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从新的古生物学及今生物学资料看羽毛的 起源与早期演化

从新的古生物学及今生物学资料看羽毛的 起源与早期演化
从新的古生物学及今生物学资料看羽毛的 起源与早期演化

第47卷 第4期

2009年10月 古脊椎动物学报

V ERTEBRATA P AL A SIATICA pp.311-329

 figs.1-5

从新的古生物学及今生物学资料看羽毛的

起源与早期演化1)

徐 星1 郭 昱1,2

(1中国科学院古脊椎动物与古人类研究所,脊椎动物进化系统学重点实验室 北京 100044)

(2中国科学院研究生院 北京 100039)

摘要:近年来关于羽毛和羽状皮肤衍生物的研究极大促进了我们对羽毛起源与早期演化的理

解三结合最新的古生物学与今生物学资料,对一些保存了皮肤衍生物的非鸟恐龙标本进行观

察研究,为这个重要的进化问题提供了新见解三推测羽毛的演化在鸟类起源之前就以下列顺

序完成了5个主要的形态发生事件:1)丝状和管状结构的出现;2)羽囊及羽枝脊形成;3)羽

轴的发生;4)羽平面的形成;5)羽状羽小支的产生三这些演化事件形成了多种曾存在于各

类非鸟初龙类中的羽毛形态,但这些形态在鸟类演化过程中可能退化或丢失了;这些演化事

件也产生了一些近似现代羽毛或者与现代羽毛完全相同的羽毛形态三非鸟恐龙身上的羽毛

有一些现代羽毛具有的独特特征,但也有一些现生鸟羽没有的特征三尽管一些基于发育学资

料建立的有关鸟类羽毛起源和早期演化的模型推测羽毛的起源是一个全新的演化事件,与爬

行动物的鳞片无关,我们认为用来定义现代鸟羽的特征应该是逐步演化产生的,而不是突然

出现三因此,对于羽毛演化而言,一个兼具逐步变化与完全创新的模型较为合理三从目前的

证据推断,最早的羽毛既不是用来飞行也不是用来保暖,各种其他假说皆有可能,其中包括展

示或者散热假说三展开整合性的研究有望为羽毛的起源问题提供更多思路三

关键词:鸟类,兽脚类,恐龙,皮肤附属物,羽毛,起源与早期演化

中图法分类号:Q915.865 文献标识码:A 文章编号:1000-3118(2009)04-0311-19

THE ORIGIN AND EARLY EVOLUTION OF FEATHERS:INSIGHTS FROM RECENT PALEONTOLOGICAL AND NEONTOLOGICAL DATA

XU Xing1 GUO Yu1,2

(1Key Laboratory of Evolutionary Systematics of Vertebrates,Institute of Vertebrate Paleontology and

 Paleoanthropology,Chinese Academy of Sciences Beijing 100044 xuxing@https://www.doczj.com/doc/1b18122092.html,)

(2Graduate University of the Chinese Academy of Sciences Beijing 100039)

Abstract Recent paleontological and neontological studies on feathers and feather?like integumentary structures have improved greatly our understanding of the origin and early evolution of feathers.New ob?servations on some non?avian dinosaur specimens preserving integumentary structures,in combination with recent paleontological and neontological data,provide additional insights into this important evolu?tionary issue.Five major morphogenesis events are inferred to have occurred sequentially early in feather

1)中国科学院百人计划,中国科学院二国家外国专家局创新团队国际合作伙伴计划,国家自然科学基金项目(编号:40121202)和国家重点基础研究发展规划项目(编号:2006CB806400)资助三

 收稿日期:2009-05-26

312 古 脊 椎 动 物 学 报47卷evolution before the origin of the Aves,and they are:1)appearance of filamentous and tubular mor?

phology,2)formation of follicle and barb ridges,3)appearance of rachis,4)appearance of planar

form,and5)formation of pennaceous barbules.These events produce several morphotypes of feath?

ers that are common among non?avian archosaurs but are probably lost later in avian evolution,and

they also produced several morphotypes of feathers that are nearly identical or identical to those of

modern birds.While feathers of non?avian dinosaurs exhibit many unique features of modern feath?

ers,some of them also possess striking features unknown in modern feathers.Several models of evo?

lutionary origin of feathers based on developmental data suggest that the origin of feathers is a com?

pletely innovative event and the first feathers have nothing to do with reptilian scales.We believe,

however,that the defining features of modern feathers might have evolved in an incremental manner

rather than in a sudden way.Consequently,an evolutionary model characteristic of both transforma?

tion and innovation is more acceptable for feather evolution.The function of the first feather is in?

ferred to be neither related to flight nor to insulation.Display or heat dissipation,among others,re?

mains viable hypotheses for initial function of feathers.An integrative study is promising to provide

much new insights into the origin of feathers.

Key words birds,theropods,dinosaurs,integumentary appendages,feathers,origin and early

evolution

1 Introduction

Feathers are the most complicated integumentary derivative of birds,and also the most char?acteristic feature of them.A typical feather is composed of hierarchical branches of rachis,barbs and barbules on a tubular structure called calamus,and it is either radially symmetrical or essen?tially in a planar form.Some feathers lack a rachis,but most feathers have a shaft(calamus of basal tubular portion and rachis of the rest solid portion)with barbs forming vanes on either side which are secondarily branched to form barbules.This basic plan shows a great diversity,and re?sults in a wide variety of forms,which differ in:implantation(in the skin or on the skeleton), thickness and stiffness of the rachis,relative sizes of rachis and barbs,type,spacing and place?ment of barbs,symmetry and curvature of vanes,presence and structure of an afterfeather,and melanin pigmentation(Stettenheim,2000).Largely corresponding to the diverse morphology, feathers also serve a diverse of functions,including physical protection,thermal regulation,loco?motion,display,tactile sensation,and water repellency,among others(Stettenheim,2000). Mainly due to the diverse morphologies and functions of modern feathers,there is little consensus on the possible earliest morphology and initial function of feathers.Early fossil feath?ers also fail to provide relevant information.Feather?like structure has been claimed to be pres?ent in the Early Jurassic theropod(Kundrat,2004),but this interpretation receives little atten?tion due to their structure is preserved only as imprint.The Late Jurassic Archaeopteryx speci?mens preserve fine feather impressions,but they are identical in morphology to modern feath?ers.Similarly,other known basal birds all have feathers of fully modern form(Zhang and Zhou,2006;Zhou and Zhang,2006).In general,the known feathers of basal avians provide little significant information concerning the origin of feathers.Though the highly specialized tail feathers with an undifferentiated vane region on either side of the central rachis in many basal birds(Zhang and Zhou,2000)and even in a non?avian theropod(Zhang et al.,2008b)have been suggested to represent a type of primitive feathers,their implications for understanding the origin of feathers have been questioned mainly due to their relatively late appearance in feather evolution(Prum and Brush,2002;Xu,2002).

Most non?avian diapsids have scaled skin.However,Longisquama insignis,a small diap?sid reptile with uncertain systematic position,has recently been suggested to have non?avian feathers(Jones et al.,2000).Its highly specialized elongated dorsal scales have recently de?scribed as feather?like in many details and have been regarded as non?avian feathers(Jones et al.,2000).However,this interpretation has been criticized from the perspective of both preser?

4期徐 星等:从新的古生物学及今生物学资料看羽毛的起源与早期演化313 vation and morphology(Reisz and Sues,2000;Prum,2001;Unwin and Benton,2001). Understanding the evolution of structures must lie in a phylogenetic framework.Over the last few decades,a wealth of fossil evidence has been found to support the theropod hypothesis of bird origins,and numerous systematic analyses also strongly corroborate this hypothesis,sug?gesting that birds are nested deeply within a group of theropod dinosaurs called Coelurosauria (Gauthier,1986;Sereno,1999).It is therefore expected that simpler feather?like integument?ary structures should be present in the closest evolutionary relatives of birds among the coeluro?saurian theropods.

Over the last decade,numerous dinosaur specimens preserving soft tissue have been recov?ered from the Early Cretaceous Jehol Group of northern China,the lacustrine beds of uncertain Jurassic?Cretaceous age in western Liaoning,and the Jurassic Daohugou Formation of eastern Nei Mongol(Xu and Zhang,2005;Xu and Norell,2006;Zhang et al.,2008b;Xu et al., 2009a).In general,these findings suggest that:1)early feathers are simple filamentous struc?tures and have appeared at least in basal coelurosaurian theropods;2)more complex penna?ceous feathers evolved early in maniraptoran theropods and some non?avian theropods even had flight feathers with asymmetrical vanes;and3)the original function of feathers has nothing to do with flight.The discoveries of these specimens have significantly advanced our understanding of the origin and early evolution of feathers,though admittedly still much information is needed to understand some critical stages for feather evolution.

In the present paper,we will review recent paleontological and neontological data relevant to the origin and early evolution of feathers,comment on their implications,and propose an evo?lutionary scenario to describe the origin and early evolution of feathers.

Fig.1A and B were provided by G.Z.Peng,Fig.1C by L.Chiappe,Fig.2A,E,and3A by H.L.You,Fig.2B by P.J.Chen,Fig.2C and3C by X.T.Zheng,Fig.2D by Y.Wang,Fig.2H by F.C.Zhang,and Fig.3B by X.L.Wang;other figures were prepared by the authors.

2 Morphologies of non?avian dinosaurian integumentary appendage

Fossil skin is rarely preserved and it is particularly true for dinosaurs that are terrestrial ani?mals.Nevertheless,integumentary morphologies have been known for some dinosaur taxa(Fig.

1),though in most cases only small patches of the skin impressions are preserved,which re?sults in only incomplete knowledge of integumentary morphologies of non?avian dinosaurs.The recent discoveries of exceptionally well preserved non?avian dinosaur specimens from China have added much new information on dinosaurian integument(Norell and Xu,2005;Xu and Norell, 2006;Zhang and Zhou,2006),suggesting that non?avian dinosaurs are diverse in integument?ary morphologies both between taxa and on different body parts(Figs.1-3).

2.1 Integumentary appendage of non?theropod dinosaurs

Typically ornithischian dinosaurs have tuberculate,polygonal scales covering their body, and these scales are variable in size and shape on different parts of the body(Czerkas,1997) as in other scaled reptiles(Fig.1).However,two ornithischian taxa are also known to bear fil?amentous integumentary appendages.

Heterodontosaurid Tianyulong has recently been reported to bear filamentous integumentary structures(Zheng et al.,2009).Three patches of filamentous integumentary structures are pre?served near the cervical,dorsal,and anterior caudal vertebrae in the holotype of Tianyulong confuciusi.The filaments are about60mm long and0.4mm wide,proportionally very large for an animal of about70cm in total body length.They are mono?filamentous,relatively rigid,and probably tubular(Zheng et al.,2009).

Some hadrosaurs are known to possess tuberculate,polygonal scales and dermal spines,

314 古 脊 椎 动 物 学 报47卷which are suggested to be composed of purely keratinous,hypertrophied tubercles(Czerkas, 1997).Large,polygonal scales of a centimeter or more in size are reported to cover the tail of iguanodonts(Czerkas,1997).

Ceratopsian skin is best represented by Centrosaurus and Chasmosaurus,which have large, round,flattened scales surrounded by prominent polygonal tubercles arranged in rosette patterns in their upper thigh and adjacent region of the torso(Czerkas,1997).Unexpectedly,an ex?ceptionally well preserved Psittacosaurus specimen from the Early Cretaceous Liaoning shows that this small ornithischian dinosaur has both scaly and thick filamentous integumentary struc?tures(Mayr et al.,2002).Psittacosaurus has typical ornithischian scales(Fig.1D)around nearly the whole skeleton,which are variable in shape and size,but also a row of long,rigid, and probably tubular monofilamentous integumentary appendages along the proximal half of the tail,which appear to grow on the caudal vertebrae(Mayr et al.,2002).

Among thyreophorans,the stegosaurian Gigantspinosaurus sichuanensis has been reported to bear small,non?overlapping polygonal scales near the shoulder region of a specimen(Fig. 1C;Peng et al.,2005).

