生物多样性分类的概念.docx

1、生物多样性 分类的概念生物多樣性 - 分類的概念何謂分類-把不同的印像及觀察組成類群-是學習的過程-由各組相似之物學習研究分類的原因-處理數量龐大的生物資料, 把資料有組織地區分成不同類別, 以便將來用作研究及參考。-替生物加上通用名詞, 有助於科學家們之間的交流及避免含糊, 也使人們更容昜查出關於某個別生物的資料。-分類能反映各組別中生物間的相似性質及進化上的關係。生物的分類這世上並無任何絕對正確的分類系統, 因為所有生物組成的是一個連續體, 分成類別只是純為方便人們研究和翻查資料用。其中有兩個較常用的系統:1. 人為分類系統 (Artificial System)- 利用易於察看的形態 (

2、Morphological) / 表現型 (Phenotypic) 之特徵。- 毋須根據種系發生的關係 (phylogenetic relationship) 方便使用2. 自然分類系統 (Natural System)- 現代基於假設的 (hypothetical) 種系發生的 (phylogenetic) 關係的分類階梯 (hierarchy) , 每個類別中的成員皆共同擁有相同的一個祖先 (ancestor) 。 假定的共同祖先的確定是基於同源的特徵 (homologous characters) , 這些特徵在起源、結構以及部位上均有著根本的相似性質, 不管它們在成體 (adult)

3、中起何種功能。The classification system is subject to change as new evidences appears.瑞典植物學家林奈 (Linnaeus) 1707-1778- 制訂了雙名系統的命名法 (Binomial System of Nomenclature) / 雙名法 (Binomial Nomenclature) 。- 每個生物的學名都有兩個拉丁文名部份, 在文章中往往以斜體字印刷或在書寫字體下加上分隔的橫線予以區別:例: ManHomo sapiens / Homo sapiens 第一部份是屬名 (第一個字母常用大楷), 第二部份為種

4、名 (全部字母以小楷寫)。林奈的生物分類階梯: 界 (Kingdom) 門 (Phylum) 綱 (Class) 目 (Order) 科 (Family) 屬 (Genus) 種 (Species)界 (Kingdom)-起初, 生物只被分類為植物及動物兩界-隨著這些數量龐大又多樣化的生物在形態上、生物化學上及生理上有更多的特徵被發現, 便需要有新的分類體制被採用。五界 (Five Kingdom)-由生態學家 Robert Whittaker 建議-是現代最受大部份生物學家接受的分類方法:i. 原核生物界 (Kingdom Monera)ii. 原生生物界 (Kingdom Protocti

5、sta)iii. 真菌界 (Kingdom Fungi)iv. 植物界 (Kingdom Plantae)v. 動物界 (Kingdom Animalia) 真菌界 動物界 植物界 原生生物界 原核生物界-而五界的進化關係 (Evolutionary relationship) 如下:種 (Species)-分類的最基本單。-種內的生物擁有結構 (structure) , 功能 (function), 及發展 (development) 上的相似性。-種內的生物能互相交配生產可以生育之後代, 而不能與別個種之生物於自然條件下交配繁殖出可生育之彼代。屬 (Genus)-把各個相近的種組成一屬。科

6、 (Family)-把各個相近似的屬組成一科。:如此類推地建成分類的階梯。 亞種 (Subspecies)-種是分類的基礎單位, 但不是常用中最小的單位。-壹些地理上分隔了的同種 (same species) 而不同生境 (habitat) 的不同種群 (populations) 常因隔離 (isolation) 而發展出某些貫的特徵把它們與同種中的其他種群有所區別。若這些不同的種群互相交配, 它們可產生有生育能力的下代, 可見它們都是屬於同一個種的。-我們稱呼這些擁有一貫而不同的特徵之各個種群為亞種 (Subspecies) 或變種 / 品種 (Varieties) 。-至於一些細小的生物如

7、細菌則稱為品系 / 菌株 (strain) 。在分類學上有兩個較界更大的範疇1. 原核生物 (Prokaryotes)- 缺少細胞核 (nucleus) , 只有無核膜的核質散佈區域。- 脫氧核糖核酸 DNA 並非存在於染色體內, 而是形成一環形DNA。- 細胞分裂時沒有紡綞體 (Spindle) 。- 鞭毛 (flagellum) 簡單 (如果存在) , 缺乏微管 (microtubules) 。- 70S 核糖體 (較小, ribosome) 。- 沒有被膜包圍的細胞器 (membrane-bounded organelles) 。例如: 內質網 (Endoplasmic reticulu

