上個(gè)世紀,大多數人類(lèi)學(xué)家都認為,現代社會(huì )醫學(xué)的進(jìn)步、細胞產(chǎn)生的抗體作用及飲食水平的提高為人類(lèi)屏蔽了很多危險,同時(shí)也阻礙了人類(lèi)基因的進(jìn)化。然而近日,美國麥克拉齊報業(yè)公司發(fā)表了一篇報道稱(chēng),人類(lèi)進(jìn)化仍在繼續,且現代快節奏的生活帶來(lái)的壓力加速了這一過(guò)程的進(jìn)行。
上周,美國人類(lèi)體格學(xué)協(xié)會(huì )在芝加哥舉行了年會(huì ),會(huì )上有關(guān)“進(jìn)化仍在進(jìn)行”的觀(guān)點(diǎn)仍然很有爭議。美國新出版的一本《一萬(wàn)年之大爆發(fā)》(The 10,000 Year Explosion)中也將這個(gè)命題當作了探討的問(wèn)題之一。
這本書(shū)的作者之一亨利-哈彭丁稱(chēng):“上個(gè)世紀的很長(cháng)一段時(shí)間內,社會(huì )學(xué)都錯誤地認為人類(lèi)進(jìn)化在很久之前就已經(jīng)停止……很明顯,這樣的想法是錯誤的,人類(lèi)進(jìn)化還在繼續。書(shū)中有人類(lèi)學(xué)家提出“過(guò)去一萬(wàn)年中,人類(lèi)的進(jìn)化是在加速,而非放緩或停止……并且這一進(jìn)程的迅速程度已經(jīng)使人類(lèi)在身體和思維上發(fā)生了重大改變”。
該書(shū)認為,輻射、吸煙及其他有毒化學(xué)物質(zhì)都能夠使DNA產(chǎn)生變異,其中有些變化是對人類(lèi)有害的,大多數不產(chǎn)生任何作用,而還有一少部分對人類(lèi)未來(lái)生存是有益的。根據達爾文提出的“自然選擇”原則,這部分有益的基因變化會(huì )被遺傳給后代。
比如說(shuō),擁有黑色皮膚的非洲人遷居到北歐后,控制膚色的基因會(huì )產(chǎn)生細微變化,而繼續留在非洲的人則不會(huì )有這樣的變化。因為黑色的皮膚可以保護那些生活在非洲的人免遭紫外線(xiàn)照射產(chǎn)生的危險,而淺色皮膚又可以使北歐人在陽(yáng)光照射下生成更多的維生素D,從而有助于他們的骨骼生長(cháng)。
哈彭丁稱(chēng),在非洲南部肆虐的艾滋病可以讓那里的人們產(chǎn)生對艾滋病病毒產(chǎn)生免疫性的基因變體,久而久之這種變體會(huì )在非洲人種中遺傳下來(lái)。
哈彭丁還指出,目前人類(lèi)已經(jīng)發(fā)生了很多基因進(jìn)化,數量至少幾百種甚至上千種。
另一位人類(lèi)學(xué)家還表示,人類(lèi)的進(jìn)化速度如今翻了上百番,而這其中一個(gè)重要原因就是人類(lèi)數量的快速增長(cháng)。
xinhuawang
http://news.xinhuanet.com/tech/2009-04/10/content_11161118.htm--------------------------------------------
人類(lèi)仍在進(jìn)化嗎?
化石記錄向我們顯示,所有的物種最終都會(huì )滅絕,但在此之前往往存在數百萬(wàn)年。與過(guò)去或現在的任何其他物種相比,人類(lèi)掌控自身命運的能力都更強——如果我們確實(shí)走向滅絕,那么幾乎可以肯定的是這一結果是由我們自身的行為造成的。
人類(lèi)仍在進(jìn)化嗎?未來(lái),進(jìn)化后的我們會(huì )擁有怎樣的外表?如同電影里一樣頭更大、腿更短嗎?人類(lèi)會(huì )有滅絕的一天嗎?
