Thread: Why does it matter if we're "not evolving"?

We live in all possible inhabitable continents (yes, we do live in Antarctica to some extent, but with advanced technology to aid us, unless -40 degree temperatures are natural for us). We also have developed medicine which cures/manages diseases that otherwise would thin our numbers.

So given basic evolutionary theory, there are few new environments for us to adapt to. Perhaps the next step in our evolution will be akin to how we became behaviourally modern, as in a rapid genetic mutation that quickly spread amongst us.

Evolution from one recognizable step to another is just mile markers on a continuous journey.
It never stops.
We are changing, generation to generation, always changing.
When the glaciers return, our species will be pushed to the brink, massive die-offs will shrink us to a precious few.
If those few are different enough, we become a new sub species, but we will still be the we that we were, and more.

We are a fleeting moment of a continuity of change.

Perhaps the next step in our evolution will be akin to how we became behaviourally modern, as in a rapid genetic mutation that quickly spread amongst us.

Who are you counting as us?

Not everyone in the advanced industrial democracies participates in or benefits much from "modern" society. Even then, the total populations of OECD countries amounted to only 1.2 billion in 2009. When the total population of the world is over 7 billion, it's a bit of an ask to count 15% or less of the total as "us".

Originally Posted by adelady

Perhaps the next step in our evolution will be akin to how we became behaviourally modern, as in a rapid genetic mutation that quickly spread amongst us.

Who are you counting as us?

Not everyone in the advanced industrial democracies participates in or benefits much from "modern" society. Even then, the total populations of OECD countries amounted to only 1.2 billion in 2009. When the total population of the world is over 7 billion, it's a bit of an ask to count 15% or less of the total as "us".

No, that's not what I meant.

I was surmising that maybe a step in our evolution would be a random mutation, such as what supposedly made us behaviourally modern. So it's not so much adapting to environments, but a change in the structure or wiring of our brains.

Evolution doesn't have an end game. Those who propagate the most genes are not necessarily the most intelligent, strongest, etc. How would a gene rapidly spread? I assume by 'modern' you mean western countries. Hint....the average Swedish women has 1.4 children....the average Kenyan almost 7. Do you think Swedish genes are going to dominate the future?

Few children in the western world do not survive to childhood. Those who are more intelligent do not have more offspring than those with the least intelligence.

Bottom line...natural human evolution will bemostly spearheaded by what happens in China, India, subsaharan Africa, etc. and in the western world largely by what today are considered the poorer class and various minorities. However, all may be moot as genetic engineering will take humans off into different tangents...again, mostly led by what the Chinese, Indians, etc. decide what to do with new breakthroughs.

Humans absolutely have not stopped evolving. Only extinct species have stopped evolving.

Bottom line...natural human evolution will bemostly spearheaded by what happens in China, India, subsaharan Africa, etc. and in the western world largely by what today are considered the poorer class and various minorities.

Many other members have already seen this video, but it's worth running again in any conversation about population growth.

Hans Rosling: Religions and babies | Video on TED.com

Originally Posted by sarnamluvu

I was surmising that maybe a step in our evolution would be a random mutation, such as what supposedly made us behaviourally modern. So it's not so much adapting to environments, but a change in the structure or wiring of our brains.

You misunderstand evolution. A random mutation (most would argue all mutations are random) is only one half of evolution. The other half is selection. We were made 'modern' by random mutations that made us fitter for our environment than we would otherwise be.

There is also a rather mindless idea that evolution has less of an impact on those 'protected' by modern medicine. That is just silly. Modern medicine and efficient hygene practices mean that idnividuals who would have been culled from the population are able to survive and reproduce. That has a huge impact on the gene pool and thus represents, if anything, an increase in evolution, not a decrease.

Originally Posted by John Galt

You misunderstand evolution. A random mutation (most would argue all mutations are random) is only one half of evolution.

I would say not even one half. The "other half" to selection is population diversity. Mutation can add to this but it is not the only source (depending on how you define "mutation", I suppose).

Originally Posted by adelady

Many other members have already seen this video, but it's worth running again in any conversation about population growth.

Hans Rosling: Religions and babies | Video on TED.com

Brilliant. As usual. Can't we put him in charge? Of, like, everything.

