NATURAL SELECTION
A complete introductory biology content review
12 lessons | Darwin • Natural Selection • Evidence • Speciation •
Hardy-Weinberg • Geologic Time
Study smarter: explain each concept in your own words, give an example, and compare it with a related
concept. Then answer the practice questions without looking at the guide.
For introductory high school biology (approximately grades 9-10). Not a complete AP Biology course guide.
EVOLUTION & NATURAL SELECTION | CONTENT REVIEW 1
, Contents
01 Darwin and the HMS Beagle
02 Scientists who influenced Darwin
03 Natural selection and adaptation
04 Fossils and the fossil record
05 Structural and embryological evidence
06 Molecular evidence
07 Microevolution and macroevolution
08 Hardy-Weinberg equilibrium
09 Speciation and reproductive isolation
10 Evolutionary rates and family trees
11 Origin of life and the first cells
12 Geologic time scale
13 High-yield comparisons and formulas
14 Practice questions with answer key
15 Sources and study notes
01 | Darwin and the HMS Beagle
Charles Darwin was a naturalist who helped explain how populations change over generations through
natural selection. He traveled on HMS Beagle from 1831 to 1836 and published On the Origin of Species
in 1859.
• During the voyage, Darwin collected specimens and observed differences among organisms living in
different places.
• On the Galápagos Islands, different tortoise populations and mockingbirds helped raise questions
about variation and adaptation.
• Darwin collected finches too, but their importance became clearer through later scientific study; the
beaks of different species are associated with different food sources.
Exam focus: Adaptations emerge in populations across generations. Individual animals do not deliberately
develop needed traits during their lifetime.
EVOLUTION & NATURAL SELECTION | CONTENT REVIEW 2