在過(guò)去幾個(gè)世紀中,我們看到的人口變化是飲食的改善和公共衛生的提高的結果,而非進(jìn)化(即基因變化)的影響。如果像達爾文和多數生物學(xué)家所言,進(jìn)化是物競天擇的結果,那么只有當頭大腿短的個(gè)體能夠比頭小腿長(cháng)的個(gè)體繁衍出生存能力更強的后代這個(gè)假設成立時(shí),人類(lèi)才可能在未來(lái)進(jìn)化得頭更大、腿更短。我懷疑這種假設的正確性。因此,科幻小說(shuō)中的預測是不可能成為現實(shí)的,而且我們也很難獲知人類(lèi)將在未來(lái)如何進(jìn)化?;涗浵蛭覀冿@示,所有的物種最終都會(huì )滅絕,但在此之前往往存在數百萬(wàn)年。與過(guò)去或現在的任何其他物種相比,人類(lèi)掌控自身命運的能力都更強——如果我們確實(shí)走向滅絕,那么幾乎可以肯定的是這一結果是由我們自身的行為造成的。
Does human being still evolve? What will we look like in future with evolution, with bigger heads and shorter legs as seen in the films? Will human being go extinct one day?
The changes we have seen in human populations over the last few centuries have been due to better diet and public health, not to evolution (i.e. genetic change). If evolution is driven by Natural Selection, as Darwin and most biologists believe, then the only way that humans could evolve bigger brains and shorter legs in the future would be if individuals with bigger brains and shorter legs left more viable offspring than those with small brains and long legs. I doubt this to be correct. So, the science fiction predictions are unlikely to come true and it is hard to see how, if at all, humans will evolve in the future. The fossil record shows us that all species eventually become extinct, but often after several million years of existence. Humans hold their fate much more in their own hands than any other species past or present - if we do become extinct it will almost certainly be down to our own actions.
Paul D. Taylor博士
Paul D. Taylor博士出生于英國赫爾市,獲得英國杜倫大學(xué)的本科學(xué)位,并且在1977年,在該大學(xué)取得了博士學(xué)位;之后又在威爾士大學(xué)斯旺西分校Derek Ager教授的指導下,取得了博士后獎學(xué)金。在此之后,1979年Taylor博士,作為一名古生物學(xué)的研究者,加入了大英博物館(自然歷史分館),即英國自然歷史博物館。自1990年起至2003年,Taylor博士一直是無(wú)脊椎動(dòng)物和植物研究部門(mén)的主任。在世界各地,Taylor博士曾開(kāi)展了一系列的科學(xué)研究工作,其中包括沙特阿拉伯、印度、日本、新西蘭、俄羅斯、斯匹次卑爾根、美國以及許多西方國家。同時(shí)他曾在奧塔歌大學(xué)(新西蘭),法國國立自然史博物館(巴黎),加州大學(xué)洛杉磯分校和日本北海道大學(xué)都有過(guò)客座研究交流的經(jīng)歷。作為倫敦林耐學(xué)會(huì )的成員;五本著(zhù)作和200多篇科學(xué)文獻的作者及編輯;Taylor博士服務(wù)于許多國家和國際科學(xué)委員會(huì ),編輯委員會(huì ),目前仍是系統古生物雜志的主編。1992年,由于它在系統古生物領(lǐng)域發(fā)表了一篇杰出的著(zhù)作,因此贏(yíng)得了古生物學(xué)大獎。Taylor博士的研究領(lǐng)域包括無(wú)脊椎動(dòng)物的化石,特別是苔蘚蟲(chóng)。他對生物的進(jìn)化以及滅絕的過(guò)程十分感興趣。在2008年12月的香港科技節上,他曾代表英國文化協(xié)會(huì ),作了兩場(chǎng)演講以及四場(chǎng)工作坊來(lái)探究有關(guān)于進(jìn)化與化石的主題。
