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Reality of Evolution

 
hannahtoo
 
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hannahtoo
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21 April 2018 15:51
 
Chaz - 21 April 2018 12:08 PM
hannahtoo - 21 April 2018 11:39 AM

I’m getting confused.  In the opening post, Chaz wrote:

This will be arguing against natural selection as a factor of evolution.

Is this a reference just to humans (and their domesticated animals)?  Or is this a general statement about evolution of all species? 

For right now, I’ll assume it is the former.  Natural selection surely continues to play a part in human evolution.  That is, human genetics still play a role in our survival.  But human intelligence (which originally was naturally selected) has complicated the future of the human species.  Behaviors and technologies shield us from purely natural forces.  So now we are evolving as a combo of natural and human-created factors.

God bless you! This definitely went off the rails while talking to the others, and I’m a bit stubborn on trying to clarify a point.

It’s actually not the former. The argument I had in mind for this topic was that natural selection is a factor of extinction rather than evolution. Evolution can only progress if the species can avoid extinction. Obviously that means they are two sides of the same coin, which is the point I’m trying to make.

I’ll stop there for you to respond.

Let’s use the well-known example of the peppered moths in the British Isles.  To summarize, this moth species naturally includes two different color patterns, some speckled black and white, and some nearly black.  Originally, natural selection favored the lighter speckled moths because they were camouflaged on lichen on the trees and walls.  Dark ones were more easily seen and eaten by birds.  So speckled dominated the population.  But in the 19th century, coal pollution killed lichen and darkened the tree trunks and walls in urban areas.  So natural selection favored the darker moths, that is, the proportion of the darker moths increased.  In the mid-20th century, pollution controls improved air quality.  Lichens regrew and the proportion of lighter moths increased.  The species didn’t become extinct.  But the prevalence of coloration changed as conditions changed. 

Natural selection works on inevitable variations within a species.

 
Chaz
 
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Chaz
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21 April 2018 16:10
 

I’m familiar with the history of the species. The problem is that it’s only an observation of how natural selection works, rather than how it effects evolution. Neither of the two adapted to survive even though both came close to extinction.

Maybe I’m not letting you get to the point, or you have something else as a better example?

Genuinely want to say thanks. You have singlehandedly saved this thread. We were going down a dark path without you.

[ Edited: 21 April 2018 16:16 by Chaz]
 
hannahtoo
 
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hannahtoo
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21 April 2018 19:11
 
Chaz - 21 April 2018 04:10 PM

I’m familiar with the history of the species. The problem is that it’s only an observation of how natural selection works, rather than how it effects evolution. Neither of the two adapted to survive even though both came close to extinction.

Maybe I’m not letting you get to the point, or you have something else as a better example?

Genuinely want to say thanks. You have singlehandedly saved this thread. We were going down a dark path without you.

Species don’t “adapt to survive.”  Variations are inevitable among the species members, and natural selection culls some of them, favors others.  More new variations arise (by mutation, for example), and natural selection continues.  Eventually, the ancestral species will evolve into something different.  Study the well-documented lineage of any species, and gradual changes are apparent.  Usually species changes occur as the environment changes.  This can occur when a subset of a population migrates into a new environment, or when the environment itself changes, as when climate changes and when landforms slowly transform. 

Check out the May National Geographic magazine article on bird evolution.  (Just got mine in the mail; it should be on news stands and in libraries soon.)  Gosh, there are countless examples of species transforming into others.

 
Chaz
 
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Chaz
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21 April 2018 19:37
 

I will have to check out the national geographic, but the rest of what you said is in favor of my point. The variations of any species can only form if they can avoid extinction. Natural selection isn’t a factor of evolution, rather it’s against it.

 
hannahtoo
 
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hannahtoo
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22 April 2018 05:33
 
Chaz - 21 April 2018 07:37 PM

I will have to check out the national geographic, but the rest of what you said is in favor of my point. The variations of any species can only form if they can avoid extinction. Natural selection isn’t a factor of evolution, rather it’s against it.

When variations inevitably arise, natural selection determines the course of evolution.  It determines which variations will survive to be passed on to the next generation, and which will be disadvantaged.

 
Chaz
 
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Chaz
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22 April 2018 07:57
 

The variations aren’t inevitable tho. If natural selection wins, evolution loses.

 
hannahtoo
 
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hannahtoo
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22 April 2018 11:19
 
Chaz - 22 April 2018 07:57 AM

The variations aren’t inevitable tho. If natural selection wins, evolution loses.

