An Introduction to the Science of Botany

Chapter 1

TTU MS 43131

LEARNING OBJECTIVES

    Briefly describe the field of botany , and give short definitions of at least five subdisciplines of plant biology Summarize and discuss the features of plants and other organisms that distinguish them from nonliving things Distinguish among the six kingdoms and three domains , and give representative organisms for each Summarize the main steps in the endeavors scientific method , and explain how science differs from many other human

LEARNING OBJECTIVE 1

 Briefly describe the field of botany , and give short definitions of at least five subdisciplines of plant biology

KEY TERMS



BOTANY

The scientific study of plants; also called plant biology

Subdisciplines 1

 Plant molecular biology  Structures and functions of important biological molecules (proteins, nucleic acids)  Plant cell biology  Structures, functions, and life processes of plant cells

Subdisciplines 2

 Plant physiology  How plants function (photosynthesis, mineral nutrition)  Plant genetics  Plant heredity and variation

Subdisciplines 3

 Plant ecology  Interrelationships among plants, and between plants ands their environment

Overgrazing in Africa

p. 5

p. 7

LEARNING OBJECTIVE 2

 Summarize and discuss the features of plants and other organisms that distinguish them from nonliving things

KEY TERMS



PHOTOSYNTHESIS

 Biological process that includes capture of light energy and its transformation into chemical energy of organic molecules that are manufactured from carbon dioxide and water 

CELLULAR RESPIRATION

 Cellular process in which energy of organic molecules is released for biological work

KEY TERMS

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DEOXYRIBONUCLEIC ACID (DNA)

 A nucleic acid present in a cell ’ s chromosomes that contains genetic information

KEY TERMS

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EVOLUTION

 Cumulative genetic changes in a population of organisms from generation to generation 

NATURAL SELECTION

 Mechanism of evolution (Charles Darwin)  Tendency of organisms that have favorable adaptations to their environment to survive and become parents of next generation

Levels of Biological Organization

Atoms Hydrogen Oxygen Molecule Water Chloroplast Macromolecule Organelle Cell Epidermis Biosphere Ecosystem Community Population Organism Tissue Organ Fig. 1-3, p. 9

Characteristics of Living Things 1

 Organization  Plants and other organisms are highly organized with cells as their basic building blocks  Energy  Plants and other organisms take in and use energy

Plant Cells

Photosynthesis

Characteristics of Living Things 2

 Interaction with environment  Plants respond to stimuli in their environment  Plants undergo growth and development  Reproduction  Plants form new individuals by asexual reproduction or sexual

Root Growth and Gravity

Response to Stimuli

Germination

Asexual Reproduction

Characteristics of Living Things 3

 Heredity  DNA molecules transmit genetic information from one generation to the next in plants and other organisms  Evolution  Plants and other organisms evolve  Populations change or adapt environments to survive in changing

Adaptation

LEARNING OBJECTIVE 3

 Distinguish among the six kingdoms and three domains , and give representative organisms for each

KEY TERMS



SPECIES

 A group of organisms with similar structural and functional characteristics  In nature, they breed only with one another and have a close common ancestry

KEY TERMS

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KINGDOM

 A broad taxonomic category made up of related phyla; many biologists currently recognize six kingdoms of living organisms 

DOMAIN

 A taxonomic category that includes one or more kingdoms

Organisms are classified into a hierarchy

   The main categories of classification are:       Domains, Kingdoms, Phyla, Classes, Orders, Families,   Genera, and Species. (e.g. house, street, city, county, state, country, continent, planet)

King Phillip Came Over Fearing Green Snakes

Three-Domain Classification

 Archaea  Kingdom archaea  Bacteria  Kingdom bacteria  Eukarya  All other kingdoms

Euglena

Kingdoms and Domains

Six-Kingdom Classification 1

1. Archaea 2. Bacteria 3. Protista  protozoa, algae, water molds, slime molds

Six-Kingdom Classification 2

4. Fungi  molds, yeasts 5. Animalia 6. Plantae

Three Domains: Bacteria Archaea Six Kingdoms: Bacteria Archaea Protista Eukarya Plantae Animalia Fungi Prokaryotes (lack membrane-bound organelles); unicellular; most are heterotrophic (obtain food by eating other organisms), but some are photosynthetic or chemosynthetic Prokaryotes; unicellular; microscopic; most live in extreme environments; differ in biochemistry and in cell wall structure from bacteria Eukaryotes; mainly unicellular or simple multicellular; maybe heterotrophic or photosynthetic; include protozoa, algae, and slime molds Eukaryotes; multicellular; photosynthetic; life cycle with alternation of generations; cell walls of cellulose Eukaryotes; multicellular; heterotrophic; most move about by muscular contraction; nervous system coordinates responses to stimuli Eukaryotes; most multicellular; heterotrophic; absorb nutrients; do not photo synthesize; cell walls of chitin Fig. 1-11, p. 14

Classification (Binomial System)

LEARNING OBJECTIVE 4

 Summarize the main steps in the scientific method , and explain how science differs from many other human endeavors

KEY TERMS



HYPOTHESIS

 An educated guess (based on previous observations) that may be true and is testable by observation and experimentation 

THEORY

 A widely accepted explanation supported by a large body of observations and experiments

The Scientific Method 1

1. Recognize a problem  or an unanswered question 2. Develop a hypothesis  to explain the problem 3. Design and perform an experiment  to test the hypothesis

The Scientific Method 2

4. Analyze and interpret the data  to reach a conclusion 5. Share new knowledge  with the scientific community

Charles Darwin’s experiment with

stems detecting light. Charles Darwin published his results on a number of different scientific studies in addition to his works on evolution. Through experimentation, he discovered that the tip of a stem detects light. (a) If the tip is covered, the stem does not grow toward the light. (b) If uncovered, the tip bends in the direction of the light.

Forming and testing

hypotheses. The scientific method consists of observations that lead to a question. One or more hypotheses tentatively answer the question. Each hypothesis is then tested by experiments, which either support it or do not support it.

Based on experimentation, the hypothesis is either accepted or rejected.

Conservation Biology

 Extinction as a consequence of human activities  Loss of Plant and Animal habitats