Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Can evolution theory work from a plan over generations ?

  1. May 27, 2007 #1
    Can evolution theory work from a "plan" over generations ?

    I saw something rather interresting on TV one day, I believe it was National Geographic. or something like that.

    The TV program was about the historical evolution and development to animals living in the sea to then develop lunghs and feets to be able to walk up on land.

    What I think I saw on TV, that's I'm not realy sure about is that some marine animals develped some bone structures to later from the rear feet over generations and thousands of years.

    Can this really be true ?

    If this evolution therory of Mr Darvin should be true, shouldent the changes and that "design improvements" that were obtained be done in smaller steps so that each generation should make some benefits of each change ?

    I think that an evelution theory that is based on a thaught or a principle that everytning just happend as a coincidense where the stronger individuals survived, so we got some lions and some tigers, and some monkeys as well, contra the evolution therory with the buildt in long term plan behind it.

    I think "believing" in a evolution therory where everything happend by coincidence contra believing in the evolution theory with the long term plan behind it will be two quite different beliefs.

    Is there anybody that knows examples of development history of some species that has such a form that the "design changes" first can serve to give some usable improvements after generations of development ?

    Could the historical deveoplment of the species have happen due to some coordinated development plan behind it or has it all happened more as an result of coincidence. Is there any proven facts that can indicate that the one or the other way of seeing things might be the right one ?
     
  2. jcsd
  3. May 27, 2007 #2
  4. May 27, 2007 #3
    Well thats about exately what I self believed for years and years about evoulution theory, until I hapend to see a TV program that described how some marine animals developed front and rear feat over generations, before they entered land.

    The TV program did not mention evolution theory at all, but I started to think myslelf, as I have allways considered the evoltuion theory to be the theroy of the survival of the fittest.

    If this should be correct there should not be possible or logically according to this theory that some species eventuelly should develop some "new design" where the benefit of this new design can be used first after thousen of years of development.

    What I actuelly were thinking about as a question was not the content of the theory itself, but rather objective observations that could indicate if the clasical evolution theory is correct or not, or if it should be reviced a bit.

    Wathcing TV program might not be the most secure source of informations, so I was courios to know if such "redesign over genrerations, befeore they could be used" really has happened for some species.

    If this should be the case, then it should be time for a small little revision how to understand the evolution theory. TV programs does not have to be dependable or reliable, espessially when you don't remember which program it was.

    What I think is interresting is not the theory itself that might be more or less precise or trustable, but the documented development history, that should be considered to be the more trustworthy way to evaluate the theory.
     
    Last edited: May 27, 2007
  5. May 27, 2007 #4
    Keep in mind that in Darwin's day, they had extremely limited knowledge about biology. They had no concept about things such as genes and DNA, protein expression, regulation, etc. It was really just an insight into the differences in anatomy of similar species. There are a multitude of "checks and balances" involved within the genome, and "natural selection" as Darwin described it only really refers to a species' "fitness" within it's environment.

    Current knowledge doesn't contradict these principles, they just describe the process in greater detail.
     
  6. May 27, 2007 #5
    Also keep in mind that apendages may evolve for one purpose but are then used for another. I know little about marine evolution, but it's possible. For instance, there's a theory that feathers started out as an alternative to hair, used to regulate body temperature, and only later became useful in flight.
     
  7. May 27, 2007 #6
    eeh so much stuff that doesnt go anywhere. Darwin is nobody in today's biology world, people are praising him too much. evolution of particular gene functions that are better than other genes is a much better way to study evolution.
     
  8. May 28, 2007 #7
    If you're talking about microbiology, I agree completely. But what would science be without heaps of unecessary speculation?
     
  9. May 29, 2007 #8
    darwin was a genius for his time, he opened the mind of people to start to look for answers other then the blind faith in religious "propaganda" that explains how and why we are here today.

    back to the subject.
    i agree with synapticself.
    for instance, the legs you mentioned langbein about how theu were created long before the creatures went on land.
    legs and forearms can be use for more then moving around.
    for instance. it can be used to dig up loose soil on the ocean floor to search for food. clams etc.
     
    Last edited: May 29, 2007
  10. May 29, 2007 #9
  11. May 29, 2007 #10

    DaveC426913

    User Avatar
    Gold Member

    This may clear up the issue:

    I believe there is a critical misunderstading here.

    A central aspect of evolution is that a feature develops for one purpose but subsequently another use is found for that feature.

    Marine animals developed bony appendages for some (unspecified) reason that helped them survive better underwater (perhaps being able to dig for food in the sea bottom). Subsequent to them developing bony appendages, they found a completely different use for them - it allowed them to venture forth onto land, where there was an unchallenged cornucopia of food supply.

    Similarly with dinosaurs developing feathers. The feathers developed for a completely different purpose (possibly heat venting, heat retention or mating rituals). Subsequent to developing feathers, they discovered that feathers helped them escape predators.


