Download Theory of Evolution

History of Life
Chapter 19
536-568
Evolution Notes 2010
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KEY Terms Chap 16, 17, and 19
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Evolution
Fossil
Artificial selection
Adaptation
Fitness
Natural selection
Biogeography
Homologous structure
Analogous structure
Vestigial structure
Darwin
Lamark
Cuvier
Lyell
Superpostion
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Relative age
Absolute age
Biogenesis
Spontaneous Generation
Extinct
Paleontologist
Radiometric dating
Half-life
Macroevolution
Gradualisms
Punctuated equilibrium
Adaptive radiation
Convergent evolution
Co evolution
Endosymbiotic theory
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Biogenesis
• All living things come from other living
things, seems reasonable to us today.
Before the 17 century it was widely
thought that living things could also arise
from nonliving things in a process called
spontaneous generation. This seemed
to explain why maggots appeared on
rotting meat and why fish appeared in
ponds that were dry the previous season
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Redi’s Experiment
• 1626-1697 Italian scientist Francesco Redi
• Studied developmental forms of flies
• Did flies generate spontaneously from
rotting meat?
• Experiment control group rotting meat left
open maggots, experimental group
rotting meat sealed no maggots
• Flies come from eggs laid by other flies
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Redi’s Experiment
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Spallanzani Experiment
• 1729-1799 Italian scientist Lazzaro
Spallanzani
• Microorganisms formed not from air but
from other microorganisms
• Boiled broth, control open becomes
cloudy, experimental group sealed
remains clear
• Those that believed in spontaneous gen
found flaws in his experiment, continued to
believe in SG
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Spallanzani Experiment
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Pasteur’s Experiment
• 1800s Paris Academy of Science offered a prize
to anyone who could clear up the issue once
and for all
• Louis Pasture (1822-1895) won
• Pasture used similar format of Spallanzani
except he used a curve neck flask no growth for
one year till the curve was broken and allowed
for microorganisms from the air to enter
 No longer believed in spontaneous
generations but  biogenesis (to live to be
born)
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Pasteur Experiment
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Theories of life's origin
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Earth’s History
• If spontaneous generation does not
happen on Earth today, then the question
remains: How did cell-based life arise in
the first place? Key to answering this
question lies in scientific hypotheses that
conditions on early Earth were very
different from present conditions.
Scientists continue to form and test these
hypotheses by modeling conditions and
process that could have given rise to the
first cellular life form.
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Formation of Earth
• Our solar system was a swirling mass of
gas and dust
• Pulled together by gravity and formed the
sun
• Planets formed through repeated collision
of this space debris
Earths age
• More than 4 billion years ago
• Studying layers of sedimentary rock
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Radiometric Dating
• Use of isotopes (change in # of neutrons)
• Mass number is the # of protons and
neutrons
• Radioactive decay- isotopes are unstable
and release particles and energy
• Radioactive isotopes occur naturally in all
matter
• Half-life- time it takes to decay, measure
the amount
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Radiometric Dating
– The half-life of
potassium-40 is
1.26 billion years.
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Radiometric Dating
•
Carbon-14 is a radioactive form of carbon naturally found in the
atmosphere. It is taken up by living organisms along with “regular”
carbon, so it can be used to date material that was once alive, such
as bones or wood.
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After an organism dies, carbon-14 in its body begins to decay
to nitrogen-14, which escapes into the air.
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Researchers compare the amount of carbon-14 in a fossil to
the amount of carbon-14 in the atmosphere, which is generally
constant. This comparison reveals how long ago the organism lived.
•
Carbon-14 has a half-life of only about 5730 years, so it’s only
useful for dating fossils no older than about 60,000 years.
