Chapter 2 - Systematics Lecture PDF

CHAPTER 2: SYSTEMATICS & TAXONOMY NORILIE JANN A. BORJA President Ramon Magsaysay State University SYSTEMATICS 1 SYSTEMATICS Systematics is the study of diversification and relationships of life forms of extinct extant. Systematics is derived from the Latinized Gree...

CHAPTER 2: SYSTEMATICS & TAXONOMY NORILIE JANN A. BORJA President Ramon Magsaysay State University SYSTEMATICS 1 SYSTEMATICS Systematics is the study of diversification and relationships of life forms of extinct extant. Systematics is derived from the Latinized Greek word ‘systema’ applied to the system of classification developed by Linnaeus in the 4th edition of his historical book Systema Nature in 1735. Today’s systematics generally makes extensive use of molecular biology and computer Programs to study organisms. Both taxonomy and evolution= SYSTEMATICS 2 SYSTEMATICS The famous paleontologist George Gaylord Simpson defined systematics as the "scientific study of the kinds and diversity of organisms and of any and all relationships among them. “STUDY OF BIODIVERSITY” TWO MAJOR COMPONENTS 1.Taxonomy 2. Phylogenetics 3 TAXONOMY derived from the Greek taxis (“arrangement”) and nomos (“law”) A discipline of classifying organism into taxa Governs the practices of naming, describing, identifying and specimen preservation. CLASSIFICATION + NOMENCLATURE=TAXONOMY 4 TAXONOMY A field of biology and paleontology that concerns the naming of living (extant) and ancient (extinct) plants, animals, and other organisms. Carl Linnaeus in the 18th century 5  STAGES IN TAXONOMY 1. Alpha taxonomy- In this stage species are identified and characterized on the basis of gross morphological features. 2. Beta taxonomy- In this stage species are arranged from lower to higher categories, i.e., hierarchic system of classification. 3. Gamma taxonomy:- In this stage intraspecific differences and evolutionary history are studied. 6 PHYLOGENETICS the study of the evolutionary relationships among organisms tree-like diagrams branching diagrams that depict hypotheses of evolutionary relationships between extant and/or extinct organisms In 1837, Charles Darwin sketched one of the earliest known phylogenetic trees in a notebook, which was followed by another such tree in On the Origin of Species in 1859 7  PARTS OF A TREE Terminal taxa are connected by branches. The branches are the line segments that make up the tree. Branches come together at branching points called nodes. Each nodes represents a common ancestor shared by two or more terminal taxa. 8 PHYLOGENETICS On a phylogenetic tree, more closely related terminal taxa are connected by shallower nodes (i.e., nodes nearer to the tips of the tree) and more distantly related terminal taxa are connected by deeper nodes (i.e., nodes nearer to the base of the tree). Graphic style of phylogenetic trees 9 10 A circle-shaped phylogenetic tree that depicts relationships among the major groups of living organisms (blue = bacteria; green = Archaea; pink = eukaryotes) Trees with many terminal taxa 11  MAJOR DIFFERENCE BETWEEN TAXONOMY & SYSTEMATICS 1. Taxonomy is the most important branch of systematic and thus systematics is a broader area than taxonomy. 2. Taxonomy is concerned with nomenclature, description, classification and identification of a species, but systematics is important to provide layout for all those taxonomic functions. 3. Evolutionary history of a species is studied under systematics but not in taxonomy. 4. The environmental factors are directly related with systematics but in taxonomy it is indirectly related. 5. Taxonomy is subjected to change in course of time, but systematics is not changed if it was properly done. 12 NOMENCLATURE derived from the Latin words nomen (name) and cloture (to call). “TO CALL BY NAME” The role of nomenclature to provide labels for taxa at all levels in order to facilitate, communication among biologists. Common names are not authentic Linnaeus- the system of naming to each organism which is called binomial nomenclature in 1758. 