- - AGRICULTURE CORE CURRICULUM - - (CLF7000) Advanced Core Area: PLANT AND SOIL SCIENCE (CLF7100) Unit Title: BOTANICAL CLASSIFICATION ____________________________________________________________________________ (CLF7101) Topic: PLANT Time Taught in Year(s) CLASSIFICATION 5 hours 3 and 4 ____________________________________________________________________________ Topic Objectives: Upon completion of this lesson the student will be able to: Learning Outcome #: (A-1) - Discuss the development of the "kingdom concept". (A-2) - Define the word taxonomy. (A-3) - List three bases by which plants can be classified (morphology, physiology, and evolution). (A-4) - Discuss three reasons for the current use of the modern system of plant classification. (e.g. language barriers, universal name, evolutionary relationships, similarities.) (A-5) - Define genus, species, and variety. (A-5) - Require students to collect ten common species in your area and memorize their generic names. (A-6) - Place the following terms in their correct descending order for plant classification: Kingdom, Division (Phylum), Class, Order, Family, Genus, Species, and Variety. (A-7) - List and discuss three applications the science of taxonomy has for the field of agriculture (e.g. plant, insect, and microorganism identification). Special Materials and Equipment: None References: T.E. Weier. et al., (1982). BOTANY. Hartman, H., Flocker, W., and Kofranek, A. PLANT SCIENCE, GROWTH DEVELOPMENT AND UTILIZATION OF CULTIVATED PLANTS. Evaluation: Quiz by instructor TOPIC PRESENTATION: PLANT CLASSIFICATION A. There are many ways to classify plants, and the value of any system depends on how the classification is to be used. 1. Plant identification has been an evolutionary process in itself, starting with simple names, and ending today in highly coded systems. 2. Any system that is used will have shortcomings. B. Taxonomy is the science dealing with describing, naming, and classifying plants and animals. C. In today's system of classification all living things are divided into groups called "taxa" (singular, "taxon"). D. The kingdom is the largest taxa. 1. All living things are divided into at least five kingdoms: the ANIMAL kingdom, the PLANT kingdom, the FUNGUS:, the PROTISTS and the MONERA. We will only consider the plant kingdom at this time. 2. Characteristics of plants. a. Most plants are stationary, animals are mobile. b. Most plants have the green pigment, chlorophyll, to synthesize their own food. They are called autotrophs. Animals rely on ready-made food, and are called heterotrophs. c. Plant cells are surrounded by rigid cell walls while animal cells lack walls. d. Many plants have unlimited growth and an indefinite number of parts while animal growth is limited. 3. There are exceptions to these stated differences. E. Plants can be classified by their morphology, physiology or evolution. 1. In the mid 1700's a Swedish physician named Carl Von Linnaeus revolutionized the field of plant and animal classification; by inventing called a binomial naming system. a. In the binomial system, each species of life has a genus name and a species name. ("binominal" means" two names.") b. His work earned him the title "father of taxonomy". c. He established groups on the basis of morphological similarities and differences. 2. Since Charles Darwin's book, ORIGIN OF SPECIES, which was published in 1859, most biologists have used the principles of evolution to classify plants. a. The idea is to group organisms on the basis of common ancestry. b. This task is simple in theory but difficult in practice. c. The task is difficult because most of the species that evolved into modern plants are now extinct. 3. Details of physiology (function) are also useful for plant classification. F. Biologists have several reasons for classifying plants. 1. Plant scientists all over the world know the plant by the same Latin name, called a binomial. a. This avoids confusion, as common names vary considerably. Example: The weed CONVOLVULUS ARVENSUS is known as morning glory in California and bindweed in the Midwest. 2. Language barriers are avoided since all names are in Latin. 3. Plant evolutionary similarities are stressed. G. Plant taxa (groups), form a nested series with the following order: Kingdom, Division (Phylum), Class, Order, Family, Genus, Species, Variety. 1. Categories from kingdom to family are called major taxa. 2. Categories below family are called minor taxa. 3. Horticulturalists are most concerned with minor taxa. a. The genus is a group in which the member plants have much in common morphologically. b. The members of a genus are somewhat capable of crossing among themselves and are absolutely incapable of crossing with plants of any other genus. c. A genus consists of smaller groups called species. d. The members of a species resemble one another more than they resemble other species. e. Throughout the world the genus and species names are written in Latin using the Roman alphabet. 1) The genus name is capitalized. 2) The species name is not capitalized. 3) Both are italicized. Examples: "PRUNUS PERSICA" (would be italicized) for peach.If italics are not available the names are underlined. f. The names are usually phonetic and, often give a clue to the plant's characteristics, or its native habitat. g. The genus and species names, together, make up the plant's binomial name. h. You can think of the genus name much as your last or family name. i. Then the species name is like your given name. j. A species can be broken down further into varieties. Examples: "Bartlett" pear, "Ranger" alfalfa, and "O'Henry" peach. k. A variety is a subdivision of a species with distinct morphological characters. 1) Botanical varieties are sufficiently different to warrant unique names to distinguish them from one another. 2) The variety is indicated by an extra name asset to the binomial. 3) For example. MEDICAGO SATIVA VAR. RANGER H. Taxonomy has applications in agriculture. 1. The examples we have used are of agricultural plants. 2. In the study of entomology (insects) the most common taxon used is the order. a. Once the order is determined, the family, genus, and species are easier to establish. Examples: the order Coleoptera contains beetles and weevils. The order Homoptera includes aphids and scales. b. The insects that make up an order, ususally have similar wings, and legs. 3. In microorganisms such as the fungi and bacteria, the binomial name is commonly used. Examples: Monilinia fructicola is the genus and species name of the fungus brown rot. Erwinia amylovora is the genus and species of the bacterium that causes fireblight in pears and apples. I. Knowledge of taxonomy may help the agriculture to: 1. To predict the cultural requirements of a plant. 2. Predict graft compatibilities. 3. Determine plants that can be used in hybridization work. 4. Find related plants that can be used in breeding crop plants that resists diseases and insects. __________________________________________________________ ACTIVITY: 1. Require students to collect, mount and preserve ten common plant species of your area. 2. Students will memorize their common name and binomial names. 3. Identify the taxonomic link between paris of species in their collection. 4. See also the Basic Core Lesson Plans, CLF225. __________________________________________________________ 6/21/90 sg #%&C