2 posts were split to a new topic: Have you seen The Ark and the Darkness?
In humans, women with small pelvis measurements have a hard time giving birth to large headed babies. In the days without c-sections, those women often died in childbirth and did not pass their body types to the next generation. It is reasonable to also consider that males will see wide hips as a positive factor in finding a mate, and that then reinforces the trait through differential reproduction… With wide availability of c-sections, that no longer is as big a selective pressure, and small pelvises will then be passed on. You can also say the same thing about large heads, coming from the other direction.
Of course, there are a lot of other factors as well, but that is a pretty simple example.
3 Likes
Thanks Phil but I still dont get it. The developing baby in the womb doesnt know how it’s going to be born. If you take an individual woman giving birth, if she chooses or has to have a c-section birth for her child, I dont see how that is passed onto that baby so that its pelvis, if female, will be slightly smaller than her mother’s. So I dont see how it is passed on reproductively.
Without C-sections, more mothers with narrow pelvises would have difficult or even fatal births - meaning those mothers won’t be passing on their genetics to near as many offspring as mothers with wider pelvises who give birth more easily. So - you’re right that this doesn’t affect the genetics of mothers and babies already existing here and now. But it does affect what the gene pool looks like generations from now when there are many fewer babies from the one kind of build and many more babies from the other. That’s a reproductive advantage for the ones on average producing more children.
But C-sections undo that advantage (to some extent) … though it may be interesting to know what percentage of humans alive would have that technology available if they needed it. A lot of other factors would all be in play too.
4 Likes
Ok that makes sense on a population level, in the years to come. It’s basically a numbers game - until very recently the majority of female babies born carried forward the traits of their mothers who had wider hips because a substantial number of babies from women with narrower hips died in childbirth, so their narrower hips were not passed on to the next generation. But with c-sections becoming more popular, many more of those babies will now be born healthy and therefore pass on the narrower hips in future generations. Thus the average size of female hips will be narrower in future generations. I get it now. It sounds similar to Darwin’s moths! Many thanks.
4 Likes
That has become an issue for some breeds of bulldog. They have been bred for such large heads that c sections are now mandatory for many breeders.
2 Likes
They’re all evolving. The issue is that we are mayflies in comparison to the process.
False. Pretty much every species is “transitioning to something else” because the mutation rate continues.
3 Likes
Nice vivid comparison!
1 Like
Well, I would agree with you if we only have 80 years to observe. But, I haven’t been talking about our lifetimes of 80 years. What I’m saying is that a fair amount of those creatures living today have been around for tens and hundreds of millions of years based on scientists estimates. So, there has been plenty of time for them to evolve. Let’s remember that according to scientists, it only takes 50-100 million years for fish to become amphibians, amphibians reptiles, and reptiles dinosaurs. So, within 10-20 million years from a species initial existence, we should see ones with significant evolution occurring.
Additionally, mutations are random. They keep coming. Evolution never stops. So, we should be seeing plenty of evolution present in current living creatures that have ancestors dating back 10 MYA or more. But, what do we find? We find none progressing from fish to amphibian. We find none progressing from amphibian to reptile. We find none progressing from reptile to mammal or dinosaur, etc. And to the big question of the day, no one has seen a living creature 25%/50%/75% transitioned to something else. Shouldn’t we be able to find at least a few that are showing this type of transition in current living species, the species that have been around for 10MY or more?
Can you cite a few that are transitioning to something else and are 25%/50%/75% there?
We already have amphibians which got there first, so that niche is taken.
Evolution does not progress in the sense of striving for a target. It is just a matter of adapting to a given environment. Neither a camel nor a whale are more progressed than the other, their traits suit their lifestyles.
Positive and neutral mutations can reach fixation. Negative mutations are selected against. If a creature is optimized for its environment, and there is continuity of that environment, it may be expected that the essential body plan of that animal be conserved. You persist in ignoring selection.
For the sake of argument, let us try to visualize this. Take a dog or eagle or whatever specific creature you like, which is 25% transitioned to something else. It is in your very hands. Explain how you know it is 25% transitioned, and how you crystal ball what it will become when the other 75% is done.