Brilliant. As usual. Can't we put him in charge? Of, like, everything.

I know I spray that religions and babies TED talk all over the place, but it's nowhere near my favourite.

That honour goes to the The Magic Washing Machine. I've yet to see a better, more concise, more vivid analysis of energy and resource needs.

Hans Rosling: The magic washing machine | Video on TED.com

Originally Posted by John Galt

Originally Posted by sarnamluvu

I was surmising that maybe a step in our evolution would be a random mutation, such as what supposedly made us behaviourally modern. So it's not so much adapting to environments, but a change in the structure or wiring of our brains.

You misunderstand evolution. A random mutation (most would argue all mutations are random) is only one half of evolution. The other half is selection. We were made 'modern' by random mutations that made us fitter for our environment than we would otherwise be.

There is also a rather mindless idea that evolution has less of an impact on those 'protected' by modern medicine. That is just silly. Modern medicine and efficient hygene practices mean that idnividuals who would have been culled from the population are able to survive and reproduce. That has a huge impact on the gene pool and thus represents, if anything, an increase in evolution, not a decrease.

yes, but what scope is there for adaptation? At least millions of years ago, there were new environments we could enter and adapt to, but there is no such thing today, bar extreme environments like deserts and polar regions. So IMO at the least, we cannot evolve that much in this sense. The only other thing I can think of is a rapid climate change, such as an ice age or increased temperatures.

Originally Posted by sarnamluvu

So it's not so much adapting to environments, but a change in the structure or wiring of our brains.

There is no such distinction. Our brains evolved to adapt so we had reproductive fitness for environments as well.

yes, but what scope is there for adaptation? At least millions of years ago, there were new environments we could enter and adapt to, but there is no such thing today, bar extreme environments like deserts and polar regions. So IMO at the least, we cannot evolve that much in this sense. The only other thing I can think of is a rapid climate change, such as an ice age or increased temperatures.

Not sure what you point is here. The Earth's biosphere is going through more rapid biotic and abiotic changes than most other times in Earth's history--so quickly and in many cases so irreversible that many scientist have adopted the term Anthropocene to reflect its indelible mark on the planet.

Originally Posted by sarnamluvu

yes, but what scope is there for adaptation? At least millions of years ago, there were new environments we could enter and adapt to, but there is no such thing today,

Good God, man! Are you blind?

You think hunter gatherers lived in an environment where those with Type I diabetes could survive to reproduce. You think they could use IVF to have children? You think immunisation and vaccination could protect the vulnerable long enough to reach child bearing age? We have created a radically different suites of environments because of medical and social change. Your ignorance of this does not surprise me. It is at least consistent.

Evolution doesn't come around just for the heck of it... Evolution is a need based phenomenon. Your physiology changes because something in your environment dictates you do, otherwise you will die.

Humans do not change for our environment... we change our environment. What would be our need to evolve now?

Originally Posted by Alpha6

Evolution doesn't come around just for the heck of it... Evolution is a need based phenomenon. Your physiology changes because something in your environment dictates you do, otherwise you will die.

Where did you get that from?

Originally Posted by Alpha6

Evolution doesn't come around just for the heck of it... Evolution is a need based phenomenon. Your physiology changes because something in your environment dictates you do, otherwise you will die.

Humans do not change for our environment... we change our environment. What would be our need to evolve now?

Evolution is more chance than need.

Darwin's finches did not undergo adaptive radiation because a niche needed to be filled, but rather because a niche could ​be filled.

Originally Posted by Alpha6

Evolution doesn't come around just for the heck of it... Evolution is a need based phenomenon.

Evolution is not related to need. It is one part chance - variation in the genome, ultimately through random mutations - and one part selection, via "survival of the fittest". Where is the need in that? If a species lacks the genetic resources to adapt to a changed environment it will become extinct. What it needs will be irrelevant.

Originally Posted by Alpha6

Your physiology changes because something in your environment dictates you do, otherwise you will die.

What changes occur to your physiology have no impact upon the evolutionary trends of your offspring, if any. Weismann demonstrated the separation of germ cells and somatic cells a century ago. It is a cornerstone of the Modern Synthesis.

