Download WHICH PATTERN IS IT?

EVOLUTION
REVIEW
Image from BIOLOGY by Miller and Levine; Prentice Hall Publishing © 2006
Traits controlled by two or
more genes
Polygenic trait
Process by which related organisms
evolve differences when they are
isolated in different environments
Divergent evolution OR
Adaptive radiation
Measuring lima beans and finding
beans come in different sizes is
an example of
Natural variation
____________
Process by which unrelated
organisms independently evolve
similarities when adapting to
similar environments
Convergent evolution
A change in a DNA sequence caused
by a mistake in DNA replication or
exposure to radiation or chemicals
mutation
Changes in the allele frequency
in a small population that are due
to random chance and don’t follow
the laws of probability
Genetic drift
All the genes, including all the
different alleles, in a
population
Gene pool
A situation in which the allele
frequencies in a population do NOT
change and the population does
NOT EVOLVE
Genetic equilibrium
Trait controlled by two or more
genes
Polygenic trait
A change in relative frequency
of alleles in a population
evolution
A change in allele frequencies due to
the migration of a small subgroup
of a population to a new place
Founder effect
Idea that allele frequency will
remain constant unless one or more
factors cause those frequencies
to change
Hardy-Weinberg Principle
Copying DNA is called __________
replication
Exchange of DNA between homologous
chromosomes during
PROPHASE I of MEISOIS
Crossing over
Mixing up of maternal and paternal
chromosomes in different combinations
during ANAPHASE of MEIOSIS
SEGREGATION &
INDEPENDENT ASSORTMENT
A trait controlled by a single
gene with two alleles
Single gene trait
The number of times a certain
allele occurs in a gene pool
compared to the number of times
other alleles for the same gene occur
Relative frequency
Tell two sources of genetic variation
in populations
Mutations
caused by mistakes in copying DNA
caused by radiation
or environmental chemicals
Gene shuffling during meiosis
crossing over
independent assortment
Type of distribution curve shown by
polygenic traits
Bell-shaped curve
(OR normal distribution)
Image from BIOLOGY by Miller and Levine; Prentice Hall Publishing©2006
The effect of natural selection
when individuals near the center of a
normal curve of distribution have
higher fitness than those at the
extremes
Stabilizing selection
Image from BIOLOGY by Miller and Levine; Prentice Hall Publishing©2006
The effect of natural selection when
individuals at one end of the
normal distribution curve have
higher fitness than individuals in
the middle or at the other end
Directional selection
Image from BIOLOGY by Miller and Levine; Prentice Hall Publishing©2006
The effect of natural selection
when individuals at the extreme
ends of the normal distribution
curve have higher fitness than
those near the center of the
curve
Disruptive selection
Image from BIOLOGY by Miller and Levine; Prentice Hall Publishing©2006
TELL THE CONDITIONS UNDER
WHICH THE HARDY-WEINBERG
PRINCIPLE HOLDS TRUE:
Random mating
LARGE population
NO mutations
NO movement IN OR OUT
NO natural selection
How does gene shuffling occur
during meiosis?
Crossing over &
independent assortment
What are some causes of mutations?
Mistakes during DNA copying
(replication)
Environmental chemicals or radiation
If all the conditions of HardyWeinberg are met, what happens
to the population?
There is NO EVOLUTION
A possible explanation for a set of
observations
or a possible answer to a scientific
question
hypothesis
Can all the conditions of
Hardy-Weinberg ever be met?
In rare populations over long periods of
time they may be met (or nearly met)
BUT MOST OF THE TIME NO WAY!
You can have small & isolated populations
(no moving in or out) BUT. . . there is
always non-random mating, mutations, &
natural selection. So there is ALMOST
ALWAYS EVOLUTION HAPPENING !
