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Chapter1
This document provides an overview of plant biology by discussing key topics such as the scientific method, plant classification, the three domains of life (Archaea, Bacteria, and Eukarya), and the five kingdoms (Monera, Protista, Fungi, Plantae, and Animalia). It describes the importance of plants for ecological services, human civilizations, and the challenges of sustaining biodiversity with a growing population.
Chapter1
- 1. About Plant Biology Chapter 1
- 2. Why Study PlantBiology? • Show interrelationships between plants and other fields of study • Prepare for careers in plant biology • Gain fundamental knowledge for upper division plant biology courses • Share expertise gained with nonbotanists
- 3. What is aPlant? • An organism that is green and photosynthetic • Additional characteristics – Cell wall composed of cellulose – Multicellular body – Can control water loss – Have strengthening tissues – Can reproduce by means of microscopic, drought-resistant spores
- 4. Ecologic Services • Sourcesof food, fabric, shelter, medicine • Produce atmospheric oxygen and organic nitrogen • Build new land • Inhibit erosion • Control atmospheric temperature • Decompose and cycle essential mineral nutrients
- 5. Importance of Plantsto Human Civilizations • Trees for lumber to make warships • Fuel to smelt metals, cure pottery, generate power and heat • Sources of wealth – spices • Sources of industrial products – Rubber – oil
- 6. Natural Plant Losses •Plant losses occurring at a faster rate than ever before • Factors include – Agriculture – Urbanization – Overgrazing – Pollution – Extinction
- 7. Environmental Laws • Describedin 1961 by plant biologist Barry Commoner • Laws becoming more true every day • Four “environmental laws” – Everything is connected to everything else. – Everything must go somewhere. – Nature knows best. – There is no such thing as a free lunch.
- 8. Scientific Method • Codefinedand promoted in 17th century by Rene Decartes and Francis Bacon • Steps involved in scientific method – Make observations – Ask questions – Make educated guesses about possible answers – Base predictions on the guesses – Devise ways to test predictions – Draw conclusions
- 9. Scientific Method • Hypothesis– “educated guess” based on observations and questioning • Predicted result occurs – hypothesis is most likely correct • Individuals using scientific method should be objective and unbiased
- 10. Scientific Method Original Hypothesis Devise method to Analyze results test hypothesis Results Results Results do not Results are so support support support original unexpected that hypothesis hypothesis but hypothesis but fall they do not suggest minor within range that support original refinements could be expected hypothesis and if original require a new hypothesis is hypothesis slightly modified Retest using Test new Test using minor hypotheses slightly modified refinements hypothesis of process
- 11. Studying Plants FromDifferent Perspectives • Plant genetics – study of plant heredity • Plant systematics – study of plant evolution and classification • Plant ecology – study of how the environment affects plant organisms • Plant anatomy – study of a plant’s internal structure • Plant morphology – study of how a plant develops from a single cell into its diverse tissues and organs
- 12. Study Plants fromTaxonomic Classification • Microbiology – study of bacteria • Mycology – study of fungi • Phycology – study of algae • Bryology – study of mosses
- 13. Interrelationships Among SeveralPlant Biology Disciplines Genes ENVIRONMENT Genetics METABOLISM Ecology Evolution Physiology Paleoecology Taxonomy & Systematics Biogeography PLANT TAXONOMIC GROUPS STRUCTURE Phycology Anatomy Microbiology DEVELOPMENT Morphology Mycology Bryology
- 14. Plant Classification • Taxonomy •Linnaean system – Easy to use – Based on idea that species never changed – Grouped organisms according to arbitrary similarities – Fails to meet needs of modern biologists
- 15. Linnaean Taxa Taxa Ending Kingdom Division -phyta Class -opsida Order -ales Family -aceae Genus No standard ending Species No standard ending
- 16. Plant Classification Whittaker’s FiveKingdoms • Developed in 1969 by Robert Whittaker • Each kingdom assumed to be monophyletic group of species • Molecular biology techniques – Cladistics – Show five kingdom system also does not recognize evolutionary groups
