Download 5-1 Darwin`s Voyage

5-1 Darwin’s Voyage
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Notes
Name
What is evolution?
Evolution is a ________________ in a __________________ over time.
Ways evolution can occur:
1. Mutations
2. Adaptations
3. Natural selection
Mutations
1. _________________ changes because of a _______________ in the DNA code
2. may be ______________ or harmful
3. helpful mutations _______________ the species’ ability to survive
4. ______________________ mutations may decrease or have no effect on the
species ability to survive.
Adaptations
1. Adaptations are ______________ that help an organism __________________.
2. Example: ______________________________________
Natural Selection
1. The __________________ and ______________________ of the individuals in a
population that exhibit the traits that are ____________________ suited for their
environment.
2. A.K.A.: “Survival of the Fittest”
3. Concept originated with ____________________________________
Factors that influence the process of Natural Selection:
1. Overproduction
2. Competition
3. Variations
Overproduction
1. Producing more ___________________ than can _____________________
2. Example: Dandelions overproduce their seeds to assure that at least some seeds
will survive
Competition
1. Offspring must _________________ with each other to survive
2. Usually indirectly, example: turtles may fail to find enough to eat
Variations
1. There are small variations or ____________________ among members of the
same species
2. _____________________ increase the amount of variations
3. Makes certain individuals better __________________ to their environment
because of the helpful traits they possess
Over a long period of time, ______________________________ can lead to
_________________________.
Helpful variations gradually accumulate in a species, while unfavorable ones
_________________________.
Isolation
1. Occurs when some members of a species are ________________________ from
the rest of the species
2. A new species forms when individuals remain ____________________________
long enough to evolve new traits
3. Geographic isolation has occurred in the past because of
_____________________________________________