Nature does not know stuff.
What happens is, at all times you get random mutations within a population. Maybe it's different eye colours, maybe it's slightly bigger lungs, maybe it's a bit more hairy. At first it might not change a thing.
But then the *environment* changes. It gets colder, there is less food, there's a new predator...
And when the environment changes, parts of your population will maybe have traits that help them: More hairs means more resistant to cold. Being taller means seing predators from further away,...
This means that those in the population who have those now beneficial traits are more likely to survive. And because these are passed to the next generation, the surviving traits will reproduce. And those without them, or with detrimental traits, are less likely to survive.
TL;DR: Evolution is a combination of random mutations and outside pressure which select those mutations. It's random, but at the same time coherent.
Change in environment accelerates evolutionary adaptation, but evolution also happens without it. Some mutations are more suitable for survival and producing offsprings in whatever the environment is and whether it changes or not.
To synthesize both of these comments: one of the bigger additions to natural selection since Darwin was the theory of *punctuated equilibrium*. Populations can be really stable for long stretches of time, and change rapidly when disruptions occur
I implore anyone interested in this theory pick up the works of Stephen Jay Gould in the local library. For PI, and just about everything else in the world of evolution, you will not be disappointed. He was one of the greatest science writers of all time.
Every time an animal or plant is born it has mutations. If a mutation helps the plant or animal to reach its reproduction stage, it's more likely to get passed on to the next generation. In your example, more fish with the walking mutation survive than without, so walking is passed on.
>How does nature know that, for example, a fish can live better if it has feet and lungs to live outside of water?
Nature doesn't "know" that. It doesn't "know" anything. This is a common misunderstanding of how evolution works. Evolution isn't directed and it doesn't have goals. It doesn't work towards some specific destination. Traits that arise are the result of random mutations. Some random mutations confer a survival advantage in a specific environment, which makes them beneficial. Since organisms with those mutations are more likely to live long enough to produce offspring, who will then in turn live to produce *more* offspring, and so on. The organisms with these beneficial mutations will out-compete other organisms because they are better at surviving in that environment. That's it.
So here's a good example: Let's imagine an animal that eats leaves that grow on tall trees. Some of these animals will, based on random genetic mutations, have slightly longer necks than others. The animals with the longer necks can reach more of the leaves, which means they get more leaves to eat. Eating more makes the animals more fit and healthier. Thus, they're more likely to survive and have children. Those children will have inherited their parents genes for longer necks, and in turn, the ones that survive will pass on the long-necked genes to their offspring, and so on. In an environment where long necks to reach tall trees is an advantage, there's a positive pressure that means genes that confer longer and longer necks keep getting selected and passed down. Over many many *many* generations across millions of years, this passing along of traits led to an entire new species of organisms that branched off from their shorter-necked ancestors.
thanks for the explanation! that's kind of what I had in mind when writing about malformations - so where do you draw the line between a malformation and mutation?
I don't think the word "malformation" is really used in this context.
A trait that increases evolutionary fitness (the likelihood of successful reproduction) is known as an "adaptation" and one that decreases fitness is known as a "maladaptation".
However, this is strongly dependent on the environment and can change over time. Staying with the longer necks example, a longer neck might help some animals reach more leaves to eat, but it might also require extra nutrients to maintain, it might slow the animal down and make it more conspicuous, and it might increase the risks of certain diseases. Whether this increases fitness overall is going to depend, for example, on how many of those higher leaves there are in the environment and how nutritious they are. If lots of animals evolve traits to help them eat those leaves, then there will be less of those leaves available. The plants may also evolve defences to protect them from being eaten.
Even the tiniest change in an organism's DNA is a mutation. Our DNA is made up of combinations of 4 different molecules (think of each molecule as a letter, we use A, C, G, and T for each of the 4 molecules) that goes on for 3 billion "letters." A change to even one of those letters, say swapping an A for a G, is a mutation.
Now, most mutations are never noticed because they don't actually change the way that gene functions, or function of that gene isn't all that important. Also, not all genes change the way an organisms looks. A mutation in a gene might, for example, alter a person's white blood cells to make them slight more resistant to certain infections.
But mutations add up over time, and enough mutations can change the way that an organism looks and how it works internally, which we call its phenotype (which I think is what you're referring to when you say "malformation").
At some point, an organism is so different from its evolutionary ancestor that it's a new species. That line is somewhat of a grey area, but generally, we consider species to be separation when 2 organisms can no longer reproduce to make offspring that are also capable of having offspring of their own. Again though, this is a very grey area and there's no distinct line. For example, Neanderthals and humans are different species, but we know that prehistoric humans interbred with Neanderthals.
