Taxonomy CA Plants Chapter 1 Plant Systematics & Evolution Flashcards
(32 cards)
What is a “plant”? In what two conceptual ways can the answer to this question be approached?
a) By the characteristics they possess. Historically, “plants” included those organisms that possess photosynthesis, cell walls, spores, and a more or less sedentary behavior. b) By the evolutionary history of life and to use that history to delimit the groups of life, including what we choose to call a “plant.”
What are the three major groups of life currently accepted?
Bacteria, Archaea, and Eukarya
Name and define the mechanism for the evolution of chloroplasts.
Endosymbiosis - by the engulfment of an ancestral photosynthetic bacterium (probably a cyanobacterium) by an ancestral eukaryotic cell, such that the photosynthetic bacterium continued to live and ultimately multiply inside the eukaryotic cell
Name some chlorophyllous organismal groups that have traditionally been called “plants” but that evolved or acquired chloroplasts independently.
euglenoids, dinoflagellates, and brown algae
Draw a simplified cladogram showing the relative relationships among the green plants (Chlorobionta/Viridiplantae), land plants (embryophytes), vascular plants (tracheophytes), seed plants (spermatophytes), gymnosperms, and angiosperms (flowering plants).
Angiosperms and Gymnosperms (collectively the Spermatophytes or seed plants) are closely related to Monilophytes. Lycophytes, Monilophytes, and Spermatophytes make up the Tracheophytes or vascular plants. Tracheophytes collectively with LIverworts, Mosses, and Hornworts make up the Embryophytes or land plants. Embryophytes with the Green Algae make up the Chlorobionta (Viridiplantae) or the green plants.
Why are land plants treated as equivalent to “plants” in this book?
Land plants make up a monophyletic group, whereas the photosynthetic eukaryotes as a whole are not monophyletic and, as a group, do not accurately reflect evolutionary history. And, practically, it is land plants that most people are talking about when they refer to “plants.”
List the many ways that plants are important, both in evolution of life on earth and in terms of direct benefits to humans.
Plants were in part responsible for the oxygenation of the earth’s atmosphere, a prerequisite to the evolution of most eukaryotes. Plants are also major primary producers on the land and in some aquatic systems. Thus, most animals are dependent on them. Plants are major components of many communities and ecosystems. Plants are of great direct benefit to people, for food, flavors (spices and herbs), beverages, building materials, fibers (cordage, clothing), numerous extracts, hallucinogens/euphorics, and medicines.
What is systematics and what is its primary emphasis?
A science that includes and encompasses traditional taxonomy, the description, identification, nomenclature, and

classifi cation of organisms, and that has as its primary goal the reconstruction of phylogeny, or evolutionary history, of life.
Define biological evolution, describing what is meant both by descent and by modification.
Descent with modification. Descent is the transfer of genetic material (enclosed within a cell, the unit of life) from parent(s) to offspring over time. Modification is a change in the genetic material that is transferred from parent(s) to offspring, such that the genetic material of the offspring is different from that of the parent(s).
What is a lineage?
A set of organisms interconnected through time and space by the transfer of genetic material from parents to offspring.
Name and define the units that undergo evolutionary change.
Populations and species. A population is a group of individuals of the same species that is usually geographically delimited and that typically have a significant amount of gene exchange. Species are groups of populations that are related to one another by various criteria and that have evolutionarily diverged from other such groups.
What are the two major mechanisms for evolutionary change?
Natural selection and genetic drift.
What is a functional feature that results in increased survival or reproduction called?
An adaptation.
Name and define the four components of taxonomy.
Description is the assignment of features or attributes to a taxon.
Identification is the process of associating an unknown taxon with a known one, or recognizing that the unknown is new to science and warrants formal description and naming.
Nomenclature is the formal naming of taxa according to some standardized system.
Classification is the arrangement of entities (in this case, taxa) into some type of order.
Define character and character state.
Characters are features. Two or more forms of a character are character states
Give one example of a character and character state from morphology or from some type of specialized data.
E.g., “leaf shape,” for which possible character states are “elliptic,” “lanceolate,” and “ovate.”
What is a dichotomous key? A couplet? A lead?
A dichotomous key is an identification device consisting of a series of two contrasting statements. Each statement is a lead; the pair of leads constitutes a couplet
What is a scientific name?
Formal names, which by convention are translated into the Latin language, determined by the International Code of Botanical Nomenclature.
Define binomial and indicate what each part of the binomial is called.
Species names, consisting of two names: a genus name and a specific epithet.
What is the difference between rank and taxon?
Ranks are hierarchical groupings, meaning that each rank is inclusive of all other ranks beneath it.
A taxon is a group of organisms typically treated at a given rank.
What is the plural of taxon?
Taxa.
Name the two main ways to classify organisms and describe how they differ.
Phenetic - based on overall similarity.
Phylogenetic - based on evolutionary history.
Define phylogeny and give the name of the branching diagram that represents phylogeny.
Phylogeny, the primary goal of systematics, refers to the evolutionary history of a group of organisms.
Phylogeny is commonly represented in the form of a cladogram (or phylogenetic tree), a branching diagram that conceptually represents the evolutionary pattern of descent
What does a split, from one lineage to two, represent?
Lineage divergence, the diversification of lineages from one common ancestor.
