BI111 Chapter 17: BI111 Chapter 17 textbook notes
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Here closely related species live in widely separated locations: dispersal is the movement of organisms away from their place or origin; it can produce a disjunct distribution if a new population becomes established on the far side of the geographic barrier, vicariance is the fragmentation of a continuous geographic distribution by external factors, convergent or parallel evolution, the evolution of similar adaptations in distantly related organisms that occupy similar environment, convergence occurs between groups of organisms that are distantly related, while parallelism occurs between more closely related forms, adaptive radiation (diversification) a cluster of closely related species that are each adaptively specialized to a specific habitat or food source, anagenesis is the accumulation of changes in a lineage as it adapts to changing environments, cladogenesis the evolution of two or more descendant species from a common ancestor, gradualist hypothesis suggests that large changes result from slow, continuous accumulations of small changes over time.