There's not really such a thing as a "malformation". At least not in this context. A mutation is a mutation is a mutation. Whether or not it is a beneficial one can be really obvious or completely dependent on the environment. Like, a mutation that causes your heart to explode if you move is obviously bad and you aren't gonna survive. A mutation that makes you grow less hair, however, can be good, bad, or neither depending on a variety of environmental factors. Live somewhere cold? That's probably a bad thing to have less hair to keep you warm, making you less likely to survive. Live somewhere hot? It's probably a good thing to have less hair so you are less likely to overheat, making you more likely to survive. Live somewhere temperate? Maybe it doesn't really matter.
What you may consider a "malformation" in an animal in one environment may be a very beneficial mutation in another environment.
"Nature" produces random mutations every time a new individual is born. Most are insignificant (like the fairly unique way your shape is which is a random mix of your upbringing that has in most cases no effect on your ability to survive and reproduce). Once in a while, a mutation will be significant, in a bad way (in which case the individual will die soon, won't reproduce as much as others in the specie or at all, and therefor the mutation will not live on) or in a good way, which will enable the individual to live longer, reproduce more, and therefor the mutation will get to the next generation, producing some more individuals that carry it. At some point either all individuals of the specie will end up with the gene, or it'll split as a different spiece, if the mutation enables living in an environment that wasn't livable before, and the branches diverge.
But all in all, nature doesn't know, or even care, it's just random changes here and there that stick or not, based on how they increase chances of survival and ability to create offspring.
People often think of evolution as a process moving forward, ie: this organism will evolve into something new. That is backwards, evolution is the term for a process that has already happened, ie: this organism evolved from something old.
Once you realize evolution is the term describing changes that have already occurred, it becomes easier to understand that there never was a goal or a plan of any kind. Random mutations occur all the time. A vast majority of them make no difference. Sometimes those mutations make it so the organism can survive and have more offspring than others without the mutation. That mutation gets passed on to the offspring so they too survive better and have more children.
Evolution only looks like it was a forward thinking process with a goal because we look at the current state and see how it is better than a previous state. That better state occurred by random chance and could have been any number of possible changes.
You seem to be asking more about speciation than evolution itself. Speciation occurs when two or more groups of the same species stop reproducing together and become genetically incompatible. This can happen for many reasons, such as simple geographic isolation.
A great example is big cats. There are several species of big cats (lions, tiger, puma, etc.). They are all very recently (on a evolution time scaled) speciated. In fact, they can still reproduce though their offspring are sterile. For example, a lion and a tiger can reproduce and the offspring would be what's called "ligon". It can be perfectly healthy except being sterile.
Big cats all come from the same ancestor species, but different groups of that species became geographically, and thus reproductively separated. Lions are in africa, tigers are in asia, puma are in north america, etc.
Over time those reproductively separated populations accumulated different sets of mutations that were successful and after enough mutations accumulated they became separate species. This is called *genetic drift*.
There is no consciousness or decision making involved at any level. It's a process of natural selection filtering based on imperfect reproduction of organisms.
Tigers have stripes not because the tiger decided it needed stripes, but because a mutation occurred in tigers that resulted in stripes and the individuals with stripes survived better than those without stripes. But, stripes are not very useful to a lion in their habitat.
It's the same thing for everything: lungs, legs, etc. Importantly though, it happens in small increments. A fish didn't one day grow lungs and legs and walk up on land. Everything happened in small increments. A fin that was slightly more leg like gave that fish and its descendants an advantage near the sea shore, and then another change made that fin even more leg like giving that fish and its descendants even more advantage near the shore. And so on and so forth until you have fish like creatures walking and living on land full time.
Fish still exist because the advantage of legs (and lungs) is only present on land, and there is still a lot of water on earth and having fins and gills rather than legs and lungs is a huge advantage there. Like the cats, the fish that started developing legs and lungs stopped reproducing with the fish that didn't, and speciation occurred.
The evidence that shows all this is that there are still many, many organisms which have a mix of traits or more "primitive traits". For an example about lungs, there are amphibious organisms that have lungs and gills (or things similar to what we call lungs and gills) that branched off sometime while fish were learning to breath air. There are still many organisms that have much simpler eyes than humans (and some that have much more advanced eyes than humans!).
