Download Chapters 15 and 16

Chapters 15 and
16
•Change over time
is known as…
Evolution
• The individual who
contributed significantly to
our understanding of
evolution was…
Charles Darwin
• Shortly after completing his
college studies, Darwin
joined the crew of the
ship…
H.M.S Beagle
•The remains of ancient
organisms are known
as…
Fossils
• Of all the Beagle’s ports of call,
the one that influenced
Darwin the most was a group
of small islands 1000 km west
of South America known as…
Galapagos Islands
• What question did Darwin
ask himself about fossils?
• Why had so many of the
species disappeared?
• How were they related to
living species?
• What detail confounded
Darwin about the
characteristics he had
observed in the many plants
and animals?
How they varied so noticeably from
one island to another
•Hutton and Lyell
helped scientists to
recognize that the
Earth…
Is millions of years old
..
•And that the
processes that
changed the earth
then…
Are the same ones that operate today.
•What is GEOLOGY?
The study of rocks and rock formations
• Darwin’s understanding of
geology, thanks to his friend
Charles Lyell, influenced him in
two ways. One was, “ If the
Earth could change over time…
Might LIFE change as well?
• Lamarck proposed that all organisms
have an innate tendency toward
complexity and perfection.
• Do you agree or disagree and why?
• Malthus reasoned that if
human population continued
to grow unchecked, sooner or
later, what would happen?
There would be insufficient living
space and food.
•Was he right? Explain…
•In ………… ……………..,
nature provided the
variation and humans
selected those variations
that they found useful.
Artificial selection
• Darwin realized that high birth
rates and a shortage of life’s
basic needs would eventually
force organisms into a
competition for resources.
This is known as…
Struggle for existence
•The ability to survive
AND reproduce in a
specific environment is
called…
Fitness
•Any inherited
characteristic that
increases an organism’s
chance of survival is
known as…
Adaptation
• Individuals that are better suited to
their environment-that is, with
adaptations to enable fitness,
survive and reproduce most
successfully. In Darwin’s terms, that
is…
Survival of the fittest
• Over time, changes in the
inherited characteristics of a
population that increases a
species’ fitness are called…
Natural Selection
• Darwin’s proposed that over time,
natural selection produces organisms
that have different structures, establish
different niches or occupy different
habitats. As a result, species today look
different than their ancestors. This
principle is called….
Descent with modification
• One argument that living
things have been evolving on
Earth for millions of years can
be found in…
• Fossil records
• Geographical distribution of living
species
• Homologous structures of living
organisms
• Similarities in early development, or
embryology.
• An organism possesses organs
with little of no function. They
are called…
Vestigial organs
• A ___________ _________
consists of ALL genes, including
all the different alleles, that are
present in a population.
Gene Pool
• The number of times that an
allele occurs in a gene pool,
compared with the number of
times other alleles for the same
gene occur is….
Relative Frequency
• In genetic terms, evolution is any
_______ in the relative frequency
of alleles in a population.
Change
•One of the two main
sources of genetic
variation is ….
• Mutation
• Genetic shuffling that results from sexual
reproduction
• A ___________ is any change in a
sequence of DNA and can occur
because of mistakes in the
replication of DNA or as a result of
radiation or chemicals in the
environment.
Mutation
Yes or No??
• Do mutations always affect
the phenotype?
•NO
• Let’s say there is a family with 4 siblings. One
of the offspring does not look like his
biological parent even though they provided
him with all his genes.
• What can we attribute that to?
Gene shuffling
• A widow’s peak is controlled by a single gene
with two allelles.The widow’s peak allele is
dominant over the allele for a hairline that
has no peak. The widow’s peak can be
described as…
Single-gene trait
• Many traits are controlled by two or more
genes. They are called…
Polygenic Traits
When individuals at one end of the
curve have higher fitness than
individuals in the middle or at the
other end, this occurs…
Directional selection
• When individuals near the
center of the curve have
higher fitness than
individuals at either end of
the curve, this occurs…
Stabilizing selection
• What happens when disruptive
selection takes place if the
pressure of natural selection is
strong enough and lasts long
enough???
Selection creates two distinct
phenotypes
• Natural selection is NOT the only source of
evolutionary change…
• Recall that genetics is controlled by the laws of
probability.
• The smaller a population is, the farther the
results may be from what the laws of
probability predict.
• This kind of random change in allele frequency
is called…
Genetic drift
• Genetic drift may occur
when a small group of
individuals colonizes a
new…
Habitat
• A situation in which allele
frequencies change as a result of the
migration of a small subgroup of a
population is called….
The founder effect
What do you call what happens when:
• 1. There is random mating.
• 2. The population is very large.
• 3. There is no movement into or out of the
populations.
• 4. There are no mutations.
• 5. There is no natural selection?
Genetic equilibrium
•What is the cool word
that means changes that
lead to the formation of
new species?
Speciation
• What three varieties of
reproductive isolation are
there?
• Behavioral (they way they act)
• Geographic (where they are)
• Temporal (when they reproduce)