BIO 306 — Systematic Biology: Lecture Note

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This is the complete lecture note for BIO 306 Systematic Biology. You can read it online below, open it in the full viewer, or download the PDF for offline study. It pairs with the course's video lectures, so you can read and watch together.

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AGE la-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS

AGE la-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS Course code: BIO 306 Course title: Systematic Biology Course credit load: 2 Units Series 1: Historical Foundations of Systematic Biology • Part 1.1: What is Systematic Biology? o Sub Part 1.1.1: Definition and scope of systematics o Sub Part 1.1.2: Relationship between systematics, taxonomy, and classification o Sub Part 1.1.3: Importance of systematics • Part 1.2: Pre-Linnaean Systematics o Sub Part 1.2.1: Ancient Greek and Roman contributions o Sub Part 1.2.2: Medieval and Renaissance developments o Sub Part 1.2.3: Immediate pre-Linnaean naturalists • Part 1.3: Linnaean Systematics o Sub Part 1.3.1: Linnaeus and the reform of classification o Sub Part 1.3.2: Sexual system and natural system o Sub Part 1.3.3: Linnaeus's lasting contributions • Part 1.4: Darwinian and Post-Darwinian Systematics o Sub Part 1.4.1: Impact of evolutionary theory on systematics o Sub Part 1.4.2: The New Systematics o Sub Part 1.4.3: Modern developments in systematics Introduction

AGE la-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS Systematics is the scientific study of the diversity of life and the relationships among organisms. It provides the framework for naming, describing, and classifying all known organisms. Understanding how systematic biology developed historically, from the natural philosophy of ancient Greece through Linnaeus's binomial system to modern molecular phylogenetics, is essential for appreciating how and why classification is practised the way it is today. This opening Series traces the history of systematic biology from pre-scientific classification through the three major eras: pre-Linnaean (before the mid-18th century), Linnaean (the period dominated by Linnaeus's methods), and Darwinian/post-Darwinian (from 1859 to the present). It establishes the conceptual and historical foundations on which all subsequent Series build. Series Learning Outcomes Upon completing this Series, you should be able to: • SLO 1.1 define systematics and distinguish it from taxonomy and classification (Linked to Part 1.1), • SLO 1.2 explain the importance of systematic biology in science and society (Linked to Part 1.1), • SLO 1.3 describe the contributions of pre-Linnaean naturalists to the development of systematic biology (Linked to Part 1.2), • SLO 1.4 describe Linnaeus's contributions to systematic biology and explain his sexual system and natural system (Linked to Part 1.3), • SLO 1.5 explain the impact of Darwinian evolutionary theory on systematics (Linked to Part 1.4), and • SLO 1.6 describe the New Systematics and modern developments in systematic biology (Linked to Part 1.4).

AGE la-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS 1.1 What is Systematic Biology? 1.1.1 Definition and scope of systematics Systematics is the scientific study of the diversity of living organisms and their evolutionary relationships. It encompasses three interrelated activities: describing the diversity of life (taxonomy); organising that diversity into a hierarchical classification; and inferring evolutionary relationships among organisms (phylogenetics). Systematics is the broadest of these three: it integrates taxonomy, nomenclature, and phylogenetics into a unified science. The scope of systematics includes: discovery and formal description of new species; identification of known specimens; construction of classifications that reflect evolutionary history; development and application of identification keys; curation of biological collections (herbaria, museums); study of patterns of biodiversity and biogeography; and provision of the nomenclatural framework that other biological sciences depend on. Every biological science from ecology to medicine ultimately depends on correctly identified and named organisms. Fill in the blank: ________ is the scientific study of the diversity of living organisms and their evolutionary relationships; it encompasses taxonomy, nomenclature, and phylogenetics as a unified science. 1.1.2 Relationship between systematics, taxonomy, and classification These terms are often used interchangeably but have distinct meanings. Taxonomy (from Greek taxis = arrangement, nomos = law) is the theoretical study of the principles, procedures, and rules underlying classification; it includes the practice of naming and describing organisms. Classification is the practical act of placing organisms into groups (taxa) based on their similarities or evolutionary relationships. Nomenclature is the system of rules for formally naming taxa. Systematics is the broader science that includes all three plus the study of evolutionary relationships and patterns of biological diversity. A systematist identifies and describes organisms (taxonomy), assigns them to named groups (classification), and interprets their

