1
   

Evolution?

Forums: Philosophy
Email this Topic • Print this Page
 
 
Buffalo
 
Reply Sat 29 Dec, 2007 08:31 pm
Why is it that an animal species can "evolve" and physically change to suite their surrounding if they are placed on a new "island", but if you cut off the tails of every newborn rat for several generations, they still continue to grow tails?
  • Topic Stats
  • Top Replies
  • Link to this Topic
Type: Discussion • Score: 1 • Views: 2,881 • Replies: 56
No top replies

 
tycoon
 
  1  
Reply Sat 29 Dec, 2007 08:34 pm
Because you didn't give the rats a suite.
0 Replies
 
Cyracuz
 
  1  
Reply Sat 29 Dec, 2007 08:38 pm
Hmmm... Cutting off the tail of a rat is hardly changing it's environment. The rat still needs the tail for balance purposes. If that changes the tail may dissappear, but it will probably take a veeeery long time.

scissor me timbers
0 Replies
 
rafamen
 
  1  
Reply Wed 2 Jan, 2008 01:40 am
cause those things run in genes which are inside every cell its not like they gona say "the h*ll with these tails, they get chop off everytime so we gona make no more" it can't change like that.
0 Replies
 
hanno
 
  1  
Reply Thu 3 Jan, 2008 08:13 pm
Cut off the tails of all rats in a population that is close to its maximum size and the ones that had invested less energy in generating the tail will be favored. Mutations resulting in the non-formation of a tail are not uncommon (just as an effect of the nature of genetic coding, like how size and coloration mutate fairly readily). Eventually rats with smaller tails, or a tail that can be cut with diminished risk of neurological dysfunction, bleeding, or infection will dominate the population. The final result (I'm guessing, since the burden of being surgically altered will tend to outweigh the benefits of having tail-structure before birth, or any benefit that can be derived from the surgery, such as immunological hardening), will tend to be tail-less rats.

The reason you wouldn't get results is your set-up wouldn't even be experiencing artificial selection - rats are such virile creatures that the burden of losing the appendage wouldn't kill an appreciable segment of the population, before you could breed 'em again, to select tail-amputation-friendly traits.
0 Replies
 
blindsided
 
  1  
Reply Sat 5 Jan, 2008 05:27 pm
Evolution isn't real and has never been proven otherwise.
0 Replies
 
ebrown p
 
  1  
Reply Sat 5 Jan, 2008 06:16 pm
blindsided wrote:
Evolution isn't real and has never been proven otherwise.


You don't read much, do you.
0 Replies
 
ebrown p
 
  1  
Reply Sat 5 Jan, 2008 06:17 pm
Buffalo,

Are you looking for an explanation of how evolution works?

From your initial question I would guess you don't really understand what evolution is.
0 Replies
 
maporsche
 
  1  
Reply Sat 5 Jan, 2008 11:20 pm
No kidding...you have no idea how evolution works.
0 Replies
 
hanno
 
  1  
Reply Sat 5 Jan, 2008 11:21 pm
I keep hearing how we've never replicated evolution, but try to bread a mastiff and a pomeranian (both breeds that have come about by deliberate human action) - they're genetically compatible, would produce viable offspring, but put two populations of them together and the lines would remain separate (although many pomeranians might die of cloacal hemorrhaging). So there you've got step 1 of speciation carried out by Saxons needing attack animals and Pomeranians needing furry abominations - proof of the mechanisms of evolution.
0 Replies
 
farmerman
 
  1  
Reply Sun 6 Jan, 2008 07:37 am
hanno, Darwin , in his 1st edition of "Origins..." devotes several chapters to artificial selection and hybridization, as compared to natural selection. Its worth a read from someone who was as blown away by the mechanism as any interested student.

Also, Id rethink your statement about cutting off the tails of a population of rats.
0 Replies
 
rosborne979
 
  1  
Reply Mon 7 Jan, 2008 02:57 pm
Re: Evolution?
Buffalo wrote:
Why is it that an animal species can "evolve" and physically change to suite their surrounding if they are placed on a new "island", but if you cut off the tails of every newborn rat for several generations, they still continue to grow tails?

This sounds like one of those trick questions they ask in Jr. High Biology class to see if you've been paying attention to the basic concepts of evolution in your classes. (Don't worry if you can't answer the question, many creationists we have online here at A2K can't answer it either)

The correct answer of course depends on what state you're in. If you're in Kansas or Florida the answer is "Because god works in mysterious ways". If you're in a state which cares about your ability to get a job in the sciences when you're out of school, then the answer can probably be found in the chapter in your book which talks about the difference between Lamark and Darwin.

Good luck.
0 Replies
 
rosborne979
 
  1  
Reply Mon 7 Jan, 2008 03:04 pm
but here's the short answer...

Animals don't acquire traits during their lives, they only pass on traits which are already in their DNA. Cutting off a rats tail doesn't change its DNA, so the trait doesn't get passed on.
0 Replies
 
baddog1
 
  1  
Reply Tue 8 Jan, 2008 09:05 am
Re: Evolution?
Buffalo wrote:
Why is it that an animal species can "evolve" and physically change to suite their surrounding if they are placed on a new "island", but if you cut off the tails of every newborn rat for several generations, they still continue to grow tails?


Buffalo:

Your example of removing rat's tails over time is interesting. One important thought (when it comes to autonomy) is whether the removal of their tails is life-threatening. I would imagine that removal of their tails would be life-threatening for various biological reasons; therefore your example should [theoretically] lead to evolutionary changes.