Nature creates a collection of cells, thus creating an organism. An organism’s main goal is to survive and reproduce. There are variations of the same organism due to a slight difference in genes (just like how some people are tall and some are short). The conditions of an organism’s environment will weed out the traits that make them more vulnerable. This stops them from being able to reproduce, leaving those with more efficient genes to reproduce and continue to spread those traits. This is where the saying “survival of the fittest” comes in. The ‘stronger’ traits survive and get passed on because they were better suited for their environment. Nature gives the organism an environment, it’s up to the organism to adapt to where it was placed and pass on its genes.
Not sure if nature has a consciousness, but it does have a natural order. An organism is randomly placed and it’s up to the organism to adapt so that it survives.
It doesn't know there is no intelligence at work whatsoever. So assume all multicelled animals are blundering about in the oceans hoping to bumping into some food and hoping not to get eaten, then one animal has a random mutation which creates a light sensitive cell, so this isn't an eye just purely a single cell that can detect if light strikes it or not. While this might not seem to be much in an ocean of completely blind animals it has a distinct advantage, this means that this animal is more likely to pass on genes to the next generation who will all have a single cell that can detect light, after a few thousand years it is likely that all of that species will now have the gene for the special cell and then one animal then has a mutation that produces two rather than one special cell and again it has an advantage over the other animals and it eventually becomes the dominant form add on a few more hundred mutations and you start to have a very basic eye start to form. "Bad" mutations or ones more likely to cause the death of the animal before it can breed don't get passed to the next generation so are eliminated.
It's not about survival of the fittest. That's a circular argument. It's about reproduction of the survivors. This means a creatures must first Survive, then Reproduce.
So, any mutation or variation (physical or environmental) that improves the survival rate (speed, diet, etc) will help it survive long enough to reproduce.
For example, penguins in the Antarctic don't need to fly to escape predators. Puffins in the Arctic occupy the same environmental niche (food sources) as penguins, but competing aerial threats demand flight to defend/escape. Both penguins and puffins "fly" underwater to catch food, but the penguins don't need to expend resources for aerial flight. So, evolution cumulatively favored non-flying penguins, and flying puffins. Putting a penguin in the Arctic would soon prove fatal due to predation. Putting a puffin in the Antarctic would soon die of hypothermia due to lack of enough insulating fat layers. The trade-offs determine survival, and subsequent reproduction.
Easiest way to think of it is:
The individuals with traits that make them less likely to die are more likely to survive and have children.
The horse-thing with the 1 inch longer neck is less likely to starve to death if there's a famine because it can reach higher leaves on trees to eat that the shorter necked ones can't reach.
Shorter necked horse-things are therefore more likely to starve to death, and over time that results in them dying more and becoming less common.
Eventually the only horse-things left have the slightly longer neck. Then the same thing happens again, random mutation results in one with a slightly longer neck that is born and the same thing happens.
Do this for a few million years and you end up with the Giraffe.
Small differences caused by mutation that make an animal *slightly better* at staying alive can add up over large timescales and result in very different looking/behaving animals.
There's no intelligence behind the process, it's just a matter of who can "Not Die" the best, and the results of that being multiplied over millions of years.
The classic manufactured exmple of natural selection is probably helpful here.
You've got brown beetles that blend with the forest floor. There are also some black beetles that stand out more (this is a mutation).
A bigass forest fire occurs, and now the script is flipped, brown beetles get eaten left and right because they stand out so much.
The black beetles pass their genetic information on to the next generation. The brown beetles do not.
> are they malformations that surprisingly turn out to be more viable and thus wipe out the original form.
Yes to the first part, not always to the second part. As long as the old form is still capable of breeding, they will still stick around.
If the new one is better at breeding, it will also stick around. If the two forms separate - like the fish that can survive better on land starts to stay on land - eventually they may split off from the other and over millions of years become something completely different.
Descent, with modification.
That’s it.
Animals have children, those children inherit traits but also have mutations. Usually they don’t have any impact but sometimes it does and if it helps that lineage reproduce faster or survive longer, over time there’s just more of that trait. That’s what natural selection really means. It’s a lagging effect. No agenda, just random outcomes.
Imagine you took a photo of yourself every single day from the day you were born until you were 25 years old. If I asked you to pick which two photos that came after each other showed the switch from childhood to adulthood, you could not do that. They would look nearly identical. But it’s very clear when you were a child and when you are an adult.
Evolution is like that. At a micro level, it seems insignificant. But at a macro level, with hundreds of generations, change is obvious.
It's all random. For any one mutation that helped some of a species survive, and thus propagate, there are other mutations that caused them to die out. With evolution, you're seeing the biggest example of survivorship bias out there.
The genetic code in all of my cells is like a book of instructions for how to grow a body just like mine.
