16 3 Beyond Darwinian Theory I Darwins Theory

16. 3 Beyond Darwinian Theory I. Darwin’s Theory Updated A. Discoveries since Darwin’s time in genetics have been added to his evolution theory of species. B. 1 st major advance was the rediscovery of Mendel’s laws of heredity C. Modern synthesis of evolutionary theory 1. Combined Darwin’s theory with fossils, anatomy, genetics, etc. 1

II. Studying Evolution at All Scales A. Microevolution 1. Refers to evolution as a change in the genes of populations. 2. Five processes than can affect microevolution. a. Natural Selection b. Migration – movement of individuals into, out of, or between populations c. Mate Choice – if mates are paired up randomly than a random assortment of genes will be passed 2 on

d. Mutation – can change the # & types of alleles e. Genetic Drift – random effects of everyday life can cause differences in gene frequencies B. Macroevolution 1. refers to the appearance of new species over time 2. There are six processes in which new species evolve a. Convergent evolution – environment strongly directs evolution of several species in different locations 3

b. Coevolution – Adaptations that species have for one another c. Adaptive Radiation – Over time species may split into two or more lines of descendants or lineages d. Extinction – Self explanatory e. Gradualism – many small changes that build up gradually over a long period of time f. Punctuated Equilibrium – species remain stable for long periods of time & then sudden environmental changes create new pressures 4

C. Speciation 1. the formation of new species as a result of evolution. 2. Can begin with the separation of populations of the same species. a. ex- two squirrel populations separated by the Rocky Mountains 5