An Introduction to the Science of Botany

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An Introduction to the Science of Botany

• Chapter 1

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TTU MS 43131
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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 scientific
  method, and explain how science differs from many
  other human endeavors

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LEARNING OBJECTIVE 1

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

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KEY TERMS

• BOTANY The scientific study of plants also
  called plant biology

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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

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Subdisciplines 2

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

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Subdisciplines 3

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

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Overgrazing in Africa
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p. 5
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p. 7
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LEARNING OBJECTIVE 2

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

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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

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KEY TERMS

• DEOXYRIBONUCLEIC ACID (DNA)
• A nucleic acid present in a cells chromosomes
  that contains genetic information

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KEY TERMS

• 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

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

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Plant Cells
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Photosynthesis
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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 or sexual
  reproduction

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Root Growth and Gravity
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Response to Stimuli
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Germination
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Asexual Reproduction
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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 to survive in
  changing environments

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Adaptation
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LEARNING OBJECTIVE 3

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

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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

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KEY TERMS

• 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

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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

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Three-Domain Classification

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

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Euglena
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Kingdoms and Domains
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Six-Kingdom Classification 1

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

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Six-Kingdom Classification 2

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

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Three Domains
Archaea
Eukarya
Bacteria
Six Kingdoms
Protista
Bacteria
Archaea
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 multicellular heterotrophic most
move about by muscular contraction nervous
system coordinates responses to stimuli
Eukaryotes most multicellular heterotrophic abs
orb nutrients do not photo-synthesize cell
walls of chitin
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
Fig. 1-11, p. 14
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Classification (Binomial System)
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LEARNING OBJECTIVE 4

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

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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

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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

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The Scientific Method 2

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

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Charles Darwins 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.
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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.
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Conservation Biology

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