Sauropod skin was suggested to be scaly nature(Czerkas,1997).In a Mamenchisaurus youngi specimen,a patch of skin impression is preserved near the distal end of the ischium(Pi et al.,1996).It is composed of numerous polygonal scales of about6~15mm in diameter, proportionally extremely small for a large sauropod(Fig.1A).Skin impression near the fore?limb in a titanosaurian sauropod specimen indicates the presence of close?packed polygonal ossi?cles,each between one and a few centimeters in diameter(Upchurch et al.,2004).Titanosau?rian embryo fossils show that the embryonic sauropods have round,non?overlapping,tubercle?like scales covering the body(Chiappe et al.,1998).

2.2 Integumentary appendage of non?avian theropod dinosaurs

Bony ossicles are present around the neck and tail of a Ceratosaurus https://www.doczj.com/doc/1b18122092.html,rge pat?ches of skin impressions are found in a Carnotaurus specimen,which are consisting of small tu?bercles about5mm in diameter,surrounding low,conical studs40~50mm in diameter that have no bony cores(Bonaparte et al.,1990;Czerkas,1997).Similar skin impression is also found in Aucasaurus(Coria et al.,2002).

The skin of compsognathids is variable in morphology between taxa.In a basal compsog?nathid Juravenator specimen,patches of skin impression near the tail(Fig.1B)and the hind?limb indicate that it has a scaly skin,which is composed of small tubercles similar in appear?ance to the small,conical and non?imbricated tubercles of many other non?avian dinosaurs (Gohlich and Chiappe,2006).Filamentous feathers are,however,present in Sinosauropteryx and they are preserved dorsal to the back half of the skull and ventral to the posterior part of the mandible,dorsal to the cervical and dorsal series,over the hips and along both sides of the tail,and near the forelimbs(Fig.2B).The filamentous feathers are mostly considerably narro?wer than0.1mm and occasionally exceed0.3mm in width,and range from2mm to over40 mm long(Currie and Chen,2001).They are rather coarse for such a small animal and thickest strands are much thicker than the hairs of the vast majority of small mammals(Chen et al., 1998;Currie and Chen,2001).Although filamentous feathers of Sinosauropteryx are likely to be branched structures,with relatively short quills and long,filamentous barbs,it is difficult to isolate a single feather to confirm the branching structure(Chen et al.,1998;Currie and Chen, 2001).It is questionable that the somewhat scalloped distribution pattern of filaments along the tail is resulted in by a frill nature of these dark impressions(Lingham?Soliar et al.,2007),but it is interesting that such a pattern appears in several specimens.

Small patches of scaly hide consisting of typical dinosaurian tubercles are reported to be present in tyrannosaurid(Czerkas,1997).However,filamentous feathers are preserved near

4期徐 星等:从新的古生物学及今生物学资料看羽毛的起源与早期演化315 the mandible and around the middle caudal vertebrae of a basal tyrannosauroid Dilong speci?men.Those attached to the distal caudal vertebrae are more than20mm in length and about 0.3mm in width.These filamentous feathers are proportionally wide for an animal of1~2 meters long.They are branched but the pattern is difficult to discern(Xu et al.,2004).

Fig.1 Scaly integuments of several non?avian dinosaurs

A.the sauropod Mamenchisaurus;

B.the compsognathid Juravenator;

C.the stegosaurian

Gigantspinosaurus;D.the ceratopsian Psittacosaurus

The basal ornithomimosaur Pelicanimimus polyodon has been reported to have filamentous integumentary structures(Pérez?Moreno et al.,1994),but this was questioned later(Xu, 2002).No other information has been published on ornithomimosaur skin,though the holotype of Pelicanimimus polyodon preserves even the impressions of muscle fibers.

In the Alvarezsauroidea,the only known integumentary fossil record is the extremely short, filamentous elements reported to be associated with Shuvuuia deserti(Schweitzer et al.,1999). The integumentary nature of these small filaments has been revealed by an immunological study that demonstrates the presence ofβkeratins in these filaments(Schweitzer et al.,1999). The therizinosauroid integument is represented by two Beipiaosaurus specimens from the Early Cretaceous Yixian Formation(Xu et al.,1999,2009b).Large patches of integumentary structures were found in close association with the ulna,radius,femur and tibia,as well as with pectoral elements of the holotype of Beipiaosaurus inexpectus.Most of the integumentary fil?aments near the ulna are about50mm long and can be up to70mm.They are probably tubular and branched distally.An unusual morphotype of filamentous appendages has been found in the holotype of Beipiaosaurus inexpectus and in a specimen referable to Beipiaosaurus(Xu et al., 2009b).They are composed of a single,rigid filament and are up to150mm long and about 2~3mm wide,which are large for an animal of about2meters in total body length.These feathers are distributed on the posterior part of the skull and mandible,anterior part of the

316 古 脊 椎 动 物 学 报47卷neck,over the shoulder girdle,and along the distal part of the tail.

Feather impressions are preserved on specimens of two oviraptorosaur taxa.In the holotype of Protarchaeopteryx robusta,plumulaceous feathers are preserved near the chest,anterior portion of the tail,and near the femur,and they are up to27mm long.Rectrices are preserved attached to the posterior caudal vertebrae.They are at least132mm long,with a basally1.5?mm?wide ra?chis and symmetrical vanes which are slightly more than5mm wide(Ji et al.,1998).The rectri?ces have plumulaceous barbs basally.In Caudipteryx,remiges are preserved along metacarpal II, phalanx II-1,and the base of phalanx II-2and also appear to be along the forearms.The longest remex is about160mm long in IVPP V12344with an about-150-mm-long femur.The remiges have symmetrical vanes on either side of the rachis.As in Protarchaeopteryx,rectrices are atta?ched to posterior caudal vertebrae.They have symmetrical vanes(The vane of the sixth feather is 6mm wide on either side of the rachis)and a rachis of about0.7mm wide.The body is covered by plumulaceous feathers of up to14mm long(Ji et al.,1998).

The holotype of the troodontid Jinfengopteryx preserves feathers around the neck,trunk, hip,upper hindlimb,tail and manus.Those near the neck,body,hip and upper legs are short and simple in morphology,similar to Sinosauropteryx,Protarchaeopteryx and some dromaeosau?rids;some feathers near the manus are also not pennaceous(Ji et al.,2005).Rectrices are, however,clearly present along nearly whole length of the tail,as in Archaeopteryx,and they have symmetrical vanes(Ji et al.,2005).In the basal troodontid Anchiornis huxleyi,there are several morphotypes of feathers including pennaceous feathers.Plumulaceous feathers cover nearly the whole body except the limbs and tail.Pennaceous feathers are present along the fore?arm and manus,along the tibia,metatarsus,and nearly whole pedal digits,and also along the tail(Hu et al.,2009).

Fossilized feathers have been reported from a number of dromaeosaurid specimens,refera?ble to several different taxa(Xu,2002).The holotype of Sinornithosaurus millenii is a sub?adult individual and it preserves three different morphotypes of feathers:compound structure composed of multiple filaments joined in a basal tuft,or multiple filaments inserting on the dis?tal end of a rachis,or multiple filaments joined at their bases in series along a central filament (Xu et al.,2001).Surprisingly,no pennaceous feathers are visible though feathers are pre?served around the whole skeleton of the holotype of Sinornithosaurus millenii.In a smaller speci?men referable to Sinornithosaurus,similar feathers have been reported(Ji et al.,2001),but some of them are closer in morphology to pennaceous feathers than those in the holotype of Si?nornithosaurus millenii.In the holotype of Microraptor zhaoianus,feather?like structures have been reported to bear prominent rachis,but no typical pennaceous feathers are visible(Xu et al.,2000).In the holotype of Microraptor gui,several different morphotypes of feathers have been reported,including short plumulaceous feathers which are preserved near the skull,along the neck,and around the hip region,short pennaceous feathers which are preserved over the skull,and flight feathers that are preserved along the forearms,manus,tibia,metatarsus,and posterior half of the tail.Noteworthy is that some of the flight feathers have asymmetrical vanes (Xu et al.,2003).The longest rectrices are more than220mm long in the holotype of Mi?croraptor gui,an individual of about77cm in total body length. Scansoriopterygidae is a newly discovered theropod higher taxon which has been placed at the base of the Avialae(Zhang et al.,2008b).Epidexipteryx hui holotype has well?preserved feathers around nearly the whole skeleton.Two morphotypes of feathers have been identified in this specimen.Short plumulaceous feathers are similar to those of other feathered dinosaurs in having branched structures,but their nearly parallel barbs appear to arise from the edge of a membranous structure(Zhang et al.,2008b).Four long tail feathers which miss the distal ends have a central rachis and unbranched vanes,a morphology similar to highly specialized tail feathers of several basal birds(Zhang and Zhou,2006).

4期徐 星等:从新的古生物学及今生物学资料看羽毛的起源与早期演化317 

Fig.2 Filamentous integuments of several non?avian dinosaurs

A.the heterodontosaurid Tianyulong;

B.the compsognathid Sinosauropteryx;

C.the therizinosauroid Beipiaosaurus;

D.the oviraptorosaur Caudipteryx;

E.the troodontid Jinfengopteryx;

F.the dromaeosaurid Sinornithosaurus;

G.the dromaeosaurid Microraptor;

H.the scansoriopterygid Epidexipteryx;

I.the avialan Pedopenna;scale bars=5cm in A-H and=0.5cm in I

318 古 脊 椎 动 物 学 报47卷

Fig.3 Close?up of filamentous integuments

A.Tianyulong;

B.Sinosauropteryx;C,D.Beipiaosaurus;E.Dilong;F.Sinornithosaurus;

G.Caudipteryx;H.Microraptor

4期徐 星等:从新的古生物学及今生物学资料看羽毛的起源与早期演化319 

3 Evolutionary origin of feathers

The integumentary appendages seen in non?avian dinosaurs document a series of transition?al forms from typical archosaurian scales to typical avian feathers.These paleontological data stimulate new discussions on the origin and early evolution of feathers in developmental biology (Harris et al.,2002;Yu et al.,2002;Sawyer et al.,2005)and significant advances have been made recently from the perspective of biochemistry,cellular biology,and molecular biology.

3.1 New insight from neontological data into feather origin

Feathers are composed of a subclass ofβ?keratins(feather typeβ?keratins orФ?keratins). However,recent studies show thatФ?keratins are not unique to feathers and they are also ex?pressed in avian scutate scales,beak,and claw and also the bristles of the wild turkey beard (Sawyer et al.,2003b),though they are slightly larger in scales than in feathers(Sawyer et al., 2000;Prum and Brush,2002).Further more,alligator claw is also composed ofФ?keratins and alligator embryonic scales have their outer layer formed byФ?keratins as well,suggesting that biochemical composition of feathers is similar to that of archosaurian scales(Sawyer et al., 2000,2003a)and is not truly innovative in this respect.

At the cellular level,recent developmental studies support the homology between the em?bryonic epidermis of alligator,the epidermal cell populations of the scutate scales and the feath?ers of avian embryo(Harris et al.,2002;Sawyer et al.,2003a),though there are some differ?ences between the cytodifferentiation of scales and feathers(avian feathers continue their epi?dermal cytodifferentiation at hatching compared to discarding the epidermal cell populations at hatching in archosaurian scales)(Sawyer et al.,2003a).These data indicate that first feathers might have evolved from their predecessors in an incremental manner rather than in an innova?tive way from the perspective of biochemistry and embryological developmental mechanism. In the molecular level,much advances have been made on the understanding of feather morphogenesis(Chuong et al.,2003;Widelitz et al.,2003;Sawyer et al.,2005).A number of genes are involved in developing epithelial appendages(Chuong et al.,2003),and among them,Bmp and Shh genes are significant in regulating the formation and balance among the ra?chis and barbs of feathers(Widelitz et al.,2003).Shh and Bmp signaling is a conserved deve?lopmental signaling module in archosaur epidermal appendage development and derived patterns of Shh?Bmp2signaling result in the novel features in feather development such as the barb ridge formation(Zou and Niswander,1996;Harris et al.,2002).A recent study further demon?strates that the antagonistic balance between noggin and Bmp4plays a key role in feather branching,with Bmp4promoting rachis formation and barb fusion,and noggin enhancing rachis and barb branching(Yu et al.,2002).These studies support the transformational mode of barb to rachis and suggest that radially symmetric feather is more primitive than the bilaterally sym?metric feather in terms of molecular and developmental mechanisms(Yu et al.,2002).

