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The Species in Conservation
Taxonomy- the science of classification
Why define species?
Species are the focus of legislation:
Endangered Species Act (ESA)
Convention on International Trade in Endangered Species (CITES)
Species Concepts Are Vague
• a species is difficult to define biologically
• The biological world is a continuum of organization…What exactly is an individual?
Typological -vs- Populational Perspectives
• Typological- categorical entities; morphologically distinct; immutable creations
• Populational- focuses on variation within species as a basis of evolutionary change
Biological Species Concept
groups of actually or potentially interbreeding populations that are reproductively isolated from other such populations
Phylogenetic Species Concept
• based on shared derived characters (synapomorphies)
• Cladistics- phylogenetic systematics
• would result in the recognition of more species than at present and perhaps greater recognition of populational diversity.
Evolutionary Species Concept
a single lineage of ancestral descendant populations of organisms that maintain an identity distinct from other such lineages
Ecological Species Concept
• …a lineage that occupies an adaptive zone different from that of other lineages.
Implications of Species Concepts on Conservation
The critical evolutionary and ecologically functional unit is the population.
Semi-isolated populations may play different functional roles in different systems.
A species level focus does not address habitat and ecosystem loss.
Wilson, E.O. 1992. The diversity of life. Harvard University Press.
A species is a population whose members are able to interbreed freely under natural conditions.
Subspecies are individuals occupying a particular part of the species range, with genes and natural history distinct from those of other subspecies