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Evolution!
Biology Standard 7
What is Evolution?
• Change of an organism over time.
• Modern orgs descended from past orgs.
• Charles Darwin !
Simple to complex
organisms
Species
•Considered
separate species if they cannot
interbreed
•Same species create viable offspring
NO Dog-Cat
Babies!
YES Panda
Babies!
Darwin
• English!
• HMS Beagle in
1831-1836.
Collected
animal/plant
specimens.
• World was
biodiverse: many
diff. types of species.
Species He Saw
Species He Saw
Species He Saw
Charles
Darwin 1859
Modern descent: orgs
change in response to
environment.
Also Talked About…
• Evolution =
SLOW!
• If an org. has
traits that allow
them to survive
and reproduce,
they are fit
(Darwinian
fitness).
So… Am I
Fit??
Not Fit…Extinct!
Dodo
Not Fit…Extinct!
Passenger
Pigeon
Not Fit…Extinct!
Stellar Sea
Cow
Adaptation
• Trait that allow orgs to be better suited to
environment.
• Orgs cannot choose to adapt  naturally
through environmental pressures.
• Org adapts to environment  SURVIVES
(passes traits to offspring).
• Org. cannot adapt DIES!!
• Darwin termed this natural selection.