Biography – Dr Paul D. Taylor
Born in Hull, England, Paul Taylor received his undergraduate degree (BSc in Geology, 1974) from the University of Durham and stayed there to complete a PhD in 1977. After undertaking a postdoctoral fellowship under the guidance of Professor Derek Ager at the University College of Swansea, he joined in 1979 the then British Museum (Natural History), now The Natural History Museum, London, as a researcher in the Department of Palaeontology. From 1990 until 2003 he served as Head of the Invertebrates and Plants Division. Dr Taylor has carried out scientific fieldwork in various parts of the world, including Arabia, India, Japan, New Zealand, Russia, Spitsbergen, many European countries and the USA. He has held Visiting Research positions at the University of Otago (New Zealand), the Museum National d’Histoire Naturelle (Paris), University of California Los Angeles, and Hokkaido University (Japan). Fellow of the Linnean Society of London and author or editor of 5 books and more than 200 scientific articles, he has served on many national and international scientific committees and editorial boards, and is currently Editor-in-Chief of Journal of Systematic Palaeontology. In 1992 he was co-recipient of the Paleontological Society’s award for the most outstanding monograph in systematic palaeontology. Dr Taylor’s research concerns invertebrate fossils, especially bryozoans. He is interested in evolution and extinction. In December 2008 he gave two lecture and four demonstrations about evolution and fossils at the Hong Kong Science Festival on behalf of the British Council.
yiwang
http://discover.news.163.com/09/0929/15/5KD10HLK000125LI.html--------------------------------------------
人類(lèi)仍在進(jìn)化的五大證據