3.2 Major feather morphotypes in non?avian dinosaurs

A few different types of filamentous integumentary structures are known from non?avian di?nosaurs and it is debated whether all these morphotypes are referable to feathers(Sawyer et al.,2003b;Xu et al.,2009b;Zheng et al.,2009).In an evolutionary context,defining feathers is a somewhat arbitrary procedure.Modern feathers are diverse in morphology and some feather morphotypes are much simpler than other morphotypes in form,but as a whole they can still be defined as complex integumentary appendages formed by hierarchical branches of rachis,barbs, and barbules which are composed ofФ?keratins and grow from a follicle.Such a structure is characteristic of a set of unique biochemical,morphological,and developmental features (Chuong et al.,2003)and is suggested to represent an evolutionary novelty(Prum,1999).

320 古 脊 椎 动 物 学 报47卷However,complex modern feathers must have been evolved from simpler structures and their morphological and developmental complexity probably has been increased incrementally in feather evolution;it is therefore somewhat arbitrary to define structures such as feathers in an evolutionary context.Nevertheless,terminology is important in science activity and in this case a definition for feathers that can been applicable to both modern feathers and its close evolution?ary predecessors is necessary for studying feather evolution and for communication and education purposes as well.

Most developmental criteria for defining modern feathers are not applicable to fossil feath?ers,though many of fossil feathers are inferred to be developed in similar way as modern feath?ers based on nearly identical or identical morphology that they shared with modern feathers.De?fining feathers thus has to depend on morphological criteria in studying fossil feathers. Several important morphological criteria for defining modern feathers include filamentous morphology produced by a proximo?distal growth mode,essentially tubular nature,presence of a follicle that has the ability to molt and regenerate,and hierarchical branches of rachis,barbs, and barbules.In an evolutionary context,these features have probably evolved in an incremen?tal manner rather than simultaneously,as also indicated by developmental data.Among these defining features,tubular nature and filamentous morphology represent the earliest ones appea?ring in feather evolution and mark the origin of feathers as indicated by both paleontological and neontological data(Harris et al.,2002;Xu et al.,2009b).Feathers are thus here defined as integumentary structures that are tubular and filamentous in morphology.Follicle,hierarchical branches,and planar form are inferred to have evolved later in feather evolution.Under such a definition,eight morphotypes of feathers are identified in non?avian dinosaurs(Fig.4). Morphotype1is known from the heterodontosaurid Tianyulong and the ceratopsian Psittaco?saurus(Mayr et al.,2002;Zheng et al.,2009).Its main characteristic is being monofilament and relatively great length and rigidity.A variant of this morphotype is seen in Beipiaosaurus,which differs from those of Tianyulong and Psittacosaurus in its relatively great width(Xu et al., 2009b).Morphotype2is a compound structure composed of multiple filaments joined basally.It is clearly present in Sinornithosaurus and Anchiornis,and probably also in Sinosauropteryx and Beipiaosaurus.Morphotype3is a distally branched filament,which is seen in the holotype of Si?nornithosaurus millenii and probably in Beipiaosaurus(Xu et al.,1999).The main characteristic of this morphotype of feather is its barbs breaking off from the tip of a central filament and distally positioned short barbs.Morphotype4is a compound structure consisting of multiple filaments branching laterally from most of the length of a central filament.It is known in Sinornithosaurus, Anchiornis,Caudipteryx,Protarchaeopteryx,and probably Dilong as well(Xu et al.,2004). Morphotype5is only known in Epidexipteryx.It consists of parallel barbs arising from the edge of a membrane structure(Zhang et al.,2008b).Given its so unusual morphology,possibility of its being part of a more complete integumentary structure could not be completely excluded,particu?larly in consideration that morphotypes2and4display distally parallel barbs in some cases. Two morphotypes of pennaceous feathers are known in non?avian theropods.Morphotype6 is known in Caudipteryx,Protarchaeopteryx,Microraptor,and Anchiornis.It is a fully penna?ceous feather with a prominent rachis and well organized,symmetrical vanes.While most of these pennaceous feathers have straight rachis,distal remiges of Anchiornis have moderately curved rachis.Morphotype7is only known in Microraptor.It is similar to morphotype6in gen?eral morphology,but differs in vane asymmetry and rachis curvature.Morphotype8is a type of highly specialized feathers known in Epidexipteryx hui(Zhang et al.,2008b),which have un?differentiated vanes on either side of a rachis.It is likely to be similar to tail feathers of some basal birds that have typical branched vanes close to their tips. Morphotypes3,4,6,7and8are shafted feathers and morphotypes1,2,and5are non?shafted feathers according to the category system proposed by Zhang and Zhou(2006).Some of

Fig.4 Known feather morphotypes of non?avian dinosaurs

A.morphotype1,single filament;

B.morphotype2,multiple filaments joined basally;

C.morphotype3, multiple filaments jointed basally on a central filament;

D.morphotype4,multiple filaments branching later?ally from most of the length of a central filament;

E.morphotype5,multiple filaments arising from the edge of a membrane structure;

F.morphotype6,compound structure composed of a prominent rachis with sym?metrical,well?organized and closed vanes on either sides;

G.morphotype7,compound structure composed of a prominent rachis with asymmetrical,well?organized and closed vanes on either side;

H.morphotype8,a prominent rachis with symmetrical,undifferentiated vanes on either side

these feather morphotypes can correspond to modern feathers,such as morphotypes6and7 (and probably morphotype8),but other morphotypes such as morphotypes1-5are difficult to be referred to a known modern feather category.They could be primitive feathers different from any modern feathers.Alternatively,this could be due to the fact that the available specimens do not preserve enough details or we are unable to observe some preserved morphologies.Neverthe?less,the distribution of these feather morphotypes across a dinosaurian phylogeny,in combina?tion with recent advances in neontological study on archosaurian integuments,reveals an evolu?tionary sequence of these structures and their possible adaptive context(Fig.5).

3.3 Major morphogenesis events in feather evolution

Five major morphogenesis events are inferred to have occurred sequentially in feather evo?lution before the origin of the Aves and they are:1)appearance of filamentous and tubular mor?phology,2)formation of follicle and barb ridges,3)appearance of rachis,4)appearance of planar form,and5)formation of pennaceous barbules.

Feather morphotype1described above might document the appearance of filamentous and tubular morphology in feather evolution.Although several studies suggest that follicle is a char?acteristic of the first feather(Prum,1999;Brush,2000),numerous studies demonstrate the formation of the embryonic feather filament prior to follicle formation(Sawyer et al.,2003a).

Fig.5 Distribution of major feather morphotypes across a simplified dinosaurian phylogeny

based on Sereno,1999,Xu,2002,and Butler et al.,2008

Numbers refer to the feather morphotypes identified in present paper and s refers

to the presence of scaly integumentary structures

An embryonic feather filament is characterized by periderm,sheath,and barb ridge cell popula?tions in crown birds,but the first feather might not be identical to the embryonic feather fila?ment of extant birds.However,the importance of the cylindrical configuration and tubular na?ture,both featuring the embryonic feather filament,has been emphasized in initiating the mor?phogenesis of modern feathers by recent development studies(Harris et al.,2002;Prum,

though a series of basally jointed filaments represents a simple branching pattern,developmen?tally a relatively complex mechanism is probably necessary for developing such a structure.Given that follicle plays a key role in producing many innovative features in feather development (Prum,1999;Brush,2000)and particularly branching occurs within the follicle during the development of modern feathers,feather morphotype2probably indicates the presence of a folli?cle.On the other hand,barb ridges are developed earlier than follicle and their development initiates the formation of follicle in modern feathers.Consequently the appearance of follicle and barb?ridges might be simultaneous in feather evolution.

Barb ridges play a central role in feather development and they finally develop into hierar?chical branches of rachis,barbs,and barbules(Alibardi,2005).The filaments of feather mor?photype2are apparently unlikely to be rachis.It remains unknown whether these filaments are just rami or complete barbs with barbules because the state of preservation does not allow either a positive identification of barbules on these filaments or a rejection of the presence of such structures.A notable feature is that the filaments in feather morphotype2are somewhat strap?like,a feature also characteristic of barbs in modern feathers,yet the filaments in feather mor?photype2are apparently proportionally wider than barbs in modern feathers.Recent develop?mental studies demonstrate the impossibility of separate formation of barb and barbule cells and suggest that primitive feathers with only barbs but not barbules are unlikely to exist(Alibardi, 2005).If this holds true,some sort of simple,small barbules might be present in feather mor?photype2or other primitive feathers.

Feather morphotype3documents the rachis formation.The rachis is formed by fusion of barb basal ends through a helical growth mode of barb ridges in modern contour feathers,but is formed in a different way in some other morphotypes of feathers,though fusion appears to be in?volved in the formation of all morphotypes of feathers with a rachis(Lucas and Stettenheim, 1972).Nevertheless,neontological data,at both embryological and molecular levels,support the hypothesis that barbs have appeared evolutionarily before rachis.The barb?first model is also supported by fossil feathers.Besides fossil evidence from Liaoning,Perrichot et al. (2008)reported a morphotype of feather that has a shaft consisting of incompletely fused,still distinguishable,partially superimposed barbs.Some isolated feathers from the Barremian limestones of Spain appear to have only barbs but not rachis(Sanz et al.,1988). Feather morphotype4might document the appearance of planar form.Planar form of feath?ers basically results from the helical growth of barb ridges within the follicle.Bilaterally ar?ranged barbs along a rachis indicate the presence of planar form,which is a critical feature for the majority of modern feathers.

Feather morphotypes6-7document the formation of pennaceous barbules.Although not being observed directly,pennaceous barbules are probably present in pennaceous feathers of Caudipteryx,Protarchaeopteryx,and Anchiornis given their well?organized vanes;barbules are visible in pennaceous feathers of Microraptor,but details are not clear.Given the significance of contour feathers(including flight feathers)in living birds,the appearance of pennaceous bar?bules and consequently of pannaceous feathers mark one of the most important events in feather evolution.The presence of pennaceous feathers in Anchiornis(Hu et al.,2009)suggest that this important event have occurred about160Ma or even earlier.

324 古 脊 椎 动 物 学 报47卷Noteworthy is the elongate ribbon?like tail feathers seen in Epidexipteryx and some basal birds as well,including confuciusonithids(Zhang et al.,2008a)and some enantiornithines (Zhang and Zhou,2000).Although these highly specialized tail feathers have been suggested to represent a type of primitive feather and their discovery to support a scale plate?rachis?barbs mo?del for feather evolution,their relatively late appearance in feather evolution,extremely limited distribution on the body,and discovery of similar tail feathers in Confuciusornis but which is dis?tally branched as the normal pennaceous feathers(Chiappe et al.,1999;Zhang and Zhou,2006) are against such a suggestion.Further more,some living birds have superficially scale?like feath?ers which are formed by the fusion of barbs(Prum and Brush,2002).Developmentally suppres?sion of Sonic hedgehog(Shh)can lead to a webby membrane remnant between barbs(Widelitz et al.,2003)and thus the scale?like feathers in Epidexipteryx and some basal birds are likely to be a similar variant of the normal pennaceous feathers produced by the same genetic change.

3.4 Feathered feet

Three non?avian dinosaurs are known to bear large pennaceous feather on their feet,inclu?ding basal dromaeosaurid Microraptor,basal troodontid Anchiornis,and basal avialan Pedopen?https://www.doczj.com/doc/1b18122092.html,rge pennaceous feathers on lower legs also appear to be common in basal avians(they are reported in Archaeopteryx,Confuciusornis,and some enantiornithines)(Christiansen and Bonde,2004;Zhang and Zhou,2006).In living birds,lower legs are not extensively feath?ered as in most other parts of the body and normally are covered by only small feathers(but in hawks,owls,and many cuckoos,a group of large feathers called a crural flag is seen in the knee region).Some living birds(such as grouse,owls,many hawks and breeds of chickens) have feathered feet,but most extant birds lack feathers completely on their feet(Lucas and Stettenheim,1972).The feathering of lower legs including feet is thus different between basal paravians,in which lower legs represent the third major anatomical region besides the forelimbs and tail bearing large pennaceous feathers,and most other birds,in which lower legs are among the least feathered regions of the body.

