BIL 160 Lecture Notes - Lecture 6: Phyletic Gradualism, Phylogenetics, Surface Mining
28 Apr 2016
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Allopatric speciation: single population is divided into two by geographic barrier/ separation. Peripatric: new species arises at the edge of the range of the original population. (ex: not common, buckwheat grows on slab where there was strip mining) Parapatric: gradient of genetic (phenotypic) difference develops across a species range (continuously distributed across population), gradient of interbreeding. Sympatric: speciation occurs without physical separation, within the range of the ancestral population. Pace of evolution: if things happen rapidly, abrupt change in fossils. Phyletic gradualism: darwin, traditional view: big changes happen slowly, ex: fossils of horses. Most you can say is that they had a common ancestor. Genetic event happened= big change, don"t have to be in one generation (ex: hybridization polyploidy) Anagenesis (phyletic evolution: conversion of entire population to new form that is a new species. Cladogenesis (diversifying evolution: two new species from an ancestral species.