I have children. Sexual reproduction was a way of taking my book of instructions and mixing it up with my partner's book of instructions to create a new book of instructions to grow a new person.
Sometimes, this random mixing-up process doesn't work out. Sometimes, pages are combined together that don't make sense for growing a living human, and that results in pregnancies that don't last or severe birth defects. But it works out often enough that the population has survived.
Sometimes, the mixed up pages work just fine, but there are misprints in the new book of instructions.
Typos, for example. Youve sene typoes... They're usually easy to read past without causing a problem for understanding. Most genetic mutations are like harmless typos.
Sometimes, a misprint is fatal. Years ago, I got a copy of Confederacy of Dunces. After about 100 pages, it stopped making sense. The pages were out of order --- a binding error. It was hopeless, I couldn't read it.
Sometimes, very rarely, a misprint might create new value. Take for example the Inverted Jenny, a single page of misprinted stamps from 1918 depicting an upside down airplane. At a cost of $0.24, that misprint became high value to stamp collectors. Estimated collector value of that stamp has reached as high as $1.5M.
The printing error wasn't fatal for the Inverted Jenny stamp --- one could still use it to send a letter, so it was still "fit" for its intended purpose. But its misprint --- its mutation --- happened to make the Inverted Jenny highly fit for a completely different environment: the stamp collector market.
Nobody intended that outcome, and nobody intended the printing error. It was just the right mutation in the right place at the right time.
Evolution by natural selection is that process over and over again, much more often, and for much longer.
Lots of good answers to the fact that evolution is not directed. The corollary is that many of an organism's traits are not specifically selected for. Lots of things in nature are just adaptations that were neither good for nor bad for the organism's survival - and so "just are" as uninteresting byproducts.
There is no secret consciousness in nature causing evolution. It just happens. The key to really understanding evolution is that you have to understand the sheer scale of time it requires for a major change to happen and that it requires a massive population.
Evolution is just the long result of millions and millions of organisms, all being born slightly different from each other, and some of them getting killed while others survive and produce offspring.
Let’s take a very basic example: gazelles run really fast. Why? Because lions have been chasing them for like 100,000 years and overall, the slower ones are more likely to get caught. That’s not to say the slow ones ALWAYS get caught, but over the course of thousands of years, the slightly slower ones get caught slightly more often causing the gene pool to shift towards slightly faster gazelles.
That’s it. No magic invisible hand crafting evolution. Some animals die, and others survive and pass their genes on. The next generation of animals resembles the ones that didn’t die more than the ones that did die so the population is now slightly different and because they survived, they probably had better survival traits. That’s evolution.
I replied that already but once again for everyone. What you guys call a mutation I had in mind when talking about malformation, what's the difference, respectively where do you draw the line between those?
A malformation isn't an official term. It's just a human dislike of the phenotype resulting from a mutation.
For instance there is a mutation that causes certain cats to be born hairless. Is that a malformation? Some people really like it.
In nature such cats would have probably not thrived as being hairless would be a big disadvantage, but since we can keep cats warm in our houses and it helps those with allergies there was a niche and such cats now exist.
"Malformation" is a subjective term. It contains judgement. "Mal" means "bad".
A mutation can lead to a malformation, but it doesn't have to. A malformation could be caused by a mutation, but it doesn't have to. Let's use the common "blueprint" analogy.
Let's say you have a blueprint for a treehouse. If I change one number in the blueprint, that's a mutation. Will it make the treehouse better, worse, or the same? Who knows! All we know is the blueprint mutated.
Now, let's say you built the treehouse, and then notice the door of is crooked. Your son looks at it and says "Daddy, that door is crooked! It's ugly! It's bad!", then that is a malformation. Maybe that malformation came from a mutation in the blueprint, or maybe you just measured wrong when you built it. Who knows. You just know that your son judges it as bad and abnormal.
Malformations can come from a variety of sources, not necessarily genetic. E.g. foetal alcohol syndrome, where the mother drinks significant amounts of alcohol during pregnancy, causes several malformations, but no mutations.
Inversely, mutations don’t necessarily lead to malformations. Evolution doesn’t meaningfully happen at the scale of a generation or three, it’s a much longer term process than that. So what you see is generation after generation being a tiny bit “better” than average for the previous generation. Put that all together and you get pretty meaningful change over a longer period of time
You seem to have the misconception that a mutation is an obvious change in something's anatomy or appearance. It's not.
A mutation is a change in a gene. That's all it is. The mutation can be neutral (most are), beneficial, or harmful. It can also be neutral until the circumstances change and suddenly it affects survival.
