物种起源导论04自然条件下的变异

IntroductiontoTheOriginofSpeciesWANGYuguo

(SchoolofLifeSciences,FudanUniversity)复旦大学生命科学学院王玉国

物种起源导论VARIATIONUNDERNATURE自然状态下的变异CHAPTERIIVariability——IndividualDifferencesDoubtfulspecies

Wideranging,muchdiffused,andcommonspeciesvarymostSpeciesofthelargergenerainanycountryvarymorethanthespeciesofthesmallergeneraManyofthespeciesofthelargergeneraresemblevarietiesinbeingveryclosely,butunequally,relatedtoeachother,andinhavingrestrictedranges.

个体间的差异物种界定的尴尬环境对物种变异的影响大属和小属物种变异的频率

Whetherorganicbeingsinastateofnaturearesubjecttoanyvariation？NorshallIherediscussthevariousdefinitionswhichhavebeengivenofthetermspecies.Species——Generallythetermincludestheunknownelementofadistinctactofcreation.Varieties——herecommunityofdescentisalmostuniversallyimplied,thoughitcanrarelybeproved.Monstrosities——someconsiderabledeviationofstructureinonepart,eitherinjurioustoornotuseful

tothespecies,andnotgenerallypropagated.VariabilityDarwin:pigshaveoccasionallybeenbornwithasortofproboscisLabuk

Bay

Proboscis

Monkey

SanctuarySandakan,Sabah,Malaysia

Ifmonstrousformsofthiskindeverdoappearinastateofnatureandarecapableofreproduction(whichisnotalwaysthecase),astheyoccurrarelyandsingly,theirpreservationwoulddependonunusuallyfavourablecircumstances.IndividualDifferencesThemanyslightdifferenceswhichappearintheoffspringfromthesameparents.Noonesupposesthatalltheindividualsofthesamespeciesarecastinthesameactualmould.Theseindividualdifferencesareof

thehighestimportanceforus,fortheyareofteninherited,asmustbefamiliartoeveryone;andtheythusaffordmaterialsfornaturalselectiontoactonandaccumulate,inthesamemannerasmanaccumulatesinanygivendirectionindividualdifferencesinhisdomesticatedproductions.个体间的差异Theseindividualdifferencesgenerallyaffectwhatnaturalistsconsiderunimportantparts.Authorssometimesargueinacirclewhentheystatethatimportantorgansnevervary.——Itwouldneverhavebeenexpectedthatthebranchingofthemainnervesclosetothegreatcentralganglionofaninsectwouldhavebeenvariableinthesamespecies;itmighthavebeenthoughtthatchangesofthisnaturecouldhavebeeneffectedonlybyslowdegrees;yetSirJ.LubbockhasshownadegreeofvariabilityinthesemainnervesinCoccus(介壳虫),whichmayalmostbecomparedtotheirregularbranchingofthestemofatree.

Polymorphic——speciesorvarieties?Hieracium(山柳菊属)Rubus(悬钩子属)Rosa(蔷薇属)Cicindelaaurulenta(金斑虎甲)Brachiopodshells(腕足类)

Thesefactsareveryperplexing,fortheyseemtoshowthatthiskindofvariabilityisindependentoftheconditionsoflife.Iaminclinedtosuspectthatwesee,atleastinsomeofthesepolymorphicgenera,variationswhichareofnoserviceordisservicetothespecies,andwhichconsequentlyhavenotbeenseizedonandrendereddefinitebynaturalselection,ashereaftertobeexplained.