Scale formation on the avian legs including feet first requires a repression of feather develop?ment(Sawyer et al.,2005),which has been suggested to indicate that the avian scutate scales are derived from feathers(Sawyer and Knapp,2003).Avian scutate scales share uniquely with avian feathers in having ectodermal placodes,though they differ temporally,morphologically,and functionally from those of feathers(Sawyer et al.,2005).Consequently,both paleontological and neontological data suggest that feathered feet are primitive condition for the Paraves and avian scutate scales might be derived structures,different from pedal scales of non?avian dinosaurs. Interestingly,the phylogenetic and anatomical distribution of large pennaceous feathers shows that these structures first evolved on the distal portions of the hindlimbs as in forelimbs and tail in maniraptoran theropods(Xu et al.,2003;Hu et al.,2009),though large leg feath?ers are reduced and lost subsequently in avian evolution.Such a distal?first pattern is also seen in the development of flight feathers in living birds(Lucas and Stettenheim,1972).

3.5 Feather tract evolution

Although developmentally feather morphogenesis starts from the formation of feather tract fields,it is probably not the first step evolutionarily as suggested by some developmental studies (Widelitz et al.,2003).Because feather tracts are characteristic of the presence of contour feath?ers,their appearance is probably associated with the evolution of contour feathers,the dominant feathers on the body of living https://www.doczj.com/doc/1b18122092.html,rge pennaceous feathers are seen in limbs and tail of Cau?dipteryx,Protarchaeopteryx,Anchiornis,and Microraptor and some short ones on the head of Mi?croraptor,but there is no evidence of extensive growth of contour feathers on the body of non?avian dinosaurs.Microraptor is clearly covered by plumulaceous feathers on most of its body;Epi?

4期徐 星等:从新的古生物学及今生物学资料看羽毛的起源与早期演化325 dexipteryx has more extensive covering of short,small plumulaceous feathers(Zhang et al.,2008b). Recent re?study on the Berlin Archaeopteryx specimen suggest that faint hair?like structures at the base of the neck may have been generated from some sort of proto?apteria’and longer feathers with vanes on back and legs grew from proto?pterylae’(Christiansen and Bonde,2004).If this obser?vation is true,feather tract is likely to have evolved first at the base of the Aves.

3.6 Functions of early feathers

Locomotion(including flight),thermoregulation,and display are three major functions for modern feathers and all have been previously suggested to represent the initial function of the feathers(Xu et al.,2009b).The discoveries of feathered dinosaurs from China reject the flight hypothesis(Ji et al.,1998;Xu et al.,1999).Although it is in many cases difficult to infer se?curely the function of fossil structures,some information is obtainable concerning the functions of early feathers and thus useful to infer the initial function of feathers.

The monofilaments in Tianyulong and Psittacosaurus(Mayr et al.,2002;Zheng et al., 2009)are apparently not related to flight functionally as they lack any aerodynamic features. They are long and rigid and are distributed on only certain parts of the body.Furthermore,their density is relatively low compared to filamentous integumentary structures of other feathered di?nosaurs.Such structures could not have formed an effective insulative layer and thus the initial function of feathers is probably not related to insulation.Display and heat dissipation,among others,remain viable hypotheses for earliest function of feathers.The length,rigidity,and limi?ted distribution on the body of the monofilaments of Tianyulong and Psittacosaurus(Mayr et al., 2002;Zheng et al.,2009)and also Beipiaosaurus(Xu et al.,2009b)suggest a display func?tion for these structures.A display function has also been suggested for the elongate ribbon?like tail feathers of Epidexipteryx(Zhang et al.,2008b).However,the possibility of being used to dissipate heat,as seen in some lizards that have frill over their vertebral column,could not be excluded for the monofilaments of Tianyulong and Psittacosaurus,particularly if these structures are hollow inside as suggested(Mayr et al.,2002;Zheng et al.,2009). Morphotypes2-4are composed of multiple filaments and interestingly these filaments are proportionally thick compared to barbs of down feathers in modern birds or hairs in extant mam?mals;and they are also more rigid than barbs of down feathers in birds.These structures are likely to have an insulation function as suggested by previous studies(Chen et al.,1998;Xu et al.,1999),but the above mentioned features suggest that they are not ideal structures for such a function or at least are not as effective in insulating body as down feathers of modern birds. One notable difference between the plumulaceous feathers of basal coelurosaurs such as Sinosau?ropteryx and those of derived ones such as Microraptor is the density.The plumulaceous feathers of the latter are more densely distributed on the body than those of the former,which implies ei?ther a functional difference or a difference in effectiveness in insulating the body.

The large pennaceous feathers seen on forelimbs and tail of Caudipteryx are probably not related to flight because they have no striking aerodynamic features and also because this taxon has little osteological features suggesting any aerial capability.Other functions,such as maintai?ning balance or producing additional thrust during running or climbing,insulating eggs,and display,are all viable hypotheses.Similar large pannaceous feathers seen in forelimbs and tail of Protarchaeopteryx and particularly Anchiornis are less clear regarding to their functions.Simi?lar to the pennaceous feathers in Caudipteryx,the large pennaceous feathers in Protarchae?opteryx and Anchiornis lack striking aerodynamic features,but their bearers are osteologically fairly close to Archaeopteryx(for example,they have significantly elongate forelimbs)and they are possible to contribute to some sort of aerial locomotion.

Little is known about the function of large symmetrical pennaceous feathers attached to the feet of Anchiornis and Pedopenna.Because they are well organized into a coherent planar sur?

326 古 脊 椎 动 物 学 报47卷face,they are possible to have some aerodynamic function.Modern analogy of feathers in some birds suggests a protection or insulation function for the pedal feathers of Anchiornis and Pe?dopenna.Another possibility is an ornamentation function,which is also inferred for feather morphotype8.The variable morphology of metatarsal feathers in basal paravians might reflect a shift in function(from flight to ornamentation,protection or insulation)and/or relative impor?tance in aerodynamics.

The large asymmetrical pennaceous feathers on the forelimbs,hindlimbs,and tail of Microrap?tor possess several striking aerodynamic features including strong curvature and asymmetry.For ex?ample,a distal metatarsal feather of Microraptor has an asymmetry ratio of more than8,comparable to the distal primary flight feathers of some extant capable flying birds.These features strongly sup?port the hypothesis that asymmetrical pennaceous feathers functioned in flight in Microraptor.

In summary,flight,insulation,and display functions are all inferred to have evolved be?fore the origin of the Aves,but flight function is the last of the three to appear in feather evolu?tion.Furthermore,insulation is inferred not to represent the initial function of feathers and it appears to have evolved later than a display function.

4 Conclusions

Recent paleontological and neontological data both support:1)the first feather is a single, tubular filament;2)barbs are structures phylogenetically appearing earlier than rachis;3)ra?dially symmetrical plumulaceous feathers are more primitive than bilaterally symmetrical penna?ceous feathers.These conclusions represent significant advances over earlier studies on the ori?gin and early evolution of feathers,but some debates remain regarding to various aspects of ear?ly feather evolution and a lot more critical information is needed to complete the reconstruction of evolutionary history of feathers.

The known developmental models of the origin of feathers all suggest that feathers are evo?lutionarily innovative structures.These studies emphasize the differences between feathers and scales,though they do demonstrate that feathers and scales share numerous similarities bio?chemically,genetically,at cellular level,and in early embryological development(they are thus partially homologous).Most developmental models accept simple filamentous integumenta?ry structures of non?avian theropods as feathers and suggest them to have grown from a follicle because the latter structure plays a central role in producing unique features of modern feathers. These models suggest that the first feathers are not homologous to scales of any form.An ex?treme example of emphasizing the novelties of feathers is the questioning of the homologous rela?tionships between feathers of modern birds and the simple filamentous integumentary structures of non?avian theropods(Sawyer et al.,2003b).For example,because the bristles of the wild turkey beard possess several striking defining features of modern feather such as expressing the feather?typeβkeratins,hollow,and branching distally,some recent developmental studies consider these features not to be the defining features of feathers any more and suggest that the simple filamentous integumentary structures of some non?avian theropods are not primitive feath?ers(Sawyer et al.,2003b).

An evolutionary model characteristic of both transformation and innovation for the origin and early evolution of feathers might be more acceptable(Xu,2006).Although being proposed as evidence against the hypothesis that simple,filamentous integumentary structures are primitive feathers,the presence of some striking defining features of modern feather in the bristles of the wild turkey beard instead suggests that these features could have evolved incrementally in the pre?decessors of modern feathers rather than have appeared simultaneously in the first feather.The discovery of the simple,monofilamentous ornithischian integumentary structures and a pattern of increasing complexity toward the Aves for those filamentous integumentary structures in non?avian

4期徐 星等:从新的古生物学及今生物学资料看羽毛的起源与早期演化327 dinosaurs also provide indirect evidence supporting an incremental pattern of the evolution of feather features.A sudden appearance of a whole set of unique,complex developmental mecha?nisms and associated morphologies is also unlikely from the perspective of adaptation.

In future study,obtaining information on the fine details of the identified feathers in non?avian dinosaurs is important for comparing them with modern feathers and thus evaluating the exact significance of these structures.It is significant to know whether these feather morphotypes have barbules,whether they have a calamus or have a short rachis,whether a follicle is pre?sent,and how the distribution pattern of various feathers on non?avian dinosaur body,which contribute significantly to the understanding of the exact evolutionary sequence of some impor?tant features of feathers and the functional inference of some early feathers.In developmental studies,more data is needed on the mechanisms of the rachis formation in non?contour feathers and of the relationships between the formation of barb ridges and follicle.An integrative study of paleontology and neontology on feather evolution promises to shed significant new insights into this extremely intriguing evolutionary issue.

Acknowledgments We thank J.Ly for editing the ms and preparing Fig.5,R.S.Li for pre?paring Fig.4,M.Kundrat for valuable comments on the ms,and F.C.Zhang and R.Prum for discussions.

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古生物学与地史学考研期末考试知识点(含答案)备课讲稿

古生物学与地史学考研期末考试知识点(含 答案)

《古生物地层学》知识点 一、填空 1、石化作用的方式有充填作用、交替作用、升馏碳化作用和重结晶作用四种方式。 2、化石的保存类型有实体化石、模铸化石和遗迹化石。 3、生物进化的总体趋势是由简单到复杂、由低等到高等和由海洋到陆地、空中。 4、生物进化的特征为进步性、阶段性、不可逆性和适应性。 5、生物适应环境的方式有趋同、趋异和并行。 6、地质历史时期发生了多次生物绝灭事件,三次较大的生物绝灭事件分别发生于泥盆纪晚期、二叠末期、白垩末期,这些时期都处于太阳系G值曲线的特征点时刻。 7、就控制物种形成的因素而言,遗传变异提供物质基础,隔离提供条件,自然选择决定物种形成的方向。 8、物种的形成方式有渐变成种、迅变成种和骤变成种。 9、就物种的绝灭方式而言,类人猿的绝灭属于世系绝灭,恐龙的绝灭属于集群绝灭。 10、海洋生物的生活方式有游泳、浮游和底栖。 11、由于生物进化具有阶段性,因此,可以利用地层中化石的阶段性表现,来划分地层的新老。 12、生物进化的不可逆性表明,各种生物在地球上只能出现一次,绝灭以后,决不会重新出现,因此,不同时代地层中的化石群是不会完全相同的。 13、由于大多数遗迹化石是原地埋藏的,因此遗迹化石对分析古沉积环境的极好样品。 14、中国的三叠纪,呈现出以秦岭-大别山为界,南海北陆的地理格局。 15、侏罗纪被称为裸子植物的时代、爬行类的时代、菊石的时代。 16、中三叠世晚期,由于印支运动的影响,华南地区发生大规模的海退,人称拉丁期大海退。 17、地层与岩层相比,除了有一定的形体和岩石内容之外,还具有时间顺序的含义。 18、地史上构造旋回的概念,是指地壳上的地槽区由到上升,由相对而转变为相对过程,这样一个过程叫做构造旋回(或褶皱旋回)。 19、全球岩石圈板块可以划分为:太平洋板块、亚欧板块、非洲板块、美洲板块、印度板块(包括澳洲)和南极板块。 20、古板块边界的识别标志主要包括蛇绿岩套、混杂堆积、双变质带、深断裂带等方面。 21、我国古太古界~新太古界的分布主要局限于华北地区,岩性以变质岩为主。 22、含铁红色砂岩和高价铁沉积铁矿的首次出现约在距今亿年左右。它们的出现确切指明大气中已有氧。 23、伊迪卡拉裸露动物群出现于晚震旦世时期。 24、寒武纪我国华北地区表现为稳定的北高南低的陆表海。 25、加里东构造阶段,华北、塔里木板块与扬子板块以古秦岭洋相隔。 26、泥盆纪华南地区存在两种类型的沉积,滇、黔、桂地区以稳定浅海环境为主,象州型分布较广,沉积物以碳酸盐岩为主;在桂西和滇东南存在一种南丹型泥盆系,含菊石、竹节石等化石,是典型的深水滞流底部缺氧的裂谷沉积。