Wild nature is what it is and lives in the moment; biologists do not tell it what to do.
3 Likes
That is only partially true. Mutations are ‘raw material’ for selection, so mutations as such are not enough to transform a species to something else. A possible exception is neutral drift because a new mutation can spread even without a selective advantage, just because of more or less random chance events. Neutral drift should only happen when the mutation is relatively neutral, meaning it does not lower the fitness of the animal much.
In other cases, the gene pool of the population changes because the environment changes (including both abiotic and biotic changes), organisms spread to a new kind of environment or start to use a new resource, or a novel geno-/phenotype (mutation) has a selective advantage in that type of environment. There is no ‘balance of nature’, environments are changing, and therefore also the gene pools of populations tend to change from one generation to the next ones (evolution). If the environment does not change much or the environmental changes fluctuate back and forth, selection may be stabilizing, meaning that selection works against changes. In such cases, the animals in the population may look the same even for millions of years (no speciation).
If we could monitor a population in a changing environment for a million years, we might see major changes in the organisms. The lifetime of a human is like a falling star, too short time to observe major changes.
4 Likes
Well of course we shouldn’t expect to see a living creature 25%/50%/75% transitioned into something else because we don’t know what the “something else” looks like.
What you are asking us to do here is to predict the future.
3 Likes
Yes, agree, though with genetics etc, can’t we see evidence of past evolution? Such as in pseudo genes etc
One misunderstanding we often have is that evolution is not goal directed…so it’s not that there is a plan to evolve into something.
2 Likes
That’s my understanding.
Part of the problem is that it’s not clear what exactly @Hubster is looking for when he talks about “seeing a living creature 25%/50%/75% transitioned into something else.”
If he means seeing a living creature, or a population of living creatures, transforming from one to another at a level above the species level within our lifetime, then he’s asking for something that the theory of evolution does not predict. But he’s already said that he doesn’t mean that.
If he means seeing a creature today at an intermediate state between something in the past and something in the future, as I said, he’s asking us to predict the future.
If he means seeing a creature today that is different from its ancestors in the past, then we’ve already got ample evidence for that.
If he doesn’t mean any of these three things, then I haven’t a scooby doo what he actually does mean. Unless of course, he’s leaving the question purposely vague, ambiguous and open ended enough that whatever we come up with, he can claim that that’s not it.
4 Likes
Of course we don’t – and if you would bother to actually study the theory of evolution the reason why would be obvious. The same is true of your other examples.
In fact your claims fail to understand the ToE on two major points: fitness, and non-directedness.
This has nothing to do with evolution – there is no such thing as “25%/50%/75% transitioned to something else” unless you have both a starting and an end point to compare. Everything is constantly transforming “to something else” but unless you can see into the future so you can find what any given species is transforming to, and pick a point in the past, there’s no way to measure if a species is transformed even 0.1% to something else.
This is again the “bricks can’t make a building” fallacy, along with failing to understand fitness.
I’m no biologist, so can anyone point to a basic explanation of evolution that could correct the misunderstandings here?
3 Likes
@Hubster , Greetings. Thank you for asking good questions.
One example of evidence of past evolution I found really interesting was in reading @DOL Dr Lamoureux’ book, "Struggling with God and Origins.". He went from faithful Catholic to atheist, to young earth creationist, to Pentecostal evolutionary creationist. One of his interesting discoveries was on the teeth of embryonic baleen whales. Because they came originally from land mammals, but never needed the teeth, they developed small teeth while developing in the uterus, but then lost them and went on to grow baleen.
There’s much more about genes, such as vitamin C, which we possess, but are broken; and other evidence of past evolution.
Keep up the good discussion.
Thank you.
Randy
2 Likes
Thanks Randy. For those who are interested, here a three examples of whale fetal teeth. Blessings, Denis
3 Likes
Thank you! I did not want to break copyright, but that’s what I’ve been reading in your very good book!
Anytime you want an image, just ask. Blessings, Denis
1 Like