LIFESCI 1 Lecture Notes - Lecture 11: Phylogenetic Tree, Phenotypic Plasticity, Reproductive Isolation
21 Jan 2015
School
Department
Course
Professor
Document Summary
Objectives: species definition, types of reproductive barriers, biogeography of speciation, 1. ) allopatry, 2. ) sympatry. To define species: defining species is very difficult, 3 species concepts (3 ways to define species, 1. ) Morphologic (phonetic) species concept evaluation of morphology/traits: 2. ) Phylogenetic species concept evaluation of phylogenetics: 3. ) Biological species concept: each of these species concepts has advantages and disadvantages, and the best would be to define species using all 3. Morphologic (phenetic) species concept: morphologic species concept: based on traditional concept of identifying species using morphological similarities, advantages, it is widely applicable living or extinct species. Sexual or asexual species: disadvantages, lack of consistency (depends on judgment of investigator) Examples: must judge whether this flower is dark purple or light purple: difficult to apply to organisms lacking measurable morphological characters. Some organisms we study lack traits that are easily measurable, especially microscopic organisms: problematic for species with sexual dimorphism.
