BISC 102 Study Guide - Final Guide: Consanguinity, Radula, Incisor
1 Nov 2020
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Document Summary
The root of the tree represents the ancestral lineage, and the tips of the branches represent the descendants of that ancestor. As you move from the root to the tips, you are moving forward in time. When a lineage splits (speciation), it is represented as branching on a phylogeny. When a speciation event occurs, a single ancestral lineage gives rise to two or more daughter lineages. Similarly, each lineage has ancestors that are unique to that lineage and ancestors that are shared with other lineages. Formations occur in proterozoic rocks, ranging in age from 1. 8 to 2. 5 billion years old. They are composed of alternating layers of iron-rich material (commonly magnetite) and silica. Each layer is relatively thin, varying in thickness from a millimeter or so up to several centimeters. The grey layer are iron oxides, consisting mostly of magnetite (can be detected because it is magnetic) and hematite.