提到人類(lèi)進(jìn)化,我們往往將目光投向數千年前,即自然選擇過(guò)程孕育出現代人。實(shí)際上,作為一個(gè)物種的人類(lèi)仍在進(jìn)化之中。根據科學(xué)家進(jìn)行的新研究,盡管人類(lèi)發(fā)明了無(wú)數現代技術(shù),盡管進(jìn)行了工業(yè)化,人類(lèi)仍在繼續進(jìn)化。英國謝菲爾德大學(xué)動(dòng)植物學(xué)系的沃爾皮-魯瑪博士指出:“人們存在一種普遍誤解,認為進(jìn)化是很久以前的事情。如果想真正了解我們自身,我們必須將目光投向獵人-采集者部落時(shí)期的早期人類(lèi)?!薄 ∪祟?lèi)不僅仍處在進(jìn)化狀態(tài),進(jìn)化速度也要超過(guò)以前。過(guò)去1萬(wàn)年時(shí)間里,人類(lèi)的進(jìn)化速度加快了100倍,形成更多基因變異。以下是能夠證明人類(lèi)仍在進(jìn)化的5個(gè)證據。
1.我們仍在喝奶
調節人類(lèi)乳糖消化能力的基因隨著(zhù)母親哺乳的停止而關(guān)閉。在我們開(kāi)始馴化牛、綿羊和山羊之后,喝這些動(dòng)物的奶成為一種重要的營(yíng)養補充。也正是從這個(gè)時(shí)候起,這個(gè)基因發(fā)生變異,允許我們消化乳糖。體內存在這種基因變異的人也更能傳播他們的基因。2006年進(jìn)行的一項研究發(fā)現,3000年前,東非人對乳糖的消化能力仍在進(jìn)化。有超過(guò)95%的北歐人攜帶這種允許消化奶的基因變異。
2.人類(lèi)正在失去智齒
我們的祖先顎部尺寸要超過(guò)我們,幫助他們咀嚼草根、堅果和葉子。需要咀嚼什么樣的食物促使人類(lèi)進(jìn)化出相應的牙齒。智齒是第三大臼齒,是人類(lèi)祖先切割食物的一個(gè)重要工具?,F在,我們可以用器具切割食物,我們的飯食比古人的軟,也更容易咀嚼。我們的顎部也因此變小。由于空間變小,智齒往往長(cháng)不出來(lái)。與闌尾一樣,智齒成為一個(gè)退化器官。據估計,35%的人天生沒(méi)有智齒。有的人認為智齒將隨著(zhù)時(shí)間的推移最終消失。
3.仍在產(chǎn)生對抗疾病的基因變異
2007年,一組尋找人類(lèi)仍在進(jìn)化證據的研究人員發(fā)現了1800個(gè)基因。這些基因在4萬(wàn)年前普遍存在,其中很多與對抗瘧疾等傳染病有關(guān)。目前,有超過(guò)12種新的對抗瘧疾的基因變異在非洲人之間傳播。另一項研究發(fā)現,自然選擇對城市居民有利。城市生活能夠產(chǎn)生允許我們進(jìn)一步抵抗肺結核和麻風(fēng)病等疾病的基因變異。英國皇家霍洛威大學(xué)生物學(xué)院伊恩-巴納斯博士表示:“這似乎是人類(lèi)仍在進(jìn)化的一個(gè)典型證據。城市的發(fā)展成為一個(gè)選擇力量,促使人類(lèi)作為一個(gè)物種進(jìn)行進(jìn)化?!?br> 4.我們的大腦正在萎縮
人類(lèi)因為巨大的大腦,智商超過(guò)其他任何動(dòng)物。在過(guò)去3萬(wàn)年時(shí)間里,我們的大腦不斷萎縮。人類(lèi)大腦的平均腦容量從1500立方厘米減至1350立方厘米,減少幅度相當于一個(gè)網(wǎng)球大小。一組研究人員認為大腦萎縮意味著(zhù)我們的智商不斷下降。大腦體積隨著(zhù)社會(huì )規模的增大和復雜性提高變小,現代社會(huì )的安全網(wǎng)絡(luò )推翻了智商與幸存之間的相關(guān)性。
另一項理論認為,我們的大腦之所以萎縮并不是因為我們變得越來(lái)越笨,而是因為大腦體積降低能夠提高效率。根據這項理論,隨著(zhù)大腦體積降低,大腦重新進(jìn)行“布線(xiàn)”,在體積降低的同時(shí)提高效率。還有一種理論認為較小的大腦是一種進(jìn)化優(yōu)勢,因為這降低了我們的攻擊性,允許我們通過(guò)合作的方式解決問(wèn)題,而不是相互將對方撕成碎片。
5.我們有藍眼睛
剛開(kāi)始時(shí),我們人類(lèi)都是褐色眼睛。大約1萬(wàn)年前,一些生活在黑海附近的人發(fā)生基因變異,褐色眼睛變成了藍色。藍眼睛為何能夠保留下來(lái)仍舊是一個(gè)不解之謎。一種理論認為,藍眼睛可用于進(jìn)行親子鑒定。一篇有關(guān)藍色眼睛的研究論文的作者指出:“男人面臨著(zhù)強大的進(jìn)化壓力,絕不能將寶貴的資源用在其他人的孩子身上?!眱蓚€(gè)藍眼睛的人不可能生出褐色眼睛的后代,我們的藍眼睛男性祖先可能選擇藍眼睛的女性結合,以確保所生的孩子就是自己親生。根據最近的一項研究發(fā)現,藍眼睛男性認為藍眼睛女性要比褐色眼睛女性更具有吸引力,褐色眼睛的男性并沒(méi)有這種偏愛(ài)。
凱立的家園
http://www.kldjy.com/forum.php?mod=viewthread&tid=861329&extra=page%3D1---------------------------------------
人是由猩猩進(jìn)化的?