8、m) 粒線體 (Mitochondrion) 葉綠體 (Chloroplast) 溶菌體 (Lysosome)等等- 沒有大液泡 (vacuoles) 。- 細胞壁 (cell wall)由氨基酸和多糖組成 (成份因種類而不同) 。- 全屬於原核生物界 (Kingdom Monera) 。2. 真核生物 (Eukaryotes)- 有細胞核 (由雙核膜包圍, 內有核仁)。- DNA與蛋白質 (protein) 組成染色體 (chromosome) 置於細胞核內。 - 80S核糖體 (80S ribosomes), 較大, 可散佈於細胞質 (cytoplasm)中, 或附於內質網上。- 被膜包圍

9、的細胞器可能存在 (單膜或雙膜) 。- 包括其餘四個界中的生物。- 鞭毛有 “9+2” 排列的微管。- 其他特質請看細胞 一課3. 其他- 例如: 病毒 (virus) -不屬於原核生物、真核生物或五界中任何一類。 生物 病毒(?) 原核生物 真核生物 原核生物界 原生生物界 真菌界 植物界 動物界 Viruses are not included in the system since the body organization is completely different from other organisms and their origin and evolution had no

10、t yet been clarified.The Five Kingdom System of grouping organismsThe most widely accepted system in recent years is the Five Kingdom System. The five-kingdom classification in current use recognises the kingdoms Prokaryotae, Protoctista, Fungi, Plantae, and Animalia. Prokaryotes appeared about 3,50

11、0 million years ago and comprise a variety of organisms collectively known as bacteria. Eukaryotes include protoctists, fungi, plants and animals. They appeared about 2,000 million years ago, and probably evolved from prokaryotes.Phylogenetic Relationships of the Five KingdomsSix Kingdoms of classif

12、ication - The classification system is subject to change as new evidences appears:Most biologists accepted the five-kingdom classification system proposed by Whittaker until the later 1980s, when molecular work verified the presence of two very different groups of bacteria. As a result, it was propo

13、sed to separate Prokaryota into two kingdoms: Archaebacteria (they are able to survive in extreme conditions: halophiles salty, methanogens in sewage and swamp sediments and thermophiles hot and acidic) and Eubacteria (comprises all the other bacteria).Such a system is subject to changes in the futu

14、re, as viruses are not yet assigned to any of the kingdom.Dichotomous key (二叉式檢索表) - 基於外在 / 可觀察特徵例: 建構一簡單二叉式檢索表以確認以下的生物類別:1a 細胞有細胞壁21b 細胞沒有細胞壁32a 有維管組織 .Fern (蕨)2b 沒有維管組織.Algae (藻)3a 單細胞生物.Amoeba (變形蟲)3b 多細胞生物.Fish (魚)Way of using the dichotomous key:1a 2b Algae (藻)Exercises:1. To construct a dichot

15、omous key to identify the following types of organisms. Suggested Simple Dichotomous Key to the Above ClassificationCOLUMN ACOLUMN B1aFlowering61bNon-flowering22aSeed-bearingGymnosperm2bSeedless33aPlant body differentiated into stem, leaves or roots43bPlant body not differentiated into stem, leaves

16、or roots54aHave distinct stem and leaves but no true rootsMoss4bStem, leaves and true rootsFerns5aCellulose cell wall, chloroplast or other photosynthetic pigments presentAlgae5bNo cellulose cell wall and photosynthetic pigmentFungi6aOne cotyledon; floral parts in 3s; fibrous root system; parallel l

17、eaf venation; stem usually herbaceous and slenderMonocotyledons6bTwo cotyledons; floral parts in 4s or 5s; tap root system; net leaf venation; stem hard, woody with secondary thickeningDicotyledons植物界Kingdom Plantae:Kingdom界: 植物Divisions門: 苔蘚植物門 真蕨門 裸子植物 被子植物門 Classes綱: Moncotyledoneae Dicotyledonea

18、e 單子葉植物 雙子葉植物植物界中各門之比較(Comparison between different Divisions of Plants):Division 門Bryophyta (Mosses)苔蘚植物門Filicinophyta (Ferns)真蕨門Gymnosperm裸子植物Coniferophyta松柏門Angiospermophyta被子植物門細胞或組織的分化分化成為簡單的莖,葉及假根,並有繁殖構造有具纖管組織的根、莖和葉, 細小成心形的原葉體有具維管組織的根、莖和葉, 並有毬果及裸露的種子用於繁殖有具維管組織的根、莖和葉, 並有花及藏於果實的種子用於繁殖生境潮濕陰暗及冷涼的地

