Understanding through Discussion


Welcome! You are not logged in. [ Login ]
EvC Forum active members: 84 (8872 total)
Current session began: 
Page Loaded: 11-17-2018 10:34 PM
221 online now:
14174dm, AZPaul3, DrJones*, Faith, marc9000 (5 members, 216 visitors)
Chatting now:  Chat room empty
Newest Member: Son of Man
Post Volume:
Total: 842,189 Year: 17,012/29,783 Month: 1,000/1,956 Week: 503/331 Day: 86/76 Hour: 1/0


Thread  Details

Email This Thread
Newer Topic | Older Topic
  
1
234567Next
Author Topic:   Question on how Evolution works to produce new characteristics
Europa
Member (Idle past 2638 days)
Posts: 68
Joined: 06-05-2010


Message 1 of 104 (563571)
06-05-2010 10:24 PM


I am confused about all the information on evolution, creation and intelligent design. Hence I joined this forum to post this question.

First to clarify evolution, I would like someone to tell me how evolution is explained in the following hypothetical scenario.

There is a green frog population in an isolated island. All frogs are green in this population and they have been living fine in their green environment for ages.

An alien species of plants invades their environment and the environment starts to change. Now, the frogs are no longer camouflaged in this environment. A bit of orange speckling on their green skin will, however, do the job of camouflaging wonderfully.

But there is not a single orange speckled frog so far in this island population.

Can someone explain to me how evolution will work to make the frogs survive?

Will orange speckled frogs be the dominant variety of frogs in this island at a later time?

Thanks in advance.

Edited by AdminAsgara, : No reason given.


Replies to this message:
 Message 3 by Taz, posted 06-06-2010 12:03 AM Europa has responded
 Message 4 by subbie, posted 06-06-2010 1:13 AM Europa has not yet responded
 Message 16 by Asking, posted 06-06-2010 10:51 AM Europa has not yet responded
 Message 17 by AZPaul3, posted 06-06-2010 11:10 AM Europa has not yet responded
 Message 18 by RAZD, posted 06-06-2010 7:06 PM Europa has not yet responded
 Message 24 by Phage0070, posted 06-07-2010 2:04 AM Europa has not yet responded

    
AdminAsgara
Administrator (Idle past 254 days)
Posts: 2073
From: The Universe
Joined: 10-11-2003


Message 2 of 104 (563578)
06-05-2010 11:43 PM


Thread Copied from Proposed New Topics Forum
Thread copied here from the Evolution thread in the Proposed New Topics forum.
    
Taz
Member (Idle past 1243 days)
Posts: 5069
From: Zerus
Joined: 07-18-2006


Message 3 of 104 (563579)
06-06-2010 12:03 AM
Reply to: Message 1 by Europa
06-05-2010 10:24 PM


First of all, nature rarely ever throw something at a population that would exterminate the whole lot if they don't change right away. Try not to watch too much science fiction movies.

But to the point. Like every population in the world, not all members of this particular population of green frogs will be completely green just like not every single member of black people have black skin. There are undoubtedly already members of this frog population with a hint of orange speckles. These members would have an advantage over the other members, and over time will become the dominant trait in the population.

But suppose we take your route. Suppose there isn't a single member of the population with orange speckles. If the change in environment is that drastic, the population will go extinct. Bye bye froggies.

Right now, you're thinking too much in one dimension. A population rarely ever have such limited traits. I live in a town of 20 thousand or so people. And even then, we have black, brown, green, white, and purple people. I've seen just about every colored eyes out there. I've also seen the very tall and the very short. What's my point? Unless there's been a severe bottleneck like what happened to the cheetahs, the probability of the population having members that have the traits to survive the environmental changes is pretty darn high.


