Chapter%205:%20Evolution%20and%20Community%20Ecology

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Chapter 5 Evolution and Community Ecology

• Mr. Manskopf
• Notes Can Also Be Found at
• http//www.manskopf.com

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Section 1 Evolution

• Describe the four primary mechanisms of
  biological evolution
• Describe how speciation and extinction affect the
  diversity of life on Earth.
• TERMS evolution, gene mutation, genetic drift,
  natural selection, fitness, adaptation,
  artificial selection, speciation, extinction.

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Incredible Diversity of Life

• 1.5 to 1.8 million known species
• Possibly 13-20 million
• Tropical Rain Forests, Coral Reefs and everywhere
  else

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Evolution

• What makes you, YOU?

What makes each species unique and different?
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Genes

• Sequences of DNA codes for each particular trait
• Tall, small, blue eyes, human, goldfish, pine
  tree
• Evolution is a change of genes over time

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Evolution

• Change over time
• Change of Gene Pool over time
• Why would genes change over time?

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4 Ways Evolution Occurs

• Mutation
• Migration
• Genetic Drift
• Natural Selection

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Mutation
Accidental change in DNA that can give rise to
variation among individuals
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Migration
Movement of individuals into (immigration) or out
of (emigration) a population
Sometimes called Gene Flow
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Gene Flow (Migration)
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Genetic Drift

• Evolution that occurs by chance
• Natural Disasters
• Run in with human nets, etc.

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Natural Selection

• Process by which traits useful for survival and
  reproduction are passed on more frequently than
  those that are not

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3 Conditions for Natural Selection

• Organisms produce more offspring than can
  survive.
• Nature has limitations (limiting factors)
• Struggle for survival

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3 Conditions for Natural Selection

• (2) Individuals vary in characteristics, some of
  which are heritable
• Not every species is same
• Some fish are faster, darker, smaller
• Genes different
• Heritable Differences

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3 Conditions for Natural Selection

• (3) Individuals vary in fitness, or reproductive
  success
• Survival of Fittest
• Fittest for its environment
• Adaptation an inherited trait that increases an
  organisms chance of survival and reproduction.

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http//www.youtube.com/watch?vxkwRTIKXaxg

• Travel to Ecuador to see how the process of
  natural selection operates

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Adaptations
Desert plants have small or no leaves at all
The insect that blends in and is able to survive
may be more likely to reproduce.
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Adaptations
White coat of polar bear helps in hunting Results
of natural selection all around us NATURE SELECTS
Big ears of desert jack rabbit allow it to cool
off quickly
Long neck of giraffe allow it to reach food
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Did You Know? Darwin privately researched natural
selection for two decades before publishing On
the Origin of Species.
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Impacts of Natural Selection Resistance
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Resistance

• Resistance the ability of one or more organisms
  to tolerate a chemical designed to kill it
• Able to survive and reproduce
• Pesticide resistance
• Antibiotic resistance

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Why is this a problem?
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Artificial Selection How Humans Use Evolution

• Artificial Selection selective breeding of
  organisms by humans
• Selecting certain desirable traits
• Size, sweetness, color, shape,
• Very common

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Artificial Selection
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Artificial Selection
Selecting desirable traits and breeding only
those with those traits.
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Speciation How did we get millions of species?
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• Speciation
• Process by which new species are generated
• Can occur in a number of different ways the most
  important way is called allopatric speciation
  Geographic Isolation
• Has resulted in every form of life on Earth
  today and in the past

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The canyon is a barrier to dispersal by small
mammals, and as a consequence the isolated
populations can diverge.
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http//www.youtube.com/watch?vS4wnJp6sq_I
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Extinction

• The disappearance of species from Earth
• Generally occurs gradually, one species at a
  time, when environmental conditions change more
  rapidly than the species can adapt
• There are five known mass extinction events, each
  of which wiped out a large proportion of Earths
  species.