我們可以肯定地說(shuō),目前無(wú)法找到任何現存的缺失環(huán)節。
人類(lèi)進(jìn)化中的缺失環(huán)節有可能被找到嗎?換句話(huà)說(shuō),人類(lèi)的祖先是否可以找到?什么是缺失的環(huán)節?人類(lèi)和黑猩猩之間有什么關(guān)系(關(guān)于這一點(diǎn)你得出了什么有趣的結論)?如何在進(jìn)化歷史中為人類(lèi)定位?如何找到我們古老的家族和祖先?如果我們永遠無(wú)法找到那些缺失的環(huán)節,那么繼續尋找是否在浪費時(shí)間?化石記錄對發(fā)現缺失環(huán)節有何作用?
達爾文和華萊士的物競天擇理論都蘊含一個(gè)主要的觀(guān)點(diǎn):即所有現存和已滅絕的生命形式都起源于同一個(gè)共同的祖先。換句話(huà)說(shuō),所有的生物都彼此相關(guān)??紤]到現有生命體的形式千差萬(wàn)別,該觀(guān)點(diǎn)有時(shí)令人難以接受,并引出一個(gè)重要的問(wèn)題:不同的生物種群之間似乎有不可逾越的鴻溝,彌合這一鴻溝的過(guò)渡形式——即生命樹(shù)上的缺失的環(huán)節——在哪里?
首先,我們可以肯定地說(shuō),目前無(wú)法找到任何現存的缺失環(huán)節。這種情況值得我們思索。黑猩猩和倭黑猩猩是與我們最接近的現存親緣物種,但我們并非由它們進(jìn)化而來(lái)。(因此,我們日常所說(shuō)的“人是由猩猩變的”其實(shí)是錯誤或不正確嚴謹的說(shuō)法)相反,我們與它們在幾百萬(wàn)年前擁有共同的祖先。從那時(shí)起,我們與它們就開(kāi)始了不同的進(jìn)化之路。我們從黑猩猩進(jìn)化而來(lái)的可能性與黑猩猩是從人類(lèi)進(jìn)化而來(lái)的可能性一樣小,即不可能。
因此,我們必須通過(guò)化石記錄找到那些所缺失的環(huán)節。但是,我們可能找到自己的直系祖先嗎?當發(fā)現某些新化石時(shí),尤其當這些化石與人類(lèi)起源有關(guān)聯(lián)時(shí),人們總是宣稱(chēng)找到了人類(lèi)的祖先。最近有關(guān)靈長(cháng)類(lèi)化石“伊達”(Ida)的報道正是如此。我認為這過(guò)于樂(lè )觀(guān)?,F存物種的數量非常龐大(介于200萬(wàn)-1億之間,其中的多數尚未被研究發(fā)現),然而這只占曾有物種總量的一小部分。在這些物種中,絕大多數的進(jìn)化后代已分化:只有寥寥數種是現存物種的直系祖先??紤]到物種成為化石的可能性較低,不同地質(zhì)過(guò)程將化石送回地球表面并被古生物學(xué)家發(fā)現的可能性更低,因此,發(fā)現我們直系祖先的幾率是微乎其微的。
那么,如果缺失環(huán)節始終難以找到,我們應該放棄尋找嗎?當然不!我們發(fā)現的每塊化石都在生命樹(shù)上有著(zhù)相對應的位置,并使我們進(jìn)一步了解到生命的進(jìn)化過(guò)程。即使“伊達”化石不是我們的直系祖先(我打賭它絕不是?。?,它仍與我們共同擁有同一的祖先,并通過(guò)她與我們(而非我們的親緣種群——猿和猴子)的相同之處來(lái)告訴我們關(guān)于這一祖先的情況。因此,從某個(gè)方面來(lái)講,我們已發(fā)現自己的祖先,雖然無(wú)法看見(jiàn)它或擁有它,但我們能通過(guò)模擬推測重建它。發(fā)現的化石越多,我們能夠重建的祖先就越多,進(jìn)而更加了解它們的后代在成為人類(lèi)或任何其他物種之前的進(jìn)化與改變。
Is it possible to find the Missing Links ever in human’s evolution? In other words, is it possible for us to find our ancestors ever? E.g. what’s Missing Links? What’s the relation between human being and chimpanzees? How to locate human being in evolution history and how to find our ancient families and ancestors? If we cannot find the missing links ever, does it mean it’s a waste of time for us to keep finding them? What do the fossil records work in finding the missing links?