This message is a reply to:
 Message 1 by Europa, posted 06-05-2010 10:24 PM Europa has responded

Replies to this message:
 Message 5 by Europa, posted 06-06-2010 4:38 AM Taz has not yet responded

  
subbie
Member
Posts: 3508
Joined: 02-26-2006


(1)
Message 4 of 104 (563589)
06-06-2010 1:13 AM
Reply to: Message 1 by Europa
06-05-2010 10:24 PM


An alien species of plants invades their environment and the environment starts to change. Now, the frogs are no longer camouflaged in this environment. A bit of orange speckling on their green skin will, however, do the job of camouflaging wonderfully.

But there is not a single orange speckled frog so far in this island population.

Can someone explain to me how evolution will work to make the frogs survive?

First, as Taz said, they may not survive. This is called extinction. It has happened millions of times. Sucks to be them.

But, to address your rather contrived scenario. Just because there is no exemplar of the perfect adaptation to a new environmental feature doesn't mean no evolution will occur. Evolution does not require the best solution to a given problem. Evolution simply says that those better suited will likely leave more offspring than those less well suited. Thus, even if orange speckling would be the ideal camouflage, there may still be some other type of skin coloring that will be better than most. That type will become more predominant in succeeding generations.

Contrary to what you may have heard, evolution is not "survival of the fittest." It's more like "survival of those better suited to survive." Not as catchy, I grant you, but considerably more accurate.

BTW, welcome to EvC. If you truly are confused, there are many here who are more than willing to help clear up any confusion. May your stay here be entertaining as well as informative.


Ridicule is the only weapon which can be used against unintelligible propositions. Ideas must be distinct before reason can act upon them; and no man ever had a distinct idea of the trinity. It is the mere Abracadabra of the mountebanks calling themselves the priests of Jesus. -- Thomas Jefferson

For we know that our patchwork heritage is a strength, not a weakness. We are a nation of Christians and Muslims, Jews and Hindus -- and non-believers. -- Barack Obama

We see monsters where science shows us windmills. -- Phat

It has always struck me as odd that fundies devote so much time and effort into trying to find a naturalistic explanation for their mythical flood, while looking for magical explanations for things that actually happened. -- Dr. Adequate


This message is a reply to:
 Message 1 by Europa, posted 06-05-2010 10:24 PM Europa has not yet responded

  
Europa
Member (Idle past 2638 days)
Posts: 68
Joined: 06-05-2010


Message 5 of 104 (563608)
06-06-2010 4:38 AM
Reply to: Message 3 by Taz
06-06-2010 12:03 AM


"There are undoubtedly already members of this frog population with a hint of orange speckles. These members would have an advantage over the other members, and over time will become the dominant trait in the population."

Thanks Taz and subbie.

My question is, if the frogs with the hint of an orange speckling survive more and make this the dominant trait of the population, will it not be a response to a 'felt need'? (Lmarkism?)

If the froggies on the other hand go extinct, will it not be because they could not respond to the 'felt need'? The 'felt need' being getting themselves orange speckled.

Edited by Europa, : No reason given.


This message is a reply to:
 Message 3 by Taz, posted 06-06-2010 12:03 AM Taz has not yet responded

Replies to this message:
 Message 6 by Dr Jack, posted 06-06-2010 5:12 AM Europa has not yet responded
 Message 7 by bluegenes, posted 06-06-2010 5:17 AM Europa has responded

    
Dr Jack
Member (Idle past 57 days)
Posts: 3507
From: Leicester, England
Joined: 07-14-2003


(1)
Message 6 of 104 (563609)
06-06-2010 5:12 AM
Reply to: Message 5 by Europa
06-06-2010 4:38 AM


My question is, if the frogs with the hint of an orange speckling survive more and make this the dominant trait of the population, will it not be a response to a 'felt need'? (Lmarkism?)

If the froggies on the other hand go extinct, will it not be because they could not respond to the 'felt need'? The 'felt need' being getting themselves orange speckled.

No. There's not 'felt need' effect going on.

Suppose there's your all-green frog population. This is because all of the various genes involved work together to produce green. If they are to get orange speckles they require a gene to emerge that produces the right pigment, or a change in the distribution of the green pigments that produces an orangey result.

