Biology 197: Professor Choate Chapter 20; Evolution of Life II: The Emergence of a New Species: Vocabulary: - Microevolution: ​evolution on a small scale as it relates to allele frequencies in a population - Macroevolution: ​evolutionary changes that produce new species and groups of species - Species: ​a group of related organisms that share a distinctive attribute in nature - Speciation: ​the formation of a new species - Subspecies: ​when two or more groups of the same species display one or more traits that are only somewhat different - Ecotypes: ​subspecies name for bacteria - Species concept: ​a way of defining the concept of a species and/or providing an approach to distinguish one species from another - Lineage: ​a series of species that forms a line of descent - Reproductive isolating mechanisms: ​prevent interbreeding between different species - Cladogenesis: ​the splitting or diverging of a population into two or more species - Allopatric speciation: ​when a population is isolated from other populations by physical barriers and evolves into one or more species - Adaptive radiation: ​a single ancestral species has evolved into a wide variety of descendant species that differ in habitat, form, and behavior - Sympatric speciation: ​members of a species that are within the same range diverge in two or more different species even when there are no physical barriers - Polyploidy: ​genetic change that can cause immediate