Darwin believed in the idea that
evolution happened slowly over a
long period of time called
__________
gradualism
Pattern of evolution in which long
Stable periods of little evolution
interrupted by brief periods of rapid
change
Punctuated equilibrium
WHICH PATTERN IS IT?
coevolution
adaptive radiation
punctuated equilibrium
divergent evolution
mass extinction
Horse evolution shows long stable periods
of little evolution interrupted by brief
periods of rapid change
Punctuated equilibrium
Biology by Miller and Levine Pearson Publishing
WHICH PATTERN IS IT?
coevolution
adaptive radiation
punctuated equilibrium
divergent evolution
mass extinction
The Galápagos finches evolved through natural
selection from a common ancestor into a wide
variety of different looking species with different
kinds of beaks
Adaptive radiation
WHICH PATTERN IS IT?
coevolution
adaptive radiation
punctuated equilibrium
divergent evolution
mass extinction
At the end of the Cretaceous period an asteroid
hit the Earth causing the loss of many species
including the dinosaurs
Mass extinction
http://images.encarta.msn.com/xrefmedia/aencmed/targets/illus/ilt/T014608A.gif
WHICH PATTERN IS IT?
coevolution
adaptive radiation
punctuated equilibrium
divergent evolution
mass extinction
The Galápagos finches evolved through natural
selection from a common ancestor into a wide
variety of different looking species with different
kinds of beaks
Adaptive radiation (divergent evolution)
WHICH PATTERN IS IT?
coevolution
adaptive radiation
punctuated equilibrium
divergent evolution
mass extinction
Hummingbirds have a beak just the right length
to reach the nectar in a cardinal flower and as
they feed their foreheads bump into the pollen
structure. Cardinal flowers are red which
hummingbirds can see, but bees can’t, and their
pollen structure is at just the right height for
the hummingbird to pick up pollen as it feeds.
coevolution
WHICH PATTERN IS IT?
coevolution
adaptive radiation
punctuated equilibrium
divergent evolution
mass extinction
Whales, sharks, and penguins all have streamlined
bodies and fins/flipper for moving in water
even though they belong in different animal groups
(mammals, fish, and birds)
Convergent evolution
WHICH PATTERN IS IT?
coevolution
adaptive radiation
punctuated equilibrium
divergent evolution
mass extinction
Beaver
Beaver
NORTH
AMERICA
Muskrat
Muskrat
Beaver
and
Muskrat
Capybara
SOUTH AMERICA
Coypu
Coypu
Beaver in North America
and capybara in South
America are closely
related species living in
very different
environments that have
evolved to look different
over time.
Adaptive radiation OR divergent evolution
BIOLOGY by Miller and Levine Pearson Publishing
WHICH PATTERN IS IT?
coevolution
adaptive radiation
punctuated equilibrium
divergent evolution
mass extinction
The tortoises on the Galapagos islands share a
common ancestor, but over time they have become
adapted for obtaining food in different habitats
on different islands by having different
neck lengths
Adaptive radiation OR
divergent evolution
WHICH PATTERN of SELECTION IS IT?
stabilizing
disruptive
directional
Human babies born smaller than average are likely
to be less healthy and less likely to survive.
Larger than average babies are likely to have
difficulty being born. The fitness of these larger
or smaller weight babies is lower than averagesized babies so human babies tend to born of
average size.
Stabilizing selection
WHICH PATTERN of SELECTION IS IT?
stabilizing
disruptive
directional
Lighter colored peppered moths were more
common in England prior to the Industrial
revolution. As pollution increased, the darker
colored moths were less likely to be eaten. Over
time darker colored moths have become more
abundant in the population.
directional selection
WHICH PATTERN of SELECTION IS IT?
stabilizing
disruptive
directional
A population of birds lives in an area where plants
with medium sized seeds are wiped out by a
fungal infection. Birds with unusually large or
small beaks would have higher fitness than those
with medium sized beaks. Over time the
population splits into two subgroups; one that eats
small seeds and one that eats large seeds.
disruptive selection
THE END