Thursday, Happy Dec. 1st!
• Please turn to page 357!
• Today’s opener is the EOC review
questions, #1-6
• Write the answers only…read slowly,
do your best!
Remember… BIO EOCT is in
NINE SCHOOL DAYS!!!
11.6 KEY CONCEPT
Evolution occurs in patterns!!
Evolution through natural selection is NOT random.
• Natural selection can have direction.
• The effects of natural selection add up over time.
evolution toward similar
traits in unrelated
species
Wings,
complex eyes,
etc.
evolution toward different traits in
closely related species
red fox
kit fox
ancestor
How do convergent and divergent evolution
illustrate the directional nature of natural
selection?
Species can shape each other over time.
2 or more species evolving together
evolutionary paths become connected
evolve in response to changes in each other
Both benefit from adaptations!!
Both respond to competitive
pressure from each other!!
Beneficial relationship!!!
Ant lives in Acacia
plant, protects plant
Competitive/evolutionary relationships!!
Species can become extinct

• elimination of a species
from Earth!!!
–
–
–
–
occur continuously at a very low rate
Same as speciation
affects a few species/small area
local changes in environment
– rare but much more
intense!!
– destroys many species at global level
– caused by catastrophic events??
– at least 5 mass extinctions in last 600 million years
– episodes of speciation occur
suddenly in geologic time
– followed by long periods of little
evo. change
•Diversification of one ancestral
species into many descendent
species
•Adapted to a wide range of
environments
Many species evolve from one species
during adaptive radiation.
– ancestral species
diversifies into
many descendent
species
– descendent
species
usually adapted
to
wide range of
environments
REVIEW SHEET from last
week…
DUE TOMORROW!
Also due:
Vocab Ch 11
Ch Review
Open-Notes Pop Quiz!