地史古生物学l要点

古生物地史学 绪论 1.什么是古生物学,地史学? 古生物学:是研究地史时期的生物及其发展规律的科学。 ①以保存在地层中的生物遗体和遗迹为研究对象。 ②研究古生物的形态、构造、分类、生态、地理及地史分布和演化发展规律。 ③了解生命的起源、生物进化,阐明生物界的发展史,充实和提高生物进化理论。 ④解决地层时代的划分和对比,恢复古地理、古气候。 地史学:是研究地壳发展历史的科学,研究内容包括生物发展史、沉积作用(及古地理变迁)发展史、地壳构造发展史等方面。 2.研究古生物学的意义? ①再造地史时期中的古地理、古气候,恢复古代的自然地理环境。再造古地理、古气候的依据是不同的生物相代表不同的生活环境。 ②探讨各地质时期古地理环境的变化及演变规律,揭示有关沉积矿产的形成和分布规律。 ③建立地质年代系统,地层层序律,生物层序律 第一篇古生物学 第一章古生物学的基本概念 1.化石 化石是保存在地层中的古生物遗体和遗迹。遗体是保存的生物体本身部分,遗迹则是被保存下来的生物生活活动的痕迹。 2.化石的形成条件:a硬体部分 b迅速掩藏、密封冷冻或干燥c石化作用 化石的保存类型:a实体化石b模铸化石c遗迹化石 3.石化作用的类型 (1)矿物填充作用(2)置换作用(3)升溜作用 4.水生生物的生活方式 底栖生物,游泳生物,浮游生物 5.指相化石 分布范围广,原地埋藏,适应性狭窄,并且能够反映某种气候特征的化石。 第二章古无脊椎动物 1.蜓壳旋壁结构的类型 致密层,透明层,疏松层,蜂巢层 2.四射珊瑚构造类型 (1)单带型(仅有隔壁和横板) (2)双带型(具有隔壁、横板和鳞板)

(3)三带型(具有隔壁、横板、鳞板及中轴或中柱) (4)泡沫型(隔壁不连续呈刺状,横板和鳞板均呈泡沫状) 3.各古生物的生存年代 蜓是灭绝的海生有孔虫,分布于石炭、二叠纪。 小纺锤蜓:中石炭纪 贵州珊瑚:早石炭纪 弓石燕:晚泥盆世至早石炭世 尖棱菊石:晚泥盆世 六方珊瑚:泥盆纪 弓笔石:中志留世 王冠虫:志留纪 震旦角石:中奥陶世 叉笔石:奥陶纪 蝙蝠虫:晚寒武世 第三章古脊椎动物 1.简述脊椎动物的演化史 脊椎动物由无颌纲开始进化到鱼纲,其中盾皮鱼亚纲,为现代鱼的祖先,已经灭绝,硬骨鱼中总鳍鱼发展成为古老的两栖类;接着发展到两栖纲,其中鱼石螈是最古老的两栖类化石;两栖动物进化出羊膜卵向陆地发展,进化成爬行纲;爬行纲的一个旁支进化成了鸟类,最早的鸟类出现在晚侏罗世,即始祖鸟;爬行纲的另一个分支发展成为哺乳纲,其中人类是最高等的哺乳动物。 2.各古生物的生存年代 盾皮鱼亚纲:晚志留世到泥盆纪,少数延续到二叠纪 鱼石螈:晚泥盆世 中华龟:侏罗纪 始祖鸟:晚侏罗世 大熊猫:更新世至全新世 三趾马:上新世至早更新世 叠层石:广泛分布于前寒武纪,奥陶纪开始衰退,现代的叠层石较少。 第四章古植物 1.叠层石 定义:具有叠状层的藻类沉积结构物。叠层石不仅包括藻本身,还包括其生命活动痕迹所形成的综合产物。 意义:研究叠层石对恢复古地理环境及划分对比地层(前寒武系)等有很大意义 2.各植物的的生存年代 鳞木:石炭纪至二叠纪 脉羊齿:石炭纪至早二叠世

古生物学与地史学补考模拟题

《古生物学与地史学》模拟题(开卷)(补) 一.名词解释 1.物种:一群与其他种群在生殖上隔离的可繁殖生物群体。 2.指相化石:能够明确指示某种沉积环境的化石。 3.间断平衡论:一个谱系的演化是由物种形成时的形态迅速变化时期和形态没有什么变化的静态平衡时期所组成。这个学说也叫点断模式或间断平衡。成种过程是突然发生的,无中间类型。 4. 生物进化:指生物与其环境之间的相互作用导致部分或整体生物种群遗传组成的一系列不可逆的变化。 5.重演律:个体发育是系统发生的简短而快速重演。 6.趋同演化:生物亲缘关系疏远的生物,由于适应相似的生活环境,而在形体上变得相似。7.寒武纪生物大爆发:寒武纪初(5.7亿年),动物界出现一次爆发式的大发展。造门的时代,几乎所有具硬体的无脊椎动物门及绝大部分纲都已出现。以节肢动物门三叶虫纲占优势,占60%,次为腕足动物门,占30%。 8.瓦尔特相律:只有那些目前可以观察到是彼此毗邻的相和相区才能原生地重叠在一起。9.碳化作用:石化作用过程中,生物遗体中不稳定的成分分解和升馏挥发,仅留下较稳定的碳质薄膜保存为化石 10.平行层理:在急流条件下,由细砂、中砂、粗砂甚至细砾形成的相互平行的层理。11.被动大陆边缘:大陆边缘包括陆棚、大陆斜坡和陆基(陆隆),没有海沟存在,也不出现地壳俯冲和消减现象。 12.化石层序律:不同时代的岩层中所含的化石不同,因此根据相同的化石来对比地层并证明属同一时代。 13.澄江动物群:澄江动物群于二十世纪八十年代发现于云南澄江、晋宁地区的下寒武统化石保存极好(软、硬体),有壳和无壳动物61属、67种,包括三叶虫、水母、蠕虫类、甲壳类、腕足类、甚至脊索动物(鱼类)等。此动物群是二十世纪最重大的发现之一。14.平行演化:亲缘关系比较近的生物分化后,分别在相似的环境中发展,它们对应的器官因适应相似的环境而产生相似的性状。 15.二名法:即在种本名之前加上它所归属的属名,以构成一个完整的种名。 16.集群绝灭:生物灭绝率突然数十倍地增高波及全球或大区;生态系统发生巨大变化。 二.简答题 1.简述生物的主要分类阶元。 答:门、纲、目、科、属、种,还可以加一些次一级分类单位,如“超”、“亚”、“次”等形容词。 2.简述四射珊瑚的内部结构特征及构造类型。 答:纵列构造:隔壁:珊瑚体内辐射排列的纵向骨板。分为一、二、三…级 横列构造:横板:横越腔肠的板,可完整地跨越体腔,也可以交错、分化 边缘构造:鳞板:位于隔壁之间上拱的小板。泡沫板:切断隔壁的大小不等的板

古生物地层学重点考点

第一章生物界及其进化 1、进化: 生物由低级到高级、由简单到复杂,体现在其形态构造的复杂变化和生理机能的提高。 2、发生在种内个体和居群层次上的进化成为小进化;种和种以上的进化被定义为大进化。 3、小进化的主要影响因素有突变、迁移、遗传漂变、适应和自然选择 4、大进化的形式 (1)适应辐射: 从一个祖先类群,在较短时间内迅速地产生许多新物种。 (2)趋同与平行演化: 趋同是指不同祖先的生物类群,由于相似的生活方式,整体或部分形态构造向同一个方向改变。平行演化是指不同类型生物由于相似的生活方式而产生相似的形态,它与趋同有时不易区分,但平行演化常指亲缘关系相近的两类或几类生物。 (3)线系渐变与间断平衡: 线系演变模式认为生物逐代的微小变化可以随时间积累导致主要的进化。间断平衡模式认为大进化的主要方式由长期的进化停滞期和短期的快速进化期所组成,新种是以跳跃的方式快速形成,新种一旦形成则处于停滞的进化状态,表型上不会有明显变化,直到下一次成种事件发生之前。 5、大爆发: 在生命进化史上可以发现阶段性地出现种以上分类单位的生物类群快速大辐射现象 6、大灭绝:

大灭绝又称为集群灭绝,即在相对较短的地质时间内,在一个地理大区的范围内,出现大规模的生物灭绝,往往涉及一些高级分类单元,如科、目、纲级别上的灭绝。 7、生存条件: 维持生物的生命活动(如新陈代谢、生长发育、生殖、、等)的基本外界条件。 8、生活环境: 由一系列彼此相关的环境因素所构成生物生存跳进的总和 9、影响生物生活的环境因素: 物理因素、化学因素、生物因素。 10、化石群落营养结构主要包括两类描述指标: 生态类群、时空分层结构 11、原地埋藏化石的主要特点: (1)化石保存完整,各部分及表面无脱落及磨损现象 (2)个体大小分选性差,大小极不一致,没有水流冲刷排列整齐的现象 (3)具两壳瓣的化石,一般两壳闭合,即使两瓣分离,在同一层位中两壳数量比例大致为1:1。 (4)基本保留了古生物原先生活时的状态或稍有变动。 第二章古生物学基础 1、古生物学: 是研究地质历史时期的生物及其发展的科学,它研究各地质历史时期地层中保存的生物遗体,遗迹及一切与生物活动有关的地质记录。

古生物学复习资料

古生物学复习资料 Coca-cola standardization office【ZZ5AB-ZZSYT-ZZ2C-ZZ682T-ZZT18】

古生物学理论1.古生物学概念 古生物学是研究地质历史时期的生物界及其发展的科学。 化石定义 保存在岩层中地质历史时期的生物遗体、生命活动的遗迹及生物成因的残留有机物分子。 化石保存条件有哪些 化石形成条件:1)生物本身条件(硬体、矿物成分) 2)生物死后的环境条件(生物方面要求水动力弱,还原条件,细 菌分解作用少、酸碱性) 3)埋藏条件(埋藏快、沉积细、搬运短、泥质) 4)时间因素(时间长) 5)成岩条件(压实与重结晶作用) 化石保存类型包括哪些 化石的保存类型: 1)实体化石:指经石化作用保存下来的全部生物遗体或部分生物遗体化石(包括不完整实体和完整实体) 2)模铸化石:指生物遗体在岩层中的印模和铸型 印痕化石:生物遗体陷落在细粒碎屑或化学沉积物中留下来生物软体的印痕 印模化石:即生物硬体在围岩表面上的印模,包括外模和内模 核化石:即生物结构形成的空间或生物硬体溶解后形成的空间,被沉积物充填固结后,形成与原生物体空间大小和形态相似的实体,包括内核和外 核 铸型化石:是当贝壳埋在沉积物中已形成了外模和内核后,壳质全部溶解,并被后来的矿物质填充所形成的化石 3)遗迹化石:指保存在岩层中古代生物生活活动留下的痕迹和遗物 4)化学化石:地史时期生物有机质软体部分虽然遭受破坏未能形成化石,但分解后的有机成分,如脂肪酸,氨基酸仍可残留在岩石中 化石化作用定义 化石的石化作用是指埋藏在沉积物中的生物遗体在成岩过程中经过物理化学作用的 改造而形成化石的作用 化石化作用类型有哪些 石化作用类型:1)矿质充填作用 2)置换作用 3)碳化作用 2.古生物的分类等级由大到小分别是 界、门、纲、目、科、属、种 5界分类系统包括 原核生物界、原生生物界、植物界、真菌界和动物界 3.国际命名法规-------双名法(P26)