The following brief abstract involving Blue crabs supports your thoughts:

Autotomy in Blue Crab (Callinectes sapidus Rathbun) Populations: Geographic, Temporal, and Ontogenetic Variation
L. D. Smith and A. H. Hines
Smithsonian Environmental Research Center, P.O. Box 28, Edgewater, Maryland 21037

Blue crab (Callinectes sapidus Rathbun) populations were examined at four sites in Chesapeake Bay and three additional sites along the southeastern Atlantic coast and Gulf of Mexico; the aims were to assess the incidence of limb autotomy and to determine whether injury patterns varied temporally, geographically, and ontogenetically. These data, which include four years of information from one site (Rhode River, Maryland, a subestuary of central Chesapeake Bay), make this study the most extensive and intensive survey of limb autotomy yet conducted in arthropods. A substantial percentage (17-39%) of the blue crab populations were either missing or regenerating one or more limbs, suggesting that autotomy is an important mechanism for their survival. The frequency of limb autotomy varied, both within and between years, and over broad geographical scales. Injury levels were generally correlated positively with crab size. Limb autotomy was independent of sex and molt stage, and frequencies varied little among sites in the Rhode River. Patterns of limb injury in C. sapidus were remarkably consistent among all sites. The most frequent injury involved loss of a single cheliped. Swimming legs suffered the least damage. Severe multiple limb loss was rare. Right and left limbs were lost with equal frequency in most populations. This consistency of autotomy pattern suggests differential vulnerability of limbs and standard behavioral response by blue crabs to various injury-causing agents. The frequency of autotomy was density-dependent in the Rhode River, indicating that intraspecific interactions (e.g., cannibalism) may be a major cause of limb loss in populations in the Rhode River subestuary and elsewhere.

http://www.biolbull.org/cgi/content/abstract/180/3/416
0 Replies
 
farmerman
 
  1  
Reply Tue 8 Jan, 2008 10:18 am
Very Happy This is better than "the Onion".PS, the word is autotomy, not autonomy.

Read what ros has said until it sinks in. Then read up on genetic variability and evolution.
0 Replies
 
baddog1
 
  1  
Reply Tue 8 Jan, 2008 12:03 pm
farmerman wrote:
Very Happy This is better than "the Onion".PS, the word is autotomy, not autonomy.


Admittedly, my spelling is far from perfect, but I think I got this one right.
baddog1 wrote:
Autotomy in Blue Crab (Callinectes sapidus Rathbun) Populations: Geographic, Temporal, and Ontogenetic Variation


farmerman wrote:
Read what ros has said until it sinks in. Then read up on genetic variability and evolution.


ros statement was technically correct, but could be misinterpreted. A more appropriate statement would have been "Cutting off a rats tail doesn't directly change its DNA...".
0 Replies
 
farmerman
 
  1  
Reply Tue 8 Jan, 2008 01:13 pm
how does it "indirectly" affect the rats DNA? You give me no reason to assume that you have any idea what you are even talking about BD>
Am I close on that assumption?
0 Replies
 
baddog1
 
  1  
Reply Tue 8 Jan, 2008 01:48 pm
farmerman wrote:
how does it "indirectly" affect the rats DNA? You give me no reason to assume that you have any idea what you are even talking about BD>
Am I close on that assumption?


Do the continuous disrespectful comments somehow make you feel better about yourself fm? While I do not announce myself as an expert at genetics; I do have a reasonable understanding of it - thus my choice to speak (and learn) on this thread.

As to the subject at hand: Rolling Eyes

The way that I understand natural selection - limb regeneration helps with survival. Is this true?

And is it true that DNA changes are happening all the time?

If true - can DNA mutation happen during natural selection?

If yes, then the mutation could indirectly affect a rat(s) DNA.
0 Replies
 
maporsche
 
  1  
Reply Tue 8 Jan, 2008 01:59 pm
baddog1 wrote:
farmerman wrote:
how does it "indirectly" affect the rats DNA? You give me no reason to assume that you have any idea what you are even talking about BD>
Am I close on that assumption?


Do the continuous disrespectful comments somehow make you feel better about yourself fm? While I do not announce myself as an expert at genetics; I do have a reasonable understanding of it - thus my choice to speak (and learn) on this thread.

As to the subject at hand: Rolling Eyes

The way that I understand natural selection - limb regeneration helps with survival. Is this true?

And is it true that DNA changes are happening all the time?

If true - can DNA mutation happen during natural selection?

If yes, then the mutation could indirectly affect a rat(s) DNA.



There is no DNA mutation when you lop off a rat's tail.
0 Replies
 
baddog1
 
  1  
Reply Tue 8 Jan, 2008 02:05 pm
maporsche wrote:
There is no DNA mutation when you lop off a rat's tail.


Your assertion is not consistent with Buffalo's example.
0 Replies
 
 

Related Topics

How can we be sure? - Discussion by Raishu-tensho
Proof of nonexistence of free will - Discussion by litewave
The Void and the Absolute Oneness of the Universe - Discussion by Relinquish
can we reconcile darkness in man with madness(lunacy) ? - Question by studentnorway
Destroy My Belief System, Please! - Discussion by Thomas
Star Wars in Philosophy. - Discussion by Logicus
Existence of Everything. - Discussion by Logicus
In the GRAND scheme of things, what matters? - Question by komr98
Is it better to be feared or loved? - Discussion by Black King
How can something come from nothing? - Question by ripple
Paradigm shifts - Question by Cyracuz
 
  1. Forums
  2. » Evolution?
Copyright © 2024 MadLab, LLC :: Terms of Service :: Privacy Policy :: Page generated in 0.04 seconds on 04/19/2024 at 02:58:43
▲ ▼