Download 7-1 Evolution

AIM
What is
Evolution?
Evolutionary Theory
• Process of change
in species over a
long time
• They are
distinctly
different from
earlier forms
Proof of Evolution
• Fossils
provide clues
to the history
of earth’s
organisms
Proof of Evolution
• DNA Analysis
(Gel
Electrophoresis)
What did organisms evolve from?
Multi-cellular
Unicellular
How do organisms acquire new traits so
evolution can occur over many years?
• Crossing-over
during meiosis
when gametes
are formed
• Mutations in
gametes
(Sperm or egg)
Mutation in Gametes
• Base pair
sequence
change
• Change
passed on to
offspring
Leads to Variety
•Sexual Reproduction
(Crossover during meiosis)
•Mutations
Variation in Dogs
Variation in Ladybugs
Variation in Frogs
Variation in Finches
Passed to Offspring
• Mutations
passed to
offspring when
they occur in
gametes(sperm
or egg)
1.Which phrase best defines evolution?
1.an adaptation of an organism to its
environment
2.a sudden replacement of one community
by another
3.a geographic or reproductive isolation of
organisms
4.a process of change in organisms over a
period of time
2.Which two factors provide the genetic
basis for variation within a species?
1.asexual reproduction and geographic
isolation
2.mutations and sexual reproduction
3.competition and protein synthesis
4.constant gene frequency and
reproductive isolation
3.As a result of sexual reproduction,
an organism can pass a gene mutation
to its offspring if the mutation occurs in
1.a body cell
2.a gamete
3.liver tissue
4.white blood cells
Aim
What conditions are
important to evolution?
Force behind Evolution
• The interaction
between
individual
organisms and
the environment
Conditions Important to Evolution
•
•
•
•
•
Variation
(Differences)
Overproduction
Finite supply of
resources (limited)
Competition
Natural Selection
Variation
• New traits that
can lead to
evolution come
from normal
variation within
species
Overproduction
• Population of a
species remains
stable
• Turtle eggs
Struggle for Survival
• Finite Resources
(not enough)
• Competition among
individuals of a
species mean only
the most adapted to
the environment will
survive
Natural Selection
• Evolution is
controlled by
nature not people
• Organism that are
best adapted to an
environment will
survive
Selection by Environment
• The proportion of
individuals with
advantageous
traits will increase
• This change over
time is evolution
Fitness
• The member
that is better
fit will survive.
• Fitness-The
ability to
survive
Adaptation
• An inherited
characteristic
that increases
an organism’s
chance for
survival
Quills
Example-Adaptation
• Long tongue
lizard is better
adapted than a
lizard with a
short tongue.
Survival of the Fittest
• Individuals that
are better suited
to their
environment survive and
reproduce more
successfully
Natural Selection
• Survival of the
fittest is also
referred to as
Natural Selection
• Environment
changes first,
those best
adapted survive
Adaptations
• Beneficial traits
will be passed on
to offspring
(More frequency)
• Unfavorable
traits will be less
common
Favorable Traits
• Those best adapted
pass on favorable
adaptations to their
offspring
• Higher frequency of
favorable traits are
passed along to
offspring increasing
chances for survival of
the species
Camouflage
Things to Remember
• Individuals that
produce the most
offspring are the
best adapted to
the environment
1.In most populations, the
individuals that produce the
greatest number of offspring are
1.always the strongest
2.usually the best adapted
3.those that have only recessive
traits
4.those that are the most intelligent
2.According to modern evolutionary theory,
genes responsible for new traits that help a
species survive in a particular environment
will usually
1.not change in frequency
2.decrease gradually in frequency
3.decrease rapidly in frequency
4.increase in frequency
3.Even though the environment changes, a
population that occupies a given geographic area
will most likely continue to be found in this area
if the
1.variations in the population decrease over time
2.members of the population decrease in
number
3.members of the population exceed the carrying
capacity
4.population passes on those genes that result in
favorable adaptations
4. The kit fox and red fox species are closely related. The kit fox lives in the desert,
while the red fox inhabits forests. Ear size and fur color are two differences that can be
observed between the species. An illustration of these two species is shown below.
Which statement best explains how the differences between these two species came
about?
1.Different adaptations developed because the kit fox preferred hotter environments
than the red fox.
2.As the foxes adapted to different environments, differences in appearance evolved.
3.The foxes evolved differently to prevent overpopulation of the forest habitat.
4.The foxes evolved differently because their ancestors were trying to avoid
competition.
Aim
What affects the rate
of evolution among
organism?
Affects Rate of Evolution
• Environmental
Change
- More Environmental
change equals more
Evolution
- Less Environmental
change equals less
Evolution
Horseshoe crab
Affects Rate of Evolution
• Offspring
Produced
- The more you
produce the
quicker organism
evolves over time
Affects Rate of Evolution
• Time of Lifespan
Lifespan for
bacteria and
insects are short
so they evolve
quicker compared
to humans
• More life cycles