19、方具有足夠的濕度於繁殖時期以利受精的地方 (例如: 山邊的空曠地方)不同的陸上生境, 尤其於溫帶地區不同的陸上及水生生境例子Funaria葫蘆蘚Dryopteris filix鱗毛蕨Pinus sylvestris松(任何正確答案)Comparison of Class Monocotyledoneae and Class DicotyledoneaeMonocotyledoneae單子葉植物Dicotyledoneae雙子葉植物Embryo has one cotyledon胚胎一片子葉Embryo has two cotyledons胚胎二片子葉Narrow leaf with paral

20、lel venation平行葉脈Broad leaf with net-like venation網狀葉脈adventitious roots不定根tap root主根, lateral roots側根Scattered vascular bundles in stem莖部的維管束分散Ring of vascular bundles in stem 莖部環狀排列的維管束Flower parts usually in threes花瓣等常是三的倍數Flower parts usually in fours or fives花瓣等常是四或五的倍數e.g. Lilium - lily百合e.g Be

21、llis - daisy雛菊Kingdom Animalia:PhylumCnidariaPlatyhelminthesAnnelidaArthropodaMolluscaEchinodermataChordataSymmetryRadial symmetry輻射對稱Bilateral symmetry兩側對稱Bilateral symmetry兩側對稱Bilateral symmetry兩側對稱Bilateral symmetry兩側對稱Pentamerous (5-rayed) symmetry Bilateral symmetry兩側對稱Supportsome have chitinou

22、s exoskeleton (Perisarc) in Obelia nil-Coelomic fluid act as hydroskeletonChitinous exoskeleton with jointed appendages on body segmentsExternal dorsal shellMesodermal calcareous plates bearing spines as endoskeletonEndoskeleton with notochord or backboneunique / specific characteristics generally f

23、ound in the phylum - Diploblastic, non-segmented acoelomate- gut腸 (enteron) with one opening as both the mouth and anus同一出口作為口部及肛門- unique獨有 Nematocysts (sting cells / cnidocytes) in tentacles帶刺細胞的觸鬚 for defence and capturing food- polymorphism 多形態現象shown: sessile hydroid固著的螅體form and mobile medusoi

24、d form移動的水母體- flat dorsoventrally背腹地扁平- unsegmented worm- beginning of cephalization開始有頭部的形成- one opening serve as mouth and anus同一出口作為口部及肛門- cylindrical metamerically segmented body身體有分節現象covered by non-chitinous cuticle被一層薄而濕潤的非幾丁質角質層覆蓋- separated opening of mouth and anus口部與肛門之開口是分開-cephalization

25、 but may be not distinct in some members- may have chaetae in segments- Coelomic fluid act as hydroskeleton- Chitinous exoskeleton with jointed appendages on body segments- expanded haemocoel as main body cavity-body basically divided into head, thorax and abdomen (may be fused)- may have compound e

26、yes-separated mouth and anus- Growth in stages after moulting.- External dorsal shell - reduced coelom, blood (with haemocyanin) flow in haemocoel-soft body covered by a dorsal shell (calcareous)-body divided into head, visceral mass / visceral hump (covered by mantle inside mantle cavity) and muscu

27、lar foot-most have radula (but absent in bivalves)-most aquatic and have gills -separated mouth and anus- Mesodermal calcareous plates bearing spines as endoskeleton - with mouth and anus separated-unqiue water vascular system -water-filled coelomic tubes -with extension of tube feet -asexual regene

28、ration- Endoskeleton with notochord or backbone- presence of notochord in embryo-notochord replaced by vertebral column in adults of vertebrates-a single, dorsal and hollow nerve cord -separated mouth and anus-gill slits in embryoExample(s)Obelia藪枝螅 (Class Hydrozoa)Jellyfish 水母coral珊瑚, sea anemone 海

29、葵Planaria渦蟲 (Class Turbellaria)tapeworm 絛虫 Earthworm / Lumbricus (Class Oligochaeta)Superclass Crustacea: Palaemon (a common prawn)Mussel (Class Bivalvia)Starfish (Class Stelleroidea)fish, amphibian, reptile, bird and mammalClass Insecta:Chorthippus(a grasshopper)Habitat of the example(s)Marine海生/ shallow coastal waters淺岸Quiet fresh water stream, ponds and under stones恬靜淡水inside human body人體內Moist terrestrial soil habitats / damp earthFresh water / marineMarineMarineTerrestrial (e.g. grassland)4.2.9 Classification of arthropods CLASSIFICATION OF VERTEBRATES 生物學探究