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First Organic CPDS
• Soviet Alexander I. Oparin (1894-1980) and
American John B.S. Haldane (1892-1964)
• Believed that earth early atmosphere contained
ammonia, hydrogen gas, wand water vapor,
carbon and hydrogen cpds
• At high temperatures gases would formed
simple organic cpds such as amino acids
• Earth cooled water vapors condensed and
created water systems
• Lighting fueled energy creating
macromolecules essential to life (proteins)
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Synthesis of organic cpds
• 1953 Stanley Miller and Harold Urey set
up and experiment to test the hypothesis
• Used gases that were assumed present in
the earths atmosphere, using an electrical
spark to simulate the lighting the
experiment produced variety of organic
compounds including amino acids
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http://www.ucsd.tv/miller-urey/
http://www.wwnorton.com/college/chemistry/chemconnections/Origins/pages/spark.html
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Beyond earth
• Some scientists believe that organic
compounds could have been carried to
Earth by debris from space
• Studied 1970 meteorite
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From molecules to cell-like
structures
• Fox (1912-1998) studied cell structures
• Some from spontaneously in the lab from
solution of simple organic chemicals
• Microspheres- spherical in shape and
composed of many protein
• Coacervates-collection of droplets that
are composed of molecules of different
types
 Do not have all the properties of life!!
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Origin of Heredity
• DNA RNA protein
• Believed that RNA molecules behave like
proteins and catalyze chemical reactions
• Chech’s found that ribozymes could act as
catalyst for their own replication support
the hypothesis that life could have started
with self-replicating molecules of RNA
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First cells
• Little or no oxygen existed on early earth
• Oldest fossils that are size and shape of
some prokaryotes
• Developed in environments filled with
organic molecules
• Believed they were anaerobic,
heterotrophic prokaryotes
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chemosynthesis
• Archaea- unicellular organisms, live in
extreme harsh environments
• Tend to be autotrophic
• Obtain energy by chemosynthesis,
oxidation of various inorganic substances
(sulfur)
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Photosynthesis and aerobic
respiration
• 3 billion yr ago
• Oldest know fossils similar to
cyanobacteria (unicellular prok,
photosynthesis), stromatolites (3.5 billion
years old)
• Creation of ozone
• Endosymbiosis (mitochondria,
chloroplasts)
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The first Eukaryotes:
Endosymbiosis (together, way of life)
(mitochondria, chloroplasts)
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Theory of Evolution
Chapter 16
448-474
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Review
• What is Genotype and phenotype
• Don’t forget that an organisms phenotype
depends on an organisms genotype
• Can you explain how DNA in an organism
determines the structure and function of
protein that a cell produces
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Objectives
• Define the biological process of evolution
• Summarize the history of scientific ideas
about evolution
• Described Charles Darwin’s contributions
to scientific thinking about evolution
• Analyze the reasoning in Darwin's theory
of evolution of by natural selection
• Relate the concepts of adaptation and
fitness to the theory of natural selection.
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What was Charles Darwin’s
contribution to science?
•
Darwin developed a scientific theory of
biological evolution that explains how
modern organisms evolved over long
periods of time through descent from
common ancestors.
•
Charles Darwin was born in England on
February 12, 1809. He grew up at a time when
the scientific view of the natural world was
shifting dramatically.
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History of Evolutionary Thought
• In the 1830s, the young English naturalist
Charles Darwin took a trip around the
world on a shop called HSM Beagle.(5
years) He was fascinated by diverse and
unique organisms, such as the giant
tortoises of the Galapagos Islands. Darwin
went ton to form one of the most important
theories in biology.
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Observations Aboard the
Beagle
What three patterns of biodiversity did Darwin
note?
– Darwin noticed that some fossils of extinct
animals were similar to living species.
– As he traveled, Darwin noticed three distinctive
patterns of biological diversity: (1) Species vary
globally, (2) species vary locally, and (3)
species vary over time.
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The Idea of Evolution
• Animals varied from island to island
• Organisms changed over time
• Development of new types of organisms from
preexisting types of organisms over time
(Evolution)
• Heritable change in the characteristics within a
population from one generation to the next
• Theory is something that takes observations,
inferences, and tested hypotheses over time
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Ideas of Darwin’s Time
• 18 century most scientists thought that all
species were permanent and unchanging
• Once believed the earth was only
thousands – not billion years old
• Evidence was emerging that organisms
were changing over time
•
http://www.youtube.com/watch?v=wl68aaiHdGo&feature=related
•
http://www.youtube.com/watch?v=cbhvfDA5Vjs&feature=related
•
http://www.youtube.com/watch?v=1NAKg46s1DA&feature=related
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Ideas about Geology
• Strata – rock layers, being studied
• Found fossils in the strata
• Cuvier (1769-1832) spent years reconstructing
organisms from fossil bones
• Found sudden changes from rocks to rocks
• Catastrophism- sudden geologic catastrophes
caused the extinction of large group of organism
in the past (geologic change  extinction)
• Lyell- uniformitarianism, geologic process that
have changed the shape of Earth’s surface in
the past continue to work in the same ways
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Lamarck’s Ideas on Evolution
• French biologist (1744-1829)
• Organisms change over time
• Could acquire traits during the life time
and pass it on to the offspring
inheritance of acquired characteristics
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Darwin’s Ideas
• The Origin of Species by Means of Natural Selection
• Descent with Modifications was used to describe the
process of evolution
• Must have descended by reproduction from preexisting
species and that species must be able to change over
time
• Was the first to argue that all came from first few species
• http://www.aboutdarwin.com/
• http://www.pbs.org/wgbh/evolution/darwin/origin/index.ht
ml
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Darwin Finches
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Evolution by Natural
Selection
Under what conditions does natural selection occur?
