The Classification of Plants and Other Organisms. Chapter 18

Transcription

1 The Classification of Plants and Other Organisms Chapter 18

2 LEARNING OBJECTIVE 1 Define taxonomy Explain why the assignment of a scientific name to each species is important for biologists

3 KEY TERMS TAXONOMY Science of describing, naming, and classifying organisms

4 Describing Plants

5 Scientific Names Biologists use scientific names to precisely identify organisms Each organism has only one scientific name Avoids confusion of many common names

6 LEARNING OBJECTIVE 2 Identify the biologist who originated the binomial system of nomenclature Describe the general scheme of the system

7 KEY TERMS BINOMIAL NOMENCLATURE System for giving each organism a two-word scientific name First used consistently by Carolus Linnaeus

8 Linnaeus

9 Binomial Nomenclature Species The basic unit of classification The scientific name of each species has two parts: generic name (genus) specific epithet

10 Tradescantia virginiana

11 Species and Subspecies

12 Gilia latiflora Gilia tenuiflora subsp. excellens subsp. davyi subsp. latiflora Fig. 18-4, p. 355

13 LEARNING OBJECTIVE 3 List and describe the hierarchical groupings of classification

14 Classification Hierarchical groups (most to least inclusive) domain kingdom phylum class order family genus species

15 Classification of Ginger

16 Domain Eukarya Kingdom Plantae 5 other kingdoms Phylum Anthophyta 9 other phyla Class Order Family Monocotyledones Zingiberales Zingiberaceae 1 other main class 18 other orders 4 other families (b) Each taxonomic level is more inclusive than the one below it. For example, the order Zingiberales consists of 5 families. The family Zingiberaceae contains 49 genera and a total of about 1300 species. Genus Zingiber (ginger genus) 48 other genera Fig. 18-5b, p. 356

17 A Dichotomous Key

18 Fig. 18-6a, p. 357

19 Fig. 18-6b, p. 357

20 LEARNING OBJECTIVE 4 Define systematics Describe the cladistic approach to systematics

21 KEY TERMS SYSTEMATICS Scientific study of the diversity of organisms and their natural (evolutionary) relationships A systematist seeks to reconstruct phylogeny

22 PHYLOGENY KEY TERMS Evolutionary history of a species or other taxonomic group MONOPHYLETIC Said of a group consisting of organisms that evolved from a common ancestor

23 KEY TERMS CLADISTICS Classification of organisms based on recency of common ancestry rather than degree of structural similarity

24 Cladistics Cladists emphasize phylogeny by focusing on when evolutionary lineages (lines of descent) divide into two branches Cladists develop cladograms

25 KEY TERMS CLADOGRAM A diagram that illustrates evolutionary relationships based on the principles of cladistics

26 Building a Cladogram

27 Characters TAXON VASCULAR TISSUES SEEDS FLOWERS Moss A A A Fern P A A Pine P P A Daisy P P P Fig (1), p. 358

28 Moss Fern Pine Daisy Node 1 Common ancestor with vascular tissues Common plant ancestor (a) All of the plant groups shown here except mosses have vascular Fig. 18-7a, p. 358

29 Moss Fern Pine Daisy Node 2 Node 1 Common ancestor with vascular tissues Common plant ancestor (b) Seeds are a shared character for all plant groups shown here except mosses and ferns. Fig. 18-7b, p. 358

30 Moss Fern Pine Daisy Node 3 Node 2 Common seedproducing ancestor Node 1 Common ancestor with vascular tissues Common plant ancestor (c) Of the plant groups shown here, only the daisy produces flowers. Fig. 18-7c, p. 358

31 LEARNING OBJECTIVE 5 List and briefly describe the three domains and six kingdoms recognized by many biologists

32 KEY TERMS DOMAIN BACTERIA Domain of metabolically diverse, unicellular, prokaryotic organisms

33 KEY TERMS DOMAIN ARCHAEA Domain of unicellular, prokaryotic organisms adapted to extreme conditions (such as very hot or very salty environments)

34 KEY TERMS DOMAIN EUKARYA Includes all eukaryotic organisms (protists, plants, fungi, and animals)

35 The Three Domains

36 Domain Bacteria Domain Archaea Domain Eukarya Common ancestor of all living organisms Fig. 18-9, p. 360

37 Six-Kingdom Classification Kingdom Bacteria (domain Bacteria) Kingdom Archaea (domain Archaea) Kingdom Protista (domain Eukarya) Kingdom Fungi (domain Eukarya) Kingdom Plantae (domain Eukarya) Kingdom Animalia (domain Eukarya)

38 The Six Kingdoms

39 Bacteria Archaea Protista Plantae Protista Animalia Fungi Common ancestor of all eukaryotes Common ancestor of all living organisms Fig. 18-8, p. 360

40 LEARNING OBJECTIVE 6 Summarize the scientific limitations of the kingdom Protista

41 KEY TERMS PARAPHYLETIC Said of a group consisting of a common ancestor and some, but not all, of its descendants

42 Kingdom Protista Ideally, all members of a kingdom should have a common ancestor Members of kingdom Protista are paraphyletic Some biologists think protists should not be grouped in a single kingdom

43 Animation: Constructing a Cladogram