A major implication of Darwin and Wallace’s theory of natural selection is that all life forms, living and extinct, are descended from a single common ancestor. In other words, all living things are related to each other. Looking at the very different forms of life living today, this idea is sometimes difficult to accept, and raises an important question: where are the transitional forms that bridge seemingly insurmountable gaps between different groups of living things – the missing links in the Tree of Life?
Well, for a start, we can safely say that we won’t find missing links alive today. This is worth thinking about for a moment. Chimpanzees and bonobos are our nearest living relatives, but we did not descend from them. Rather, we share a common ancestor that lived a few million years ago. Since then, our evolutionary paths have been separate. We have as little right to claim that we evolved from chimpanzees as chimpanzees have to claim that they evolved from us!
So it is to the fossil record that we must look to find the missing links. But will we ever find them – our direct ancestors? This is often claimed to be the case when certain new fossils come to light, especially if they have anything to do with the origin of humans, such as the fossil primate 'Ida’ that has been in the news recently. This is, in my opinion, outrageously optimistic. The number of living species is very large (somewhere between 2 million and 100 million, most of which haven’t been described), but this is a mere fraction of the total number of species that have ever lived. The vast majority of these had their evolutionary lineages cut short: only a few are the direct ancestors of species living today. Now consider the improbability of a member of a species being fossilised and the further improbability of various geological processes bringing that fossil back to Earth’s surface today, and the further improbability that a palaeontologist stumbles upon it. The odds against any one of our direct ancestors ever being found are astronomical.
So, if the missing links will always remain missing, should we give up looking? Absolutely not! Every fossil we find can be slotted into the Tree of Life, and can tell us a little more about how life evolved. Even if 'Ida’ turns out not to be our direct ancestor (and I’ll bet any money that it isn’t!), it still shares a common ancestor with us, and can therefore tell us about that ancestor by what we (rather, our group – the apes and monkeys) have in common with her. So, in a way, we have found our ancestor, but we can’t see it or hold it, we can only reconstruct it. The more fossils we find, the more ancestors we will be able to reconstruct, each telling us a little more about the evolutionary changes that took place on the lineage leading to humans, or any other species for that matter.
網(wǎng)易
http://news.163.com/09/0925/18/5K2UVQ92000125LI.html----------------------------------------------------------
適者生存是如何發(fā)揮作用的?
“適者生存”這種說(shuō)法常常被誤用,因為生存下來(lái)的并不一定是那些身體最棒、力量最強的個(gè)體。某個(gè)個(gè)體的特定屬性能夠在多大程度上促進(jìn)它在所處環(huán)境中的生存和交配,這一點(diǎn)起著(zhù)決定作用。因此某個(gè)個(gè)體可能適應某一種環(huán)境,而對另一種環(huán)境則不適應。
What’s Survival of Fittest and how it works? E.g. what’s the definition of the fittest? Is it part of the natural selection process? Is it a random process? Does it means only the fittest could survive? What’s the position and influence from human being towards survival of fittest?
什么是適者生存理論,它又是如何發(fā)揮作用的呢?例如“適者”的定義是什么?適者生存是物競天擇過(guò)程中的一部分嗎?它是一個(gè)隨機偶然的過(guò)程嗎?它是否意味著(zhù)只有“適者”才能生存下來(lái)?人類(lèi)對于適者生存理論的定位和影響有哪些?
Survival of the fittest relates to an individual’s ability to pass on its genes to the next generation. Correspondingly the fittest individual can be defined as “the one that produces the most grandchildren”. The phrase “survival of the fittest” is often misused as it does not necessarily relate to physical fitness or strength in any sense. It is determined by how well an individual’s particular attributes allow it to survive and mate in its local environment. Therefore an individual may be fit in one environment but not another.