- 17. Whittaker’s Five Kingdoms Kingdom Description Included bacteria Monera Included molds, mildews, rusts, Fungi smuts, and mushrooms Included simple organisms, some Protista were photosynthetic, mostly aquatic organisms called algae Included more complex Plantae photosynthetic organisms that typically grew on land Included typically motile, Animalia multicellular, nonphotosynthetic organisms
- 18. Plant Classification Cladistics • Basedon evolutionary groups • Compare DNA base pair sequences of organisms to determine relatedness • Obtain percent similarity between organisms
- 19. Plant Classification • Clades– evolutionary groups • Cladogram = phylogenetic tree – Branching diagram – Emphasizes shared features from common ancestor – Future discoveries may require modifications of cladogram
- 20. Plant Classification • Domain – Neutral term – Groups of organisms as large or larger than a kingdom – Monophyletic • Three domains based on cladistics – Eukarya – Bacteria – Archaea
- 21. Domain Eukarya • Madeup of Whittaker’s plant, animal, and fungal kingdoms • Eukaryotic cells – Membrane-bounded organelles • Linear chromosomes • Protists – Not monophyletic – Controversy over where to place organisms
- 22. Domain Bacteria • Organismsoriginally were placed in Whittaker’s Kingdom Monera • Microscopic • Prokaryotic cells – No membrane-bounded organelles – Circular chromosome • Sexual reproduction unknown • Found in every habitat on Earth
- 23. Domain Bacteria Beneficial aspects •Decomposers • Some carry on photosynthesis – Cyanobacteria or blue-green algae • Nitrogen fixation – Convert inorganic N2 into ammonium for plant use – Cyanobacteria
- 24. Domain Bacteria Detrimental effects •Pathogens – cause diseases • Human diseases – Botulism, bubonic plague, cholera, syphilis, tetanus, tuberculosis • Plant diseases
- 25. Domain Archaea • Organismsoriginally were placed in Whittaker’s Kingdom Monera • Prokaryotic • Different cell structure and chemistry than organisms in Domain Bacteria
- 26. Domain Archaea Divided intothree groups based on habitat • Bacteria of sulfur-rich anaerobic hot springs and deep ocean hydrothermal vents • Bacteria of anaerobic swamps and termite intestines • Bacteria of extremely saline waters – Extreme halophiles – Photosynthetic – pigment bacteriorhodopsin
- 27. Three Domains Domain Cell Type Description Membrane bounded organelles, linear Eukarya Eukaryotic chromosomes Found in extreme environments, cell Archaea Prokaryotic structure and differ from members of Domain Bacteria Ordinary bacteria, found in every habitat Bacteria Prokaryotic on earth, play major role as decomposers
- 28. Kingdom Fungi • Eukaryoticcells • Typically microscopic and filamentous • Rigid cell wall made of chitin • Reproduce sexually in a variety of complex life cycles and spores • Widely distributed throughout world – mainly terrestrial
- 29. Kingdom Fungi Economic importance •Decomposers • Form associations with roots of plants • Important foods for animals and humans – Mushrooms, morels • Decomposing action of yeast – Flavored cheeses, leavened bread, alcoholic beverages
- 30. Kingdom Fungi Economic importance •Production of antibiotics – Penicillium • Pathogens – Invade both plant and animal tissue – Cause illnesses – Reduce crop yields
- 31. Kingdom Protista • Eukaryoticcells • Reproduce both sexually and asexually • Catch-all group – Photosynthetic organisms – algae – Nonphotosynthetic organisms – slime molds, foraminiferans, protozoans
- 32. Kingdom Protista Algae • Arrangements – Single cells, clusters, filaments, sheets, three- dimensional packets of cells • Photosynthetic • Float in uppermost layers of all oceans and lakes
- 33. Kingdom Protista • Phytoplankton – “grasses of the sea” – Microscopic algae – Form base of natural food chain – Produce 50% of all oxygen in atmosphere
- 34. Kingdom Plantae • Includedall organisms informally called plants • Bodies more complex than bacteria, fungi, or protists • Eukaryotic
- 35. Kingdom Plantae • Uniquebiochemical traits of plants – Cell walls composed of cellulose – Accumulate starch as carbohydrate storage product – Special types of chlorophylls and other pigments
- 36. Kingdom Plantae Ecologic andeconomic importance of plants • Form base of terrestrial food chains • Principal human crops • Provide building materials, clothing, cordage, medicines, and beverages
- 37. Challenge for 21Century st While the human population increases, the major challenge of retaining natural biological diversity and developing a sustainable use of the world’s forests, grasslands, and cropland remains. As you study plant biology, think of the ways that you can contribute to this challenge.