BSAA Ch. 5 Basic Principles of Plant Science
5.1 Characteristics of Plant Life
Life is determined by certain characteristics.
1. Living things have a specific kind of organization:
 Chemical processes take place within living
things, make energy.
 Have the ability to maintain appropriate internal
environment
 They grow
 Ability to develop
 They reproduce
 Respond to environmental stimuli
 Made of cells
 They adapt to environmental change
2. Living things are made of basic organizational units
called cells.
a. Some are single celled, other are multicellular
i. Multicellular organisms are plants and
animals
ii. Made up of billions of cells
3. The chemical reactions that take place within cells
involve the transformation of energy into useful
forms.
a. These are critical for nutrition, growth and
development.
b. Metabolism = all the physical and chemical
processes involved in the life of a plant.
c. These processes are constantly occurring!
d. Homeostasis = ability of an organism to
regulate its internal environment
4. Living things Grow and Develop
a. Growth = increase in mass related to
enlargement of cells, or increase in number of
cells.
b. Development = change of an organism over time
5. Living things must be able to reproduce .
a. Sexual Reproduction :
i. uses specialized reproductive cells, the
sperm and egg
ii. These cells unite during fertilization and
eventually develop into a mature plant
b. Asexual Reproduction
i. No special cells
ii. A new plant forms from a part of a mother
plant
iii. Offspring is identical to the mother plant
6. Living things adapt to a stimuli
a. Stimuli = changes to the internal or external
environment of an organism
b. Stimuli produce responses from the living
things.
c. Examples:
i. Plants respond to the angle of light and
intensity of light
ii. Respond to gravity
7. Living things must also be able to evolve or change
as their environment changes.
a. Through evolution, organisms develop traits
that improve their ability to survive in a
particular environment.
5.2 Classification and Naming
Taxonomy = the branch of biology that deals with
identifying and naming organisms.
1. 1700’s Carl von Linne of Sweden first identified 2
kingdoms: planate and animalia.
2. 1969 Robert Whittaker proposed five kingdoms
a. Four of the five kingdoms consist of eukaryotes
page 82
i. Eukaryotes = cells that have a nucleus and
other membrane-bound organelles
ii. They are plantae, animalia, fungi (mold and
yeast) and Protista (protozoa, algae, water
molds and slime molds).
iii. The fifth kingdom is Prokaryotae (singlecelled bacteria and algae).
b. Taxonomic classification is based on the degree
to which organisms are related.
c. Dichotomous Key = a written set of choices that
leads to the name of a plant.
3. 7 major taxonomic groups: kingdom, division
(phylum), class, order, family, genus and species.
a. King Philip cried Oh for goodness sake!
b. Cultivated plants are often given additional
variety and cultivar names.
4. Plant Nomenclature
a. Plants may have multiple common names that
create confusion.
b. Nomenclature = the naming of organisms
c. System where plants have two names, a
scientific one and a common one.
d. The genus (scientific name) is written with a
capital letter and then underlined or italicized.
e. The specific common name is written in
lowercase.
f. Species = composed of organisms with
characteristic that distinguish them from other
groups in a genus. Can pass distinct
characteristics from one generation to the next.
(ex: dogs)
g. Genus= closely related organisms of one or
more species (ex: dogs and wolves)
h. Variety= cultivated plants within a species that
show a significant difference from other plants
in the species.
i. Cultivar= a cultivated plant with distinguishing
characteristics from other plants in a species but
does not transfer those characteristics to its
offspring.
5. Plant Classification by Life Cycle
a. A life cycle is the time required for a seed to
geminate, for the seedling to grow vegetatively
and for the plant to flower and produce viable
seed.
b. Three categories:
i. Annual: a plant that completes it life cycle
within one year, or one growing season.
ii. Biennial: A plant that normally requires two
growing seasons. In the first growing
season, the plant grows vegetative.
1. They then go dormant over the winter
and growth and seed production is
resumed the spring of the second
season.
iii. Perennial: A plant with a life cycle of more
than two growing seasons.
1. May be woody or herbaceous