適者生存理論與某個(gè)體向下一代傳遞基因的能力有關(guān)。相應地,“適者”可以被界定為“繁殖了最多后代子孫”的個(gè)體?!斑m者生存”這種說(shuō)法常常被誤用,因為生存下來(lái)的并不一定是那些身體最棒、力量最強的個(gè)體。某個(gè)個(gè)體的特定屬性能夠在多大程度上促進(jìn)它在所處環(huán)境中的生存和交配,這一點(diǎn)起著(zhù)決定作用。因此某個(gè)個(gè)體可能適應某一種環(huán)境,而對另一種環(huán)境則不適應。
Survival of the fittest is an important part of natural selection and thus evolution because over successive generations it can lead to changes in the gene pool which may in turn lead to changes in the overall attributes of a population. These changes may be enough to make the population incapable of breeding with individuals of other populations of the original species, ultimately leading to development of a new species. It is particularly powerful in small populations geographically isolated from other populations of the same species.
適者生存是物競天擇乃至生物進(jìn)化過(guò)程中很重要的一部分,因為經(jīng)過(guò)一代又一代的發(fā)展,它可以導致基因庫發(fā)生變化,進(jìn)而使得某一群體的整體屬性發(fā)生改變。這些變化可能足以使得這一群體無(wú)法與原始物種衍生的其他群體進(jìn)行繁殖,最終帶來(lái)一個(gè)新物種的產(chǎn)生。這對于那些在地理上與同一物種下的其他群體隔離生存的小群體來(lái)說(shuō)作用尤其強大。
Humans certainly do influence the fitness of individual animals. They can influence it directly by determining which animals breed and which do not. This is referred to as “artificial selection” and is evident in domestic dogs, pigeons and many farm animals. Humans can also affect the fitness of individual animals indirectly by changing or destroying an animal’s natural environment. A particularly detrimental effect is in the widespread use of antibiotics leading to the development of more and more drug resistant strains of bacteria.人類(lèi)當然也對個(gè)體動(dòng)物的適應性帶來(lái)了影響。人類(lèi)可以通過(guò)決定讓哪些動(dòng)物繁殖以及讓哪些動(dòng)物不繁殖直接施加影響。這被稱(chēng)之為“人工選擇”,這在家養犬、鴿子以及許多農場(chǎng)動(dòng)物中尤為明顯。人類(lèi)還可以通過(guò)改變或者破壞某一動(dòng)物的自然生存環(huán)境,間接影響個(gè)體動(dòng)物的適應性??股氐膹V泛使用,導致出現了越來(lái)越多的抗藥物細菌品系,這是一個(gè)尤為負面的“人工選擇”所帶來(lái)的結果。
(本文來(lái)源:網(wǎng)易探索
http://discover.news.163.com/09/0907/16/5IKEJA3A000125LI.html)
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物競天擇是如何發(fā)揮作用的?
物競天擇是一個(gè)可以致使新物種產(chǎn)生的過(guò)程。它需要具備以下條件:存在對各種資源的競爭、某一特定物種的不同個(gè)體在各種屬性上存在差異以及這些屬性具有代代相傳的遺傳性。
What’s Natural Selection and how it works? E.g. does natural selection refer to a group of random process? How does natural selection work on human beings? Does this process against emotions and cultures evolved in human and broader animal communities? Does natural selection only work on physical or it also work on mental as well?
什么是物競天擇理論,它又是如何發(fā)揮作用的呢?例如物競天擇指的是一系列隨機偶然的進(jìn)化過(guò)程嗎?物競天擇對人類(lèi)又是如何發(fā)揮作用的?人類(lèi)或者更廣泛的動(dòng)物群體中涉及的思緒情感和文化是否不受物競天擇這一過(guò)程的支配和影響?物競天擇理論究竟是只在自然物質(zhì)方面起作用呢還是也在精神方面起作用?
