10 minutes ago, BusaDave9 said:

When compared to animals we are far more likely to pass on our genes to the next generation. 200 years ago people would have 8 children but most would not make it to adulthood. Wild animals have it worse than that.

Except, of course animals that produce dozens or hundreds of offspring each season, of course. Again, this comparison makes no sense.

6 hours ago, swansont said:

I will once again ask you for examples of evolution in humans

One example of human evolution that I've been thinking about lately is Lactase Persistence. All baby mammals drink milk. Lactose is hard to digest. Mammal babies make the enzyme lactase to digest milk. As the mammals grow they stop making the enzyme lactase. We humans have evolved to continue making this enzyme.

I wonder how this came about. Do you think this was natural selection? Do you think people drank milk, some died and no one made the connection until enough people died to evolve.

I don't know but I'll listen to opinions.

Just now, CharonY said:

Except, of course animals that produce dozens or hundreds of offspring each season, of course. Again, this comparison makes no sense.

True, in general, the larger the animal the fewer offspring. We'd have to do the comparison with other large animals.

I talked about this earlier and pointed out that spiders may lay hundreds of eggs at a time.

6 hours ago, swansont said:

I think a problem here is that you are narrowing your field of view on this, but still trying to apply it to a broader conclusion.. Avoiding predators is not the only avenue of natural selection.

Agreed. I have used examples of finding food and a broken bone is a death sentence for a deer or many other animals. I think the majority of the examples apply more to animals than humans.

Can you think of any examples of natural selection that affect humans more than animals. I realize there are lots of examples but I think living in the wild is harder than living in civilization.

7 hours ago, CharonY said:

This is again conflating survival with reproductive success.

I know the difference. I've talked about both. The post you quoted me I talked about natural selection.

Then when I talked about reproductive success I said "Next lets look at ..." as I changed the topic.

In wild animals I think the main driving force for evolution is natural selection but mutations must be present.

Do you think reproductive success is the main driving force for human evolution? I don't know but I don't think so. I think everyone can have a couple offspring. Since we have such a high survival rate people may decide to have 2 children, expecting both to survive. Animals have as many as possible without realizing the link between sex and offspring.

Is genetic drift the main driving force for human evolution? I very much doubt that.

Edited 20 hours ago20 hr by BusaDave9
to clarify

11 minutes ago, BusaDave9 said:

I wonder how this came about. Do you think this was natural selection? Do you think people drank milk, some died and no one made the connection until enough people died to evolve.

I don't know but I'll listen to opinions.

Research is good. Wikipedia or other free web sources provide a wealth of information on the nature of the LP gene, and consulting them would quickly make clear that it wasn't about people dying from milk consumption. Roughly 5 billion people in the world still lack the LP gene, and before 8-12000 years ago, almost no one had it. People who tried milk before then didn't die of flatulence and diarrhea, they just felt sick and decided milk wasn't a viable protein source. As do billions still. (Unless having access to lactose free diary products, as is common now in developed countries) Look up the topic and learn how selective advantage might have arisen for those having the LP phenotype - I gave you a strong hint a couple sentences back there.

Also note that at least six mutations (single-nucleotide polymorphisms – SNPs) have been associated with lactase expression. Can you see how these mutations might shift from being neutral to beneficial in certain environments? Look back through the thread and I think you can put this together. And also, a courtesy of replying to posts is appreciated. Several here are going to some trouble to help the learning process.

Edited 20 hours ago20 hr by TheVat

7 hours ago, swansont said:

I will once again ask you for examples of evolution in humans

Breasts are an interesting example of human evolution due to reproductive success.

Sexual attraction is the main reason women have breasts from puberty to death. Sure breasts are used to nurse infants but that is a very small percentage of their lives.

Think about this: no other animal, not even apes, bonobos and chimpanzees, our closest relatives have breasts until they have a baby and start to lactate.

Guys love breasts. That's why women have them even when they are not lactating.

Guys look at breasts and think "I want to have babies with her!" and they are NOT thinking "They would be able to feed our baby nicely.

