How did the senses develop?

Discussion in 'Science and Technology' started by Zanman, Jan 5, 2005.

  1. Zanman

    Zanman Member

    I think it has been correctly stated that we do not so much experience the Universe but rather ourselves.

    So we have the senses of sight, touch, smell, hearing and taste, and perhaps one or two others depending on your degree of skepticism.

    I am most interested in sight though. It seems amazing to me that something blind, like the origins we presumably came from, can develop into what we have now ... and does that develop into recognition of a larger area of the spectrum in the future - do we eventually get to "see" ultra and Infra?

    But I mean, at what point did trilobites get eyes?
     
  2. Kandahar

    Kandahar Banned

    Well, I suppose it depends on your definition of what constitutes an "eye." Even some unicellular organisms are sensitive to light, but can't really see anything. So there's some degree of opinion regarding whether or not certain animals can "see." I'd probably place the date of the evolution of sight at about 400 million years ago, during the Devonian Period, when boned-fish and amphibians evolved.
     
  3. underwhelmed

    underwhelmed Member

    There are so many more senses than the common five of touch smell taste sight and hearing...

    Principle senses of all creatures (according to Murchie)
    - SIGHT...including seeing polarized light and seeing without eyes (like the sun sense of plants)
    - sense of ones own AWARENESS OF OWN VISIBILITY (or invisibility)...transparency, camouflage...etc
    - sensitivity to RADIATION other than visible light
    -TEMPERATURE sense...ability to inulate, hibernate
    - ELECTROMAGNETIC sense...ability to generate current (electric eel) and just the sesitivity to electromagnetic fields
    -HEARING...includes sonar and infra and ultra-sonic frequencies
    -awareness of PRESSURE...usually underground and underwater
    -FEEL...touch on the skin
    - sense of WEIGHT and BALANCE
    - sense of SPACE and PROXIMITY
    - CORIOLIS sense...awareess of the effects of the earths spin
    -SMELL...even beyond nose
    -TASTE...even beyond tongue
    -APPETITE...hunger, urge to kill
    - HUMIDITY...thirst, evaporation controll...
    -PAIN... external, internal, spiritual, mental distress and capacity to weep
    - sense of FEAR...dread of injury or attack or death or falling or suffocation
    - PROCREATIVE URGE....sex awareness, mating, maternity, raising the young
    -sense of PLAY...sport, humor, laughter
    -TIME sense... biological clock
    -NAVIGATION sense... awareness of land, position of sun, of time, moon and stars
    -DOMINEERING and TERRITORIAL sense...capacity to repel, intimidate others
    -COLONIZING sense...parasites, slaves, hosts, all the way to superorganism
    -HORTICULTURAL...able to cultivate crops, fungus grows algae
    -LANGUAGE and ARTICULATION....express feelings, convey info
    -REASONING...memory, capacity for logic
    -INTUITION....subconcious deduction
    -ESTHETIC...creativity and appreciation of music and arts
    -PHYSCHIC...foreknowledge, animal instincts
    -HYPNOTIC POWER....capacity to hyptnotize other creatures
    -RELAXATION and SLEEP...dreaming, meditation, brain wave awareness, dying
    -SPIRITUAL....capacity for sublime love, ecstasy, sense of sin, sacrafice....

    they may overlap a good bit, or some may be called just "instincts" but they should be mentioned while one the subject of senses....
     
  4. erowid

    erowid Member

    I just have to say Ive put many hours of thinking into this one months before and I truely feel this question in my mind anyways is the bridge between straight natural selection/mutation divine evolution, for when you truly think about it how could that first cell just have had the knowledge of detecting light, I don't beleive god reached his hand from up hey and popped a rod and some cones on the little bugger, yet I beleive in a link between living things and there enviroment on a fundamental yet unconscious level. Theres trees in south africa that naturally evolved seeds that drop on gliders with the most efficient low spped flight design known to man.
     
  5. TrippinBTM

    TrippinBTM Ramblin' Man

    here's a cool site, about how the eye evolved, and how that caused a brain to evolve. The link takes you to a page giving a brief overview of how the brain came from the eye, but other pages talk about how the eye itself evolved. http://www.don-lindsay-archive.org/creation/eye_brain.html
     
  6. ~Sam~

    ~Sam~ Cosmic Traveler

    From no eyes to eyes involves mutation. Populations (all the members of a species that live in a defined geographic region at a given time) are the essential units that evolve and exhibit characteristics of DNA mutation.

    * genotype - the genetic makeup of any organism.

    * phenotype - any observable traits that an organism has, including its physical characteristics and behavior.

    * alleles - varient forms of genetic material, i.e., Alleles for coloration. In sexual reproduction, phenotypes for coloration come in two variant forms, with offspring inheriting one allele from their father and one from their mother. Though both alleles help code for coloration, one may result in slightly lighter or darker coloration than the other. The lighter colored offspring may become prey and eventually become extinct. The darker color may hide the organism from predators, leading to the continuation of the darker colored species variant.

    * A mutation is any permanent alteration in an organism's DNA. Some of these alterations are heritable, meaning they can be passed on to future generations. Mutations can be as small as a change in a single base pair in the DNA chain (a point mutation) or as large as the addition or deletion of a whole chomosome or parts of it. Whatever the case, a mutation is a change in the informational set an organism possesses.

    The rate of mutation is very low in most organisms; during cell division in humans, it might be just one DNA base pair per billion. And of the mutations that do arise, very few are beneficial or "adaptive." Most do nothing, and many are harmful to organisms. Thus mutations usually are not working to further survival and reproduction. Given this, they generally are not likely to appear with greater frequency in successive generations. The upshot is that mutation are not likely to account for much of the change in allele frequency that is observed in any population.

    But a few mutations occur that are adaptive. These genetic alterations are something like creative thinkers in a society: They are rare but very important. Such mutations are the only means by which new genetic information comes into being - by which new proteins are produced that can modify the form or capabilities of an organism. The evolution of eyes or wings had to involve mutations. No amount of shuffling of existing genes could get the living world from no eyes to eyes.

    Of course, no mutation can bring about a feature such as eyes in a single step; such changes are the result of many mutations, followed by rounds of genetic shuffling and natural selection, generally over millions of years.
     

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