    This was a key point that Darwin's theory fell short on. He thought adaptations were "driven" by "need".
     
  12. May 29, 2007 #11

    DaveC426913

    User Avatar
    Gold Member

    Sure, in the same way Newton is a nobody in today's physics world. :uhh:
    Forming a new foundation and forever altering the science you are in is overrated.
     
  13. May 29, 2007 #12
    Is this for sure ?

    Well, I do not think that TV programs is a very dependentable source of information, but what I think I saw was the development of some bone structures that should be rather little well deigned for marine use, but that had just that structures from the beginning that would be suitable for on land use.

    Could this really be true or was it just some other TV show ..

    Darwin woldn't interest me at all, he was just mentioned for giving some assosiations to soemthing more well nown.

    Can it be said for sure that bone structures thet were developed by marine animals were allways optimized for marine use and not a later on land use ?
    (When it comes to practical/technical design.)
     
  14. May 29, 2007 #13
    Wasn't that Lamarck? He had the theory about the behavior driving anatomy changes (the giraffe straining to reach higher leaves grew longer necks).

    Darwin postulated that random variations over time along with "survival of the fittest" drove evolution.

    In a way, they were both kind of right......
     
  15. May 29, 2007 #14

    DaveC426913

    User Avatar
    Gold Member

    1] It is very easy - in hindsight - to look at a given feature and think it is optimized for a certain task. But would you say our spines and legs are optimized for upright land movement? Well, they're not. Consider all the health problems related to backs and spines.

    2] Surely the show is greatly oversimplifiying the issues for the purpose of demonstration.
     
  16. May 30, 2007 #15
    Well try this experiment:

    1. Stand up on your feet. Bend forward until your hands touch the ground.
    2. Walk arount like this for one week.

    I must admit that I know very little about sea animals walking up to land, but if I ever should do, I would tru to look into this problems. Its quite interesting.

    By the way - Thanks for your answer !
     
  17. May 30, 2007 #16

    siddharth

    User Avatar
    Homework Helper
    Gold Member

    And what is the purpose of this experiment?
     
  18. May 30, 2007 #17
    Im not sure if this is the same species or story in your TV show, but I came across this article: http://scienceweek.com/2007/sw070105.htm

    4. PALEONTOLOGY: A NEW FOSSIL FISH

    The following points are made by SCIENCE News Staff (Science 2006 314:1850):

    1) Paleontologists made a major splash this year (2006) with the debut of a fossil fish that long ago took a deep breath and made some tentative but ultimately far-reaching steps onto land. With its sturdy, jointed fins, the 375-million-year-old specimen fills an evolutionary gap and provides a glimpse of the features that helped later creatures conquer the continents.

    2) All limbed vertebrates, known as tetrapods, evolved from lobe-finned fishes some 370 million to 360 million years ago. Many of these sophisticated fishes had skeletons with modifications, such as enlarged bones in their fins, that would ultimately prove useful for weight-bearing limbs. The new species is the most tetrapodlike fish yet discovered.

    3) Three specimens were found during a 2004 field expedition to Ellesmere Island in the far north of Nunavut, Canada. They were named Tiktaalik roseae for "large freshwater fish" in the Inuktitut language and a donor who helped fund the expedition, respectively. With fins and scales, the 3-meter-long Tiktaalik is clearly a fish. It had a flat head with eyes on top and lived in shallow streams. What makes Tiktaalik unique among fish is that each of the front fins has a wrist and elbow, providing flexible motion. Also unlike other fish, Tiktaalik sported a neck -- the oldest one known in the fossil record -- and could move its head. Achieving that flexibility required losing a bone called the operculum, which modern fish use to pump water over their gills. Tiktaalik still had well-developed gills, and it probably used its neck and stout limbs to push its head above water to inhale.

    4) Another feature that makes Tiktaalik close kin to tetrapods is its robust, overlapping ribs. Although their function isn't completely clear, researchers think they could have helped support its body out of water and aided in breathing. Forays onto land would have offered an escape from sharks and other predators, as well as insects to eat. Tiktaalik isn't a perfect tetrapod, of course -- among other traits, it lacks fingers and toes -- but it was certainly a big step in the right direction.

    Science http://www.sciencemag.org

    ScienceWeek http://scienceweek.com
     
  19. May 30, 2007 #18
    I believe to demonstrate that indeed the human spine and hips are better designed for upright walking than they are for getting around on "all fours". :biggrin:
     
  20. May 30, 2007 #19
    Maybe after that we can submerge our heads to demonstrate that our lungs are better at filtering oxygen out of air as opposed to water.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Can evolution theory work from a plan over generations ?
  1. Is Human Evolution Over? (Replies: 67)

  2. The theory is evolution? (Replies: 14)

Loading...