Okay but seriously, I don't think this plays a big part when we are seriously looking for a wife. When guys are young they are just out to have fun and are attracted to breasts.

8 hours ago, BusaDave9 said:

One example of human evolution that I've been thinking about lately is Lactase Persistence. All baby mammals drink milk. Lactose is hard to digest. Mammal babies make the enzyme lactase to digest milk. As the mammals grow they stop making the enzyme lactase. We humans have evolved to continue making this enzyme.

I wonder how this came about. Do you think this was natural selection? Do you think people drank milk, some died and no one made the connection until enough people died to evolve.

I don't know but I'll listen to opinions.

True, in general, the larger the animal the fewer offspring. We'd have to do the comparison with other large animals.

I talked about this earlier and pointed out that spiders may lay hundreds of eggs at a time.

Agreed. I have used examples of finding food and a broken bone is a death sentence for a deer or many other animals. I think the majority of the examples apply more to animals than humans.

Can you think of any examples of natural selection that affect humans more than animals. I realize there are lots of examples but I think living in the wild is harder than living in civilization.

I know the difference. I've talked about both. The post you quoted me I talked about natural selection.

Then when I talked about reproductive success I said "Next lets look at ..." as I changed the topic.

In wild animals I think the main driving force for evolution is natural selection but mutations must be present.

Do you think reproductive success is the main driving force for human evolution? I don't know but I don't think so. I think everyone can have a couple offspring. Since we have such a high survival rate people may decide to have 2 children, expecting both to survive. Animals have as many as possible without realizing the link between sex and offspring.

Is genetic drift the main driving force for human evolution? I very much doubt that.

@CharonY did actually give a number of examples of environmental selection pressures that affect humanity, in response to a post of mine: climate adaptation, pathogen exposure and metabolic syndromes related to diet that reduce the chance of reproduction. (I might speculate in addition that tolerance to, say, certain pervasive pollutants in the human environment, such as oestrogen mimics, might confer a reproductive advantage.) Such factors are relevant measures of “fitness” in the Darwinian sense for humanity, whereas for example short sightedness arguably no longer is.

(This is important to understand. Darwinian “fitness” means suitability to the environment, not closeness to some standard of perceived physical perfection.)

One further interesting point he made in that post is that people with a genetic disability cannot be treated as if the disability is their sole contribution to the gene pool of humanity. They also contribute to the width of the gene pool in other respects, which may turn out to have evolutionary advantages at some point.

Edited 12 hours ago12 hr by exchemist

11 hours ago, BusaDave9 said:

Guys love breasts. That's why women have them even when they are not lactating.

It would help if you could reply to the posts responding to your question about lactase persistence. And do the homework that's needed to really engage with this topic.

13 hours ago, BusaDave9 said:

One example of human evolution that I've been thinking about lately is Lactase Persistence. All baby mammals drink milk. Lactose is hard to digest. Mammal babies make the enzyme lactase to digest milk. As the mammals grow they stop making the enzyme lactase. We humans have evolved to continue making this enzyme.

I wonder how this came about. Do you think this was natural selection? Do you think people drank milk, some died and no one made the connection until enough people died to evolve.

I don't know but I'll listen to opinions.

I’l lactose intolerant, as are others, so it’s not “we humans,” it’s “some humans”

It certainly could be that this ability persisted because dairy is a way to turn indigestible grass, etc. into useful calories, and that’s something that would give improved survival probability and increase the odds of passing down the gene(s) responsible

I asked for examples that supported your premise, i.e. ones that allowed you to draw your conclusion, and this doesn’t fit the bill. Evolving to adapt to new food sources is definitely something observed in wild animals.

12 hours ago, BusaDave9 said:

Breasts are an interesting example of human evolution due to reproductive success.

Sexual attraction is the main reason women have breasts from puberty to death. Sure breasts are used to nurse infants but that is a very small percentage of their lives.

Think about this: no other animal, not even apes, bonobos and chimpanzees, our closest relatives have breasts until they have a baby and start to lactate.

