Download Darwin`s Theory of Natural Selection Date:2-4

Darwin’s Theory of
Natural Selection
EQ: How does evolution occur?
Date:1-27-16 Spiral pg.
What important observations
did Darwin make on his
voyage?
What is a theory?
How does Natural Selection
work?
Darwin’s Observations
►
Darwin made many observations as he
sailed the HMS Beagle to the Galapagos
Islands:
 Diversity of living things
 Fossil bones of animals that died
long ago
►A fossil is the preserved
remains or traces of an
organism that lived in the
past.
 Adaptations, a trait that helps
an organism survive and
reproduce in its environment
Examples: Bird Beaks
Natural Selection
► Darwin
proposed that evolution occurs
through a mechanism called Natural
Selection.
 Natural Selection, individuals that are
better adapted to their environment are
more likely to survive and reproduce than
other members of the same species
Evolution
► Darwin’s
Reasoning:
 Darwin’s ideas are referred to as the theory
of Evolution
 Evolution, the gradual change in a species
over time
 A Scientific Theory is a well-tested concept
that explains a wide range of observations.
Factors of Natural Selection
Factors of Natural Selection
1.
Overproduction:
organisms produce more offspring
than will survive. EX: sea turtles & insects
2. Variations:
differences among individuals.
3. Competition: organisms compete for resources.
4. Selection: those organisms with the best adaptations will
survive and reproduce.
Evolution
► Selective
Breeding: The
process of modification of a
species through human
actions which encourage
the breeding of certain traits
over others
Examples:
Dogs
.
Complete on p. 110 in your
notebook
Make a
Flow Chart
To demonstrate
The factors of
Natural Selection
Over Production
Variations
Competition
Selection
Survival and Reproduction