Originally Posted by Alpha6

Humans do not change for our environment... we change our environment. What would be our need to evolve now?

And because we change our environment alleles that would be detrimental in another environment are allowed to flourish. Thereby the ratio of alleles in the population changes and that is, by definition, evolution.

Welcome to the forum by the way.

How is living in a sealed box kept within a small range of temperatures, cut off from natural environmental influences not a relatively new environment for homo sapiens?

Where did this idea of "humans stopped evolving" come from?

Some possible evolutionary pressures:
(I realize these are very speculative so I hope I don't have to zip up the flame suit.)

As more women delay childbirth into their 30s or 40s, the ones that can't conceive won't pass on their genes. The ones that can, will, so that could result in an extension of childbearing years in women, and I think this could happen even if young women continue to reproduce. Of course this is not true all over the world, but there have been genetic changes like resistance to disease that hasn't taken place all over the world.

Drug addicition. Debilitating drug addiction affects infant mortality, seems to interfere with normal nuturing and protective mechanisms in parents enough to have a possible selective effect against it.

pollutants

new viruses, HIV

physical aggression - with fewer wars and an arguably less need to defend oneself physically, physical aggression has few benefits, and often puts people at opposition with society, law enforcement, etc. which I think might be great enough to decrease ones opportunity and ability to parent offspring. The question might be, though, to what extent is physical aggression tied to non-physical aggression or competitiveness, in which case it might not be weeded out.

People used to have babies essentially to produce workers on large family farms or provide care in ones old age, and of course there was no birth control. Now babies are considered almost a luxury item, not a natural process of life. I believe that this is true at both ends of the economic scale. Although not a lot of thought seems to go into a sixteen year old's pregnancy, I would argue that people reproduce more when they think there are supportive economic structures to protect their offspring, whether that means a stable economy and the likelihood of continuing employment, help from family members, or support from society.
I think these type of cooperative social structures and behavior could be selected for.

Suicide seems like a big killer of healthy young people, but to be honest I cant identify what the biggest environmental pressure or predictor of this behavior would be or how evolution would select against it.

A few years ago I would have said the ozone layer and cancer, but that seems to have improved considerably in the last year or so.

How is living in a sealed box kept within a small range of temperatures, cut off from natural environmental influences not a relatively new environment for homo sapiens?

It's called a cave.

But a tent or an awning or other simple structure to protect from the worst of the elements is easily within the capabilities of any human in any era. Their need or desire to do so depends on what food and water sources are available in an area and whether they need to be able to move on to get to other sources.

Humans are dextrous enough and intelligent enough to choose to break up rocks and reassemble them into shelters where they want them rather than move away from an area just because it doesn't provide convenient shelters in hillsides.

If there are no hills, or people don't want to be confined to living in one place, humans can handily assemble shelters from animal skins, or from foliage / sticks arranged as a humpy or similar, or from plant material or animal material woven or otherwise converted into usable fabric. Animal skins are preferable in many circumstances because they're already pretty waterproof and very flexible.

Originally Posted by Ninja Pancakes

Where did this idea of "humans stopped evolving" come from?

People who make this claim have no real understanding of evolution. For them, evolution = natural selection. The two terms are seen as synonymous. In reality, natural selection is but one aspect of evolution. In the absence of strong environmental selection, processes such as recombination, mutation, drift and gene flow do not suddenly cease to operate. Genome replication, sex, stochastic processes and population movements guarantee that evolution will never stop.

Besides, as others have pointed out, we don't live in a selection-free world - not even close - so the whole "evolution stopped" thing is truly mind-boggling.

To answer your question: I hope I'm wrong, but I'd wager that no evolutionary biologist has ever made this claim. If they did, their words were likely taken out of context.

Originally Posted by Zwirko

People who make this claim have no real understanding of evolution. For them, evolution = natural selection.

Or they think, "evolution = change". Then you get the argument that "evolution must be wrong because species X hasn't changed for N million years".

Apart from the fact that "hasn't changed" isn't actually true, it is evolution that has kept them broadly similar for such a long period. Without evolution then effects like random mutation and genetic drift would have caused large changes over time. But selection has kept them the same good fit for their environment that they always were (even if genetically they are quite different).