Variations are inevitable.  DNA mutations occur all the time.  So often, that there are complex mechanisms cells to repair most mutations or errors.  There are countless documented examples of mutations involving just one or a few nucleotides, for example.  Sometimes the results are harmful, like cystic fibrosis.  Sometimes they are harmless, like eye color.  Sometimes they have both positive and negative effects (sickle cell anemia, if inherited from just one parent, may provide some protection from malaria).

I feel like we’re making some progress in the discussion.  But you keep wanting to separate natural selection from evolution, and I keep reiterating that natural selection is the mechanism of evolution.  Changes in DNA that occur and offer no selective advantage nor disadvantage may cause some genetic drift.  However, changes that have consequences are what drive evolution, creating new species, and yes causing others to go extinct.

Think of whales.  Their ancestors were land mammals which returned to the sea more and more to utilize the food sources there.  (It’s interesting that their closest land relative in modern times are hippos, which also spend a lot of time in the water.  Hippos and whales share a common ancestor.)  Within the whale lineage, fossil evidence shows increasing adaptations to a swimming life.  For example, nostrils migrated over many generations, from the front of the snout to the top of the head. The tail became a fluke.  Teeth, in one branch of whales, became baleen, which filters plankton and krill.  Whales can sleep at the surface and even give birth and raise their young completely at sea.  These evolutionary changes were naturally selected over millions of years.

 
Chaz
 
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Chaz
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22 April 2018 13:40
 
hannahtoo - 22 April 2018 11:19 AM
Chaz - 22 April 2018 07:57 AM

The variations aren’t inevitable tho. If natural selection wins, evolution loses.

Variations are inevitable.  DNA mutations occur all the time.  So often, that there are complex mechanisms cells to repair most mutations or errors.  There are countless documented examples of mutations involving just one or a few nucleotides, for example.  Sometimes the results are harmful, like cystic fibrosis.  Sometimes they are harmless, like eye color.  Sometimes they have both positive and negative effects (sickle cell anemia, if inherited from just one parent, may provide some protection from malaria).

I feel like we’re making some progress in the discussion.  But you keep wanting to separate natural selection from evolution, and I keep reiterating that natural selection is the mechanism of evolution.  Changes in DNA that occur and offer no selective advantage nor disadvantage may cause some genetic drift.  However, changes that have consequences are what drive evolution, creating new species, and yes causing others to go extinct.

Think of whales.  Their ancestors were land mammals which returned to the sea more and more to utilize the food sources there.  (It’s interesting that their closest land relative in modern times are hippos, which also spend a lot of time in the water.  Hippos and whales share a common ancestor.)  Within the whale lineage, fossil evidence shows increasing adaptations to a swimming life.  For example, nostrils migrated over many generations, from the front of the snout to the top of the head. The tail became a fluke.  Teeth, in one branch of whales, became baleen, which filters plankton and krill.  Whales can sleep at the surface and even give birth and raise their young completely at sea.  These evolutionary changes were naturally selected over millions of years.

LoL that’s the point of the thread remember? I’m supposed to separate natural selection from evolution. I’ll admit that we can’t make much progress until we realize that we are saying the same thing to each other with different interpretations. I’ll stop the headache I’m sure you will have if I don’t confess that I know I’m just as wrong as I am correct. I did already say that evolution and extinction are two sides of the same coin which is where you should have gotten me. That’s the point of natural selection, if the species can survive extinction then it is by all intensive purposes naturally selected. You have been correct with every post on how natural selection works and that it doesn’t force adaptations, but governs whether they were the correct adaptations to be made.

You are now my favorite person on the planet. This is the first time I’ve ever played a game of devil’s advocate and forfeited. I could’ve kept it going forever, but I didn’t want you to lose your patience and get a headache.  I hope you’ll play again.

 
Chaz
 
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Chaz
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26 April 2018 15:44
 
Antisocialdarwinist - 18 April 2018 08:11 PM

Interestingly enough, there’s technically no such thing as an immunity to poison ivy. The rash is caused by certain immune cells in the body reacting to the poison. In your case, your immune cells don’t react to the poison anymore. In other words, you’re no longer allergic to poison ivy. I know, it’s a subtle difference saying you’re immune, but it’s similar in a way to peanut allergy. It’s not that most people are immune to peanuts, it’s that some people are allergic to them. With poison ivy, most people are allergic to it.

I figured out how to articulate what I meant. Your body has to produce antibodies to fight allergies, but immunities are part of your DNA. That has to help. One factor of adapting to an environment is digesting and absorbing other things of that environment, processing it throughout your entirety, so you can adjust accordingly.

I know I said this was a game of devil’s advocate, but you can’t play with lies, that ruins the validity of it. Everything I said in previous posts was in all honesty.

 
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