Evolution questions: round 3

[painted wolf]

Ok... so I've had two of these up before:
http://www.religiousforums.com/forum/evolution-vs-creationism/94931-ask-biologist-19.html
http://www.religiousforums.com/foru...onism/79784-questions-about-evolution-24.html

And it looks like we have some new people around who may want to ask questions on how evolution works and what it actually says. Got a good handle on Evolution and want a point clarified... I'll see what I can do!

So, have fun... all honest questions are welcome!

My updated credentials... I have my Bachelors in Biology now and I'm working on my research proposal and other needed papers for getting into a PhD program in Evolutionary studies/Paleontology. Though my plans have been delayed for family reasons, with any luck, this time next year I should be sending off applications.
I have taught/or assisted labs on general science and basic evolutionary theory as well as tutoring in several biology subjects.

I only have one publication to my name at this point (a poster on Horseshoe Crab population genetics)
I'm still a geek who loves reading primary literature, but I sneak in the odd pop-sci book for variety.

wa:do

 

[Photonic]

Ok... so I've had two of these up before:
http://www.religiousforums.com/forum/evolution-vs-creationism/94931-ask-biologist-19.html
http://www.religiousforums.com/foru...onism/79784-questions-about-evolution-24.html

And it looks like we have some new people around who may want to ask questions on how evolution works and what it actually says. Got a good handle on Evolution and want a point clarified... I'll see what I can do!

So, have fun... all honest questions are welcome!

My updated credentials... I have my Bachelors in Biology now and I'm working on my research proposal and other needed papers for getting into a PhD program in Evolutionary studies/Paleontology. Though my plans have been delayed for family reasons, with any luck, this time next year I should be sending off applications.
I have taught/or assisted labs on general science and basic evolutionary theory as well as tutoring in several biology subjects.

I only have one publication to my name at this point (a poster on Horseshoe Crab population genetics)
I'm still a geek who loves reading primary literature, but I sneak in the odd pop-sci book for variety.

wa:do

Congratulations! Always great to see a fellow scientist!

 

[painted wolf]

Congratulations! Always great to see a fellow scientist!

Thanks!

wa:do

 

[Jayhawker Soule]

What do you think of Eldridge and Gould's Punctuated Equilibrium?

 

[painted wolf]

What do you think of Eldridge and Gould's Punctuated Equilibrium?

It's very useful in explaining how species respond to open niches and how beneficial mutations can lead to rapid speciation. A good example of this is the London Underground Mosquito... who rapidly diverged from it's above ground ancestral population.

It's not the whole picture though. Gradualism is the general state most of the time, with minor genetic changes building up and subtly changing species over time. This is how ring species and subspecies form.

Flaws with "Punk eck" include the fact that species change genetically faster than they change morphologically and the fact we simply know more about the fossil record and genetics today than we did in the 1970's-80's.

So it is useful for describing one set of circumstances but it's not the only way speciation happens.

wa:do

 

[nnmartin]

And it looks like we have some new people around who may want to ask questions on how evolution works and what it actually says. Got a good handle on Evolution and want a point clarified... I'll see what I can do!

What came first, Evolution or Adam and the apple?

 

[Landerage]

Oh thanks for the thread, always wanted to ask a few questions about evolution:
Does evolution explains the presence of herbs that have medical benefits for humans or animals? Or other plants used in medicine ?
Does evolution study the impact of electric fields, light, density of air/liquids on life forms?
Does evolution say that all living forms came from one cell that the origin is uncertain, or gives another hypothesis or is not related to the origin of life?

 

[Jayhawker Soule]

It's not the whole picture though. Gradualism is the general state most of the time, with minor genetic changes building up and subtly changing species over time.

... and it doesnlt get more gradual than this.

 

[ScottySatan]

Are all of the known mechanisms of evolution combined fast enough to account for the observed rate of evolution in nature, or do we predict that there must be yet another major fast mechanism out there? How do you calculate it? Can you define your variables this time please?

 

[painted wolf]

Oh thanks for the thread, always wanted to ask a few questions about evolution:
Does evolution explains the presence of herbs that have medical benefits for humans or animals? Or other plants used in medicine ?

Sure, most plants that have medicinal properties for humans produce those compounds for their own benefit not ours. Which is why so many medicinal herbs also have compounds toxic to humans and the line between medicine and poison can be so blurry (ie. Foxglove).

Does evolution study the impact of electric fields, light, density of air/liquids on life forms?

It does indeed... the space station and the shuttles before it have been invaluable in the study of how life responds to such things.