– Natural selection occurs in any situation in which more
individuals are born than can survive (the struggle for
existence), there is natural heritable variation (variation
and adaptation), and there is variable fitness among
individuals (survival of the fittest).
– , Darwin realized that if more individuals are produced
than can survive, members of a population must
compete to obtain food, living space, and other limited
necessities of life.
– Darwin described this as the struggle for existence
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Natural Selection
mechanisms for descent with modifications
4 main parts
1. Overproduction
2. Genetic variation
3. Struggle to survive
4. Differential reproduction
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1. Overproduction
• More offspring can be produced than can
survive to maturity
• Humans: war, disease, lack of food
• Environment limits the populations of all
organisms by causing death or by limiting
successful births
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Genetic variation and survival
2.GV
• Population individuals have different traits
• Some can be inherited
• Occasionally new traits may appear
3.Struggle to survive
• Compete among population “struggle for
existence”, can improve or reduce chance
• Adaptation- makes survival a success
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Variation and Adaptation
–
Darwin knew that individuals have natural variations among
their heritable traits, and he hypothesized that some of those
variants are better suited to life in their environment than others.
– Any heritable characteristic that increases an organism’s ability
to survive and reproduce in its environment is called an
adaptation.
– Adaptations can involve body parts or structures, like a tiger’s
claws; colors, like those that make camouflage or mimicry
possible; or physiological functions, like the way a plant carries
out photosynthesis
– The scarlet king snake exhibits mimicry—an adaptation in which
an organism copies, or mimics, a more dangerous organism.
Although the scarlet king snake is harmless, it looks like the
poisonous eastern coral snake, so predators avoid it, too.
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4.Differential reproduction
• Organisms with the best adaptations are
most likely to survive and reproduce
through inheritance the adaptations
become more frequent in the populations
• Over time the populations begin to change
• Natural selection nature changes the
species by selecting traits
• Survival of the fittest- individuals
hereditary
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Survival of the Fittest
• According to Darwin, differences in adaptations affect an individual’s
fitness.
• Fitness describes how well an organism can survive and reproduce
in its environment.
• Individuals with adaptations that are well-suited to their environment
can survive and reproduce and are said to have high fitness.
• Individuals with characteristics that are not well-suited to their
environment either die without reproducing or leave few offspring
and are said to have low fitness.
• This difference in rates of survival and reproduction is called
survival of the fittest. In evolutionary terms, survival means
reproducing and passing adaptations on to the next generation.
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Natural Selection
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Natural Selection
– This hypothetical
population of
grasshoppers changes
over time as a result of
natural selection.
– Grasshoppers can lay
more than 200 eggs at a
time, but only a small
fraction of these offspring
to reproduce.
Evolution survive
Notes 2010
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Natural Selection
–
Certain variations, called
adaptations, increase an individual’s
chances of surviving and
reproducing.
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In this population of grasshoppers,
heritable variation includes yellow
and green body color.
–
Green color is an adaptation: The
green grasshoppers blend into their
environment and so are less visible to
predators.
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Natural Selection
– Because their color
serves as a camouflage
adaptation, green
grasshoppers have
higher fitness and so
survive and reproduce
more often than yellow
grasshoppers do.
