Research shows not only the fittest survive

Mar 27, 2011

Darwin's notion that only the fittest survive has been called into question by new research published today in Nature.

A collaboration between the Universities of Exeter and Bath in the UK, with a group from San Diego State University in the US, challenges our current understanding of evolution by showing that biodiversity may evolve where previously thought impossible.

The work represents a new approach to studying evolution that may eventually lead to a better understanding of the diversity of bacteria that cause human diseases.

Conventional wisdom has it that for any given niche there should be a best species, the fittest, that will eventually dominate to exclude all others.

This is the principle of survival of the fittest. Ecologists often call this idea the `competitive exclusion principle' and it predicts that complex environments are needed to support complex, diverse populations.

Professor Robert Beardmore, from the University of Exeter, said: "Microbiologists have tested this principle by constructing very simple environments in the lab to see what happens after hundreds of generations of bacterial evolution, about 3,000 years in human terms. It had been believed that the genome of only the fittest bacteria would be left, but that wasn't their finding. The experiments generated lots of unexpected ."

This test tube proved controversial when first observed and had been explained away with claims that insufficient time had been allowed to pass for a clear winner to emerge.

The new research shows the experiments were not anomalies.

Professor Laurence Hurst, of the University of Bath, said: "Key to the new understanding is the realisation that the amount of energy organisms squeeze out of their food depends on how much food they have. Give them abundant food and they use it inefficiently. When we combine this with the notion that organisms with different food-utilising strategies are also affected in different ways by genetic mutations, then we discover a new principle, one in which both the fit and the unfit coexist indefinitely."

Dr Ivana Gudelj, also from the University of Exeter, said: "The fit use food well but they aren't resilient to mutations, whereas the less efficient, unfit consumers are maintained by their resilience to mutation. If there's a low mutation rate, survival of the fittest rules, but if not, lots of diversity can be maintained.

"Rather nicely, the numbers needed for the principle to work accord with those enigmatic experiments on bacteria. Their mutation rate seems to be high enough for both fit and unfit to be maintained."

Dr. David Lipson of San Diego State University, concluded: "Earlier work showed that opposing food utilisation strategies could coexist in complex environments, but this is the first explanation of how trade-offs, like the one we studied between growth rate and efficiency, can lead to stable diversity in the simplest possible of environments."

Explore further: Illuminating the dark side of the genome

Related Stories

Time in a bottle: Scientists watch evolution unfold

Oct 18, 2009

A 21-year Michigan State University experiment that distills the essence of evolution in laboratory flasks not only demonstrates natural selection at work, but could lead to biotechnology and medical research ...

Researchers devise way to calculate rates of evolution

Oct 03, 2007

“Survival of the fittest” has popularly described evolution for more than a century, but a new study published in the Royal Society journal Biology Letters provides further evidence that random genetic mutations over m ...

Stability and Diversity in Ecosystems

Aug 03, 2007

Is biodiversity important for predicting human impacts on ecosystems? If diverse ecosystems were as a consequence more stable, the answer would be yes.

How bacteria evolve into superbugs

Jul 27, 2007

Researchers at McGill and Oxford Universities have applied ecological and evolutionary theory to demonstrate how bacteria become resistant to antibiotics in hospitals.

Recommended for you

'Killer sperm' prevents mating between worm species

24 minutes ago

The classic definition of a biological species is the ability to breed within its group, and the inability to breed outside it. For instance, breeding a horse and a donkey may result in a live mule offspring, ...

Rare Sri Lankan leopards born in French zoo

3 hours ago

Two rare Sri Lankan leopard cubs have been born in a zoo in northern France, a boost for a sub-species that numbers only about 700 in the wild, the head of the facility said Tuesday.

Japan wraps up Pacific whale hunt

4 hours ago

Japan announced Tuesday that it had wrapped up a whale hunt in the Pacific, the second campaign since the UN's top court ordered Tokyo to halt a separate slaughter in the Antarctic.

Researchers uncover secrets of internal cell fine-tuning

4 hours ago

New research from scientists at the University of Kent has shown for the first time how the structures inside cells are regulated – a breakthrough that could have a major impact on cancer therapy development.

