But not all variation is dramatically morphological, and you are just ignoring selection.
If you actually demand to see an egg laying fish transitioning to a furry mammal in front of your eyes, then consider your demand unmet. You have convinced yourself that the history of life is untrue, even though what you request is contrary to evolution. Peace be on you.
But by the same strained logic as you are presenting, please explain how the select species contained on the ark became the innumerable count of species alive and many more extinct. Given the crazy pace of post flood speciation, should we not be seeing much more transitioning such as Fluffy giving birth to saber tooth cats, and Fido giving birth to foxes?
Well of course you don’t see it happening now, but the theory of evolution doesn’t tell you to expect to see it happening now. As I’ve already pointed out, if you are going to argue against a scientific theory on the grounds that you don’t see something, you MUST make sure that the thing you don’t see is something that the theory actually tells you to expect to see. Claiming that something doesn’t happen at all just because it happens too slowly to be visible in our lifetimes is a violation of this rule, a non-sequitur, and wilful ignorance. Especially when the theory tells us what evidence we should expect to see of it having happened in the past, and when we do actually see that evidence as predicted.
It also falls under the category of unrealistic expectations. This is a common trope in every form of science denial, whether the science being denied is evolution, man made climate change, the effectiveness of vaccines, or the link between smoking and cancer. Such people set standards for evidence in favour of the theory so high that if you applied the same standards to every area of science, we would still be stuck in the Stone Age. At the same time, they set standards for evidence against the theory so low that if you applied the same standards to every area of science, you would kill people.
Well you’re entitled to your own opinions, but you’re not entitled to your own facts.
No more amazing than that we should find a puddle of water is the perfect shape to fit into the hole that it occupies. Mutations are random - yes. But evolution is not. It is driven by those ecological niches that will yield reproductive differential between various mutations over time so that the species that do thrive most are the ones best adapted to an environmental niche such as exists for them at the time.
They are evolving. As you point out, their genomes continue to accumulate mutations.
If the theory of evolution is true then we shouldn’t observe what you are asking for. All species will be 100% of what they are right now. None should be transitional because they are all at the end of their evolutionary lineages.
Yes, we do. We see new mutations being selected for and moving towards fixation.
Excuse my ignorance, but how does more women having c-sections to give birth affect future generation’s pelvic size? I dont understand how that works logically in evolutionary mechanisms.
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.
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.
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.
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?
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.
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.
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.
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.