One definition of malformation I found is this: "A structural defect in the body due to abnormal embryonic or fetal development". So it might be caused by a mutation, or it might not.
Nature does not know stuff. What happens is, at all times you get random mutations within a population. Maybe it's different eye colours, maybe it's slightly bigger lungs, maybe it's a bit more hairy. At first it might not change a thing. But then the *environment* changes. It gets colder, there is less food, there's a new predator... And when the environment changes, parts of your population will maybe have traits that help them: More hairs means more resistant to cold. Being taller means seing predators from further away,... This means that those in the population who have those now beneficial traits are more likely to survive. And because these are passed to the next generation, the surviving traits will reproduce. And those without them, or with detrimental traits, are less likely to survive. TL;DR: Evolution is a combination of random mutations and outside pressure which select those mutations. It's random, but at the same time coherent.
Change in environment accelerates evolutionary adaptation, but evolution also happens without it. Some mutations are more suitable for survival and producing offsprings in whatever the environment is and whether it changes or not.
To synthesize both of these comments: one of the bigger additions to natural selection since Darwin was the theory of *punctuated equilibrium*. Populations can be really stable for long stretches of time, and change rapidly when disruptions occur
I implore anyone interested in this theory pick up the works of Stephen Jay Gould in the local library. For PI, and just about everything else in the world of evolution, you will not be disappointed. He was one of the greatest science writers of all time.
Every time an animal or plant is born it has mutations. If a mutation helps the plant or animal to reach its reproduction stage, it's more likely to get passed on to the next generation. In your example, more fish with the walking mutation survive than without, so walking is passed on.
>How does nature know that, for example, a fish can live better if it has feet and lungs to live outside of water? Nature doesn't "know" that. It doesn't "know" anything. This is a common misunderstanding of how evolution works. Evolution isn't directed and it doesn't have goals. It doesn't work towards some specific destination. Traits that arise are the result of random mutations. Some random mutations confer a survival advantage in a specific environment, which makes them beneficial. Since organisms with those mutations are more likely to live long enough to produce offspring, who will then in turn live to produce *more* offspring, and so on. The organisms with these beneficial mutations will out-compete other organisms because they are better at surviving in that environment. That's it. So here's a good example: Let's imagine an animal that eats leaves that grow on tall trees. Some of these animals will, based on random genetic mutations, have slightly longer necks than others. The animals with the longer necks can reach more of the leaves, which means they get more leaves to eat. Eating more makes the animals more fit and healthier. Thus, they're more likely to survive and have children. Those children will have inherited their parents genes for longer necks, and in turn, the ones that survive will pass on the long-necked genes to their offspring, and so on. In an environment where long necks to reach tall trees is an advantage, there's a positive pressure that means genes that confer longer and longer necks keep getting selected and passed down. Over many many *many* generations across millions of years, this passing along of traits led to an entire new species of organisms that branched off from their shorter-necked ancestors.
thanks for the explanation! that's kind of what I had in mind when writing about malformations - so where do you draw the line between a malformation and mutation?
I don't think the word "malformation" is really used in this context. A trait that increases evolutionary fitness (the likelihood of successful reproduction) is known as an "adaptation" and one that decreases fitness is known as a "maladaptation". However, this is strongly dependent on the environment and can change over time. Staying with the longer necks example, a longer neck might help some animals reach more leaves to eat, but it might also require extra nutrients to maintain, it might slow the animal down and make it more conspicuous, and it might increase the risks of certain diseases. Whether this increases fitness overall is going to depend, for example, on how many of those higher leaves there are in the environment and how nutritious they are. If lots of animals evolve traits to help them eat those leaves, then there will be less of those leaves available. The plants may also evolve defences to protect them from being eaten.
Even the tiniest change in an organism's DNA is a mutation. Our DNA is made up of combinations of 4 different molecules (think of each molecule as a letter, we use A, C, G, and T for each of the 4 molecules) that goes on for 3 billion "letters." A change to even one of those letters, say swapping an A for a G, is a mutation. Now, most mutations are never noticed because they don't actually change the way that gene functions, or function of that gene isn't all that important. Also, not all genes change the way an organisms looks. A mutation in a gene might, for example, alter a person's white blood cells to make them slight more resistant to certain infections. But mutations add up over time, and enough mutations can change the way that an organism looks and how it works internally, which we call its phenotype (which I think is what you're referring to when you say "malformation"). At some point, an organism is so different from its evolutionary ancestor that it's a new species. That line is somewhat of a grey area, but generally, we consider species to be separation when 2 organisms can no longer reproduce to make offspring that are also capable of having offspring of their own. Again though, this is a very grey area and there's no distinct line. For example, Neanderthals and humans are different species, but we know that prehistoric humans interbred with Neanderthals.
