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07 Sep

再談進化論

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再談進化論。

生物的進化大部分是漸進的。突變性的進化方式,像X-Man那樣,即使有,比例也是非常的小。因為像這類突變,通常很難適應當時的環境而被淘汰。

甚麼是漸進式的進化?舉個例子,眾所周知,斑馬身上的斑紋是在大草原上用來掩飾與偽裝自己,不被天敵發現。那些斑紋是如何進化來的?它并不是應需求而產生的,而是依照“適者生存”的條件演變成如今的這種圖案。怎么說?幾千萬年前斑馬的遠祖,身上沒有斑紋。但在繁殖的過程中,有一組身上開始產生一點的斑紋。沒有任何自我保護因素,純粹是基因上的不完美,就像你我身上的雀斑。後來,這一組馬群由于這些額外的斑點模糊了天敵的視覺而得以生存下來。其他沒有斑點的馬群被狩獵的機會就相對的大幅度增加。像這樣不斷的循環下,斑點就逐漸進化成如今斑紋。

問:那其他種類的馬呢?它們沒有像斑馬一樣的斑紋也一樣能存活到今天。當然了,因為它們跑得快呀,在進化的過程中,那一組的腿就進化的特別的長。斑馬相對的慢吞吞。

再問:如果只是隨機產生的斑紋,怎麼可能長得那麼的完美?這有兩方面的原因。第一,當然是這樣的條紋比較能偽裝,存活率較高。第二,這是物理方面的解釋了。科學(數學)上證明了斑紋會自然的形成一些特定的圖案。舉個例子,在小面積的地方,斑紋會自然形成條狀,就像花豹的尾巴尖端,即使花豹身上的圖案是斑點而非條紋。不相信?拿幾千根火柴,閉上眼睛往前隨機的扔出去。一千根之後打開眼睛看看,會形成甚麼圖案。次序是能在隨機下產生的。

總括來說,進化是隨機的(物競),然后優勢的進化保存下來,劣勢的被淘汰(天擇)。而且是從地球形成初期的四十億年前就已經開始了。這過程是漫長的。這也說明了為甚麼即使是萬物之靈的人類(哈哈)還是不完美,變不成超人。

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  1. ktang
    September 11th, 2009 at 18:14 | #1

    do you know how long can a concrete structure last?

    The answer from web is 50,000 years (wonder how they work it out as history of mankind is much lesser??)

    • drkhtang
      September 12th, 2009 at 14:06 | #2

      I guess that’s just a close approximate. But that doesn’t matter, it is still negligible compared to the entire life of the Earth and the Universe.

  2. 阿洪
    September 9th, 2009 at 17:08 | #3

    Life first emerge on earth 3.5billion years ago; dinosaur appears 200million years ago & extinct 65million years ago.

    Chimz & our great ancestor went on different evolution path 3million years ago & homo sapien (modern man) only appears 100thousand years ago.

    萬物之靈?? hhh since when the humble homo sapien become such arrogant creature. Looking at the life evolution on earth, human just a tiny little dot on the timeline.

    http://en.wikipedia.org/wiki/Evolutionary_history_of_life

    • drkhtang
      September 9th, 2009 at 19:12 | #4

      Ok lah.. humans are indeed much much more intelligent than other creatures on earth.. but like you said, we could have been more humble than calling ourselves 萬物之靈. maybe 萬惡之靈 is more appropirate =)

    • ktang
      September 10th, 2009 at 10:11 | #5

      it is a tiny dot alright, but what this tiny dot has brought to the whole globe is complete damaging. If you think about it, all creatures left nothing but their bones on earth after their time.

      Human gonna leave big piece of shit on earth after our time.

      • drkhtang
        September 10th, 2009 at 11:12 | #6

        It’s OK. The nature will restore everything eventually, although it might be a painful process. This is the law of the universe.

  3. jiarenyouyou
    September 9th, 2009 at 08:53 | #7

    因为上帝要让我们继续接受磨练

    • drkhtang
      September 9th, 2009 at 14:32 | #8

      哈哈 =_=

  4. shiam
    September 9th, 2009 at 08:34 | #9

    你的意思是,為什麼除了人類這麼進化的生物還存在之外,還有一些不進化的生物,憑什麼存在嗎?是因為人類跟其他生物一樣,因為不完美,所以繼續進化,適者生存嗎?

    • drkhtang
      September 9th, 2009 at 14:32 | #10

      對。“隨機”就表示了物種不會為了適應環境而衍生出特定功能。而是,“不小心”擁有特別功能的物種得以生存下來。人類為甚麼有十根手指也是“不小心”擁有的。再怎麼說,有十六根手指遠比十根手指來得強(除了打字快之外,十六進位是數位電腦的基礎),如果是為了適應環境,為甚麼不進化成十六根手指?

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