Hello, people. This is the Bad Scientist Read, talking today about human evolution.
We have changed over time, and we're still changing.
This comes from two articles. One is from Science, April 16, 2026, page 241, about how the rise of farming and cultural changes accelerated human evolution. The other comes from Scientific American, September 2026, page 15, discussing what genetics is teaching us about the human sense of smell.
Put those two subjects together and you get an interesting question:
Did civilization stop human evolution, or did it simply change what evolution rewards?
For most of human history, smell mattered.
Imagine living without refrigerators, expiration dates, grocery stores or health inspectors.
Is that fruit ripe?
Has this meat spoiled?
Is there smoke nearby?
Is there something dead in that direction?
Odor provides information about the world, and differences in our ability to detect particular chemicals can sometimes have a genetic basis.
Humans have roughly 400 types of functional olfactory receptors. They don't work like 400 individually labeled smells. Different odor molecules stimulate different combinations of receptors, and the brain interprets those patterns as an enormous variety of odors.
And we're not all genetically identical.
Some people can detect particular chemicals extremely well. Others can barely smell them or cannot detect them at all.
Thousands of years ago, some of those differences could potentially have influenced whether somebody found food, avoided spoiled food or recognized environmental dangers.
Today?
You can have a terrible sense of smell and order dinner from your telephone.
That's what technology does to evolution.
It doesn't necessarily stop natural selection. It changes the environment in which natural selection operates.
🌾 Then We Invented Farming
Agriculture was one of the greatest environmental changes humans ever created for ourselves.
Hunter-gatherers faced one collection of survival pressures. Farmers encountered another.
Farming produced more dependable supplies of certain foods and eventually supported vastly larger populations. But early agriculture wasn't necessarily an easier or healthier life. Farmers could experience malnutrition, crop failures, repetitive physical labor and infectious diseases spreading through increasingly dense settlements.
Then we started living beside domesticated animals.
Pathogens had new opportunities.
Our diets changed.
Our communities became larger.
And evolution responded.
One of the classic examples is lactase persistence.
Most mammals stop producing large amounts of the enzyme needed to digest lactose after infancy. But after some human populations domesticated dairy animals, genetic variants allowing adults to continue digesting milk became extraordinarily valuable.
People changed their culture.
Culture changed the environment.
And the new environment changed the frequencies of human genes.
That's gene-culture coevolution.
👓 Technology Changes the Rules Again
Now look at eyesight.
Suppose somebody can't see clearly at a distance.
In an ancient environment, severe visual impairment could have been a serious disadvantage.
Today?
Put on glasses.
Or contact lenses.
For appropriate patients, corrective surgery is another possibility.
The genetic variation didn't necessarily disappear. Instead, technology reduced some of its consequences.
Medicine does this constantly.
Conditions that once might have killed somebody before adulthood can now be treated. People survive illnesses, injuries and inherited disorders that previous generations could not.
That doesn't mean humans are "devolving."
Evolution doesn't have a destination.
There isn't a perfect human being that natural selection is trying to manufacture.
Evolution simply means inherited characteristics change in frequency across generations.
🏙️ Civilization Is Our Environment Now
There's another side to this.
Human societies discourage some behaviors that might have been advantageous under completely different circumstances.
Extreme aggression might help an individual in some environments. In an organized society, the same behavior can bring punishment, imprisonment, retaliation or social exclusion.
Meanwhile, characteristics useful in modern society can provide entirely different advantages.
Intelligence.
Cooperation.
Communication.
Patience.
Technical ability.
Social skills.
And occasionally extremely specialized sensory abilities.
Consider the professional perfumer.
Some people have exceptional abilities to recognize and distinguish odors. Combined with extensive training, that can become a valuable professional skill.
Nobody needs to identify hundreds of perfume ingredients to survive a winter anymore.
But civilization can take an unusual human ability and give it entirely new value.
👶 And Evolution Ultimately Comes Down to Reproduction
Evolution doesn't care how much money somebody earns, how strong somebody is or how intelligent somebody is by itself.
From an evolutionary standpoint, what ultimately matters is whether inherited characteristics contribute to descendants being produced and surviving to reproduce themselves.
Modern societies have dramatically changed that equation.
People make conscious decisions about whether to have children and how many to have. Economics, education, contraception, religion, culture and personal preference all influence reproduction.
Those are enormous cultural forces.
Whether particular reproductive preferences themselves have a meaningful genetic component is a much harder scientific question, so we shouldn't automatically assume that people who choose larger families possess a genetic "resistance" to smaller-family culture.
But the larger principle remains fascinating:
Culture can change which traits are passed into future generations.
🧬 We Never Stopped Evolving
Agriculture didn't end evolution.
Cities didn't end evolution.
Eyeglasses didn't end evolution.
Medicine hasn't ended evolution.
Technology continuously changes the environment in which evolution operates.
Sometimes technology removes an old selection pressure.
Sometimes it creates a completely new one.
And sometimes culture changes so quickly that biology hasn't had anything close to enough time to catch up.
So when somebody asks what humans will evolve into next, don't imagine evolution sitting there with a blueprint for Humanity 2.0.
Look at the environment we're creating.
Look at our food.
Look at our diseases.
Look at our technology.
Look at whom we're having children with and how many children we're having.
Because those things are part of the environment shaping whatever humanity becomes next.
Thank you very much for listening.
This is the Bad Scientist Read, signing off.
🔬 Science & Keywords
Science, April 16, 2026, p. 241 • Scientific American, September 2026, p. 15 • human evolution • gene-culture coevolution • agriculture • lactase persistence • olfactory receptors • genetic variation • natural selection • modern medicine • reproductive fitness
✅ What's Well Established
Humans continue to evolve. Agriculture produced major new evolutionary pressures involving diet, pathogens and population structure. Lactase persistence is a particularly strong example of culture influencing subsequent genetic evolution. Humans possess roughly 400 types of functional olfactory receptors, with considerable genetic variation between individuals.
⚠️ Important Distinction
Modern medicine allowing people with particular conditions to survive isn't biological "devolution." Evolution has no objective of making organisms stronger, faster or healthier.
Likewise, differences in family size can affect which genes reach future generations, but that doesn't establish that wanting many or few children is itself primarily genetic.
The more scientifically interesting idea is broader:
Humans created culture, culture transformed our environment, and that new environment became another force acting on human evolution.
Open with a stronger smell example
Clarify the farming tradeoffs
Connect smell back to civilization