Does evolution say that all living forms came from one cell that the origin is uncertain, or gives another hypothesis or is not related to the origin of life?

Evolution says that we all share a common ancestor... but can't say if this ancestor was the only living thing of it's time. And it would have been evolving from even more simple lifeforms that weren't quite like cells as we know them.

Evolution only covers thing that evolve.. That is generally limited to things that are alive. It doesn't cover how RNA or DNA form outside of a self replicating system. That is abiogenesis. Once you have self replication and decent with modification you have evolution.

Hope this helps.

wa:do

 

[painted wolf]

... and it doesnlt get more gradual than this.

While morphologically simple, bacteria are wonderfully diverse and genetically complex. Be careful not to confuse looking the same in a general way to your ancestors and not having changed.

Bacteria are a perfect example of how evolution can work both gradually and rapidly at different times.
Unlike us Eukaryotes, they can actually change the speed and accuracy at which they copy their DNA. Which allows them to reproduce more slowly when food is limited and then switch to explosively rapid growth when food is plentiful or when under certain types of extreme stress. Rapid reproduction introduces more mutations into the DNA leading to rapid change.

wa:do

 

[Jayhawker Soule]

Bacteria are a perfect example of how evolution can work both gradually and rapidly at different times.

I thought that was my point.

 

[painted wolf]

Are all of the known mechanisms of evolution combined fast enough to account for the observed rate of evolution in nature, or do we predict that there must be yet another major fast mechanism out there?

We seem to have a handle on the mechanisms involved... the real discussion is which ones are more important in which situations.

How do you calculate it? Can you define your variables this time please?

Rates of evolution are determined by studying the rates of neutral mutations in various areas of the genome, comparing them across individuals of the same species and across different species. As well as using fossil data.

Some of the variables in this sort of calculation are:
Generation length (long generations change more slowly than fast ones)
Selection pressure (you want a region that is under little or no pressure)
Population size (to account for genetic drift)

We also measure how traits change in living species and see how long it takes new alleles to spread in populations. This gives us an idea of how fast evolution can work.

Hope this helps.

wa:do

 

[painted wolf]

I thought that was my point.

My bad...

I'm so used to people using bacteria as an example of how things don't change... they often miss the fact that just because something doesn't look like it's changed doesn't mean it hasn't evolved.

wa:do

 

[Jayhawker Soule]

My bad...

:flower2:

 

[nnmartin]

Does evolution study the impact of electric fields, light, density of air/liquids on life forms?

It does indeed... the space station and the shuttles before it have been invaluable in the study of how life responds to such things.
wa:do

You see, even NASA is aware of an extra dimension to be reckoned with!

Why would a study of evolution even care about an electric field if it was believed that evolution was controled by natural selection only?

 

[camanintx]

You see, even NASA is aware of an extra dimension to be reckoned with!

Why would a study of evolution even care about an electric field if it was believed that evolution was controled by natural selection only?

Are you saying that electric fields are not natural?

 

[painted wolf]

You see, even NASA is aware of an extra dimension to be reckoned with!

Why would a study of evolution even care about an electric field if it was believed that evolution was controled by natural selection only?

um... electric fields occur in nature. From the magnetic field to the ones produced by living things.

And animals like the electric eel can produce their own very potent ones.
Sharks evolved to use the weak electric signals produced by living things to hunt.

No "extra dimensions" needed.

wa:do

 

[nnmartin]

Electric and magnetic fields occur in nature sure - but are you going to write that off as natural selection as well?

Certain crystals and rocks also give off electric signals - it is one of the ways in which God guides evolution.

All these 'natural' phenomena are natural yes, but God is Nature.

 

[ScottySatan]

We seem to have a handle on the mechanisms involved... the real discussion is which ones are more important in which situations.

Rates of evolution are determined by studying the rates of neutral mutations in various areas of the genome, comparing them across individuals of the same species and across different species. As well as using fossil data.

Some of the variables in this sort of calculation are:
Generation length (long generations change more slowly than fast ones)
Selection pressure (you want a region that is under little or no pressure)
Population size (to account for genetic drift)

We also measure how traits change in living species and see how long it takes new alleles to spread in populations. This gives us an idea of how fast evolution can work.

Hope this helps.

wa:do

Sorry, no it doesn't. I'm actually looking for the numbers, or a reference that has them. And it's not until we have those that we can come close to claiming that we know we have all of the mechanisms. The rate at which we discover new mechanisms of evolution is going up, not down. So history alone actually predicts that don't have them all yet.