1ST GENUS & 2ND SPECIES 13 IMPORTANT REQUISITE OF TAXA NAMES UNIQUENESS- name should be unique. UNIVERSALITY- name should be name all over the world. STABILITY- name should not be change. The International Code of Zoological Nomenclature-a set of rules for naming of animals and for resolution of nomenclature problems. 14 BINOMIAL NOMENCLATURE Combination of 2 names TRINOMIAL NOMENCLATURE Indian Lion – Panthera leo persica (Linn.) Trinomen is used to recognized a subspecies 15 Section Title 2 Subtitle 16 APPROCHES TO CLASSIFYING ORGANISM 17 The Three Domains of Life 18  Phylogeny refers to the evolutionary relationships between organisms. The Three Domain System, proposed by Carl Woese and others, is an evolutionary model of phylogeny based on differences in the sequences of nucleotides in the cell's ribosomal RNAs (rRNA), as well as the cell's membrane lipid structure and its sensitivity to antibiotics. 19  The Bacteria Bacteria (also known as eubacteria or "true bacteria") are prokaryotic cells that are common in human daily life, encounter many more times than the archaebacteria Bacteria include mycoplasmas, cyanobacteria, Gram-positive bacteria, and Gram-negative bacteria. 20  The Bacteria possess the following characteristics: a. Bacteria are prokaryotic cells. b. Like the Eukarya, they have membranes composed of unbranched fatty acid chains attached to glycerol by ester linkages (Figure 1.). c. Cell walls of Bacteria contains peptidoglycan. d. Bacteria are sensitive to traditional antibacterial antibiotics but are resistant to most antibiotics that affect Eukarya. e. Bacteria contain rRNA that is unique to the Figure 1. Bacteria as indicated by the presence molecular regions distinctly different from the rRNA of Archaea and Eukarya. 21  The Archaea The Archaea possess the following characteristics: a. Archaea are prokaryotic cells. b. Unlike the Bacteria and the Eukarya, the Archaea have membranes composed of branched hydrocarbon chains (many also containing rings within the hydrocarbon chains) attached to glycerol by ether linkages (Figure 1.). c. No peptidoglycan on cell wall. 22  The Archaea The Archaea possess the following characteristics: d. Archaea are not sensitive to some antibiotics that affect the Bacteria, but are sensitive to some antibiotics that affect the Eukarya. e. Archaea contains rRNA 23  The Eukarya a. Eukarya have eukaryotic cells. b. Like the Bacteria, they have membranes composed of unbranched fatty acid chains attached to glycerol by ester linkages. c. Not all Eukarya possess cells with a cell wall, but for those Eukarya having a cell wall, that wall contains no peptidoglycan. 24  The Eukarya d. Eukarya are resistant to traditional antibacterial antibiotics but are sensitive to most antibiotics that affect eukaryotic cells. e. Eukarya contain rRNA that is unique to the Eukarya as indicated by the presence molecular regions distinctly different from the rRNA of Archaea and Bacteria. 25 The Eukarya are subdivided into the following four kingdoms: 1. Protista Kingdom: Protista are simple, predominately unicellular eukaryotic organisms. Examples includes slime molds, euglenoids, algae, and protozoans. 26 The Eukarya are subdivided into the following four kingdoms: 2. Fungi Kingdom: Fungi are unicellular or multicellular organisms. The cells have cell walls but are not organized into tissues. They do not carry out photosynthesis and obtain nutrients through absorption. Examples include sac fungi, club fungi, yeasts, and molds. 27 The Eukarya are subdivided into the following four kingdoms: 3. Plantae Kingdom: Plants are multicellular organisms composed of eukaryotic cells. The cells are organized into tissues and have cell walls. They obtain nutrients by photosynthesis and absorption. Examples include mosses, ferns, conifers, and flowering plants. 28  The Eukarya are subdivided into the following four kingdoms: 4. Animalia Kingdom: -multicellular organisms -The cells are organized into tissues and lack cell walls. -They do not carry out photosynthesis and obtain nutrients primarily by ingestion. Examples include sponges, worms, insects, and vertebrates 29 THANK YOU !!! QUIZ ON NEXT MEETING 30