This will happen (or not happen) because, just by chance, there is a mutation in the genome of a particular frog. This is no more likely to happen when the mutation is "needed" than when it is not needed.

In the new environment the speckled frog, and all of its offspring that carry the gene, will have a selective advantage over the green frogs so slightly more of them will survive to the next generation. Had it happened in the all-green environment then the new mutation would be selected against, and tend to die out.


This message is a reply to:
 Message 5 by Europa, posted 06-06-2010 4:38 AM Europa has not yet responded

  
bluegenes
Member (Idle past 429 days)
Posts: 3119
From: U.K.
Joined: 01-24-2007


(1)
Message 7 of 104 (563610)
06-06-2010 5:17 AM
Reply to: Message 5 by Europa
06-06-2010 4:38 AM


Europa writes:

My question is, if the frogs with the hint of an orange speckling survive more and make this the dominant trait of the population, will it not be a response to a 'felt need'? (Lmarkism?)

No. In that scenario, it would be "differential reproduction" that would change the average colour scheme of the frogs over time.

What that means is that those with better camouflage in relation to the new plant environment have a better chance of surviving their predators, and are therefore likelier to live longer than the average.

Living longer means a better chance of producing more offspring, so the "better camouflage" characteristics will become more common in the population over generations.

The time it takes for the population to be as well camouflaged as they were before the environmental change will depend mainly on three factors. These are (1) what (if any) chance variations happened to exist in the population at the time of change that suit the new environment; (2) how soon individuals receive new mutations that happen to give them a better colouring - another chance element - and (3) how important camouflage is to their survival (the more important, the faster the new characteristics become fixed over the population).

Hope that helps, and welcome to the board.


This message is a reply to:
 Message 5 by Europa, posted 06-06-2010 4:38 AM Europa has responded

Replies to this message:
 Message 8 by Europa, posted 06-06-2010 5:31 AM bluegenes has responded

  
Europa
Member (Idle past 2638 days)
Posts: 68
Joined: 06-05-2010


(1)
Message 8 of 104 (563611)
06-06-2010 5:31 AM
Reply to: Message 7 by bluegenes
06-06-2010 5:17 AM


Thanks guys.

Two questions arise in my mind.

1. Why do you say this -- orange speckling -- isn't Lamarkism?

2. If orange speckling, by chance, occurs due to a single mutation on a single frog, will it be capable of making this the dominant trait of the colony over time? Is this how evolution works? I mean by the chance mutation of a favourable trait on a single organism?


This message is a reply to:
 Message 7 by bluegenes, posted 06-06-2010 5:17 AM bluegenes has responded

Replies to this message:
 Message 9 by bluegenes, posted 06-06-2010 5:35 AM Europa has not yet responded
 Message 10 by Dr Jack, posted 06-06-2010 5:39 AM Europa has responded
 Message 20 by Dr Adequate, posted 06-06-2010 7:42 PM Europa has responded

    
bluegenes
Member (Idle past 429 days)
Posts: 3119
From: U.K.
Joined: 01-24-2007


Message 9 of 104 (563612)
06-06-2010 5:35 AM
Reply to: Message 8 by Europa
06-06-2010 5:31 AM


Europa writes:

1. Why do you say this -- orange speckling -- isn't Lamarkism?

Because the variation in colouring isn't produced according to need, but by chance.

2. If orange speckling, by chance, occurs due to a single mutation on a single frog, will it be capable of making this the dominant trait of the colony over time? Is this how evolution works? I mean by the chance mutation of a favourable trait on a single organism?

Yes. Although chance favourable mutations could occur in more than one individual over the time involved.