这些事实令人困惑，因为它们表现出的这些变异，似乎和生活条件无关。我猜想，因为这些变异，至少在某些多型属内对物种本身并无利害关系，所以自然选择既没有对它们起作用，也没有使这些特征固定下来。对此，我将在后文再做解释。Greatdifferencesofstructure,independentlyofvariationDoubtfulSpeciesTaxonomyAiluropodamelanoleuca1868年，法国传教士佩雷·阿曼德·戴维，在中国看到黑腿白熊毛皮……1929年，美国西奥多和克米特·罗斯福射杀了一只正在树上睡觉的大熊猫……Panda可疑物种Somalibutcherbird?DiversityofMusselsDarwinwasmuchstruckhowentirelyvagueandarbitraryisthedistinctionbetweenspeciesandvarieties.Speciesorvarieties？TheQuercusrobur(夏栎)hastwenty-eightvarieties,allofwhich,exceptingsix,areclusteredroundthreesub-species,namely,Q.pedunculata(有柄栎),sessiliflora(无柄花栎),andpubescens(毛栎).Cycasmicholitzii叉叶苏铁

Cycassiamensis

云南苏铁Cycaspanzhihuaensis

攀枝花苏铁Cycasrumphii华南苏铁Cycasszechuanensis四川苏铁/南盘江苏铁Cycashainanensis海南苏铁Cycasangulata

角苏铁Cycasguizhouensis贵州苏铁Cycassegmentifida叉孢苏铁石山苏铁Cycasmiquelii

台湾苏铁Cycastaiwaniana蓖齿苏铁

Cycas

pectinata

Cycas

couttsiana

Cycas

machonie

Cycas

cincinalis西米苏铁Cycasrevoluta

苏铁Ceratozamiarobusta

粗壮苏铁(墨西哥)长籽苏铁(津巴布韦)Encephalartusmanikensis

Zamiaintegrifolia

全缘大苏铁苏铁科，裸子植物,11属，约110种Microcycascalocoma

小苏铁

Macrozamiamoorei

摩耳大苏铁Lepidozamiaperoffskyana

东澳苏铁大头苏铁Encephalartosgratus

可爱苏铁Encephalartosfriderici-guilielmii

Dioon

spinulosum刺苏铁StangeriaeriopusBowenia

spectabilis

CrowdedNoah'sArk美国DigitalGlobe公司

“快鸟”2003年拍摄到的“亚拉腊山异物”卫星照片Mt.Ararat“诺亚方舟”长300英尺、宽50英尺，高30英尺，分为上、中、下三层。这个尺寸是长133.29米、宽22.22米、高13.33米。方舟每层甲板的面积有3000多平方米，约为泰坦尼克号的一半。它的总重量为1.4万吨，完全由木头构成。宾西法尼亚州艺术家爱德华-希金斯的画作《诺亚方舟》有人认为多乌巴亚泽特是诺亚方舟的所在地

Tigers:PastandPresent123虎8个变种，3个已经绝灭巴厘虎(BalineseTiger)分布于印尼巴里岛二十世纪40年代灭绝爪哇虎(JavanTiger)分布于印尼爪哇岛二十世纪80年代灭绝里海虎(CaspianTiger)分布于土耳其至亚洲中部以及西部二十世纪70年代灭绝123苏门达腊虎

(SumatranTiger)东北虎(SiberianTiger)华南虎(SouthChinaTiger)印支虎(Indo-chineseTiger)孟加拉虎(Pantheratigristigris)甲虫——33万种向热带森林喷洒杀虫剂——上千种新甲虫已经记录的真菌7万专家估计尚未发现的还有100万种全世界哺乳动物5000个类型还可能发现3000个新类型一把海底淤泥可能有100个类型的线虫海洋养育的动物类型可能多达50-1000万saolaHyemoschusaquaticusMoschiolameminnaTragulus美洲豹蛙(Ranapipiens)northernleopardfrog----渐变群(cline)的经典例子如果种群很大，或者同一物种的多个种群散布在大片地理区域中，邻近的种群虽然仍可杂交，但位于极端的种群，彼此相隔很远，已不能杂交，它们只能和相邻的种群杂交，而这一相邻的种群又可和它周围的种群杂交。Mouse’slegend——Itallstartedwithamouse.小鼠(Musmusculusmusculus)

家鼠(Musmusculusdomesticus)SubfamilyMurinae(OldWorldratsandmice)

