BIO153H5 Lecture Notes - Lecture 4: Dik-Dik, Neoteny, Sexual Maturity
Document Summary
Macroevolution = evolution at or above species level. Macroevolution means evolution on the grand scale, and it is mainly studied in the fossil record. It is contrasted with microevolution, the study of evolution over short time periods, such as that of a human lifetime or less. Microevolution therefore refers to changes in gene frequency within a population macroevolutionary events are more likely to take millions, probably tens of millions of years. Macroevolution refers to things like the trends in horse evolution described by simpson, and occurring over tens of millions of years, or the origin of major groups, or mass extinctions, or the. Speciation is the traditional dividing line between micro- and macroevolution. Changes in: size shape position association with other parts differentiation (complexity) Example: serially homologous elements -- repeated elements based on the same developmental plan (e. g. petals, ribs, vertebrae, body segments )