This message is a reply to:
 Message 8 by Europa, posted 06-06-2010 5:31 AM Europa has not yet responded

  
Dr Jack
Member (Idle past 57 days)
Posts: 3507
From: Leicester, England
Joined: 07-14-2003


Message 10 of 104 (563613)
06-06-2010 5:39 AM
Reply to: Message 8 by Europa
06-06-2010 5:31 AM


1. Why do you say this -- orange speckling -- isn't Lamarkism?

Lamarkism is the inheritance of derived traits. It would be a frog somehow "learning" how to have orange speckles during its lifetime and then passing that trait onto its offspring

2. If orange speckling, by chance, occurs due to a single mutation on a single frog, will it be capable of making this the dominant trait of the colony over time? Is this how evolution works? I mean by the chance mutation of a favourable trait on a single organism?

Yes - mathematical modelling shows that a dominant trait that emerges in a single organism can reach fixation even if it only provides a slight fitness advantage - and yes and yes; but it's a bit more complicated than that.


This message is a reply to:
 Message 8 by Europa, posted 06-06-2010 5:31 AM Europa has responded

Replies to this message:
 Message 11 by Europa, posted 06-06-2010 5:49 AM Dr Jack has responded

  
Europa
Member (Idle past 2638 days)
Posts: 68
Joined: 06-05-2010


Message 11 of 104 (563614)
06-06-2010 5:49 AM
Reply to: Message 10 by Dr Jack
06-06-2010 5:39 AM


I am not arguing for the sake of arguing. But ...

The often quoted example of Lamarkism is the elongation of a giraffe's neck. Now, the giraffe did not 'learn' how to have a long neck. But this is Lamarkism.

How is the orange speckling of the froggies any different?

Edited by Europa, : No reason given.


This message is a reply to:
 Message 10 by Dr Jack, posted 06-06-2010 5:39 AM Dr Jack has responded

Replies to this message:
 Message 12 by Dr Jack, posted 06-06-2010 6:22 AM Europa has not yet responded
 Message 13 by Huntard, posted 06-06-2010 6:22 AM Europa has not yet responded
 Message 14 by Modulous, posted 06-06-2010 6:24 AM Europa has not yet responded
 Message 15 by cavediver, posted 06-06-2010 6:27 AM Europa has not yet responded
 Message 19 by Dr Adequate, posted 06-06-2010 7:22 PM Europa has not yet responded

    
Dr Jack
Member (Idle past 57 days)
Posts: 3507
From: Leicester, England
Joined: 07-14-2003


(1)
Message 12 of 104 (563616)
06-06-2010 6:22 AM
Reply to: Message 11 by Europa
06-06-2010 5:49 AM


The often quoted example of Lamarkism is the elongation of a giraffe's neck. Now, the giraffe did not 'learn' how to have a long
neck. But this is Lamarkism.

The Lamarkian notion was that the giraffe got a longer neck because during the lifetime of a giraffe they would strain to reach higher leaves, and in doing so slightly lengthen the neck, and then pass this slightly lengthened neck on to their offspring. You'll note that a) animals necks don't actually get longer by straining to reach things and b) even where traits can be environmentally acquired they are not passed on to the offspring*.

How is the orange speckling of the froggies any different?

If the frogs could acquire their orange speckles from the environment, and then pass this acquired characteristic on it then it would be Lamarkian. If they are born with orange speckles because of a mutation, and then pass that mutation on to their offpsring, it is Darwinian.

* - epigenetics aside. But that's a very limited case with preset limits.


This message is a reply to:
 Message 11 by Europa, posted 06-06-2010 5:49 AM Europa has not yet responded

  
Huntard
Member (Idle past 247 days)
Posts: 2870
From: Limburg, The Netherlands
Joined: 09-02-2008


Message 13 of 104 (563617)
06-06-2010 6:22 AM
Reply to: Message 11 by Europa
06-06-2010 5:49 AM


Hello europa, welcome to EvC.

europa writes:

The often quoted example of Lamarkism is the elongation of a giraffe's neck. Now, the giraffe did not 'learn' how to have a long neck. But this is Lamarkism.


