BLG 316 Lecture Notes - Lecture 4: Species Complex, Dna Barcoding, Evolutionary Taxonomy
19 Apr 2019
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Exclusive - the smallest distinct grouping that share ancestry and descent. Typological concept - define species by fixed, essential features. Cryptic species - populations that appear same but are different species. Phenotypic plasticity - genes can be expressed differently under different circumstances. Biological concept - species as reproductive community of pop. Cannot be applied to all organisms (asexual reproduction) For example, tigers and lions can interbreed and produce reproductively viable progeny but are different species (hybrids) Evolutionary concept - species is single of ancestor dependent population. Species = smallest grouping that has gone under independent evolutionary change. Different from evolutionary because we are creating a phylogeny. Take mitochondrial dna, deeply shared sequence (standard gene present in all animals) Even closely related species there is a threshold for how similar their dna has to be to be considred a species. Homologous characters - similarities due to shared ancestry. Homologous structures similar morphology, embryology and anatomy etc dissimilar in their functions.