AGE la-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS evolutionary history (phylogenetics). In practice, the terms taxonomy and systematics are often used synonymously, though systematics carries a stronger implication of the study of evolutionary relationships. Fill in the blank: ________ is the practical act of placing organisms into named groups; taxonomy is the theoretical study of the principles and rules of classification; systematics is the broader science that includes both, plus the study of evolutionary relationships. 1.1.3 Importance of systematics Systematics underpins all of biology. Without correctly identified and named organisms, no biological experiment can be reliably repeated by other scientists, no medical treatment can be safely based on a specific organism, and no conservation programme can target the right species. Systematics also provides the only comprehensive inventory of biodiversity, essential for monitoring species loss, prioritising conservation, and assessing ecosystem function. Practical applications of systematics in Nigeria: identifying crop pests and the most effective biocontrol agents; correctly identifying medicinal plants (many Nigerian herbal medicines depend on specific plants that must be correctly identified to avoid toxic substitutions); identifying disease vectors (Anopheles mosquitoes, tsetse flies, blackflies causing river blindness); agricultural quarantine (identifying whether an intercepted pest is a known species or a new invasive); and support of traditional ecological knowledge systems that depend on reliable species names. Fill in the blank: Systematics underpins all of biology because without correctly ________ and named organisms, no biological experiment can be reliably repeated and no conservation programme can target the right species.

AGE la-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS Figure 1.1: Diagram illustrating the relationship among systematics, taxonomy, classification, nomenclature, and phylogenetics Pilot questions 1.1 1. Define systematics and state three activities it encompasses. 2. Distinguish between systematics, taxonomy, and classification. 3. State four practical applications of systematics in Nigeria. 4. Explain why systematics is described as underpinning all of biology. 5. Define nomenclature and explain its role within systematics.

AGE la-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS 1.2 Pre-Linnaean Systematics 1.2.1 Ancient Greek and Roman contributions The systematic study of organisms began with ancient Greek natural philosophers. Aristotle (384-322 BC) made the most significant early contribution: he classified approximately 500 animal species based on structural and functional similarities, dividing them into Enaima (animals with blood; vertebrates) and Anaima (animals without blood; invertebrates); he described developmental patterns, habitats, and behaviour. His classification was not hierarchical in the modern sense but demonstrated the principle of grouping organisms by shared characters. Theophrastus (371-287 BC), Aristotle's student and successor, applied similar methods to plants; he described approximately 500 plant species in Historia Plantarum and Causae Plantarum. He distinguished between trees, shrubs, undershrubs, and herbs (a classification still broadly useful today); he described plant morphology, ecology, and uses. Pliny the Elder (23-79 AD) compiled Naturalis Historia, a 37-volume encyclopaedia of natural history based largely on earlier sources; it was the primary reference for natural history in the Roman world. Fill in the blank: ________ (384-322 BC) classified approximately 500 animal species, dividing them into Enaima (blood-bearing animals) and Anaima (bloodless animals); he is regarded as the founder of zoology and the first systematic biologist. 1.2.2 Medieval and Renaissance developments During the medieval period in Europe, natural history largely stagnated; Latin translations of Aristotle and other classical texts were the main references. Islamic scholars, however, advanced botanical knowledge significantly: Ibn Sina (Avicenna; 980-1037) included descriptions of approximately 800 medicinal plants in his Canon of Medicine; Ibn al-Baitar (1197-1248) described over 1,400 plant species in Compendium on Simple Medicaments. Their work preserved and extended the Greek tradition through the medieval period. The Renaissance (14th to 17th centuries) stimulated renewed interest in natural history through the recovery of classical texts, the invention of printing, and increased exploration. German

AGE la-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS "Fathers of Botany": Otto Brunfels (1488-1534), Hieronymus Bock (1498-1554), and Leonhard Fuchs (1501-1566) produced illustrated herbals with first-hand plant observations; they began moving away from reliance on classical descriptions toward direct observation of specimens. Conrad Gessner (1516-1565) compiled Historia Animalium, an illustrated encyclopaedia covering all known animal groups. Fill in the blank: During the Renaissance, the German "Fathers of Botany" (Brunfels, Bock, and Fuchs) produced illustrated ________ based on first-hand plant observations, moving away from the classical tradition of relying on ancient descriptions. 1.2.3 Immediate pre-Linnaean naturalists Several naturalists in the late 16th and 17th centuries made critical advances immediately before Linnaeus. Andrea Cesalpino (1519-1603): the first to base plant classification on reproductive organs (fruits and seeds) rather than habit or use; he described approximately 1,500 plant species in De Plantis (1583). John Ray (1627-1705): English naturalist who introduced a more rigorous species concept based on common descent from

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