No it isn't. Lamarckism states that the giraffe got the long neck because the ancestors of the giraffe stretched their necks, leading them to get longer necks because of that, and then passing this on to their offspring. However, this is not the case. The giraffe got the longer neck from a random mutation, was then able to reach more leaves, and because of this could survive better and pass this trait on to its offspring.

This is exactly the case with the frogs. They don't aquire the speckles because they need to, they aquire them by chance (or not, then they wil go extinct).


This message is a reply to:
 Message 11 by Europa, posted 06-06-2010 5:49 AM Europa has not yet responded

    
Modulous
Member (Idle past 56 days)
Posts: 7789
From: Manchester, UK
Joined: 05-01-2005


Message 14 of 104 (563618)
06-06-2010 6:24 AM
Reply to: Message 11 by Europa
06-06-2010 5:49 AM


On the origin of speckliness by means of Natural Selection
The often quoted example of Lamarkism is the elongation of a giraffe's neck. Now, the giraffe did not 'learn' how to have a long neck. But this is Lamarkism.

How is the orange speckling of the froggies any different?

In Lamackism the giraffe might stretch its neck a little bit to get some food. Somehow (and there were some fun theories, including by Darwin) the acquired trait may 'feedback' into the chain of inheritance so the children of the giraffe have the slightly stretched neck.

In the frog example some frogs would have to somehow produce orange speckles by effort. I'm guessing if I asked you to do that, you might have some difficulty. How do you do the equivalent of stretching to 'reach' for orange speckles? The most 'likely' method is that eating the orange plants (or eating something that eats the orange plants) results in a transfer of pigmentation causing the frogs to become speckly. IF this characteristic could be inherited it would be Lamarckism.

But speckliness isn't all that we're worried about. There are other ways to cope with predation than blending in. They could change their development cycle (which is in fact what many animal populations 'try' first) so they have either more children (to counteract the number that will die from predation), or they have children at a younger age (to counteract their reduced life expectency) or something similar. If predation is really fierce, and they survive we might even see the frogs falling all the way back to living in perma-larvae stage!

So really, the question is, where did the orange speckling come from? Was it a mutation that lead to a frog being born speckly when it's parent's were not? Or was it a change that occurred to a parent after the parent was born that it then passed on.

The former is basic Darwinism, the latter is Lamarckism. The real picture is more messy than that. But that's the key difference: the origin of the speckliness.

If it was a genetic copying error around the reproductive event it was random mutation.
If it was an event during the normal lifetime of a frog that fortuitously lead to it developing orange speckles, then that is an acquired characteristic.

If it happened without foresight it was chance.
If it happened through some effort, inadvertent or otherwise, that might be 'felt need'.

Since frogs almost certainly have absolutely no clue what the best strategy is, they probably don't close their eyes and wish for speckles really hard in order to obtain them.


This message is a reply to:
 Message 11 by Europa, posted 06-06-2010 5:49 AM Europa has not yet responded

  
cavediver
Member (Idle past 1595 days)
Posts: 4129
From: UK
Joined: 06-16-2005


Message 15 of 104 (563619)
06-06-2010 6:27 AM
Reply to: Message 11 by Europa
06-06-2010 5:49 AM


The often quoted example of Lamarkism is the elongation of a giraffe's neck.

Yes, because in the age old story, our giraffe wanted so much to reach those tasty leaves up high, that he streeeeetcheeeeed his neck so he could reach them. And low and behold he now had a long neck. Which by Lamarkism he passed onto all of his descendenrts. But by evolution, of course, he did not. He was just one long necked giraffe, and all his descendents had the same short necks as he had at birth.

You can only pass on the genes you inherited at conception, which may be modified by later germline mutations.


This message is a reply to:
 Message 11 by Europa, posted 06-06-2010 5:49 AM Europa has not yet responded

  
1
234567Next
Newer Topic | Older Topic
Jump to:


Copyright 2001-2015 by EvC Forum, All Rights Reserved

™ Version 4.0 Beta
Innovative software from Qwixotic © 2018