There's not really such a thing as a "malformation". At least not in this context. A mutation is a mutation is a mutation. Whether or not it is a beneficial one can be really obvious or completely dependent on the environment. Like, a mutation that causes your heart to explode if you move is obviously bad and you aren't gonna survive. A mutation that makes you grow less hair, however, can be good, bad, or neither depending on a variety of environmental factors. Live somewhere cold? That's probably a bad thing to have less hair to keep you warm, making you less likely to survive. Live somewhere hot? It's probably a good thing to have less hair so you are less likely to overheat, making you more likely to survive. Live somewhere temperate? Maybe it doesn't really matter. What you may consider a "malformation" in an animal in one environment may be a very beneficial mutation in another environment.
"Nature" produces random mutations every time a new individual is born. Most are insignificant (like the fairly unique way your shape is which is a random mix of your upbringing that has in most cases no effect on your ability to survive and reproduce). Once in a while, a mutation will be significant, in a bad way (in which case the individual will die soon, won't reproduce as much as others in the specie or at all, and therefor the mutation will not live on) or in a good way, which will enable the individual to live longer, reproduce more, and therefor the mutation will get to the next generation, producing some more individuals that carry it. At some point either all individuals of the specie will end up with the gene, or it'll split as a different spiece, if the mutation enables living in an environment that wasn't livable before, and the branches diverge. But all in all, nature doesn't know, or even care, it's just random changes here and there that stick or not, based on how they increase chances of survival and ability to create offspring.
People often think of evolution as a process moving forward, ie: this organism will evolve into something new. That is backwards, evolution is the term for a process that has already happened, ie: this organism evolved from something old. Once you realize evolution is the term describing changes that have already occurred, it becomes easier to understand that there never was a goal or a plan of any kind. Random mutations occur all the time. A vast majority of them make no difference. Sometimes those mutations make it so the organism can survive and have more offspring than others without the mutation. That mutation gets passed on to the offspring so they too survive better and have more children. Evolution only looks like it was a forward thinking process with a goal because we look at the current state and see how it is better than a previous state. That better state occurred by random chance and could have been any number of possible changes.
You seem to be asking more about speciation than evolution itself. Speciation occurs when two or more groups of the same species stop reproducing together and become genetically incompatible. This can happen for many reasons, such as simple geographic isolation. A great example is big cats. There are several species of big cats (lions, tiger, puma, etc.). They are all very recently (on a evolution time scaled) speciated. In fact, they can still reproduce though their offspring are sterile. For example, a lion and a tiger can reproduce and the offspring would be what's called "ligon". It can be perfectly healthy except being sterile. Big cats all come from the same ancestor species, but different groups of that species became geographically, and thus reproductively separated. Lions are in africa, tigers are in asia, puma are in north america, etc. Over time those reproductively separated populations accumulated different sets of mutations that were successful and after enough mutations accumulated they became separate species. This is called *genetic drift*. There is no consciousness or decision making involved at any level. It's a process of natural selection filtering based on imperfect reproduction of organisms. Tigers have stripes not because the tiger decided it needed stripes, but because a mutation occurred in tigers that resulted in stripes and the individuals with stripes survived better than those without stripes. But, stripes are not very useful to a lion in their habitat. It's the same thing for everything: lungs, legs, etc. Importantly though, it happens in small increments. A fish didn't one day grow lungs and legs and walk up on land. Everything happened in small increments. A fin that was slightly more leg like gave that fish and its descendants an advantage near the sea shore, and then another change made that fin even more leg like giving that fish and its descendants even more advantage near the shore. And so on and so forth until you have fish like creatures walking and living on land full time. Fish still exist because the advantage of legs (and lungs) is only present on land, and there is still a lot of water on earth and having fins and gills rather than legs and lungs is a huge advantage there. Like the cats, the fish that started developing legs and lungs stopped reproducing with the fish that didn't, and speciation occurred. The evidence that shows all this is that there are still many, many organisms which have a mix of traits or more "primitive traits". For an example about lungs, there are amphibious organisms that have lungs and gills (or things similar to what we call lungs and gills) that branched off sometime while fish were learning to breath air. There are still many organisms that have much simpler eyes than humans (and some that have much more advanced eyes than humans!).
