Chapter 13 : How Populations Evolve Evolution

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Chapter 13 How Populations Evolve (Evolution)
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What We Will Cover In Chapter 13

• We will explore the life and times of the father
  of evolution, ____________ _____________
• We will define evolution
• We will define macroevolution and microevolution
  and discuss examples of each
• We will revisit natural selection
• We will examine the most commonly accepted
  evidence of the evolution of species
• We will look at the mechanisms of microevolution
• Genetic Drift
• Gene flow
• Mutation

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The Life of Charles Darwin

• Born 1809, the son of a physician . He was a
  born naturalist.
• His Grandfather, Erasmus Darwin, founded the
  Lunar Society
• Was sent to _______________ school at age 16 but
  hated it and dropped out
• Went to Christ College in Cambridge England to
  become a ____________ got a BA in theology
• At the recommendation of one of the teaching
  ministers he was sent on a sea voyage around the
  globe aboard the HMS Beagle (1831) aged 22 years.
  

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Charles Darwin and the Voyage of the Beagle

• Served as the naturalist aboard the Beagle
• Spent most of his time collecting specimens on
  shore
• Noted the _________________that plants and
  animals exhibited based on the environment they
  were living in
• Struck by the wide variety of _________________spe
  cifically adapted to the various Galapagos island
  habitats. Here he collected his famous
  _______________.

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Charles Darwin and the Origin of Species
The ___________ of ____________ was published 30
years after the voyage of the Beagle The book
never mentioned the word ________________ His
theory stated two main points 1). Current
species on Earth descended from ancestral species
Descent With Modification 2). Argued that
Natural Selection was the reason why species
changed over time. Natural Selection is the
mechanism of evolution.
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Evolution Defined
From Your Texts glossary Genetic change in a
population or species over generations. The
heritable changes that have produced earths
current diversity of organisms.
Instead of the term evolution, Darwin used the
phrase ______________ With _____________________
to describe his idea on how speciation occurred
in response to environmental pressures.
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Macroevolution Vs. Microevolution
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__________________ describes the change in a
populations gene pool over a few generations
occurring in a relatively brief period of time.
(Chapter 13 -How Populations Evolve) ___________
____ is evolutionary change on a grand scale,
describing the origin of new taxonomic groups,
and mass extinctions over the last 4 billion
years (Chapter 14 How Biological Diversity
Evolves)
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Darwins Theory of Natural Selection
Observation 1 Overproduction - populations
of all species produce more offspring than the
environment can _____________.
Observation 2 Individual Variation -
Individuals within a _______________ vary in many
heritable traits
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Darwins Theory of Natural Selection
Observation 1 Overproduction Populations of
all species produce more __________________
than the environment can support
Observation 2 Individual Variation.
Individuals within a population vary in many
heritable traits. Those who possess the traits
best suited for survival and reproduction pass on
those characteristics and the species changes or
____________.
Loggerhead Shrike aka Butcher Birds
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Darwins Theory of Natural Selection
Those individuals with traits best suited to
the local environment generally produce more
surviving, fertile offspring. In other words,
natural selection promotes evolutionary
adaptations or ________________ over _________of
populations. (species)
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Evidence of Evolution
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The Fossil _______________ Comparative
_____________ Comparative ______________ Molecul
ar ________________
Famous quote in research science Absence of
evidence is not evidence of absence.
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The Geology of the Fossil Record
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The Fossil Record
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Oldest most ___________ organisms are found on
the bottom. More recently evolved more __________
animals are nearer the surface.
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Comparative Anatomy
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A comparison of body structures (anatomy)
between different species is called comparative
anatomy. Comparative anatomy suggests that
____________is a remodeling process in which
ancestral structures become modified as they take
on new ____________. This is what Darwin would
call descent with modification.
This similarity in skeletal design of the
forelimb suggests that all these
mammals descended form a common ancestor.
Scientists have also found extinct whales that
had hind limbs suggesting that they evolved from
four legged land animals.
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Comparative Embryology
Early on in development all vertebrates look more
alike than different.

• Comparative embryology is the comparison of
  anatomical
• structures that appear during the early stages of
  ______________.
• gill pouches appear on the sides of the
  _________.
• post-anal tail.
• Another Famous Quote in Science
• Ontogeny recapitulates phylogeny.

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Comparative Embryology
Embryos of all vertebrates look more alike than
different.
Ontogeny Recapitulates Phylogeny.
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Molecular Biology
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• Darwins most controversial claim is that all
  forms of life are related to some extent through
  branching evolution from the earliest organisms.
• molecular biology has added strong evidence
  showing that DNA and other ____________ and
  processes (protein synthesis) (cell division) are
  nearly identical.
• Therefore, evolution has
• changed very little at the
• _____________
• level but has lead to
• great species diversification at the population
  level.

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Populations as the Units of Evolution
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It is true that natural selection acts on
individuals. But the evolutionary impact of
natural selection is only apparent when we track
how a ____________ changes over time.
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Microevolution
Microevolution describes the change in a
populations ___________ pool over a relatively
brief period of time. Evolution is a generation
to generation change in a populations frequency
of _________________. Because this is evolution
on the smallest scale it is called
_________________. Some Mechanisms of
Microevolution Include 1). Gene Flow
Immigration and emigration 1). Genetic drift
changes in gene pool due to chance a. The
bottleneck effect b. The founder effect 3)
Mutation spontaneously forming new alleles
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The Gene Pool
The ___________ ____________ is defined as all
the genes in a population at any one time.
Migration Immigration potential __________of
alleles as animals move __________ a population
Emigration Potential _________ of alleles as
animals move __________ of a population
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Mechanisms of Microevolution Genetic Drift
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In small populations less common _____________can
be lost within the gene pool due to chance. In
the example above, if only a few flowers survive
each year the chances that less common traits can
be lost is very possible leading to a loss of
genetic ________________.
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Gnetic Drift and the Bottleneck Effect
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When a catastrophe strikes a population only a
few individuals survive to carry on the
_____________. Therefore only the alleles those
organisms carry will remain in the population
gene__________.
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Genetic Drift and the Founder Effect
In a very small colony of new inhabitants, the
genetic _______________will represent only a
fraction of that of the original ______
______. Therefore, only a few alleles will be
present in that Founding Population. .
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Mechanisms of MicroevolutionMutation
A mutation that occurs in _________ or __________
can immediately change the gene pool of a
population by substituting one allele for another
.
Mutation is the original source of the genetic
variation that serves as raw material for
____________ selection
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Three Outcomes of Natural Selection
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• Directional Selection -
• Disruptive Selection -
• Stabilizing Selection -

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Thats All for Chapter 13Homework is due ______?
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