Some random discussion on evolution...

[OldWiseGuy]

Really? Individual A experiences a mutation. It has several offspring. The mutation provides a marginal benefit in the environment. Consequently, some of those offspring have a better survival rate and some of them pass the mutation onto their offspring. Thus the mutation spreads through the population, changing it.

So mutation isn't actually part of evolution?

 

[Ophiolite]

So mutation isn't actually part of evolution?

What? How did you possibly get that out of what I said? The mutation leads to a population with different genes and different anatomy, or metabolism, or behaviour. When a sufficient number of mutations have built up in the population we would recognise a different species from the "original" population that organism A lived in.

 

[OldWiseGuy]

What? How did you possibly get that out of what I said? The mutation leads to a population with different genes and different anatomy, or metabolism, or behaviour. When a sufficient number of mutations have built up in the population we would recognise a different species from the "original" population that organism A lived in.

So evolution can indeed begin with a single individual?

 

[Ophiolite]

So evolution can indeed begin with a single individual?

Evolution continues with an individual that is the member of a population.

 

[pitabread]

Where does evolution begin. For example it is said that the horse evolved a long snout to get his eyes above the grass so he could see predators coming as he fed. Where did the process start? With the grass? With his eyes? With his snout? At the subatomic, atomic, molecular, cellular, level?

The process of evolution is ongoing in populations of living organisms. In a nutshell, the process of evolution involves the changes in populations of organism over time.

In the case of horse evolution, the process of evolution would have already been occurring in the organisms ancestral to modern horses, all the way up to and including modern horse populations. It's a continuous process.

When something begins to change, where does it start and what are the processes involved?

Changes in organisms occur in DNA during reproduction (specifically in reproductive cells). In the case of sexual reproduction, organisms produce either sperm or eggs. During cell replication in the production of sperm and eggs, DNA is copied but the process is not perfect. Thus copying errors (called mutations) are introduced.

The resulting offspring is a combination of the DNA found in the sperm and eggs of the parents (offspring inherit approximately half of the DNA from each parent). Any mutations in the sperm and eggs will them make up the DNA of the offspring.

Depending on the mutations in the DNA, it may result in changes to the resulting offspring.

And can they be demonstrated in the lab?

Of course, there are laboratory experiments on evolution all the time. As long as you have a population of organisms that reproduce, you have evolution.

 

[pitabread]

So the whole population must have the same 'variant' at the same time for the process to proceed?

Of course not. Organisms reproduce, which results in new individuals that make up the population. These offspring replace prior individuals which eventually die off. In this respect, populations continuously replenish themselves over time.

If a single organism has a particular trait and they successfully produce offspring, that trait may be passed down through subsequent generations. And if that organism's offspring are particularly successful at reproduction, it's possible for that trait to eventually spread throughout the entire population (over time) and eventually become "fixed" in the population.

What else does an organism have to have in order for evolution to proceed, and where do those components come from?

Organisms simply need to reproduce. And they tend to do that; a lot.

I'm not sure what "components" you are referring to?

What is the mechanism that excites a whole population to make the same evolutionary changes?

I'm not sure what this question is asking. As explained, entire populations don't all change at the same time. It is through reproduction and the passing down of genetic material from parents to offspring that results in evolutionary changes over time.

 

[OldWiseGuy]

The process of evolution is ongoing in populations of living organisms. In a nutshell, the process of evolution involves the changes in populations of organism over time.

In the case of horse evolution, the process of evolution would have already been occurring in the organisms ancestral to modern horses, all the way up to and including modern horse populations. It's a continuous process.



Changes in organisms occur in DNA during reproduction (specifically in reproductive cells). In the case of sexual reproduction, organisms produce either sperm or eggs. During cell replication in the production of sperm and eggs, DNA is copied but the process is not perfect. Thus copying errors (called mutations) are introduced.

The resulting offspring is a combination of the DNA found in the sperm and eggs of the parents (offspring inherit approximately half of the DNA from each parent). Any mutations in the sperm and eggs will them make up the DNA of the offspring.

Depending on the mutations in the DNA, it may result in changes to the resulting offspring.



Of course, there are laboratory experiments on evolution all the time. As long as you have a population of organisms that reproduce, you have evolution.

So an incredibly complex system must be in place before evolution can occur?

 

[pitabread]

So an incredibly complex system must be in place before evolution can occur?

Evolution requires the existence of self-replicating organisms with the capability of inheritance.

(Actually that's probably a bit of over simplification, since technically things like viruses also evolve but they aren't considered living things.)

 

[OldWiseGuy]

Of course not. Organisms reproduce, which results in new individuals that make up the population. These offspring replace prior individuals which eventually die off. In this respect, populations continuously replenish themselves over time.