GenusMus(OldWorldmice)SpeciesMusbaoulei

(Baoule'smouse)SpeciesMusbooduga

(littleIndianfieldmouse)SpeciesMusbufo

(toadmouse)SpeciesMuscallewaerti

(Callewaert'smouse)SpeciesMuscaroli

(Ryukyumouse)SpeciesMuscervicolor

(fawn-coloredmouse)SpeciesMuscookii

(Cook'smouse)SpeciesMuscrociduroides

(Sumatranshrewlikemouse)SpeciesMusfamulus

(servantmouse)SpeciesMusfernandoni

(Ceylonspinymouse)SpeciesMusfragilicauda

(sheath-tailedmouse)SpeciesMusgoundae

(Goundamouse)SpeciesMushaussa

(Hausamouse)SpeciesMusindutus

(desertpygmymouse)SpeciesMusmacedonicus

(Macedonianmouse)SpeciesMusmahomet

(Mahometmouse)SpeciesMusmattheyi

(Matthey'smouse)SpeciesMusmayori

(Mayor'smouse)SpeciesMusminutoides

(pygmymouse)

SpeciesMusmusculoides

(Kasaimouse)Species

Musmusculus

(housemouse)

SpeciesMusneavei

(Neave'smouse)SpeciesMusorangiae

(orangemouse)SpeciesMusoubanguii

(Oubanguimouse)SpeciesMuspahari

(Gairdner'sshrewmouse)SpeciesMusphillipsi

(Phillips'smouse)SpeciesMusplatythrix

(flat-hairedmouse)SpeciesMussaxicola

(rock-lovingmouse)SpeciesMussetulosus

(Peter'smouse)SpeciesMussetzeri

(Setzer'spygmymouse)SpeciesMusshortridgei

(Shortridge'smouse)SpeciesMussorella

(Thomas'spygmymouse)SpeciesMusspicilegus

(mound-buildingmouse)SpeciesMusspretus

(Algerianmouse)SpeciesMustenellus

(delicatemouse)SpeciesMusterricolor

(earth-coloredmouse)SpeciesMustriton

(gray-belliedpygmymouse)SpeciesMusvulcani

(volcanomouse)SpeciesoftheLargerGeneraineachCountryVarymorefrequentlythantheSpeciesoftheSmallerGenera.

ManyoftheSpeciesincludedwithintheLargerGeneraresembleVarietiesinbeingveryclosely,butunequally,relatedtoeachother,andinhavingrestrictedranges.

Wide-ranging,muchdiffused,andcommonSpeciesvarymost.分布广、扩散大的常见物种极易发生变异各地区较大属内的物种比较小属内的物种更容易发生变异与物种内各变种间的情况相似，一个大属内的许多物种也都彼此程度不等地密切相关，而且在分布上都有局限性IngaedulisIngavera

Ingalaurina

Ingapunctata

Inga印加豆属(豆科-含羞草亚科Leguminosae-Mimosoideae)Summary

Finally,varietiescannotbedistinguishedfromspecies,—except,first,bythediscoveryofintermediatelinkingforms;and,secondly,byacertainindefiniteamountofdifferencebetweenthem.

----Ingenerahavingmorethantheaveragenumberofspeciesinanycountry,thespeciesofthesegenerahavemorethantheaveragenumberofvarieties.----Inlargegenerathespeciesareapttobeclosely,butunequally,alliedtogether,forminglittleclustersroundotherspecies.----Speciesverycloselyalliedtootherspeciesapparentlyhaverestrictedranges.Whatarevarietiesbutgroupsofforms,unequallyrelatedtoeachother,andclusteredroundcertainforms—thatis,roundtheirparent-species?Inalltheserespectsthespeciesoflargegenerapresentastronganalogywithvarieties.Andwecanclearlyunderstandtheseanalogies,ifspeciesonceexistedasvarieties,andthusoriginated;whereas,theseanalogiesareutterlyinexplicableifspeciesareindependentcreations.

Wehave,also,seenthatitisthemostflourishingordominantspeciesofthelargergenerawithineachclasswhichonanaverageyieldthegreatestnumberofvarieties;andvarieties,asweshallhereaftersee,tendtobecomeconvertedintonewanddistinctspecies.Thusthelargergeneratendtobecomelarger;andthroughoutnaturetheformso