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Biodiversity has increased over time, but mass
extinctions are also natural events (5 major
events) How do we get this data?
Did You Know? During the Permo-Triassic
extinction 250 million years ago, 70 of all land
species and 90 of all marine species went
extinct.
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Extinctions

• Species gone forever
• NORMAL
• Mass Extinction short period of time when large
  number of species go extinct (65 MYA)
• Currently in mass extinctioncaused by humans
• Rapid climate change

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Extinctions
The zebra mussel has completely displaced 20
native mussel species in Lake St. Clair.
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Section 1 Evolution Review

• Describe the four primary mechanisms of
  biological evolution
• Describe how speciation and extinction affect the
  diversity of life on Earth.
• TERMS evolution, gene mutation, genetic drift,
  natural selection, fitness, adaptation,
  artificial selection, speciation, extinction

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Section 1 Quiz

• 1) Which of the following best describes a
  successful individual in evolutionary terms?
• A. A successful individual possesses traits that
  are different from the traits of the rest of the
  population.
• B. A successful individual produces many
  offspring that possess unique traits.
• C. A successful individual is well adapted to its
  environment and produces offspring that survive
  to pass on genes.
• D. A successful individual will be well adapted
  to its environment and produce a few high quality
  offspring.

A. A successful individual possesses traits that
are different from the traits of the rest of the
population.
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2) In the history of the world, how many mass
extinctions have occurred?A. 5B. 7C. 10D. 13
A. 5
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3) In a mass extinction, the rate of extinction
exceedsA. 99 percent.B. 85 percent.C. the rate
of environmental change.D. the rate of
background extinction.
D. the rate of background extinction
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4) A reintroduced population of wolves in a
national park is 90 grey and 10 black,
consistent with the wolf population in other
regions. After several generations in isolation,
the national parks wolf population is 60 grey
and 40 black. The wolf population has likely
experiencedA. natural selection.B. genetic
drift.C. mutations.D. migration.

• genetic drift
• Evolution that occurs by chance

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5) When the environment changes too quickly for
an organism to adapt, what will occur?A)
EvolutionB) SpeciationC) Genetic DriftD)
Extinction
D. Extinction
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True or False
6) Two populations of a deer species are
separated when a glacier forms. After the glacier
melts, the two populations have become different
species. This is an example of allopatric
speciation.
TRUE
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Short Answer
7) A disaster wipes out 50 percent of a small
population of birds. Prior to the disaster, about
half the birds had a green wing patch and half
had a blue wing patch. Several generations after
the disaster, only 10 have a blue wing patch,
and 90 have a green wing patch. What do you
infer happened, and why?
The bird population experienced genetic drift as
the result of a sudden catastrophe. The disaster
reduced genetic diversity in the population and
changed the proportion of birds with a green wing
patch vs. a blue wing patch.
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Short Answer
8) Pronghorn are a species of extremely fast
hooved mammal that live on the plains of western
North America. They are so fast that no current
North American predator can catch them. During
the ice age, cheetahs occupied North America.
Speculate about how pronghorn became so fast.
Pronghorn probably evolved in an evolutionary
arms race with the cheetah population. They
became faster and faster to escape from cheetahs,
which were probably fast enough to catch them.
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Section 2 Species Interaction

• Discuss the factors that influence an organisms
  niche
• Compare and contrast predation, parasitism,
  herbivory
• Describe mutualism and commensalism
• TERMS niche, tolerance, resource partitioning,
  predation, coevolution, parasitism, symbiosis,
  herbivory, mutualism, commensalism.

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Species Interaction
What resources are the plants in this picture
competing for?
Competition for resources all around us
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Niche

• Describes an organisms use of resources and
  functional role in a community
• Habitat
• Food It Eats
• When, How Reproduces
• What organisms does it interact with

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Niche Impacted By Tolerance and Competition

• Affected by an organisms toleranceits ability
  to survive and reproduce under changing
  environmental conditions
• Often restricted by competition

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Tolerance Limits
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Fundamental vs. Realized Niche

• Fundamental Without competition
• Realized With competition (restricted niche)

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Competition

• Organisms compete when they seek the same limited
  resource.
• In rare cases, one species can entirely exclude
  another from using resources.
• To reduce competition, species often partition
  resources, which can lead to character
  displacement.

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Resource Partitioning
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• The zebra mussel has completely displaced 20
  native mussel species in Lake St. Clair.

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Predation (/-)

• The process by which a predator hunts, kills, and
  consumes prey
• Causes cycles in predatory and prey population
  sizes

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Predator/PreyCycles
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Predation

• Defensive traits such as camouflage, mimicry, and
  warning coloration have evolved in response to
  predator-prey interactions.

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Predation

• Some predator-prey relationships are examples of
  coevolution, the process by which two species
  evolve in response to changes in each other.