If a single organism has a particular trait and they successfully produce offspring, that trait may be passed down through subsequent generations. And if that organism's offspring are particularly successful at reproduction, it's possible for that trait to eventually spread throughout the entire population (over time) and eventually become "fixed" in the population.



Organisms simply need to reproduce. And they tend to do that; a lot.

I'm not sure what "components" you are referring to?



I'm not sure what this question is asking. As explained, entire populations don't all change at the same time. It is through reproduction and the passing down of genetic material from parents to offspring that results in evolutionary changes over time.

I have asked this question a dozen times and have been assured that evolution only occurs in a 'population', not an individual. So even if successful the change in an individual is not technically evolution and cannot lead to evolution in a population. Have I got this right?

 

[OldWiseGuy]

Evolution requires the existence of self-replicating organisms with the capability of inheritance.

(Actually that's probably a bit of over simplification, since technically things like viruses also evolve but they aren't considered living things.)

That begs the question again. When does evolution begin if not with the most primitive organisms. And do they even have the means to evolve.

I'm seeing some circular reasoning with the answers.

 

[pitabread]

I have asked this question a dozen times and have been assured that evolution only occurs in a 'population', not an individual. So even if successful the change in an individual is not technically evolution and cannot lead to evolution in a population. Have I got this right?

Maybe an analogy would help:

Is a single raindrop a flood? No.

However, could an accumulation of raindrops form a body of water that results in a flood? Yes.

It's similar with the process of evolution:

A single individual by themselves is not evolution.

However, a group of individuals that make up a population that reproduces to produce more individuals resulting in changes to the population over time... that is evolution.

 

[pitabread]

That begs the question again. When does evolution begin if not with the most primitive organisms. And do they even have the means to evolve.

If you're looking for the ultimate beginning of evolution on Earth, then yes, it would start with the first living things (or possibly pre-cursors to living things) on Earth.

Where it gets a little fuzzy though is trying to define exactly the starting point since that is currently unknown; even the boundary between life and non-life is fuzzy when you're dealing with origin of life scenarios.

 

[OldWiseGuy]

Maybe an analogy would help:

Is a single raindrop a flood? No.

However, could an accumulation of raindrops form a body of water that results in a flood? Yes.

It's similar with the process of evolution:

A single individual by themselves is not evolution.

However, a group of individuals that make up a population that reproduces to produce more individuals resulting in changes to the population over time... that is evolution.

How many individuals are needed to make a population?

 

[pitabread]

How many individuals are needed to make a population?

In the context of biological evolution, more than one.

Now in that regard, it's possible to start a population from a single organism. But in order for evolution to occur, that organism needs to reproduce and produce offspring.

The process of evolution occurs via the process of reproduction. No reproduction, no evolution.

 

[OldWiseGuy]

If you're looking for the ultimate beginning of evolution on Earth, then yes, it would start with the first living things (or possibly pre-cursors to living things) on Earth.

Where it gets a little fuzzy though is trying to define exactly the starting point since that is currently unknown; even the boundary between life and non-life is fuzzy when you're dealing with origin of life scenarios.

Not the origin of life, just the point at which the means of evolution appeared. The mechanism of evolution must be at least as complex as evolution itself. So how did it develop?

 

[OldWiseGuy]

In the context of biological evolution, more than one.

Now in that regard, it's possible to start a population from a single organism. But in order for evolution to occur, that organism needs to reproduce and produce offspring.

The process of evolution occurs via the process of reproduction. No reproduction, no evolution.

So you could have a 'population' of a two offspring as long as the mutation was passed to them?

 

[pitabread]

Not the origin of life, just the point at which the means of evolution appeared. The mechanism of evolution must be at least as complex as evolution itself. So how did it develop?

I'm not entirely sure what you are asking here. I'm don't know what "the mechanism of evolution must be at least as complex as evolution itself" is supposed to mean.

I'm also not sure it's relevant to try to characterize relative complexity, since we're not working with any sort of base line definition here.

 

[pitabread]

So you could have a 'population' of a two offspring as long as the mutation was passed to them?

Sure. If you start with an asexual organism, and that organism reproduces and there are genetic changes in the offspring, then you have evolution. The population has changed over time.

 

[Kylie]

Basically what you are saying is, "If I hadn't believed it I wouldn't have seen it with my own eyes."

No.

This is a case of evidence based reasoning.

Look at the evidence from the real world and see what it indicates.

 

[Kylie]

Not the origin of life, just the point at which the means of evolution appeared. The mechanism of evolution must be at least as complex as evolution itself. So how did it develop?

Are you saying if X creates Y, then X must be more complex than Y?