古生物学复习

古生物学复习 文档编制序号:[KK8UY-LL9IO69-TTO6M3-MTOL89-FTT688]

古生物学理论1.古生物学概念 古生物学是研究地质历史时期的生物界及其发展的科学。 化石定义 保存在岩层中地质历史时期的生物遗体、生命活动的遗迹及生物成因的残留有机物分子。 化石保存条件有哪些 化石形成条件:1)生物本身条件(硬体、矿物成分) 2)生物死后的环境条件(生物方面要求水动力弱,还原条 件,细菌分解作用少、酸碱性) 3)埋藏条件(埋藏快、沉积细、搬运短、泥质) 4)时间因素(时间长) 5)成岩条件(压实与重结晶作用) 化石保存类型包括哪些 化石的保存类型: 1)实体化石:指经石化作用保存下来的全部生物遗体或部分生物遗体化石(包括不完整实体和完整实体) 2)模铸化石:指生物遗体在岩层中的印模和铸型 印痕化石:生物遗体陷落在细粒碎屑或化学沉积物中留下来生物软体的 印痕

印模化石:即生物硬体在围岩表面上的印模,包括外模和内模 核化石:即生物结构形成的空间或生物硬体溶解后形成的空间,被沉积物充填固结后,形成与原生物体空间大小和形态相似的实 体,包括内核和外核 铸型化石:是当贝壳埋在沉积物中已形成了外模和内核后,壳质全部 溶解,并被后来的矿物质填充所形成的化石3)遗迹化石:指保存在岩层中古代生物生活活动留下的痕迹和遗物 4)化学化石:地史时期生物有机质软体部分虽然遭受破坏未能形成化石,但分解后的有机成分,如脂肪酸,氨基酸仍可残留在岩石中化石化作用定义 化石的石化作用是指埋藏在沉积物中的生物遗体在成岩过程中经过物理化 学作用的改造而形成化石的作用 化石化作用类型有哪些 石化作用类型:1)矿质充填作用 2)置换作用 3)碳化作用 2.古生物的分类等级由大到小分别是 界、门、纲、目、科、属、种 5界分类系统包括 原核生物界、原生生物界、植物界、真菌界和动物界 3.国际命名法规-------双名法(P26) 4.小壳动物群含义 小壳动物群:在灯影组顶部,以小壳动物的出现做为寒武系的底界,为第

地史古生物学考试重点复习内容(整理篇)

古生物地史学 绪论 1、古生物学地史学 古生物学:是研究地史时期的生物及其发展规律的科学。 (1)以保存在地层中的生物遗体和遗迹为对象; (2)研究古生物的形态、构造、分类、生态、地理及地史分布和演化发展规律;(3)了解生命的起源,生物进化,阐明生物界的发展史,充实和提高生物进化理论; (4)解决地层时代的划分和对比,恢复古地理,古气候。 地史学:是研究地壳发展历史的科学,研究内容包括生物发展史,沉积作用(及古地理变迁)发展史,地壳构造发展史等方面。 2、研究古生物学的意义 (1)再造地史时期中的古地理,古气候,恢复古代的自然地理环境.再造古地理,古气候:依据不同的生物相代表不同的生活环境; (2)探讨各地质时期古地理环境的变化及演变规律,揭示有关沉积矿产的形成和分布规律; (3)建立地质年代系统,地层层序律,生物层序律。 第一篇古生物学 第一章古生物学的基本概念 1、化石 化石是保存在地层中的古生物遗体和遗迹。遗体是保存的生物体本身部分,遗迹则是被保存下来的生物生活活动的痕迹。 2、化石的形成条件 硬体部分、迅速掩藏、密封冷冻或干燥、石化作用 3、化石的保存类型 实体化石、模铸化石、遗迹化石

4、石化作用的类型 (1)矿物填充作用(2)置换作用(3)升溜作用 5、水生生物的生活方式 底栖生物、游泳生物、浮游生物 6、指相化石 分布范围广,原地埋藏,适应性狭窄,并且能够反映某种气候特征的化石。 第二章古无脊椎动物 1、蜓壳旋壁结构的类型 致密层、透明层、疏松层、蜂巢层。 2、四射珊瑚构造类型 (1)单带型(仅有隔壁和横板) (2)双带型(具有隔壁横板和鳞板) (3)三带型(具有隔壁,横板,鳞板,及中轴或中柱) (4)泡沫型(隔壁不连续呈刺状,横板和鳞板均呈泡沫状) 3、各古生物的生存年代 蜓是灭绝的海生有孔虫,分布于石炭,二叠纪。 小纺锤蜓:中石炭纪 六方珊瑚:泥盆纪 贵州珊瑚:早石炭纪 弓石燕:晚泥盆世至早石炭世 震旦角石:中奥陶世 尖棱菊石:晚泥盆世 蝙蝠虫:晚寒武世 王冠虫:志留纪 叉笔石:奥陶纪 弓笔石:中志留纪

《古生物学》复习提纲

一、名词解释(每小题1.5分,共12分) 1.古生物学; 古生物学是地质学与生物学交叉的一门边缘学科,是研究地质时期生命起源与演化的科学。课程内容包括:①理论古生物学,主要讲述生物分类、生命起源与生物演化和绝灭等基本理论;②门类古生物学,主要介绍各种化石的基本特征、分类与地史分布等,这对于确定地层的地质年代,恢复古环境以及研究地壳的演化等具有重要意义。 ①研究生物体的形态、结构、构造、分类、个体发育和系统发生、生物演变和环境适应,乃至生物的生理和生物化学等; ②研究古生物的地质时间含义、古生物的兴衰与迁移、古生物地理以及古生物与能源、矿产等。 2.地史学; 地史学也称历史地质学,是研究地球地质历史及其发展规律的科学,具体包括地球岩石圈、水圈、大气圈、生物圈的形成,演化历史和不同圈层(包括宇宙圈)间的耦合关系;在空间上已经扩大到了全球大陆,海洋和深部岩石圈,在时间上已经追溯了40亿年左右。地史学是一门涉及了多方面知识的综合性,历史性均很强的学科。 3.化石 指保存在沉积地层中,各地质历史时期的生物的遗体、遗迹以及古生物残留的有机组分。 4.标准化石 指那些演化速度快、地理分布广、数量丰富、特征明显、易于识别的化石。利用标准化石不仅可以鉴定地层的时代,也可以用于地层的年代对比。 5.实体化石 指生物的遗体或其中一部分保存为化石。可分为未变实体化石和变质实体化石。 6.遗迹化石 指古代生物生活时期在生活场所留下的各种痕迹。如足迹、粪便、潜穴等 7.模铸化石 指古代生物遗体在沉积物或围岩中留下的印模和复铸物。常见的有: 外模-生物外表特征保留在围岩上的印模; 内模-生物内部特征保留在围岩上的印模; 内核-生物遗体中空部分的充填物; 复形-生物遗体溶失及其内部空间的充填物; 铸形-生物遗体溶失被其它物质注入。 8.物种 物种,简称“种”,物种是生物分类学的基本单位。物种是互交繁殖的相同生物形成的自然群体,与其他相似群体在生殖上相互隔离,与其它生物不能性交或交配后产生的杂种不能再繁衍。并在自然界占据一定的生态位。 9.双名法 2. 生物的命名方法 (1)命名法规 《国际动物命名法规》、《国际植物命名法规》 (2)学名(名称)

古生物学期末总结(纯手打)

一、三叶虫(寒武到二叠) 三叶虫的演化和地史分布: 分布时限:寒武至二叠 繁盛:寒武,统治地位 退居次要:奥陶 急剧衰退:志留,泥盆,石炭,二叠,只留少数类别

绝灭:二叠末 演化: 早寒武世三叶虫:头大,尾小,胸节多,头鞍长,且为锥形,鞍沟明显,眼叶发育且靠近头鞍,胸节肋刺发育 中晚寒武世三叶虫:尾甲变大,异尾型,胸节减少,头鞍变短,多内边缘,眼叶变小,鞍沟数量减少且很少穿过头鞍 奥陶纪三叶虫:尾甲更大,等尾甚至大尾型,胸节更少,8到9节,头鞍向前扩大,鞍沟背沟颊沟都不发育 志留至二叠三叶虫:急剧衰退 二、笔石动物(分类位置未定,为奥陶志留的标准化石) 主要分两大类: 树形笔石:树枝状,底栖固着 正笔石:列式,漂浮——指相化石;只有正胞 硬体构造:胎管——胞管——笔石枝——笔石体——笔石簇

胞管:第一个胞管由亚胎管上的小孔长出,分为正胞,副胞,茎胞 始端为近胎管一侧 共通管在背部连接各个胞管

笔石的演化以正笔石的比较清楚,正笔石是由树形笔石演化而来,正笔石的演化如下: 无轴到有轴,双列到单列,胞管由简单到复杂(直管状到内弯到外弯),多枝到少枝,生长方向由下垂到上攀 笔石的保存岩性:在各类沉积岩中,以页岩为主,尤其黑色页岩——指相化石 笔石大量保存在黑色页岩中,表明当时的沉积环境闭塞 笔石的地史分布: 始于中寒武世,寒武纪以树形笔石类为主,奥陶纪正笔石类极盛,志留纪开始衰退,早泥盆世末正笔石类绝灭,树形笔石少数延续到早石 炭世绝灭,笔石类全部绝灭。

三、腕足动物(寒武纪到今天) 定向:(背上前下) 正视铰合向上,开口向下,上部为后,下部为前 侧视先背后腹 前视开口朝前,上背下腹 外壳构造——后部构造 内部构造:铰合构造,主突起,支腕构造(腕基,腕棒,腕带,腕螺)铰合构造: 腹:铰齿、牙板、匙形台(牙板相向延伸相连)、中板(匙形台下 的支撑构造)、 背:铰窝(牙槽)

古生物学复习整理加强版

古生物学基本理 一、化石:是指保存在各地史时期岩层中的生物遗体或遗迹。 二、化石的保存类型: (一)实体化石 指地史时期中保存下来的生物遗体,为生物遗体的全部或某一部分,多为骨骼部分 1、未变质实体(这类化石很少,只能在特定的情况下保存。他们一般没有经过明显的变化。如琥珀、干尸、细菌、猛犸象等) 2、变质实体(当生物被沉积物掩埋后,经过了明显变化(石化)才形成的化石) (二)模铸化石 指在岩层中保存下来的生物遗体的印模和铸型 1印痕化石(生物体印在岩层中的顶底层面上的痕迹,一般是扁平的生物或不太硬的生物所形成。如:树叶、笔石、水母等) 2印模化石(具凸凹壳的生物体印在围岩上的痕迹) (1)外模-生物体的外凸部分印在围岩上的凹形,相反地体现了生物壳外表的大小形态和纹饰。 (2)内膜-生物壳的凹面印在围岩上的痕迹,它相反地为凸形,反映了壳内表面的大小、形态和构造 3核化石(反映生物壳内外空间形态的整体,这样的复铸物称为核。) (1)外核-当生物壳体溶解后,外模使其填充物保持了壳体原来的外形,但他们没有内部构造,是实心体。 (2)内核-壳体内部的空腔被填充后的形态体。 4铸型化石(外内模之间的壳被溶解后,填充物又在原来的地方铸成了形态逼真的“壳”。这种“壳”没有壳的微细构造,但有内核或内模。) (三)遗迹化石 在地史时期的沉积物中所保存下来的生物活动时留下的遗迹或遗物。 如:足迹、爬迹、粪、卵、孔、穴、石器 (三)化学化石 古生物体中的有机质保存在地层中,但他经过了一定的分解才能保存到现在。 如:蛋白质分解后形成的氨基酸、脂肪酸、烃等。 三、古生物的命名法则(界、门、纲、目、科、属、种) 生物的命名就是给生物起名字。在国际上有统一的命名规则,其中最基本的规则有以下几方面内容: (一)生物分类的各个单位名称都采用拉丁文或拉丁化的文字来命名 (二)从门至科级分类单位的命名 都采用单名法名字,用正体字书写或印刷,第一字母大写 例如 Protozoa 原生动物门 Rhizopoda 根足虫纲 门、纲、目的名称没有固定的词尾。科级名称则有固定的词尾,它是由属于这个科的一个典型属名的词根加上一个固定的词尾-idae或-aceae构成的。

