of all, you need to understand what a theory is. It is a conceptual framework that ties together all of the known facts and properties of the system in question in such a way as to enable the scientist to make testable predictions.
In this case, the system is the biosphere, and the changes over time which have been observed for millennia.
The variety and diversity of life all over the planet is the biggest consequence of the processes which are conceptualized within the theory of evolution. The Gobi desert and the deserts of the western United States are extremely similar in climate and appearance. Yet the plants that grow in each desert are completely different. Without the theory of evolution, there is utterly no explanation of why the flora and fauna of each desert would be so different when the deserts themselves are so similar. If you believe that one of the versions of the creation story is a scientific document, rather than a morality lesson, there is truly no explanation for the diversity of life over the world. There is no explanation for the existence of any species that is not mentioned in the Bible, etc.
And so on and so forth.
“They” just have not found all of the transitory fossils yet. /s
“Without the theory of evolution, there is utterly no explanation of why the flora and fauna of each desert would be so different when the deserts themselves are so similar.”
Really? Seems like a pretty big leap of faith to assert this.
“Actually, most of my work in the medical research field is incredibly dependent on understanding the theory of evolution.”
More details, please. How exactly does the theory of evolution apply to your research, and why is it necessary?
Not saying that there is no such thing as survival of the fittest - that is reality - but which species has ever evolved into another species?
Actually, not. Eukaryotes exist because, hundreds of millions of years ago, some of the single cell organisms found a survival advantage in living inside other single cell organisms. Similarly, mitochondria are bacteria that found an advantage to living inside other cells; there are still pathogenic species of the same bacteria (rickettsia) that became mitochondria. Chloroplasts are also ancient bacteria that found an advantage in living inside other cells. Plants arose when cells that contained both mitochondria and chloroplasts gained advantages by living in colonies, and the colonies in which some cells took on specialized functions gained advantages that other colonies did not have. Animals developed through a similar process.
In the study of microbiology, you can examine examples of microorganisms that are at different stages of the process of becoming true multi celled organisms. Euglena, for example, are single celled plants that form spheres. Inside the spheres, smaller spheres form. Dictyostelium live as single celled organisms until food becomes scarce. At that point, they send signals into the environment to communicate with each other, and they move together and form a small slug-like organism. And the cells specialize; eventually some of the cells become a stalk and others become a fruiting body, within which new Dictyostelium cells grow, waiting for food to become available again. Then they live as single cells.
And so on. Not only are there no "critical events" that only happened one time, the key developments in the progression of multi celled life are ongoing and observable; there are examples of organisms at all stages of their evolutionary progress.
Show one what that isn't a fraud? I've never seen a fraudulent phylogenetic tree, and I've seen hundreds of them.
Try this search and look at the images: https://www.bing.com/images/search?q=phylogenetic+tree&form=HDRSC2&first=1&cw=1108&ch=662
Please tell me which ones are frauds, and provide your evidence.
I’m right and you offered nothing to refute (but I know you think you did).
I can post links links from people smarter than me and more knowledgeable than both of us on this particular subject.
Not hardly.
If you take the biblical creation story as a scientific explanation of life on earth, there is utterly no explanation of why the flora and fauna of the Gobi would be so different than the flora and fauna of the western US deserts. In fact, there is no explanation of how the flora and fauna in either desert even exist, since they are not documented in the creation story and are not typical of the flora and fauna in the biblical lands. The creation story allows for no variability in species, and scammers like Ken Ham et al. who invent concepts like "adaptation" are neither scientific nor biblical with their scams.
If the creation story were a scientific description, the natural consequences would be that there would be little species variability across the world. All temperate deserts would have exactly the same plants and animals. Ditto for all temperate forests, all rainforests, all tundra, etc. And there would be no variability in humans, either. We'd all be the swarthy type of Caucasian that is common in the middle east, and everyone would look nearly identical. Since no one has ever observed anything of the sort, it stands to reason that the creation story is not, in fact, a scientific description.
Where do you want me to start?
One example is the influenza virus. This is actually a group of viruses. Each virus in the group infects people for a few years, but each person who gets infected and survives develops an immunity to that virus. So the virus changes from year to year in response to the immunity. The RNA that codes for key proteins mutates, such that the proteins it makes are different. Sometimes, the mutations help the virus to evade the pre-existing immunity, and viruses with those mutations can multiply and infect people who are immune to previous "versions" of the virus. This is why new flu vaccines have to be made every year, and why the flu vaccines are sometimes ineffective (as what happened with the H3N2 component of the vaccine this year).