Rough-Skinned Newt
Did You Know? A single rough-skinned newt
contains enough poison to kill 100 people.
Unfortunately for the newt, its predator, the
common garter snake, has coevolved resistance to
the toxin.
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Coevolution
The Madagascar star orchid produces nectar at the
bottom part of its slim, foot-long throat. After
observing a specimen, Charles Darwin predicted
the existence of a moth with a proboscis long
enough to reach that nectar. Sure enough, decades
later the giant hawk moth of Madagascar was
discovered.
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Parasitism and Herbivory (/)

• Parasitism One organism (the parasite) relies on
  another (the host) for nourishment or for some
  other benefit
• Herbivory An animal feeding on a plant

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Parasitism and Herbivory (/)
Malaria is a disease caused by a parasite called
Plasmodium that is spread to humans by the bite
of an infected Anopheles mosquito.
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Parasitism and Herbivory (/)
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Mutualism (/) and Commensalism (/0)

• Mutualism a relationship in which two or more
  species benefit
• Commensalism a relationship in which one species
  benefits while the other is unaffected

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Mutualism (/) and Commensalism (/0)

• Clown Fish and Sea Anemones demonstrate mutualism
  because Anemones provide the Clown Fish with
  protection from predators while Clown fish defend
  the Anemones from Butterfly fish who like to eat
  Anemones.

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Mutualism (/) and Commensalism (/0)
Barnacles adhering to the skin of a whale or
shell of a mollusk
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Section 2 Review Species Interaction

• Discuss the factors that influence an organisms
  niche
• Compare and contrast predation, parasitism,
  herbivory
• Describe mutualism and commensalism
• TERMS niche, tolerance, resource partitioning,
  predation, coevolution, parasitism, herbivory,
  mutualism, commensalism.

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Section 2 Quiz

• 1) Madagascar, several species of lemur eat
  bamboo, but each species specializes in one part
  of the bambooone species eats mature bamboo
  stalks, one species eats bamboo shoots, and one
  species eats leaves. This is an example of
• A. speciation.
• B. resource partitioning.
• C. competition.
• D. niche partitioning.

B. Resource Partitioning
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• 2) In the example above, one lemur species eats
  only bamboo shoots. Bamboo shoots contain a high
  level of cyanide, a toxic chemical. This lemur
  species has developed a tolerance for a certain
  amount of cyanide. What do you think will happen
  over time?
• A. The level of cyanide in the bamboo population
  will increase.
• B. The level of cyanide in the bamboo population
  will decrease.
• C. The level of cyanide in the bamboo population
  will remain the same.
• D. The level of cyanide in the lemur population
  will decrease.

A. The level of cyanide in the bamboo population
will increase.
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3) Two species of finch live in the same
environment. Over time, one develops a larger
beak to consume larger seeds, while the other
develops a narrow beak to consume more delicate
seeds. This is an example ofA. resource
partitioning.B. character displacement.C. coevol
ution.D. competitive exclusion.
C. coevolution.
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4) An interaction in which an individual of one
species kills and consumes an individual of
another is calledA. predation.B. parasitism.C.
herbivory.D. symbiosis.
A. predation
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5) In the western United States, at the southern
edge of their range, moose are sometimes so
severely infested with ticks that they die. The
tick/moose relationship is best described
asA. predatory.B. parasitic.C. symbiotic.D. mu
tualistic.
B. parasitic.
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6) A beehive depends on pollen from flowers to
survive. Flowers depend on bees to pollinate
them. The relationship among these two sets of
organisms isA. parasitic.B. commensalist.C. her
bivoryD. mutualistic.
D. mutualistic.
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7) A niche restricted by competition is
aA. fundamental niche.B. realized
niche.C. resource partitioned niche.D. displaced
niche.
B. realized niche
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8) A deer browsing on a shrub is an example
ofA. predation.B. parasitism.C. herbivory.D. p
hotosynthesis.
C. herbivory.
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True or FalseYou have many species of bacteria
living in your gut that help you with digestion.
This relationship is best defined as commensalism.
False Mutualism
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Short Answer9) Explain the difference between
mutualism and commensalisms, with examples.
In mutualism and commensalism, both species are
unharmed. In mutualism, both species benefit, as
in the example of the hawk moth pollinating the
flower the flower is pollinated and the moth is
fed. In commensalism, one species benefits while
the other doesnt experience a negative or a
positive effect. Trees providing shade and
moisture to desert shrubs is an example of
commensalism.
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