Transcript Theories of Evolution

Theories of
Evolution
Headings
Vocabulary
Important Info
• Trace the history of the theory of
evolution.
• Explain how fossil and biochemical
evidence support the theory.
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Beetle
Theories of Evolution
• Evolution: a change
over time
• 1809: Jean Baptiste
Lamarck proposed 1st
evolutionary theory
• “Inheritance of
Acquired
Characteristics”
• Ex: Giraffes’ long
necks result from
stretching to eat
leaves; this change is
passed to offspring
Charles Darwin: Origin of Species
• Charles Darwin sailed
around the coast of S.
America on the HMS Beagle
as a naturalist
• He noticed that species on
the island resembled those
on the mainland
• Yet they were adapted to
their environment
• Species change through
time
• But why?
About Darwin
Theory of Natural Selection
• Those with helpful differences are more
likely to survive and reproduce
• Reproduction allows passing on of traits
(DNA)
• Vast #s of offspring are produced; those
with the “best” traits reproduce more
often: “Survival of the Fittest”
• Over time; the “best”* DNA will be
present in most of the population
• This process takes a LONG time…..millions
of years
Natural Selection is NOT…
Evidence for Evolution: Adaptations
• Structural Adaptations:
thorns on roses; quills
• Evolution of Antibiotic
Resistance: Experiments
show that evolution has
occurred within
populations of
antibiotic-resistant
bacteria
Ex: Tuberculosis
bacteria
• Mimicry: a
nonpoisonous
species looks
like a
poisonous one
• Camouflage:
organisms
blend into
the
environment
Evidence for Evolution:
Fossils
• Fossil record allows us to see how
organisms have changed through
time
• Ex: evolution of the horse
Why did the
change in horse
foot structure
occur over
time?
What was
different?
Evidence for Evolution: Anatomy
Evidence of Common
Ancestry!
• Homologous
Structures:
similar in
structure and
function
• Ex: whale; bird
and human
forelimbs have
same bones in
the same
arrangement
Evidence for Evolution: Embryology
• Most embryos are very similar in
appearance; even from radically different
species
Common
Ancestry?