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Natural Selection
– Green grasshoppers become
more common than yellow
grasshoppers in this population
over time because more
grasshoppers are born than can
survive, individuals vary in color
and color is a heritable trait,
and green grasshoppers have
higher fitness in this particular
environment
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Natural Selection
– Natural selection does not make organisms
“better.” Adaptations don’t have to be
perfect—just good enough to enable an
organism to pass its genes to the next
generation.
– Natural selection also doesn’t move in a
fixed direction. There is no one, perfect way of
doing something. Natural selection is simply a
process that enables organisms to survive
reproduce in a local environment.
Evolution and
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Common Descent
–
Darwin based his explanation for the
diversity of life on the idea that species
change over time.
– For evidence of descent with modification
over long periods of time, Darwin pointed to
the fossil record.
–
This page from one of Darwin’s notebooks
shows the first evolutionary tree ever drawn.
This sketch shows Darwin’s explanation for
how descent with modification could produce
the diversity of life.
–
A single “tree of life” links all living things.
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Objectives
• Relate several inferences about the history of life
that are supported by evidence from fossils and
rocks.
• Explain how biogeography provides evidence
that species evolve adaptations to their
environments.
• Explain how the anatomy and development of
organisms provide evidence of shared ancestry.
• Compare the use of biological molecules with
other types analysis of evolutionary
relationships.
• Describe the ongoing development of
evolutionary theory
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Evidence of Evolution
• Many kinds of evidence give insight into
the history of life n Earth and the patterns
of change among organisms. Fossils that
are different from organism living today
are strong evidence that organisms on
Earth can change over time. But evidence
of evolution is also found inside living
organisms.
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1. Fossil Record
is the remains of traces of an organism that died
long ago
• Superposition- if the rock strata at a location
have not been disturbed, the lowest stratum was
formed before the strata above it, geologic time
scale
• Relative age- age compared to that of other
fossils
• Absolute age- use radiometric dating, time
since formation
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Distribution of Fossils
Inferences
1. that diff organism live at diff times
2. Today's organisms are diff from past
3. Adjacent layers are similar than ones
below or above
4. Where they lived, existed, adapted
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Geologic Time Scale
– Geologists and
paleontologists have
built a time line of
Earth’s history called
the geologic time
scale.
– The basic divisions
of the geologic time
scale are eons, eras,
and periods.
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Transitional species
• Features that are intermediate between
those of hypothesized ancestors and later
descendant species
• Once believed whales had legs
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Recent Fossil Finds
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Recent Fossil Finds
The limb structure of
Ambulocetus (“walking
whale”) suggests that these
animals could both swim in
shallow water and walk on
land.
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Recent Fossil Finds
The hind limbs of Rodhocetus
were short and probably not
able to bear much weight.
Paleontologists think that these
animals spent most of their
time in the water.
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Recent Fossil Finds
– Basilosarus had a
streamlined body and
reduced hind limbs.
These skeletal
features suggest that
Basilosarus spent its
entire life swimming
in the ocean.
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Recent Fossil Finds
– Modern whales retain
reduced pelvic bones
and, in some cases,
upper and lower limb
bones. However, these
structures no longer
play a role in
locomotion.
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Recent Fossil Finds
– Other recent fossil finds connect the dots
between dinosaurs and birds, and between
fish and four-legged land animals.
– All historical records are incomplete, and the
history of life is no exception. The evidence
we do have, however, tells an unmistakable
story of evolutionary change.
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2.Biogeography
• Study of the locations of organisms around
the world
• Organisms seemed closely related yet
were adapted to different environments in
nearby regions
• Yet some organisms seemed unrelated
and had similar adaptations
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3.Anatomy and 4.Embryology
• Anatomy- the study of the body structure of an
organism
• Embryology- the study of how organism
develop
• Homologous structures- similar structures with
common ancestors diff functions
• Analogous structures- related functions not
derived from the same ancestral structure
• Vestigial structures- no longer have function
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Vestigial structures
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5.Biological Molecules (DNA)
• The greater the number of similarities between
any given species, the more closely the species
are related trough a common ancestor
• New information constant debate
• Modern synthesis of evolutionary theory
• Many aspects are still poorly understood or
unexplained
• We use phylogeny to so relationships
(classification)
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Objectives
• Describe how convergent evolution can
result among different species.
• Explain how divergent evolution can lead
to species diversity
• Compare artificial selection and natural
selection
• Explain how organisms can undergo
convolution.