User comments : 23

Adjust slider to filter visible comments by rank

Display comments: newest first

antialias
4.9 / 5 (16) Mar 27, 2011
This only calls Darwin into question if you have a mono-causal approach towards what constitutes 'fit' and what constitutes 'unfit'

The authors of the study obviously haven't understood that there are many factors which add up to a 'fit' and that therefore there can by dynamic equilibrium of many species competing in one niche (more precisely: by their own behaviour they aren't competing _exactly_ for the same niche)
frajo
2.5 / 5 (4) Mar 27, 2011
therefore there can by dynamic equilibrium of many species competing in one niche (more precisely: by their own behaviour they aren't competing _exactly_ for the same niche)
Yes. But this is equivalent to saying that there is no "fittest" species.
210
2.2 / 5 (9) Mar 27, 2011
Adaptive Evolution would require 'fitness' NOT the fittest.
See...Dinosaurs in their progressive domination of the earth exceeding a billion years roughly NEVER learned to make a toenail clipper or a dishwasher, or a submarine, or a written word. Not very SOPHISTICATED but they were CERTAINLY fit enough to endure and thrive by the rules of 'survival of the fit.'
They HAD to be KILLED off (They did not just DIE off) IF we were ever going to get a shot because at the root of the argument for whatever the earth wanted to see roaming about on her, the DNA of massive, swift, and powerful dinosaurs was too 'dangerous' for 'that-which-would-come,' next.
They were fit, we have a chance of claiming the fittest title if we can develop the means to survive what wiped them out,and IF we do not wipe ourselves out; ALSO something the fit (Dinosaurs) could never do...wipe each other out!
You/we have to have a college degree and a computer (Windows PC) to do that!!
-word-to-ya-muthas-
Subvertia
5 / 5 (6) Mar 27, 2011
Having worked in the bar business for 20 years now, I could have proven this years ago.
antialias
4.2 / 5 (5) Mar 27, 2011
Yes. But this is equivalent to saying that there is no "fittest" species.

It is. But there is no single, identical, niche that two species compete for. So each species is the most fit for its niche.
Parsec
4.7 / 5 (7) Mar 27, 2011
So what I am reading here is that fitness is a multi-variable function, and that when an environment that contains multiple stressors, (in this case high mutation causes and moderate food shortage), different sub-populations evolve so that each is the most fit for it's particular niche.

I don't find this remarkable, except to note that this is a different route for creating new species. The number of potential stress differentiators are enormous.
kaasinees
3.6 / 5 (5) Mar 27, 2011
Reminds me of the fish that evolved to live near chernobyl in the radiation. Its an article on physorg not to long ago.
Jotaf
4.7 / 5 (6) Mar 27, 2011
Actually, you don't want to overfit or you'll be wiped out as soon as the environmental conditions change. Having lots of mutations makes a species less fit for a particular environment, but in a broader sense the species is fitter, because if the environment changes they have a good pool of diverse genes to draw from. That's why bacteria mutate faster than us while we have anti-mutation systems in place; both are valid niches/ways of life; we're more complex which requires stability, they are more adaptive.

So as Antialias pointed out, the evolutionary pressures at work here are just different from the typical pre-conceived notion of a local fit. For those who can think in a little more abstract terms, there's this: http://en.wikiped...rfitting
hush1
5 / 5 (1) Mar 27, 2011
"Rather nicely, the numbers needed for the principle to work accord with those enigmatic experiments on bacteria. Their mutation rate seems to be high enough for both fit and unfit to be maintained."


Below is what the "enigmatic experiments on bacteria" is referring to - a kind of hypermutation response (within hours) to growth-limiting environments.

Adaptive amplification and point mutation are independent mechanisms

"Adaptive mutation" denotes a collection of processes in which cells respond to growth-limiting environments by producing compensatory mutants that grow well, apparently violating fundamental principles of evolution.
frajo
4.7 / 5 (3) Mar 28, 2011
Yes. But this is equivalent to saying that there is no "fittest" species.

It is. But there is no single, identical, niche that two species compete for. So each species is the most fit for its niche.
IF each species is occupying its own, exclusive niche in the biosphere THEN the fitness measure has lost its meaning. And IF fitness has no meaning THEN there is no "fittest".
frajo
4.3 / 5 (3) Mar 28, 2011
So what I am reading here is that fitness is a multi-variable function
...
I don't find this remarkable
It _is_ remarkable as there are uncountable texts, notions, and philosophical as well as political movements building (justifiably or erroneously) on exactly that concept of the "survival of the fittest". To get rid of this idea is revolutionary.
Sanescience
5 / 5 (2) Mar 28, 2011
The process of natural selection can also be viewed from "top down", meaning that the environment frequently molds how inhabitants look and behave. An example being unrelated fish in the arctic and antarctic regions separately adapting to surviving in the cold with the same amazing molecular tricks.

So what becomes seen as the "fittest" or not might just be a case of not fully understanding the environment that is shaping them.