In addition to the influenza viruses being able to evade immunity year after year through mutations, they trade bits of genetic material with each other. In this way, new species of influenza viruses appear.
There are many other details about influenza virus biology which make it one of the most difficult viruses to study (and develop countermeasures for). The bottom line is that nothing about the complicated biology of the influenza virus is explicable or can be studied outside of the context of the evolutionary process.
Be honest. There is no evidence I could produce, because you have rejected science. Therefore, no evidence will convince you. There is not a lot of difference between you and the kooks who claim that X or Y chromosomes have nothing to do with gender.
If you had any actual links to scientific evidence produced by genuine scientists that shows that the theory of evolution is incorrect or invalid, you would have linked them. You didn't link anything. Ergo, you have no links to post.
That’s not what I asked.
I asked for an example of a single scientific fact for which the theory of evolution is a necessary ontological foundation.
Whoa. The theory of evolution is very correct.
Here’s the first link which is concerned with early life, the fact that there is only one common ancestor and that there is only one tree of life. It was the first evolutionary event that only happened one time.
https://www.nytimes.com/2016/09/01/science/oldest-fossils-on-earth.html?_r=0
The relevant quote:
But the argument that life seems to have evolved very early and quickly, so therefore is inherently likely, can be turned around, Dr. Joyce said. “You could ask why, if life were such a probable event, we don’t have evidence of multiple origins,” he said.
In fact, with trivial variations, there is only one genetic code for all known forms of life, pointing to a single origin.
I gave a very detailed explanation of how the theory of evolution places a very strong framework to explain the diversity of life, using the example of how different plants and animals fill the same ecological niches in two different regions of the world which are actually very similar. And how the story of creation completely fails to explain why the biome of each desert is so different.
I think that you are very aware that it is impossible to take one isolated fact and use it to prove anything. So you set up the task for me to produce one isolated fact (I.e. data element) that cannot exist outside of evolution, when you know very well that no one can provide your "proof."
All I can do, of course, is look at the body of knowledge--consisting of countless facts and analysis--and ask whether the theoretical framework is sufficient to provide order and meaning to the data set. And what do I have to work with here? One, the theory of evolution, which has existed since at least the ancient Greeks,and has been refined continuously since then. Two, the creation stories out of the Bible, which are not internally consistent, not consistent with each other, and provide no conceptual framework with which to understand the biome. And three, the distorted mishmash of Lamarck's theory of evolution (poorly described, at that) and the biblical creation stories that is spouted by the likes of Ken Ham and his ilk.
Since the real goal of the creationist is to try to discredit the theory of evolution so that people embrace some form of creationism by default, the only thing I can do is to take a set of facts and compare which conceptual framework best supports them. Within that context, the question becomes very straightforward. Does the creation story explain why two very similar deserts have utterly different biomes? No, because implicit in the creation story is the idea that life is invariable. God is perfect, hence life is perfect, hence two very similar deserts should have very similar biomes. And the corollary to that is that there should be no variability when members of a species are observed in different parts of the world. The deer I saw in Mongolia should have been identical to the deer I see waiting to jump in front of cars in the US. But they weren't. They were bigger, had different coat patterns, were extremely wary, and showed no sign of the suicidal tendencies of American deer. Does the garbled mix of distorted elements of evolutionary theory and creation story give an acceptable theoretical framework to the data set? No, and it is not worth pursuing that further, since the creationist hucksters make up stuff that is neither biblical nor scientific. Now, is the difference in biome between two similar but geographically distant deserts adequately conceptualized within the framework of evolutionary theory? Yes, very nicely. And the simplest reason for that is that the theory of evolution allows for change over time--in fact, that is the definition of evo!ution.
If you want to "disprove" the theory of evolution (the theory of change over time), all you have to do is demonstrate that samples of flora or fauna collected from identical environments in disparate regions of the world are, in fact, genetically identical and that it is impossible to construct phylogeny trees that would show any meaningful differences due to geographical distances.
Seriously, the way that creationists "argue" reminds me a lot of the way Democrats campaign. No facts on your side, so you try to discredit the other side. That's not an intellectual argument.
I didn’t intend to make you so defensive.
The theory of evolution claims there is change over time. But it doesn’t demonstrate speciation.
If God is who Christians claim he is, then it’s entirely consistent with simple logic to state he can create two similar environments each containing unique forms of life.
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