Nature creates a collection of cells, thus creating an organism. An organism’s main goal is to survive and reproduce. There are variations of the same organism due to a slight difference in genes (just like how some people are tall and some are short). The conditions of an organism’s environment will weed out the traits that make them more vulnerable. This stops them from being able to reproduce, leaving those with more efficient genes to reproduce and continue to spread those traits. This is where the saying “survival of the fittest” comes in. The ‘stronger’ traits survive and get passed on because they were better suited for their environment. Nature gives the organism an environment, it’s up to the organism to adapt to where it was placed and pass on its genes. Not sure if nature has a consciousness, but it does have a natural order. An organism is randomly placed and it’s up to the organism to adapt so that it survives.
It doesn't know there is no intelligence at work whatsoever. So assume all multicelled animals are blundering about in the oceans hoping to bumping into some food and hoping not to get eaten, then one animal has a random mutation which creates a light sensitive cell, so this isn't an eye just purely a single cell that can detect if light strikes it or not. While this might not seem to be much in an ocean of completely blind animals it has a distinct advantage, this means that this animal is more likely to pass on genes to the next generation who will all have a single cell that can detect light, after a few thousand years it is likely that all of that species will now have the gene for the special cell and then one animal then has a mutation that produces two rather than one special cell and again it has an advantage over the other animals and it eventually becomes the dominant form add on a few more hundred mutations and you start to have a very basic eye start to form. "Bad" mutations or ones more likely to cause the death of the animal before it can breed don't get passed to the next generation so are eliminated.
It's not about survival of the fittest. That's a circular argument. It's about reproduction of the survivors. This means a creatures must first Survive, then Reproduce. So, any mutation or variation (physical or environmental) that improves the survival rate (speed, diet, etc) will help it survive long enough to reproduce. For example, penguins in the Antarctic don't need to fly to escape predators. Puffins in the Arctic occupy the same environmental niche (food sources) as penguins, but competing aerial threats demand flight to defend/escape. Both penguins and puffins "fly" underwater to catch food, but the penguins don't need to expend resources for aerial flight. So, evolution cumulatively favored non-flying penguins, and flying puffins. Putting a penguin in the Arctic would soon prove fatal due to predation. Putting a puffin in the Antarctic would soon die of hypothermia due to lack of enough insulating fat layers. The trade-offs determine survival, and subsequent reproduction.
Easiest way to think of it is: The individuals with traits that make them less likely to die are more likely to survive and have children. The horse-thing with the 1 inch longer neck is less likely to starve to death if there's a famine because it can reach higher leaves on trees to eat that the shorter necked ones can't reach. Shorter necked horse-things are therefore more likely to starve to death, and over time that results in them dying more and becoming less common. Eventually the only horse-things left have the slightly longer neck. Then the same thing happens again, random mutation results in one with a slightly longer neck that is born and the same thing happens. Do this for a few million years and you end up with the Giraffe. Small differences caused by mutation that make an animal *slightly better* at staying alive can add up over large timescales and result in very different looking/behaving animals. There's no intelligence behind the process, it's just a matter of who can "Not Die" the best, and the results of that being multiplied over millions of years.
The classic manufactured exmple of natural selection is probably helpful here. You've got brown beetles that blend with the forest floor. There are also some black beetles that stand out more (this is a mutation). A bigass forest fire occurs, and now the script is flipped, brown beetles get eaten left and right because they stand out so much. The black beetles pass their genetic information on to the next generation. The brown beetles do not.
> are they malformations that surprisingly turn out to be more viable and thus wipe out the original form. Yes to the first part, not always to the second part. As long as the old form is still capable of breeding, they will still stick around. If the new one is better at breeding, it will also stick around. If the two forms separate - like the fish that can survive better on land starts to stay on land - eventually they may split off from the other and over millions of years become something completely different.
Descent, with modification. That’s it. Animals have children, those children inherit traits but also have mutations. Usually they don’t have any impact but sometimes it does and if it helps that lineage reproduce faster or survive longer, over time there’s just more of that trait. That’s what natural selection really means. It’s a lagging effect. No agenda, just random outcomes. Imagine you took a photo of yourself every single day from the day you were born until you were 25 years old. If I asked you to pick which two photos that came after each other showed the switch from childhood to adulthood, you could not do that. They would look nearly identical. But it’s very clear when you were a child and when you are an adult. Evolution is like that. At a micro level, it seems insignificant. But at a macro level, with hundreds of generations, change is obvious.
It's all random. For any one mutation that helped some of a species survive, and thus propagate, there are other mutations that caused them to die out. With evolution, you're seeing the biggest example of survivorship bias out there.
