BIO120H1 Chapter Notes - Chapter 1: Carl Linnaeus, Botany, Speciation
ProfessorJean Jiang Nash
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Chapter 1: What is Evolution?
•Living things are well designed (not perfect as observed later) to live
•Paley’s example of the watch and its parts.
oGod made perfect creations that make a perfectly synchronous
•1859: Darwin’s book/theory introduced.
•Darwin NOT THE FIRST TO THINK OF EVOLUTION but first to
prove it with data.
Summary “Life on Earth evolved gradually beginning with one
primitive species—perhaps a self-replicating molecule—that
lived 3.5 billion years ago; it then branched out over time,
throwing off many new and diverse species; and the mechanism
of most but not all of evolutionary change is natural selection.”
oEvolution: species change due to change in DNA over millions
of years (starts as mutation). Theory can’t predict change, nor
the rate of change.
oGradualism: idea that change occurs over billions of
generations. Bacteria evolve fast due to short life span but
changes like reptiles to birds happen over many generations.
oSpeciation: Changes in genes so vast that two descendants’
groups can’t interbreed. Otherwise there would be only one
-each time one species splits into two, it doubles chances for
oCommon Ancestry: Common ancestors don’t look
dramatically different. Ex: ancestor of birds and dinosaurs
simply split to two descendant groups: one supporting flight and
other bipedal dinosaurs.
-Phylogenic trees grouped based on shared traits.
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