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