Natural selection is a process that may lead to the origin of new species. It requires that there is competition for resources, variation in the attributes of individuals of a particular species, and heritability of those attributes from generation to generation.
物競天擇是一個(gè)可以致使新物種產(chǎn)生的過(guò)程。它需要具備以下條件:存在對各種資源的競爭、某一特定物種的不同個(gè)體在各種屬性上存在差異以及這些屬性具有代代相傳的遺傳性。
It is the genes possessed by an individual that largely determine its particular attributes and also allow most of these attributes to be passed on to its offspring. An animal’s particular attributes will determine its ability to successfully mate and have offspring in its local environment (its “fitness”). As there is variation in attributes between individuals, the “fittest” individuals will pass on more genes to the next generation than others. As the process is determined by the interaction of organisms and their environment it is not strictly random. However, chance events, such as asteroid impact can radically alter the environment and thus change which individuals are best adapted to pass on their genes, and thus the fittest. The process does not require divine intervention to operate.
某個(gè)體的特定屬性在很大程度上是由該個(gè)體擁有的基因所決定的,同時(shí)基因也使得這些特定屬性可以傳遞給后代。某種動(dòng)物的特定屬性將決定它成功交配并在生存環(huán)境中孕育后代的能力(它的“適應性”)。由于不同個(gè)體的屬性存在差異,那么“最適應”的個(gè)體將比其他個(gè)體傳遞更多的基因給下一代。由于這一過(guò)程是由生物體及其所在環(huán)境的相互作用而決定的,因此它并非具有嚴格的隨機性。但是,一些偶然事件,比如小行星撞擊地球可以徹底改變生存環(huán)境,從而會(huì )改變哪些個(gè)體最適應環(huán)境來(lái)傳遞基因,進(jìn)而使其成為“最適應”的個(gè)體。這一過(guò)程的運用并不需要神靈的干預。
For the past few hundred years humans have been under reduced natural selection because after advances in sanitation, plumbing, and some aspects of medicine they have a lot of power over their own environment. Most individuals have the opportunity to have children. Nevertheless, a clear example of natural selection operating in humans is the higher frequency of sickle cell anaemia in geographic areas with malaria. Sickle cell anaemia fully expressed is very disadvantageous but individuals with the genes from only one parent have protection from malaria which is potentially more lethal.
在過(guò)去的幾百年中,人類(lèi)受到物競天擇理論的影響已經(jīng)減弱,因為在環(huán)境衛生、飲水設施以及醫療條件的方方面面已經(jīng)得到大大的改善之后,人類(lèi)對于自己所生存的環(huán)境有了很強的控制力。大多數的人類(lèi)個(gè)體有機會(huì )孕育子孫后代。然而,物競天擇理論對人類(lèi)仍然發(fā)揮作用的一個(gè)最典型的例子就是在瘧疾橫行的地區更容易出現鐮狀細胞貧血癥。鐮狀細胞貧血如果被完全傳遞給后代那是相當不利的,但是如果父母雙方只有一方將該基因傳遞給后代,那么這些后代個(gè)體對于更加致命的瘧疾就會(huì )產(chǎn)生抗體。
It has been argued that “ideas” and “culture” are subject to a process similar to natural selection. This is because there is variation between ideas, competition between ideas and ideas can be passed on from one generation to the next by word of mouth, writing, or audio and visual media. 一直以來(lái),人們都在爭辯,“思想觀(guān)念”和“文化”是否被某個(gè)類(lèi)似物競天擇的過(guò)程所支配。因為思想觀(guān)念之間存在差異、不同的思想觀(guān)念之間存在競爭,并且思想觀(guān)念還可以通過(guò)口口相傳、書(shū)面文字或者音頻視頻媒體傳遞給下一代。
來(lái)源: 網(wǎng)易探索
http://discover.news.163.com/09/0907/16/5IKEF35P000125LI.html