Guys love breasts. That's why women have them even when they are not lactating.

Guys look at breasts and think "I want to have babies with her!" and they are NOT thinking "They would be able to feed our baby nicely.

Okay but seriously, I don't think this plays a big part when we are seriously looking for a wife. When guys are young they are just out to have fun and are attracted to breasts.

Sexual selection. Definitely something that happens in wild animals.

Mammals generally have breasts, they just aren’t prominent when not lactating in most mammals. My understanding is that it’s part of the evolution of the human reproductive “strategy” where women aren’t just fertile for a short period of time (estrous) - humans don’t have a breeding season. Lots of inter-related elements in this. The specifics are human-centric but the process is not.

Your examples don’t support your thesis.

I wonder where the word mammals comes from.

There were mammals 66 million years ago, long before there were any humans.

Breasts are a spurious argument.

Here is a proposal I think worthy of consideration.

I suggest the main difference between humans and their evolution and other creatures and their evolution is that humans are generalists and very very adaptable.

Many, if not most, other creatures tend to develop (evolve) specialist traits and characterisation not possessed by humans or by many other creatures.

3 hours ago, studiot said:

Here is a proposal I think worthy of consideration.

I suggest the main difference between humans and their evolution and other creatures and their evolution is that humans are generalists and very very adaptable.

Many, if not most, other creatures tend to develop (evolve) specialist traits and characterisation not possessed by humans or by many other creatures.

Agree. I think the specific series of changes humans underwent is specific to humans, but the overall process is the same as all organisms, as it must be.

More specialized traits leave a species susceptible to extinction if/when the environment changes

3 hours ago, studiot said:

Here is a proposal I think worthy of consideration.

I suggest the main difference between humans and their evolution and other creatures and their evolution is that humans are generalists and very very adaptable.

Many, if not most, other creatures tend to develop (evolve) specialist traits and characterisation not possessed by humans or by many other creatures.

That is an interesting point. Generally speaking, specialist species tend to do develop within stable environments. The reason is that under unchanging conditions, there are certain optimizations (e.g. resource use) that provide relative fitness benefits (e.g. moving towards a set of fixed maxima in a fitness landscape). Generalists are more commonly found in changing environments, as optimizations do not provide the same fitness benefits. Humans are a bit different as they extend their generalist ability by being able to create fairly static habitats. I.e. they are not necessarily genetically as generalist as other species, but I would argue that their optimization of traits related to higher brain functions allowed them to expand the concept adaptability. Some other species do similar things, but not at that scale.

4 hours ago, TheVat said:

It would help if you could reply to the posts responding to your question about lactase persistence.

Thanks, that was interesting but to be honest I haven't really done any research beyond reading what you've posted. Maybe I'll find time after work.

4 hours ago, swansont said:

Your examples don’t support your thesis.

My thesis is that natural selection does not affect modern human evolution as much as with wild animals. You want examples? If I found few examples of human evolution due to natural selection and lots of examples of animal evolution would that be what you want?

I'm just interested in the conversation. I see lots of people surviving even with major genetic deficiencies such as blindness and deafness. I believe animals with these same problems would never reach reproductive age.

I realize people with genetic disability "also contribute to the width of the gene pool in other respects". That's true but they also pass on blindness and deafness.

20 minutes ago, BusaDave9 said:

I'm just interested in the conversation. I see lots of people surviving even with major genetic deficiencies such as blindness and deafness.

This is again shows a focus on the wrong elements. You should instead ask, do folks with blindness and deafness have higher or lower reproductive success than those without. This is the actual basis on how fitness is being calculated (the relative ability of a genotype compared to another).

Surviving is not the key part of the equation. And again, you can only compare reproductive success within species not between.

IOW, what you are interested in engaging with is more like a narrative discussion (similarly like would Godzilla win against King Kong) but it is not based on evolutionary science.

I've mentioned this several times in several ways but the OP seems uninterested in the bald fact that nearly have the human lifespan is beyond the reproductive stage, unlike most other creatures and life forms.

So they are only considering the contribution of half an average human's total.