The beauty of evolution: one formula that links the size of the creature to its metabolism, and is valid for both animals and plants.
Why does a mouse's heart beat during its lifetime about the same number of times as an elephant's heart, even though a mouse lives for about a year while an elephant can live 70 years? Why do small plants and animals evolve faster than large creatures? Why did nature choose many configurations for the flowering trees while the tiger is symmetrical?
These riddles have intrigued those involved in the life sciences since ancient times. Now members of a multidisciplinary team of researchers from the University of Maryland and the University of Padua in Italy offer a possible answer, based on a mathematical formula known for generations, which until now has not been properly understood. In a study published on February 17, 2014 in the Journal of the National Academy of Sciences (PNAS), members of the research team suggest rethinking the formula known as Kliver's law. They see this formula as one of the mathematical expressions of an evolutionary fact, according to which new forms of plants and animals are created at the same time in order to be more efficient in terms of energy.
Kleiver's law states that the metabolism is equal to the body mass to the power of three quarters. The formula named after the Swiss biologist Max Kleiber (Max Kleiber) is one of the most common formulas in biology and was formulated by Kleiber in the 20s. The formula shows that the larger the organism, the more its metabolism and life span increase at a predictable rate . It is suitable for comprehensive observations, starting from the animal's energy consumption and ending with the number of its offspring. In addition to this, the formula is used to calculate the correct dosage of drugs for humans that should be tested on mice.
However, why did Kleiver's law apply? Generations of scientists have not been able to find a simple and convincing explanation for this.
In the new study, the researchers present a hypothesis according to which the forms of animals and plants evolved as a response to the same mathematical and physical principles. By using the logic of Cleaver's mathematical formula and applying it separately to the geometric configuration of animals and plants, the research team members were able to explain decades of observations.
"The forms of animals and plants evolved more or less simultaneously," says botanist Todd Cooke from the University of Maryland. "The first animals and plants had simple shapes, but natural selection acted on both groups, so that the geometry of trees and animals in modern times shows impressive energy efficiency. Both are compatible with each other, and this is what Kliver's Law shows us."
Imagine two creatures: a tree and a tiger. In evolutionary terms the tree has the easier task: to convert sunlight into energy and transport it within its body in order to survive. In order to perform the task in the most efficient way, the tree developed branches and leaves with a large surface area.
"The surface area of a tree and the volume of space it occupies are more or less the same," says physicist Jayanth Banavar, dean of the School of Computer Science, Mathematics and Neuroscience at the University of Maryland. He adds that "the nutrients of the tree move at a constant rate regardless of its size".
Equipped with these variables, the researchers examined the relationship between the masses of different tree species and their metabolic rate, and found that this relationship is in accordance with Kliever's law.
And what about the animals? To maintain its mass, the animal must eat. Burning food creates heat, and the animal must find a way to get rid of the excess heat. The most effective way to do this is cooling using the surface facing outwards - the skin. However, since the surface of the tiger skin, for example, is small in relation to its mass, they fail to meet the task; The shell of the skin heats up and its fur may burn. Therefore, the larger the animals, the more their metabolism increases at a slower rate than the volume, otherwise they would not be able to get rid of the excess heat. The metabolism must grow at the rate at which the creature itself grows to the power of two-thirds. However, Kliever's law and the observations on which it is based speak of a power of three quarters.
It is evident that there is a missing factor in the picture, and to discover it the researchers dug into the data. Some of them suggested adding to the equation the part occupied by the internal organs; Others focused on the branching or fractal form, characteristic of tree branches and animal blood vessels, but added new assumptions about the volume of liquids in the fractal branches.
The researchers determined that another variable should be examined, which is the rate of food movement through the animal's body and the heat it consumes. The members of the research team calculated the heartbeat rate, which indicates the strength of the blood pumping in the heart, and discovered that the change in blood flow speed is equal to the mass of the animals to the power of one divided by twelfth.
"The data was there all along but it had to be noticed," said hydrologist Andrea Rinaldo from the University of Padua in Italy from the Ecole Polytechnique Federale in Switzerland. He adds that "the animals must adjust the flow of nutrients and heat to changes in their mass to maintain maximum energy efficiency. This is the reason why the animals need a pump - the heart - and the trees do not need it."
By adding this variable into the equation, the researchers arrived at a complete explanation of Kliver's Law.
"An elegant answer is sometimes the right answer, and this answer has elegance in the sense of using simple geometric arguments," explains physicist Amos Maritan from the University of Padua. "The formula does not require special structures and has very few prerequisites. We have two lineages - animals and plants - and despite being very different from each other, in both we reach the same conclusion. This is called convergent evolution and the amazing result is that it derives from the laws of physics and mathematics."
For information on the University of Maryland website
26 תגובות
You are right about the progress. An enlightened person thinks that it is enough that the ancient Greeks said something to make it untrue. The height of enlightenment.
And especially an enlightened person tends to ignore the main claims and does not admit that he does not understand what it is about, only that the other is stupid.
point
You are a bit confused. A bit much I think
My computer uses power on the table... and there is no transmission in motion.
"A stone has an ambition to be drawn towards the earth" - that's how the ancient Greeks thought, you have to move with the times 🙂
The continuation of your response is only worse, and does not deserve to be addressed...
In order to preserve something you must take an action that will prevent it from being preserved. And that's exactly what Law of Nature does. It's the same thing from two opposite points of view.
The law of conservation of energy always holds. The law of conservation of momentum always holds. Force is simply a derivative of momentum.
