Chapter 1 - Taxonomy Flashcards
What is taxonomy?
A formal system for naming and classifying species based on common descent.
Taxonomy organizes animal diversity in a nested hierarchy of groups based on shared features.
What is systematics?
The broader science of classifying organisms based on studies of variation among populations revealing their evolutionary relationships.
Systematics accommodates various alternative taxonomic viewpoints.
Who designed the current system of classification?
Carolus Linnaeus.
Linnaeus published ‘Systema Naturae’ which used morphology for classification.
What are the problems of the original Linnaean system?
Original classification scheme was very limited and has been drastically altered.
The basic principle is still followed today, however.
What are the seven mandatory major taxonomic ranks?
- Kingdom
- Phylum
- Class
- Order
- Family
- Genus
- Species
Each major rank can be further subdivided into smaller levels of taxa.
What is binomial species nomenclature?
Linnaeus’s system for naming species consisting of two words, the genus and specific epithet.
The scientific name should be italicized or underlined if handwritten.
What is the biological species concept?
A species is a reproductive community of populations that occupy a specific niche in nature and are reproductively isolated from others.
Interbreeding is central to this concept.
How does morphology differ between classification and systematization?
In classification, taxonomists ask whether a species being classified contains the defining feature of a particular taxonomic class;
In systematics, taxonomists ask whether the characteristics of a species reject or confirm the hypothesis that it descends from the most recent common ancestor of a particular taxon
What does ‘homology’ refer to in phylogenetic analysis?
Character similarity resulting from common ancestry.
It is used to identify shared features inherited from a common ancestor.
What is a clade?
A unit of evolutionary common descent that includes an ancestral lineage and all its descendants.
Synapomorphy is a derived character shared by members of a clade.
What are the two currently popular theories of taxonomy?
- Evolutionary (traditional) taxonomy
- Phylogenetic systematics (cladistics)
Both are based on evolutionary principles but differ in application.
What is the major goal of systematics?
To infer the evolutionary tree or phylogeny that relates all extant and extinct species.
This is accomplished by identifying organismal features called characters.
What is the difference between monophyly, paraphyly, and polyphyly?
- Monophyly: Includes the most recent common ancestor and all descendants.
- Paraphyly: Includes the recent common ancestor and some but not all descendants.
- Polyphyly: Does not include the most recent common ancestor of all members.
These terms describe different types of taxonomic groups based on phylogenetic relationships.
What is DNA barcoding?
A technique for identifying species using standard gene sequences present in all animals.
It typically uses the mitochondrial gene cytochrome c oxidase subunit 1 to differentiate species.
What is the evolutionary species concept?
A definition of a species as a single lineage of ancestor-descendant populations maintaining identity from other lineages.
Proposed by George Gaylord Simpson in the 1940s.
What is character variation?
Variation among characters can be used to reconstruct phylogeny.
It determines which variant form of each character was present in the common ancestor.
What is a cladogram?
A branching diagram showing a nested hierarchy of clades.
It is not the same as a phylogenetic tree, which represents real lineages in evolutionary history.
What are the three domains of life proposed by Woese, Kandler, and Wheelis?
- Eucarya (all eukaryotes)
- Bacteria (true bacteria)
- Archaea (variant bacteria)
This classification is based on ribosomal RNA sequences.
