BISC208 Chapter Notes - Chapter 25: Adaptive Radiation, Antimicrobial Resistance, Macroevolution
19 Jun 2017
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Document Summary
Evolution that occurs at the population level such as the evolution of antibiotic resistance is referred to by some biologists as microevolution. Macroevolution events often occur over millions of years. Biologists use two major analytical tools to reconstruct the history of life: phylogenetic trees, fossil record. Once diverged both species continue to evolve not just one or the other. Number of nodes on a tree is not useful for deciphering relationships because the number of nodes depends on the number of taxa that are included. Relationships depicted in phylogenetic trees must be estimated from the best available data. First step in inferring evolutionary relationships is to decide which populations, species, or higher taxa to compare and which characteristics to use. Only fossil record provides direct evidence about what organisms that lived in the past looked like, where they lived and when they existed.