Suppose you are holding a stone in your hand. So you oppose its acceleration towards the Earth. You feel the effort you put in. You feel the power. This force that you feel just proves that the stone has an aspiration to be drawn towards the earth. This ambition is influenced by the future. The stone knows where the minimum is and it strives there. This is called having influence from the future. If the stone did not know about the future, no force would act on it.
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You are contradicting yourself: "taking care to preserve them" and "acting on them" are two different things. There are mathematical models according to which we know how to predict what a physical cave will do as time progresses.
Example: A stone falls and accelerates. The stone accelerates because a force is applied to it, and not to comply with the law of conservation of energy.
I asked you to give me an opposite example...
Miracles, we can't say why it is, so we call it a law of nature.
When we define a law of nature those things that nature takes care to preserve (act on them).
But why does nature even care about the laws of nature? What is the purpose of this? We have no answer.
Does all this lead anywhere? We have no answer.
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Why do you think nature takes care of this? What is his motive? After all, worry has a purpose, right?
I don't understand what is unclear in what I said.
In other words: out of all the possible paths (S) for the next moment, nature will make sure that dS=0. This means that out of all the possible actions in the present (for the purpose of the matter there are infinite possibilities), nature makes sure to take the option that will give minimum action from the present to the next moment (which is in the future). And all this is just classic mechanics.
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I'm not ignoring you, I'm the one responding to you. Didn't you notice?
You say "nature takes care of minimization for the future" - and I responded that this is not true. What for nature and the future? In nature there is only a present that is guilty of the past. that's it.
If you think otherwise - show me a phenomenon that happens because of the future and not because of the past. Start with Newton's physics, where it will probably be easier for you.
Miracles I am talking to you exactly about classical physics and for some reason you ignore what I say and refer to marginal things like the personification of nature.
"The formula shows that the larger the living thing, the more its metabolism and life span increase at a predictable rate."
Humans, turtles and lobsters are small animals with long lifespans. Why is the formula not valid for them?
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Again - you personify nature. Does nature "care"? …. Definately not.
In classical physics at least, the future has no effect on the present.
Miracles. When things happen because of things in the past then that's really the cause and effect you're talking about. But when things happen because of things in the future then it is considered a goal/purpose.
The next moment is the future. And if nature takes care of minimization for the future, then it is purposefulness.
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Does nature choose? Is nature watching? Where exactly is your understanding here? Things happen because of things, not for things.
The members here do not understand physics that much.
In short, from a physical point of view, nature chooses the route (the action) with some certain minimum. That is, nature does look at what can happen in the next moment and chooses the minimum. Then it definitely meets the definition of purpose.
her daughter
I mean why - for what purpose, why - because of what.
A baby kangaroo (why a kangaroo?) acts without any purpose. The mother wets the fur and the cub (not that this is the correct name) climbs along the wet fur. It's instinct, like a hatchling turtle running towards the sea.
If a researcher is asked to explain why a baby kangaroo crawls into a pocket, what do we do if the answer is "this is its purpose". It's just like Aristotle's explanation of the falling stone lemma.
Also in psychology - if we say that a person wants to be in society because that is his goal, what have we learned? is nothing? You should always ask what the reason is. That's what you learn from. Otherwise, it becomes like a religion…..
daughter
You are making a mistake that many repeat. Let's take the kangaroo cub for example.. the jump into his mother's pocket, he does it out of instinct. No conscious thinking is done. Every intelligence needs a language, an arrangement of a work plan or a series of actions done one after the other that can testify to. Thinking.. When talking about goals, it should be done in cognitive contexts
Miracles,
According to the Hebrew language why and why are the same thing.
And in addition, I think you were right in regards to the title, but you should have stopped there because, for example, a kangaroo cub that is born has a goal to climb and reach its mother's pocket, and this cub is not acting rationally, and this is just one example of many in nature, so even animals that are not rational have goals .
If anywhere it says "why" or "why"
It was written: For what, or what is the advantage, or why is it good,
If things were more in line with reality,
And there was a better fit to the Kliver equation / law.
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You can also say that a stone falls to the ground because that is its natural place - but that does not make it true.
A plane coming in for an automatic landing raises its nose in preparation for landing. The "purpose" of lifting the nose is to reduce speed, but the plane lifts anyway because that is how its steering control computer is programmed.
It may seem like philosophizing to you, but after that people believe that the purpose of a bird's wings is to fly. And if there is a goal, then there is a being whose goal is his, and then suddenly there is God and all kinds of nonsense like that.
In my opinion, it is always correct to ask "why" and not "why", because only intelligent beings have goals.
This equation is very "clean" in relation to what really happens in nature, because even if the metabolism, for example, is constant, at the same time the tree or the animal has to fight pests and diseases whose goal is to eliminate their host, and this requires a great deal of energy and ingenuity. It seems to me that this is a study that talks about one adapted component in evolution, but this is certainly not the goal or a driving factor, as written here.
When something has to happen, you can say that this is his goal.
I would change the word "purpose" to "motivating factor" - like reactions in chemistry, which have no purpose but have a factor that makes them go in a certain "direction".
Saving energy is the goal of every physical process and biology is part of physics
Mr = tiger
hi father
The photo attached to the article is of Tigris and not of Mr. Please replace a photo or name about the life that appears in it.
There are several inaccuracies in the body of the article, but I don't know if they are due to the translation or the claims of the researchers. Unfortunately, the time I can devote to this week's topic is over.
my father
The phrase "purpose" of evolution bothers me. Processes have no goal, they are the result of preconditions.
I'll be even more extreme - people don't really have goals either. We always act because of something, and not for something.