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Evolution in Action
• Evolution is a continuous process.
Evolution is going on today in populations
of living species and can be observed,
recorded, and tested. Patterns of evolution
repeat in different times and places.
Interactions between species , including
humans, affect their ongoing evolution.
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Types of evolution
• Convergent- different species evolve similar
traits
• Divergent- descendants of a single ancestor
diversify into species that each fit diff parts of the
environment
• Adaptive radiation- new population in a new
environment will undergo divergent evolution
until the population fills many parts of the
environment
• Artificial selection- pick traits
• Co evolution- two or more species have
evolved adaptation to each other’s influence
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Chapter 17 Evolution of
Populations
For extra help go to:
http://bioactive.mrkirkscience.com/submenus/part4index.html
p. 480-504
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Objectives
• Identify traits that vary in populations and
that may be studied.
• Explain the importance of the bell curve to
population genetics
• Compare three causes of genetic variation
in a population
• Explain Hardy-Weinberg genetics
equilibrium
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Genetic Equilibrium
• By the time of Darwin’s death, in 1882, the
idea of evolution by natural selection had
gained wide acceptance among scientists.
Within the next century, an increasing
scientific understanding of genetics
became strongly linked with theories of
evolution and natural selection.
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Variation of Traits within a
population
• Population- consists of a group of
individuals of the same species that
routinely interbreed, smallest unit in which
evolution occurs
• Population genetics- study of evolution
from a genetic point of view
• Microevolution- change in the collective
genetic material of a population
• Populations can vary in traits (bell curve)
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Causes of Variation
1. Environmental factors (food)
2. Heredity
3. Range of phenotypic possibilities (body
sizes)
4. Mutation- random change in genes
5. Recombination- reshuffling of genes
6. Random paring of gametes
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Hardy-Weinberg Equilibrium
Gene Pool- Used to describe the total
genetic information available in a
population
Based on a set of assumptions about an
ideal hypothetical population that is not
evolving (theoretical state)
1.
2.
3.
4.
5.
No net mutations occur
Individuals neither leave or enter
Populations are large
Individuals mate randomly
Selection does not occur
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Objectives
• List five conditions under which evolution takes
place
• Explain how migration can affect the genetics of
populations
• Explain how genetic drift can affect population of
different sizes
• Contrast the effects of stabilizing selection,
directional selection, disruptive selection on
populations over time
• Identify examples of nonrandom mating
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Disruption of Genetic Equilibrium
• Evolution is the change in a population’s
genetic material over generations, a
change of the population’s alleles
frequency or genotype frequency. Any
exception to the fiver conditions necessary
for Hardy-Weinberg equilibrium can result
in evolution.
• Web 13d
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mutation
•
•
•
•
Very low rates under normal conditions
Environmental factors can influence
Change genetic equilibrium- new alleles
Natural selection works slowly
• (first rule to HW)
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Gene Flow
•
•
•
•
Second rule to HW- no one leaves/enters
Where they go so does the traits
Immigration- movement into a population
Emigrating- movement out of a
population
• Gene flow- process of genes moving from
one population to another, migration of
individuals or dispersal of seeds or spores
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Genetic Drift
• Third law- pop large
• Genetic Drift- random change in allele
frequency
• Failure of even a single organism to
reproduce can significantly disrupt the
allele frequency of the population
• Small pop lager impact
 bottleneck effect
 founder effect
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Types Genetic Drift
Founder Effect
bottleneck effect
• Two groups from a
• is a change in allele
large, diverse
frequency following a
population could
dramatic reduction in the
produce new
size of a population.
populations that differ
from the original group.
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Nonrandom Mating
• 4th rule- random mating
• Often influence by location
• Traits similar to own-Assortative mating
Sexual selection- picking a mate bases on
looks or certain traits
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Natural selection- 5th rule
1. Stabilizing selection- avg form of a trait have
the highest fitness
2. Disruptive selection- individuals with either
extreme variation of a trait have greater fitness
that individuals with the avg form of the trait
3. Directional selection- individuals that display
a more extreme form of a trait have greater
fitness than individuals with an avg form of the
trait
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objectives
• Relate the biological species concept to
the modern definition of species
• Explain how the isolation of populations
can lead to speciation
• Compare two kinds of isolation and the
pattern of speciation associated with each
• Contrast the model of punctuated
equilibrium with the model of gradual
change
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Formation of Species
• How many species of organisms exist on Earth today?