And then there is the whole question of cyclic feedback systems where the environment effects the inhabitants, then the inhabitants effect the environment, and the inhabitants have and effect *as* the environment on themselves and others resulting in endless rock-paper-scissors like games. Which was the actual topic of a recent paper on physorg.

http://www.physor...ity.html
DavidMcC
5 / 5 (2) Mar 28, 2011
This only calls Darwin into question if you have a mono-causal approach towards what constitutes 'fit' and what constitutes 'unfit'

The authors of the study obviously haven't understood that there are many factors which add up to a 'fit' and that therefore there can by dynamic equilibrium of many species competing in one niche (more precisely: by their own behaviour they aren't competing _exactly_ for the same niche)

Frajo, antialias is correct, the term "fittest" only refers to the specific niche being competed for. If that niche gets split, then there is still only one fittest allele for each niche.
DavidMcC
5 / 5 (2) Mar 28, 2011
Actually, population-dependent selection casn also create more than one "fittest" allele. IF they found that the populations were counter-oscillating, that would suggest that this is happening.
antialias
4 / 5 (4) Mar 28, 2011
And IF fitness has no meaning THEN there is no "fittest".

You are perfectly correct: Since each particular niche (consiting of the environment AND that particular organisms's effect on the environment) is unique then there is no real point in calling any organism 'fittest'.

A term which has no alternative carries no information and therefore can be omitted. In this case being 'unfit' is not an option.

On the other hand if you take the long term view and look at which species survive rather than the niches then you can delineate fit from unfit (alive from extinct). But that again would lead to the question: What is fitter? A species that is alive now but will probably be extinct in a year or one that is extinct but was alive for millions of years at a time?
Chevyzilla
1.8 / 5 (10) Mar 30, 2011
Ever notice how the evolution scientific community constantly changes what they believe once they realize how rediculous the previous statement was or how it contradicts the previous and can't really explain it. They will say that it is because they learned something new and all things are constantly changing so they have to adapt. Well that means that technically nothing is ever really fact only theory so therefore quit stating everything as fact when you really have no idea at all. Instead you would rather we all believe that we came from a rock 4.5 billion years ago. You can tell by how the evolutionists change thier wording such as instead of all matter being the size of a pin head and exploding, now they say it expanded. Same thing. What happens when something explodes. IT EXPANDS. Duh Huh. but that doesn't sound so rediculous. The whole scientific community is nothing but one big contradiction. Science is great but you won't find your answers because thats not how we got here.
antialias
4.3 / 5 (6) Mar 30, 2011
Well that means that technically nothing is ever really fact only theory

Duh. That's why all scientific principles are called theories (Theory of Relativity, Newton's theory of motion, ... )

Instead you would rather we all believe that we came from a rock 4.5 billion years ago.

Belief would be necessary if there was no test for this. Since there are many (independent) tests you can make to check this (and each of them are consistent with each other) the probability is very high that that theory correlates well with reality. Certainly the confidence value inthat theory is a lot higher than relying on 'In my book it says something differently without any kind of test/proof/corroboration'

Science goes with the theory that best explains all observations 8and has th best track record of predicting future events which are relevant to the field). Being 'correct' isn't the issue. It's just being 'best available' which counts. _Of course_ this means that all is open to change
DavidMcC
3.7 / 5 (3) Mar 30, 2011
Chevyzilla, the real problem with the OP article is that it doesn't allow for division of the niche. By assuming no division, it incorrectly concludes that the theory is wrong, even though it already incorporates such diversification.
Terrible_Bohr
4.3 / 5 (6) Mar 30, 2011
Ever notice how the evolution scientific community constantly changes what they believe once they realize how rediculous the previous statement was or how it contradicts the previous and can't really explain it. They will say that it is because they learned something new and all things are constantly changing so they have to adapt.


I know -- It's like they're making models based on observation! How naive is that?

The whole scientific community is nothing but one big contradiction. Science is great but you won't find your answers because thats not how we got here


Better to just stick to one arbitrary answer to everything, and then place your horse blinders on, eh?
Terrible_Bohr
4.5 / 5 (4) Mar 30, 2011
On the other hand if you take the long term view and look at which species survive rather than the niches then you can delineate fit from unfit (alive from extinct). But that again would lead to the question: What is fitter? A species that is alive now but will probably be extinct in a year or one that is extinct but was alive for millions of years at a time?


Given those two choices, you would have to look at total spans of time. Otherwise, you'd be saying that being alive right now is somehow more significant than living in a different era.
dogbert
2 / 5 (4) Apr 03, 2011
Not to worry.

Evolution theory is broad enough to encompass almost anything.
ormondotvos
5 / 5 (1) Apr 03, 2011
So everyone's an evolutionary statistician and Darwin theory analyst now?

How interesting.
ColdDimSum
not rated yet Apr 19, 2011
Darwin covers this in Origin of Species. The flaw is in your understanding of what was meant by 'Fittest' - you are applying your own subjective criteria and not the objective criteria of Nature. Read the book.