BSC 314 Lecture Notes - Lecture 41: Carl Linnaeus, Tulip, Begonia
27 Jun 2018
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Modern Taxonomy Includes Phylogenetics
Systematics is the name for the branch of biology concerned with the study of the
kinds of organisms, their relationships to one another, and their evolutionary history.
Taxonomy, a term often used interchangeably with systematics, is the part of
systematics involved in the description, naming, and classification of organisms.
Phylogenetics, another part of systematics, is the study of the phylogeny or
evolutionary history of an organism or a group of organisms. Two underlying goals of
plant systematics, thus, are to:
Find, describe, give unique names to, and organize into categories the species of
plants of the world (a goal of taxonomy).
Organize plants and plant groups to reflect their evolutionary relatedness and
their descent from a common ancestor (a goal of phylogenetics).
Systematics today is a vigorous and exciting field that has been given great impetus by
the discoveries of molecular biologists, who now are describing organisms at their most
fundamental level—the DNA sequences of the cells—and providing the systematists
new data on which to base their phylogenetic trees. Phylogenetic trees are the graphic
representation of the evolutionary divergences of organisms that put together on the
same branches the organisms most closely related, with oldest ancestors near the
base, youngest descendants near the top. The trees obtained from the DNA sequences
basically trace the history of how the genes have changed through time.
Naming Plants
Biologists around the world use today a single method with standardized rules to name
plants and animals: the bionomial system of nomenclature.
The binomial system in use today gives a single name recognizable throughout the
world to each individual kind of organism. The scientific nameconsists of two parts (in
Latin): the name of the genus (plural: genera), plus the name of the particular species.
The system originated with Carl Linnaeus in the middle of the eighteenth century as a
shortcut to the cumbersome polynomial system then in use that required 12 word ‐
descriptions to be written as part of the name. In the binomial system, the scientific
name is italicized in print and the genus is capitalized, but the species is not.
Lay people often ridicule scientific names as unpronounceable atrocities, but these
same scoffers use many genera names with little complaint. Geranium,
chrysanthemum, aster, asparagus, primula, begonia, and rhododendron (as well as
hundreds of others) are not only common plant names, but genera names as well.
Other common names are recognizable as anglicized versions of such genera names
as: Pinus, Juniperus, Cyperus, Rosa, Hyacinthus, Tulipa, Lilium and others.
Scientific names are important because they are exact: one kind of plant, one name.
Common names vary from place to place and language to language, but scientific
names in Latin remain the same and are recognizable anywhere in the world.
Taxonomic hierarchy
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Systematics is the name for the branch of biology concerned with the study of the kinds of organisms, their relationships to one another, and their evolutionary history. Taxonomy, a term often used interchangeably with systematics, is the part of systematics involved in the description, naming, and classification of organisms. Phylogenetics, another part of systematics, is the study of the phylogeny or evolutionary history of an organism or a group of organisms. Two underlying goals of plant systematics, thus, are to: Find, describe, give unique names to, and organize into categories the species of plants of the world (a goal of taxonomy). Organize plants and plant groups to reflect their evolutionary relatedness and their descent from a common ancestor (a goal of phylogenetics). Phylogenetic trees are the graphic representation of the evolutionary divergences of organisms that put together on the same branches the organisms most closely related, with oldest ancestors near the base, youngest descendants near the top.