• Undiscovered species may be so numerous that we
have no accurate answer. Even small areas of tropical
rain forest can contain thousands of species of plants,
animals, and microorganisms.
• New species are discovered and others become extinct
at an increasing rate.
• How can one species become two through speciation?
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Concept of species
• Speciation- existing species are essentially
changed version of older species, results in
closely related species, can become diff over
time
Morphological concept of species
• Morphology- internal/ external structures and
appearance of an organism, used to classify
species
Biological species Concept- a species is a pop
of organisms that can successfully interbreed
but can not breed with other groups
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Speciation
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Isolation and speciation
4 major types
•
•
•
•
Geographic isolation
Allopatric speciation
Reproductive isolation
Sympatric speciation
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Geographic isolation
• Physical separation of members of a
population
• Habitat becomes divided, geographic
barriers
• Gene flow stops
• Natural selection and genetic drift cause
pop to diverge incompatible for mating
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Allopatric Speciation
• Happens when species arise as a result of
geographic isolation, “different homelands”
• No longer a gene flow
• Genetic drift, mutations, natural selection
• Small populations
• Could still produce fertile offspring?
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Allopatric speciation- Geographic
isolation
• http://wps.prenhall.com/esm_freeman_biosci_1/7/1951/499633.cw/i
ndex.html
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Geographical and
temporal isolation
• http://bioactive.mrkirkscience.com/19/ch19c1.html
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Reproductive Isolation
•
Barriers to successful breeding between
populations groups in the same area
Two types
1. Prezygotic isolation- before fertilization
2. Postzygotic- after fertilization
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Prezygotic barriers- isolation
Prevent mating or fertilization
• Temporal - mating or flowering occurs at
different season or times of day
• Habitat – populations live in different habitats
and do not meet
• Behavioral- there is little or no sexual
attraction between different species
• Mechanical – structural differences in genitals
or flowers prevent copulation or pollen transfer
• Gametic- male/female gametes die before
unite
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Behavioral isolation
An Eastern Meadowlark
Eastern meadowlark call eastern
meadowlark call
(http://www.naturesongs.com/eam
e1.wav))
Evolution Notes 2010
A Western Meadowlark
Western meadowlark call western
meadowlark call
(http://www.naturesongs.com/w
eme1.wav
105
Habitat isolation
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Behavioral isolation
• Different species of
fireflies do not
recognize each
others' mating signals
and, as a result, do
not generally
interbreed.
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108
Reproductive barriers
Example of thale cress suffering from hybrid
necrosis. Left and right are the healthy
parents; center is the sick hybrid offspring.
Pup fish-death valley
Evolution Notes 2010
Credit: Image: Kirsten Bomblies
109
Sympatric speciation
• Two subpopulations become
reproductively isolated with in the same
geographic area
• Gain adaptive advantages by using
different niches
• Could lead to group being isolated
• Wood frog and leopard frog have mating
times and calls
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111
Rates of speciation
Two types:
• Gradualism- nvolves a
slow, steady change in a
particular line of descent.
• The fossil record shows that
many organisms have
indeed changed gradually
over time.
Evolution Notes 2010
• Punctuated equilibriumsudden rapid change with
periods of little change
• The fossil record reveals
periods of relatively rapid
change in many groups of
organisms
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113
Rapid Evolution After
Equilibrium
– Rapid evolution may occur after a small
population becomes isolated from the main
population. This small population can evolve
faster than the larger one because genetic
changes spread more quickly among fewer
individuals.
– Rapid evolution may also occur when a small
group of organisms migrates to a new
environment. That’s what happened with the
finches.
Evolution Galápagos
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114
Rapid Evolution After
Equilibrium
– Mass extinctions open many ecological
niches, creating new opportunities for those
organisms that survive. Groups of organisms
that survive mass extinctions evolve rapidly in
the several million years after the extinction.
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animations
• http://www.classzone.com/cz/books/bio_0
7/get_chapter_group.htm?cin=4&rg=anim
ated_biology&at=animated_biology&var=a
nimated_biology
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