古生物学复习资料

化石是指保存在各地质历史时期岩层中的生物遗体或遗迹 化石的保存条件: (1)自身条件需要有能够保存下来的硬体,以矿质硬体为佳。软体不利于保存 (2)埋藏条件需要有利的环境,能迅速地将生物埋藏起来,并且不遭受其他因素(如地下水)破坏。 (3)时间因素需要一定的时间,使生物进行石化作用过程 (4)成岩作用的条件沉积物在固结成岩过程中的压实作用和结晶作用都会影响化石的保存条件石化作用即形成变质实体化石的地质作用,主要有如下三种类型: a充填作用生物硬体内部的各种空隙被地下水中的矿物质所充填的一种作用。能使硬体变得更加致密。 这种石化作用没有改变生物体原来的组织结构,但增加了重量和成分。如龙骨(中新生代脊椎动物化石)。 b交代作用(交替作用)生物硬体被埋藏后,不断被地下水所溶解,同时又被地下水所携带的矿物质所交代。这种石化作用保持了生物硬体的形态大小和结构构造(有时可以以分子进行交代,因此可以看清其细胞结构),但它改变了生物硬体的成分。 c升溜作用这些有机质中的易挥发成分(氧、氢、氮)在地下的高温高压作用下,往往被遗失掉,留下比较稳定的炭质形成薄膜。如: 植物的xx、笔石和某些节肢动物。 化石的保存类型 (1)实体化石古生物遗体本身(特别是硬体)保存下来的化石

①未变质实体这是在特殊条件下,避开了空气的氧化和细菌的腐蚀,原来的生物硬体和软体完整的保存下来成为岩石。 ②变质实体——生物遗体经不同程度的石化作用,全部硬体或部分硬体保存为化石。 (2)模铸化石生物遗体在岩层中留下的印模和铸型等总称 ①印痕化石生物体印在岩层中的顶底层面上的痕迹,一般是扁平的生物或不太硬的生物所形成。 ②印模化石具凸凹壳的生物体印在围岩上的痕迹 a.外模——生物体的外凸部分印在围岩上的凹形,相反地体现了生物壳外表的大小形态和纹饰。 b.内模——生物壳的凹面印在围岩上的痕迹,它相反地为凸形,反映了壳内表面的大小、形态和构造 c.复合模—内模和外模重叠在一起的化石 ③核化石反映生物壳内外空间形态的整体,这样的复铸物称为核。 外核——当生物壳体溶解后,外模使其填充物保持了壳体原来的外形,但它们没有内部构造,是实心体。 内核——壳体内部的空腔被填充后的形态体 ④铸型化石。外内模之间的壳被溶解后,填充物又在原来的地方铸成了形态逼真的“壳”。这种“壳”没有壳的微细构造,但有内核或内模特点: 铸型化石在大小、形态和表面装饰等方面与原生物体一致,但内部构造完全不同。 (3)遗迹化石在地史时期的沉积物中所保存下来的生物活动时留下的遗迹或遗物。 (4)化学化石古生物体中的有机质保存在地层中,但它经过了一定的分解才能保存到现在。

古生物学适合地大学子复习资料大全

古生物学是研究地史时期的生物及其发展的科学。以化石为对象,研究古生物的形态、构造、分类、生态、地理及地史分布和演化发展规律。(古生物学以化石为研究对象,是研究地质时代中的生物及其发展演化规律的科学。)化石:指保存在岩层中地质历史时期的生物遗体和遗迹。(具备生物特征:形状、结构、纹饰、有机化学成分、生活活动痕迹等。或者具有生命活动信息:生物遗迹、遗物、工具等。)假化石与化石相似,但与生命活动无关,主要是矿物集合体、泥裂、砾石、矿质结核、树枝状铁质沉积物等。如姜结石、龟背石、鹅卵石等。古生物的时间界限:距今大约1万年左右,即全新世以前 化石形成的条件:1.生物本身的条件1)生物硬体矿化硬体矿化程度 矿化组分比较稳定的是方解石、硅质化合物、磷酸钙等不太稳定的是霰石、含镁方解石2)有机质硬体如几丁质薄膜、角质层、木质物等2.生物死后的环境条件(即生物死后所处的外界环境条件):物理条件、化学条件、生物条3.埋藏条件:与埋藏的沉积特性质有关:圈闭较好的沉积物易于保存,如化学沉积物、生物成因的沉积物;一些特殊的沉积物还能保存生物软体部分,如松脂、冰川冻土等;具孔隙的沉积物中的古生物尸体易被破坏基底上的内栖生物,以及一些表栖生物也能破坏沉积物内的生物遗体。 4.时间条件 a 埋藏前的暴露时间 b 及时埋藏有利于形成化石 c 埋藏后不被再挖掘出来 d 石化作用时间 e 经过地质历史时间的成岩石化作用 f 短暂、近期内的生物埋藏不成为化石 5.成岩石化条件 a:埋藏的尸体与周围的沉积物一起,在漫长的地史成岩过程中,逐步石化,形成岩石的一个部分b:沉积物固结成岩过程中的压实作用、结晶、作用都会影响化石的石化作用和化石的保存石化作用:埋藏在沉积物中的生物体,在成岩作用中经过物理化学作用的改造而成为化石的过程。 化石的保存类型:a实体化石(全部生物遗体或部分生物遗体的化石) b模铸化石(印痕:生物软体在围岩上留下的印痕、印模:生物硬体在围岩表面上的印模、核:生物硬体所包围的内部空间或生物硬体溶解后形成的空间,被沉积物充填固结形成的化石、铸型:原壳体被全部溶解后,沉积物在原空间再次充填形成的化石)c遗迹化石(包括痕迹和遗物)保存在岩层中古代生物活动留下的痕迹和遗物d化学化石(分子化石)分解后的古生物有机组分残留在地层中形成的化石 化石的用途:a.确定和对比地层时代;b.阐明古地理、古气候;c.阐明某些沉积矿产的成因和分布 标准化石:地质历史时期中,演化迅速、生存时间短、数量多、平面分布广泛,能准确确定地层年代。 指相化石:能指示特定沉积环境的化石。 早期生物的发生和演化四大飞跃:

古生物地层学重点

古生物地层学重点 第一章生物界及其进化 1.什么是间断平衡论? 答:间断平衡论指物种的形成是由突变(间断)和渐变(平衡)的结合。进化有两种过程:成种作用,即大多数物种的形成是在地质上课忽略不计的段时间内完成的;线性渐变,即物种形成后在选择作用下十分缓慢的变异过程。其中成种作用是演化的主流。 2.物种的定义。 答:指互相繁殖的相同生物形成的自然群体,与其他相似群体在生殖上相互隔离,并在自然界占据一定的生态位。 3.趋同的定义。 答:是指不同祖先的生物类群,由于相似的生活方式,整体或部分形态构造向同一个方向改变。 4.趋异的定义。 答:是指在生物进化过程中,起源于同一始祖的生物,为适应不同的生态条件而发生分化,产生新的生物类群。 5.什么是特化? 答:特化是由一般到特殊的生物进化方式。指物种适应于某一独特的生活环境、形成局部器官过于发达的一种特异适应,是分化式进化的特殊情况。 第二章古生物学基础 1.什么是化石?化石的保存类型有哪几种?

答:化石是保存在岩层中的地质时期的生物的遗体和遗迹。【Time>1万年】其保存类型有实体化石、模铸化石、遗迹化石和化学化石。 2.化石形成的条件有哪些? 答:1 生物本身条件2生物死后的环境条件3埋藏条件4时间条件5成岩作用的条件 3.化石化作用过程可以分为哪几种形式? 答:①矿质充填作用②置换作用③碳化作用④重结晶作用。 4.解释双名法sp.cf.aff.sp.nov. 答:略 第三章原生生物界 1.“虫筳”繁盛于(晚石炭世)的温暖、清澈、盐度正常的(浅海)环境中,是该时期的标准化石。 2.“虫筳”的演化趋势及演化的阶段性。 答:演化趋势1.壳体由小变大2.壳形由短轴型的凸镜型、盘型演化为等轴型的球形和长轴型的纺锤型、圆柱型3.旋壁构造由简单到复杂4.隔壁褶皱增强,但也有不少进化种类的隔壁为平直的4.旋脊由发育变为细小以致消失,另一些则演变成拟旋脊5.通道由单一演变为复通道或列孔。 阶段性;早石炭晚期出现,晚石炭世繁盛,早中二叠是全盛时期,晚二叠世减少,二叠末绝灭。 3.“虫筳”的旋壁分层类型及其分层组合类型有哪些? 答:旋壁分层类型有原始层、致密层、透明层、疏松层和蜂巢层; 分层组合类型有一层式、二层式、三层式和四层式。

古生物学与地层学(含古人类学)

古生物学与地层学(含:古人类学) 攻读硕士学位研究生培养方案 一、培养目标 古生物学与地层学(含:古人类学)学科是地球科学领域中的基础学科,培养的硕士研究生应在德、智、体诸方面全面发展,具有创业精神和创新能力、从事科学研究、工程技术及管理的高级专门人才,以适应社会主义现代化建设的需要。具体要求如下: 1、努力学习马列主义、毛泽东思想和邓小平理论,拥护中国共产党,拥护社会主义,具有高度的精神文明和较高的综合素质,遵纪守法,品行端正,作风正派,服从组织分配,愿为社会主义经济建设服务。 2、在本门学科内掌握坚实的地质基础理论以及古生物学和地层学的系统理论知识和基本实验技能,了解本领域的研究动态,基本上能独立开展与本学科有关的科学研究和生产工作。掌握一门外国语,能熟练地进行专业阅读并能撰写论文摘要;具有从事本学科领域内科学研究、大学教学或独立担负专门技术工作的能力,具有较强的综合能力,包括创新能力、分析问题与解决问题的能力、语言表达能力及写作能力,具有实事求是,严谨的科学作风。 3、坚持体育锻炼,具有健康的体魄。 二、学习年限 硕士研究生的学习年限为2-3年,课程学习和学位论文的时间各占一半。 硕士生应在规定学习期限内完成培养计划要求的课程学习和学位论文工作。若提前完成培养计划,经院校学位委员会审查,学校批准,可进行论文答辩毕业,通过者获得理学硕士学位。 三、研究方向 根据新的形势和要求,结合本学科专业当前发展的方向,可设置出本学科、专业的研究方向3个。 1、油气区古生物学 2、勘探地层学与油气储层预测 3、油气区古生态学与沉积学 四、课程设置 课程设置包括学位课、选修课和实践课,课程总学分为34或以上。学位课为必修课,含公共课、专业基础课,学分不低于20学分;选修课不低于12学分;实践课为必修课,含专业实践、社会实践和教学实践,学分为2学分。 理科硕士生选修数学课程的总学分不少于5学分,其中学位课中数学课等于或大于2学分;外语课总学分为6学分,提倡加强更多的外语课,通过考试取得相应学分,但不计入34学分内。 (一)学位课六至八门(共21学分) (1)公共学位课3门,10学分 包括自然辩证法、科学社会主义理论与实践和第一外国语。 (2)专业学位课5门,11学分 本学科点的专业学位课包括数理统计与随机过程、地层学原理与方法、古生态学与古遗迹学、地质统计学和面向对象程序设计。 (二)选修课20门(38学分) 选修课由指导教师和研究生根据专业培养方案的要求,根据研究方向的需要,以及研究生原有的基础和特长,爱好共同确定,给研究生留有充分的自学时间和选修的灵活性,鼓励研究生跨学科、跨专业选修课程,至少2学分,以拓宽研究生知识面,培养他们的适应能力,但所选课程学分不低于12学分。 在导师指导下研究生应阅读60篇以上的中、外文文献资料,且外文资料比例应占三分之一以上,并做到有检查,有考核。

