evolutionary timescales are long

[keannu]

SOURCE : Korean SAT English by English Broadcasting System, 2024, 22p

What does "evolutionary timescales are long" mean?
The answer in the question is "evolution is too slow to address modern obesity", but I can't understand the whole passage.
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In the past there was little genetic pressure to stop people from becoming obese. Genetic mutations that drove people to consume fewer calories were much less likely to be passed on, because in an environment where food was scarcer and its hunting or gathering required considerable energy outlay, an individual with that mutation would probably die before they had a chance to reproduce. Mutations that in our environment of abundant food now drive us towards obesity, on the other hand, were incorporated into the population. Things are of course very different now but the problem is that evolutionary timescales are long. It’s only in the last century or so, approximately 0.00004 percent of mammalian evolutionary time, that we managed to tweak our environment to such a degree that we can pretty much eat whatever we want, whenever we want it. Evolution has another couple of thousand years to go before it can catch up with the current reality of online food shopping and delivery.

 

[emsr2d2]

Each tiny step in evolution takes a very long time.

 

[keannu]

How is it related to being unable to catch up with current online shopping? Can you take an example?

 

[Tarheel]

How is it related to being unable to catch up with current online food shopping? Can you give an example?

No, I can't give you an example. Also, you unaccountably left out an important word (food) in your question. In any case, I doubt that it's a big part of food purchases. I think most people still buy their food at the grocery store.

 

[keannu]

I don't understand the whole passage

 

[Tarheel]

Before food was so readily available obesity was rare. People put most of their energy into simply staying alive.

 

[SoothingDave]

Human beings evolved over millennia to become very efficient at converting calories consumed into useful energy for the body. This was a result of an environment where gathering and raising food was a major consumer of effort for nearly all people. People had to walk and do physical labor.

Now, with the taming of cheap, reliable energy and application of industrial processes to food production, we live in a time where food is abundant, calorific, and delicious. Meanwhile, we have machines to move us around and do much of the physical labor.

This all happened in the past 200 years or so. Evolution happens much more slowly.

 

[Tarheel]

I don't understand it at all.

Changes in society have happened much too fast for evolution to keep up.

Human societies change through innovation, not evolution. (In fact, there is no reason to expect evolution to keep up (whatever that means).)

 

[keannu]

I was really confused with the term "mutations" below, thinking it means "genetically inherited mutation", but it seems to mean "some acquired change". So it seems to mean that abundant foods can make us fat, but our effort to get slim through inheritance doesn't work.

Mutations that in our environment of abundant food now drive us towards obesity, on the other hand, were incorporated into the population.

 

[5jj]

'Mutations' in that sentence does mean 'genetically inherited mutation'. We cannot make efforts to 'get slim through inheritance'.

 

[jutfrank]

The mutations mentioned are those that allow our bodies to efficiently store excess calories as fat. Nowadays, in a world where we have plenty of food, this means it's easy to become obese (which is bad for us), but back in the past when there wasn't so much food it was good for us, which is why it was selected for.

 

[Tarheel]

I don't know who wrote that, but I don't think there were ever as any such mutations. Getting enough food to survive has always been a full-time job. That is, it had been until fairly recently. Nowadays many people have occupations that are sedentary. Also, food is not scarce. It is abundant.