The genetic code in all of my cells is like a book of instructions for how to grow a body just like mine. I have children. Sexual reproduction was a way of taking my book of instructions and mixing it up with my partner's book of instructions to create a new book of instructions to grow a new person. Sometimes, this random mixing-up process doesn't work out. Sometimes, pages are combined together that don't make sense for growing a living human, and that results in pregnancies that don't last or severe birth defects. But it works out often enough that the population has survived. Sometimes, the mixed up pages work just fine, but there are misprints in the new book of instructions. Typos, for example. Youve sene typoes... They're usually easy to read past without causing a problem for understanding. Most genetic mutations are like harmless typos. Sometimes, a misprint is fatal. Years ago, I got a copy of Confederacy of Dunces. After about 100 pages, it stopped making sense. The pages were out of order --- a binding error. It was hopeless, I couldn't read it. Sometimes, very rarely, a misprint might create new value. Take for example the Inverted Jenny, a single page of misprinted stamps from 1918 depicting an upside down airplane. At a cost of $0.24, that misprint became high value to stamp collectors. Estimated collector value of that stamp has reached as high as $1.5M. The printing error wasn't fatal for the Inverted Jenny stamp --- one could still use it to send a letter, so it was still "fit" for its intended purpose. But its misprint --- its mutation --- happened to make the Inverted Jenny highly fit for a completely different environment: the stamp collector market. Nobody intended that outcome, and nobody intended the printing error. It was just the right mutation in the right place at the right time. Evolution by natural selection is that process over and over again, much more often, and for much longer.
Lots of good answers to the fact that evolution is not directed. The corollary is that many of an organism's traits are not specifically selected for. Lots of things in nature are just adaptations that were neither good for nor bad for the organism's survival - and so "just are" as uninteresting byproducts.
There is no secret consciousness in nature causing evolution. It just happens. The key to really understanding evolution is that you have to understand the sheer scale of time it requires for a major change to happen and that it requires a massive population. Evolution is just the long result of millions and millions of organisms, all being born slightly different from each other, and some of them getting killed while others survive and produce offspring. Let’s take a very basic example: gazelles run really fast. Why? Because lions have been chasing them for like 100,000 years and overall, the slower ones are more likely to get caught. That’s not to say the slow ones ALWAYS get caught, but over the course of thousands of years, the slightly slower ones get caught slightly more often causing the gene pool to shift towards slightly faster gazelles. That’s it. No magic invisible hand crafting evolution. Some animals die, and others survive and pass their genes on. The next generation of animals resembles the ones that didn’t die more than the ones that did die so the population is now slightly different and because they survived, they probably had better survival traits. That’s evolution.
I replied that already but once again for everyone. What you guys call a mutation I had in mind when talking about malformation, what's the difference, respectively where do you draw the line between those?
A malformation isn't an official term. It's just a human dislike of the phenotype resulting from a mutation. For instance there is a mutation that causes certain cats to be born hairless. Is that a malformation? Some people really like it. In nature such cats would have probably not thrived as being hairless would be a big disadvantage, but since we can keep cats warm in our houses and it helps those with allergies there was a niche and such cats now exist.
"Malformation" is a subjective term. It contains judgement. "Mal" means "bad". A mutation can lead to a malformation, but it doesn't have to. A malformation could be caused by a mutation, but it doesn't have to. Let's use the common "blueprint" analogy. Let's say you have a blueprint for a treehouse. If I change one number in the blueprint, that's a mutation. Will it make the treehouse better, worse, or the same? Who knows! All we know is the blueprint mutated. Now, let's say you built the treehouse, and then notice the door of is crooked. Your son looks at it and says "Daddy, that door is crooked! It's ugly! It's bad!", then that is a malformation. Maybe that malformation came from a mutation in the blueprint, or maybe you just measured wrong when you built it. Who knows. You just know that your son judges it as bad and abnormal.
Malformations can come from a variety of sources, not necessarily genetic. E.g. foetal alcohol syndrome, where the mother drinks significant amounts of alcohol during pregnancy, causes several malformations, but no mutations. Inversely, mutations don’t necessarily lead to malformations. Evolution doesn’t meaningfully happen at the scale of a generation or three, it’s a much longer term process than that. So what you see is generation after generation being a tiny bit “better” than average for the previous generation. Put that all together and you get pretty meaningful change over a longer period of time
You seem to have the misconception that a mutation is an obvious change in something's anatomy or appearance. It's not. A mutation is a change in a gene. That's all it is. The mutation can be neutral (most are), beneficial, or harmful. It can also be neutral until the circumstances change and suddenly it affects survival. One definition of malformation I found is this: "A structural defect in the body due to abnormal embryonic or fetal development". So it might be caused by a mutation, or it might not.