BIOL 23 Lecture 6: Microtaxonomy

Microtaxonomy and Infraspecific Categories

• Microtaxonomy is a branch of taxonomy that focuses on the classification and categorization of organisms at the species level and below.
• It involves the study of subtle variations, morphological traits, genetic differences, and ecological adaptations among individuals or populations within a species.

History of Infraspecific Categories

• Carolus Linnaeus recognized varieties in 1751 and used the category frequently in his book Species Plantarum (1753).
• Christiaan Hendrik Persoon recognized subspecies in botany in his book Synopsis Plantarum (1805-1807).
• Friedrich Anton Wilhelm Miquel used the term "form" in 1843.
• Henry Bates recognized subspecies in zoology in 1861.

Infraspecific Ranks

• Subspecies: a category used in both botany and zoology to describe populations that are genetically distinct but can still interbreed.
• Variety: a category used in botany to describe plants with distinct morphological traits.
• Form: a category used in botany to describe minor variations in plant morphology.

Speciation

• Speciation is the process by which new species arise.
• There are four primary modes of speciation: allopatric, peripatric, parapatric, and sympatric.
• Allopatric speciation occurs when populations become geographically isolated, leading to genetic divergence and reproductive isolation.
• Peripatric speciation is a special case of allopatric speciation in which a small peripheral population becomes isolated and undergoes genetic drift.
• Parapatric speciation occurs when populations occupy adjacent but distinct habitats, leading to genetic divergence and reproductive isolation.
• Sympatric speciation occurs when new species evolve from a single ancestral species within the same geographic area without physical barriers to gene flow.

Examples of Infraspecific Categories

• Sovia lucasii: a species with a new subspecies, S. lucasii minor, found in the northeastern and eastern parts of the Sichuan Basin in China.
• Cautleya gracilis: a species with a new variety, C. gracilis var. hispida, which exhibits environmentally induced variation.

References

• Zhai et al. (2017): DNA barcoding-based sexual association of Sovia lucasii and S. lii (Lepidoptera: Hesperiidae), with description of a new subspecies.
• Aishwarya et al. (2021): Taxonomic revision of the genus Cautleya (Zingiberaceae) in India with a description of a new variety.
• Vinarski (2015): The Fate of Subspecies Category in Zoological Systematics.
• Stuessy (2009): Plant Taxonomy: The Systematic Evaluation of Comparative Data.

This quiz covers the basics of microtaxonomy, a branch of taxonomy that focuses on the classification of organisms at the species level, including the study of subtle variations and genetic differences.