Naked Science Forum

Life Sciences => Cells, Microbes & Viruses => Topic started by: iacopo.russo on 06/10/2021 14:46:11

Title: Does the fittest always survive?
Post by: iacopo.russo on 06/10/2021 14:46:11
Tony wrote to us to ask:

Hey guys, Iím trying to find a paper I once read, is about E coli and the survival of the fittest, more specifically is about a experiment that shows that survival of the fittest might not be completely true under some circumstances, he put two version of E coli in a petri dish, one is the basic version, the other is a much more evolved, in theory the evolved one should wipe the basic one right out, but after a while they actually reached a balance where the evolved one have most of the territories but leave the basic one a good area to live.

Have you heard of that paper? What do you think of the results mentioned by Tony?
Title: Re: Does the fittest always survive?
Post by: Janus on 06/10/2021 16:00:34
"Survival of the Fittest", means the "best fit" for the present environment.  So, the newer strain could have just been better adapted to a wider range of conditions, if the petri dish was an environment that suited the original strain, there would no reason for the new strain to have an advantage over it since both could flourish under those conditions.
However, if you changed the conditions so that was more to the liking of one and less to the other, then one strain would dominate.
Title: Re: Does the fittest always survive?
Post by: alancalverd on 06/10/2021 16:33:43
Definition of fittest: that which survives or dominates in a competitive environment.

Collaboration or tolerance is sometimes advantageous.
Title: Re: Does the fittest always survive?
Post by: Zer0 on 25/10/2021 00:15:45
Hello Tony & thank you for your Question.
🙂

Now that the OP is Answered...

I wonder what happens to the %percentage of people who are willing to sacrifice their own lives, inorder to save others.

Like firefighters & lifeguards.

If they do not have kids before sacrificing their lives, then does the number/percentage of such good samaritans keep decreasing in the population?

Ps - is this, or might this also be a reason or contributing factor for increase in self preserving, selfish & greedy individuals in the society?
(If the Brave & Courageous keep dying in silly wars, would cowardice become a global trend)
Title: Re: Does the fittest always survive?
Post by: alancalverd on 25/10/2021 00:25:27
(If the Brave & Courageous keep dying in silly wars, would cowardice become a global trend)
To quote General Patton, who knew a thing or two about warfare: "No goddam sonofabitch ever won a war by dying for his country. You win a war by making the other goddam sonofabitch die for his country."
Title: Re: Does the fittest always survive?
Post by: evan_au on 25/10/2021 10:55:28
There is a model system used to demonstrate such equilibrium states, called hawks and doves.
- There is an input parameter indicating the damage done by a hawk
- Depending on the value of this parameter, you end up with a different equilibrium condition.

There are many other model systems like this.
See: https://en.wikipedia.org/wiki/Evolutionary_game_theory#Hawk_dove
Title: Re: Does the fittest always survive?
Post by: Bored chemist on 25/10/2021 12:35:38
I wonder what happens to the %percentage of people who are willing to sacrifice their own lives, inorder to save others.

Like firefighters & lifeguards.
Fire fighters wear breathing apparatus.
As far as I can tell, all lifeguards can swim.

This tells you that they are not willing to die .

They are prepared to put their lives at (limited) risk.
They do it for money.
That's not a rare motivator

Title: Re: Does the fittest always survive?
Post by: alancalverd on 25/10/2021 15:33:39
Fire fighters wear breathing apparatus.
As far as I can tell, all lifeguards can swim.
And sensible soldiers wear camouflage and armor.
Title: Re: Does the fittest always survive?
Post by: Bored chemist on 25/10/2021 18:50:08
Fire fighters wear breathing apparatus.
As far as I can tell, all lifeguards can swim.
And sensible soldiers wear camouflage and armor.
They also carry weapons.
Patton was right.
Title: Re: Does the fittest always survive?
Post by: evan_au on 26/10/2021 21:48:23
There is a similar question about why around 10% of the world's population is left-handed.
- If left-handedness had no impact on fitness, then you might expect it to be 50%
- If left-handedness was a genetic disadvantage, then you would expect it to die out

One theory suggests that in a world of right-handers, the occasional left-hander has the advantage of surprise - right handers are not used to facing a left-hander, while left-handers are familiar with facing right-handers (even in cricket or baseball, let alone hand-to-hand battle).
Title: Re: Does the fittest always survive?
Post by: alancalverd on 26/10/2021 22:25:28
I have an alternative theory. Start with some observations:
10% is an unexpected statistic in nature: most things happen half/half the time (male/female ratios) or most of the time/very rarely (double/triple sex chromosomes)
A great deal of the human brain is involved in walking and talking. Other mammals tend to be ambidextrous or weakly handed.

Suppose half the population has a genetic defect that prevents us from using our left hand as effectively as the right. This might arise from the need to develop speech and erect bipedal motion leaving insufficient brain capacity to finely control the left hand in childhood. (Why the bias? because we cannot be perfectly bilaterally symmetric - that would lead to a singularity down the middle! so most hearts are displaced to the left, etc)

The other half  are born ambidextrous so for the convenience of all, society is righthanded.  This gives the ambis a choice - run with the herd, or do your own thing. Assuming a Bayesian stance and no social pressure, this would lead to about 25% elective lefties and maybe a few obligate lefties  (remember that about 1 in 100,000 has a reversed heart!).

Interestingly, since UK schools stopped insisting on dextralism, the number of lefties has increased towards the predicted 25%. And several people have remarked on the dominance of sinistrals among undergraduate mathematicians and music composers, and the fact that lefthanded CEOs earn on average 10% more that dexrtrals!

There has also been a gradual increase in the number of professional cricketers who bowl right but bat left.

Title: Re: Does the fittest always survive?
Post by: Zer0 on 27/10/2021 16:22:29
SideNote - Not related to Alan's Questions.

But i found something, rather accidentally.

https://api.nationalgeographic.com/distribution/public/amp/animals/article/wildlife-watch-news-tuskless-elephants-behavior-change
🐘

Ps - i wonder, why don't Chicken pass on wisdom to their chicks.
When will they learn to use those damm wings & just fly away!
🐔
(Perhaps Wisdom cannot be transferred thru Genes, orelse they won't be layin fried on our plates)
Title: Re: Does the fittest always survive?
Post by: alancalverd on 27/10/2021 19:17:32
Ps - i wonder, why don't Chicken pass on wisdom to their chicks.
When will they learn to use those damm wings & just fly away!
Seems to be a bit of reverse evolution: some feathered dinosaurs returned to the ground, kept their feathers for warmth, and developed their pectoral muscles for scratching and fighting rather than flying. Despite having a huge sternal keel and tasty pectorals, a chicken doesn't have the aerodynamics of a duck even though its takeoff power to weight ratio appears comparable or even greater. The physiology has also evolved differently: duck breast meat is much darker, suggesting a better cruise performance through better oxygenation - jet engine versus steam engine!