古生物地史学复习题1

古生物地史学复习题 答:地层是指具有某种共同特征或属性的岩石体,能以岩石界面或经研究后推论的某种解释界面与相邻岩层和岩体相区分。 4、小壳动物群(4分) 答:小壳动物群是指个体微小(1~2mm),具有外壳的多门类海生无脊椎动物,包括软舌螺、单板类、腹足类、腕足类等。 5、超覆和退覆(4分) 超覆是海进过程中地层形成向大陆方向的上超;退覆是在海退过程中地层向海洋方向的退却或下超。 一、填空题(每空0.5分,共10分) 1、古生物学的研究对象是化石 2、化石化作用是指埋藏在沉积物中的生物体在成岩作用中经过物理化学作用的改造而成为化石的过程。化石化作用可以分为矿质充填作用、臵换作用和炭化作用。 3、化石可以根据其保存特点,分为实体化石、模铸化石、遗迹化石和化学化石四类。 4、古生物学的研究意义在于:通过古生物学的研究,对了解生命的起源、生物进化、阐明生物界的发展史、充实生物进化理论、解决地层时代划分和对比、恢复古地理、古气候和指导找矿等方面具有十分重要的意义。 5、生物地层对比的理论依据是生物层序律。

6、豫西地区石炭系上统本溪组赋存的主要矿产资源是山西式铁矿和铝土矿,其中也赋存有陶瓷粘土矿。 7、豫西地区太华岩群中的沉积变质铁矿的工业类型是鞍山式铁矿,具有重要的工业意义。 8、板块边界的直接证据是地缝合线。沿地缝合线线断续分布有蛇绿岩套、混杂堆积、双变质带、深断裂等特殊的地质记录。 9、古生界自下而上可分为寒武系、自留系、泥盆系、石炭系、二叠系,均属年代地层单位。 10、根据四射珊瑚纵列构造、横列构造及轴部构造组合,从简单到复杂的演化过程可分为单带型、双带型、三带型和泡沫型四种构造类型。其中三带型四射珊瑚地史分布为自留纪至泥盆纪。 11、乳房贝 Acrothele,属无绞纲。壳近圆形或横阔卵形、腹壳隆突、呈近锥形、背壳缓突。壳面具同心状生长线和纹饰。地史分布为早中寒武世。 12、原蕨植物也称裸蕨植物植物,因其基轴裸露无叶而得名,又称无叶类。植物体矮小,高不足一米高,茎结构简单。二歧式分支,具假根、原生中柱,孢子囊大都顶生。地史分布为晚自留世至晚泥盆世。 三、判断题(每题0.5分,共10分) 1、采用现代化的手段和分析仪器,在侏罗纪地层中检测到有脂肪酸和氨基酸。但脂肪酸和氨基酸还不能称为化石。(×) 2、硅化木,硅化非常完全,抛光后十分好看,和玉石基本一样,不能称为化石(×)

最新古生物学重点

古生物学重点

无脊椎动物 蜓类 蜓类属原生动物门-有孔虫纲-蜓目-蜓超科,因其外形多为纺锤形,故也称之为纺锤虫,也可见透镜状或球状,大小一般为3厘米左右。 始于早石炭世晚期,早二叠世达于极盛,晚二叠世开始衰落,二叠纪末全部绝灭。是石炭、二叠纪的重要标准化石。生活于水深100米左右的热带或亚热带正常浅海环境,营底栖生活。壳体一般大小如麦粒,最小不到1厘米,最大可达20__30厘米以上。具多房室包旋壳,见上图。初房—最初的房室。房室—两隔壁之间的空间。隔壁—分割两隔壁的壳室。前壁—终室前方的壳壁。旋壁——蜓的外壳。轴切面—垂直壳壁生长方向的切面。旋切面—平行壳壁生长方。

珊瑚——四射珊瑚,横板珊瑚 一般特征:是腔肠动物门的珊瑚纲,腔肠动物门为真正的两胚层多细胞动物;体制为辐射对称;大部分为钙质骨骼,少量为角质骨骼;体型为水螅型;单体或者群体生活。是一种指相化石--浅海,全部为水螅世代,有外骨骼。珊瑚纲中主要的类别为四射珊瑚和横板珊瑚。珊瑚全属海生,是固着底栖动物,主要富集在温暖的浅海环境。 四射珊瑚的特征:四射珊瑚因其外壁表面常覆以生长皱纹,又称皱纹珊瑚;一级隔壁仅在4个部位生长,隔壁数一般为4的倍数。

横板珊瑚的特征:因隔壁发育微弱,横板特别发育而得名;个体无单体,全部为复体;隔壁不发育,一般呈刺状;无边缘构造和轴部构造;联接构造特别发育。 腕足动物 腕足动物是海生的底栖动物, 全为单体,有两瓣外壳,两壳不等大,大的一个叫腹壳,小的一个叫背壳,但每壳两侧对称。壳的后端具有供肉茎伸出的洞孔,使肉茎钻穴或固着于它物上。腕足动物大多数生活在温暖的浅海环境,大都营底栖固着生活。

古生物学复习资料

期末古生物学复习资料 1、古生物学:研究全新世以前的生物界及其发展的科学。 2、化石:保存在岩石中的古生物的遗体或遗迹,分为遗体化石和遗迹化石。 3、古生物:生活在距今一万年以上的生物,一万年以内是考古学和现代生物学研究的范畴。 4、标准化石:演化快、地理分布广泛、特征明显、数量丰富,易于识别的化石。 5、指相化石:形成化石的生物常只分布在某一特定的环境中,常能指示某种特定环境条件的化石。 6、试论述化石记录保存的不完备性: 化石的形成需要严格的形成条件和保存条件,从形成条件来说,生物化石的形成条件包括生物自身条件(最好有硬体)、埋藏条件(细粒碎屑物掩埋)、时间条件(迅速掩埋此后没有暴露,长期埋藏,长期石化)、成岩条件(经历一定程度、不很严重的压实和重结晶作用)。从保存条件说,生物遗体必须经过长期埋藏且此后未暴露,处于还原条件下,未经生活的动物吞食和微生物的破坏。因此,只有很少一部分生物死亡后能够形成化石,已经形成的化石又会经过自然界的地质作用(构造变形作用、风化作用等)的破坏,人类已经发掘的化石只占已经形成的化石的一小部分,未发掘的化石还在经历地质作用的破坏,所以化石记录保存是不完备的。 7、石化作用:使古生物遗体改造为化石的作用。 (1)充填作用:生物硬体的内部孔隙被地下水中的矿物质充填的一种石化作用。 使硬体致密坚硬,质量增加,保持硬体原来的特征。 (2)交代作用:生物硬体的成分被地下水溶失,随后被外来矿物质充填的一种石化作用。能保持原有的化石形态和结构,如硅化木。 (3)重结晶作用:组成生物硬体的矿物,在地热和地层压力的影响下,发生脱水、晶体变粗、晶格转化或离子析出而造成的一种石化作用,是最普遍进行的一种石化作用。 (4)升馏作用:生物硬体中的H、O、N等组分在地热的作用下挥发转移散失,只留下黑色炭质残余。这种化石通常为黑色,质软,易磨损。 8、生物进化的总趋势:生物体的结构和构造由简单到复杂,生物种类由少到多,生物类型由低等到高等,生物 的生活环境由海生到陆地到空中。 生物进化的证据:形态学证据、胚胎学证据、古生物学证据 9、物种的概念:能够自由相互交配并繁殖可育后代的一个自然生物居群,一般具有以下特点:有共同的起源、 有基本相同的形态、结构构造和生理特点、有相同的地理分布和生态特征,能够自由相互交配 并繁殖后代。物种是生物遗传和繁殖的基本单位。 10、物种形成的因素:遗传变异、自然选择、隔离。 11、海洋生物的生存方式:浮游、游泳、底栖(固着底栖、爬行底栖或移动底栖、底埋底栖、钻孔底栖)。 海洋环境因素对生物的影响:温度、盐度、光照、底质、气体 12、世代交替:有性世代(配子体-配子)和无性世代(合子-裂殖体)交替进行的现象。 13、双形现象:由于世代交替造成同一物种具有两种不同形态的现象。 14、壳饰:有孔虫壳面上有的光滑,有的具有网、肋、刺、条纹等纹饰,这些纹饰称为壳饰。 15、有孔虫多房室壳的种类:列式壳、平旋壳、螺旋壳、绕旋壳、混合壳 有孔虫壳的成分和细微构造:假几丁质壳、胶质壳、钙质微粒壳、钙质无孔壳、钙质多孔壳 16、蜓类的演化趋势:①壳体由小变大; ②壳型由短轴型,经等轴型到长轴型; ③旋壁由一层式经三层式发展到四层式或蜂巢式,再发展到具有副隔壁的蜂巢式旋壁; ④隔壁由平直到轻微褶皱到强烈褶皱,具拟旋脊蜓类的隔壁始终保持平直。 ⑤旋脊大到小最后消失,部分原始蜓类的旋脊发展为拟旋脊。 17、蜓类的地史分布:∈~Rec.,三个繁盛时期: ①C~P,内卷虫类和蜓类占优势,特别是蜓类,P出现玻璃质壳的轮虫类。 ②Mz,玻璃质壳轮虫类分化和发展的时期。K3是第二个繁盛期,螺旋壳大轮虫类为主, 出现底栖大有孔虫。 ③Cz,轮虫类占优势,与现代基本相同。

古生物学复习重点总结

⊙总论: 一、古生物学(概念)-研究地史时期生物界及其发展的科学。其范围应包括各个地史时期的地层中保存的一切与古生物有关的资料。 二、化石(概念):指保存在各地质时期岩层中的生物遗体和生命活动的痕迹。 三、化石的保存条件:1、生物的自身条件。需要有能够保存下来的硬体,以矿质硬体为佳。软体不利于保存。1)矿化组分:比较稳定的是方解石、硅质化合物、磷酸钙等。不太稳定的是霰石、含镁方解石。2)有机质硬体:如几丁质薄膜、角质层、木质物等。 2、生物死后的环境条件。(1)物理条件:如高能水动力条件下生物尸体易被破坏;(2)化学条件:如水体pH值小于7.8时,CaCO3易于溶解;氧化环境中有机质易腐烂;(3)生物条件:如食腐生物和细菌常破坏生物尸体。 3、埋藏条件。(1)需要有利的环境,能迅速地将生物埋藏起来,并且不遭受其他因素(如地下水)破坏。 (2)与埋藏的沉积物性质有关:圈闭较好的沉积物易于保存,如化学沉积物、生物成因的沉积物。 (3)一些特殊的沉积物还能保存生物软体部分,如松脂、冰川冻土等。 (4)具孔隙的沉积物中的古生物尸体易被破坏。 (5)基底上的内栖生物,以及一些表栖生物也能破坏沉积物内的生物遗体。

4、时间条件。1)埋藏前的暴露时间:及时埋藏有利于形成化石;埋藏后不被再挖掘出来。2)石化作用时间:需要一定的时间,使生物进行石化作用过程。3)经过地质历史时间的成岩石化作用。短暂、近期内的生物埋藏不成为化石。 5、成岩石化条件。埋藏的尸体与周围的沉积物一起,在漫长的地史成岩过程中,逐步石化,形成岩石的一个部分。石化作用:埋藏在沉积物中的生物体,在成岩作用中经过物理化学作用的改造而成为化石的过程。沉积物固结成岩过程中的压实作用和结晶作用都会影响化石的石化作用和化石的保存。 四、化石的保存类型:(一)实体化石(指地史时期中保存下来的生物遗体,为生物遗体的全部或某一部分,多为骨骼部分):1、未变质实体(这类化石很少,只能在特定的情况下保存。他们一般没有经过明显的变化。如琥珀、干尸、细菌、猛犸象等)。2、变质实体(当生物被沉积物掩埋后,经过了明显变化(石化)才形成的化石)。(二)模铸化石(指在岩层中保存下来的生物遗体的印模和铸型)。1、印痕(生物体印在岩层中的顶底层面上的痕迹,一般是扁平的生物或不太硬的生物所形成。如:树叶、笔石、水母等)。2、模:具凸凹壳的生物体印在围岩上的痕迹。(1)外模-生物体的外凸部分印在围岩上的凹形,相反地体现了生物壳外表的大小形态和纹饰。(2)内模-生物壳的凹面印在围岩上的痕迹,它相反地为凸形,反映了壳内表面的大小、形态和构造。3、核。反映生物壳内外空间形态的整体,这样的复铸物称为核。外核-当生物壳体溶解后,外模使其填充物保持了壳

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