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Chapter 13 Notes
Charles Darwin’s Theory of
Evolution by Natural Selection
• 5 year voyage on the HMS _________
• Naturalist who collected specimens and
studied varieties of plants and animals
• Theorized that the fittest (best adapted to
that environment) would survive and pass
on their genes
Evolution
• Biological _____________over time (due
to mutations)
• Some mutations are ________, some bad
• Observable (how we know it happened)
through extensive ___________record
• Natural selection is nature’s way of picking
the most ____________traits of a
_________ or species and allowing
individuals to pass these genes on
• Natural selection takes a _________time
but eventually produces a population
better suited to the environment
• Darwin noted that around the world,
similar species of animals had a few small
_________________that made them
better adapted to their individual
environment
• He theorized that these similar animals
came from one common
__________________and evolved to
better suit the individual environment
• Ex: Penicillin when introduced in WWII,
killed all bacteria. Gradually some
bacteria ____________and were not
killed. They reproduced and produced a
population of bacteria that are totally
______________to penicillin
Adaptations and Natural Selection
• _____________—adaptation of copying
the appearance of another species for
protection
• Ex: king snake and coral snake
• Camouflage—adaptation that allows organism to
blend into its _________________Ex: flounder
on ocean floor,
walking stick insects
• Both adaptations allow organism to escape
predators and survive to ________________
Artificial selection
• ____________chooses certain traits and
breeds for them
• Takes a very _____________time to
achieve results
• Ex: cat born with no tail—these accidental
offspring were bred to produce a new
breed of cat
Evidence for evolution
• _________________structures—similar
structures in different organisms suggest a
common ancestor
• _____________structures—different
structures with similar functions—suggest
evolutionary relationship is not close
Evidence for evolution (cont)
• _____________structures—body structures no
longer used Ex. Appendix, wings in flightless
birds
• ________________development—suggests
common ancestor—many embryos are very
similar in early development
• Genetic comparisons—using
_______________sequences to compare
relationships—the more the genetic code is
similar, the closer the relationship.