Evolution and Ecology

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Evolution and Ecology
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Evolution and Ecology Evolution and ecology are
intimately related
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Evolution and Ecology Evolution and ecology are
intimately related Ecology describes the
interactions between organisms and the
environment These interactions may be the product
of evolutionary change And these interactions may
select and direct future change
Past Evolutionary Responses
Current Ecological Dynamics
New Evolutionary Direction
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Peter and Rosemary Grant - 30 years of Research
on Darwin's Finches
Geospiza fortis
medium sized ground finch
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Peter and Rosemary Grant - 30 years of Research
on Darwin's Finches
pronounced drought in '76-'78 G. fortis on
Daphne major crashed...
Geospiza fortis
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Peter and Rosemary Grant - 30 years of Research
on Darwin's Finches
and seeds got larger.....
Geospiza fortis
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Peter and Rosemary Grant - 30 years of Research
on Darwin's Finches
and the survivors of the drought had
significantly larger bills for cracking these
larger seeds.....
Geospiza fortis
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Evolution and Ecology I. Responses to
Environmental Change - BY INDIVIDUALS
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Evolution and Ecology I. Responses to
Environmental Change - BY INDIVIDUALS Obviously
these responses are under selective control at
the level of the population, and the tendency to
respond in these ways can be inherited and
selected for.
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Evolution and Ecology I. Responses to
Environmental Change A. Habitat Selection
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Evolution and Ecology I. Responses to
Environmental Change A. Habitat Selection -
an adaptive response to variation in habitat
quality is to select the highest quality habitat.

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Evolution and Ecology I. Responses to
Environmental Change A. Habitat Selection -
an adaptive response to variation in habitat
quality is to select the highest quality habitat.
- this may even be at the level of
microhabitats
Desert Iguana - keeps temp in a fairly narrow
range by dial microhabitat selection. Basking to
warm and finding shade to cool.
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Evolution and Ecology I. Responses to
Environmental Change A. Habitat Selection -
an adaptive response to variation in habitat
quality is to select the highest quality habitat.
- this may even be at the level of
microhabitats
Desert Iguana - keeps temp in a fairly narrow
range by dial microhabitat selection. Basking to
warm and finding shade to cool. In this case,
habitat quality keeps the lizards temp fairly
constant. A good habitat has a range of refuges
from heat and cold
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Evolution and Ecology I. Responses to
Environmental Change A. Habitat Selection -
an adaptive response to variation in habitat
quality is to select the highest quality habitat.
- this may even be at the level of
microhabitats - habitat selection may depend on
population density
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1. Organisms select the highest quality habitat
High
Habitat Quality
Medium
Low
Low
High
Population Density
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1. Organisms select the highest quality
habitat 2. As density increases, quality declines
High
Habitat Quality
Medium
Low
Low
High
Population Density
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1. Organisms select the highest quality
habitat 2. As density increases, quality
declines. 3. Eventually, it is equal in
quality to empty habitat of medium quality
High
Habitat Quality
Medium
Low
Low
High
Population Density
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1. Organisms select the highest quality
habitat 2. As density increases, quality
declines. 3. Eventually, it is equal in
quality to empty habitat of medium quality
High
Habitat Quality
Medium
4. So both will fill and decline in quality
This is the Fretwell-Lucas model of habitat
selection.
Low
Low
High
Population Density
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Evolution and Ecology I. Responses to
Environmental Change A. Habitat Selection -
an adaptive response to variation in habitat
quality is to select the highest quality habitat.
- this may even be at the level of
microhabitats - habitat selection may depend on
population density - it may involve long
distance migration
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1.5 million wildebeest migrate throughout the
year, following seasonal rains
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1.5 million wildebeest migrate throughout the
year, following seasonal rains
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Evolution and Ecology I. Responses to
Environmental Change A. Habitat Selection -
an adaptive response to variation in habitat
quality is to select the highest quality habitat.
- this may even be at the level of
microhabitats - habitat selection may depend on
population density - it may involve long
distance migration - or temporal "selection"
through hibernation/aestivation/diapause
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13-lined ground squirrel
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Tardigrades can survive in a dehydrated 'cask'
state called a 'tun'. The process is
cryptobiosis, and they then rehydrate and
survive.
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Tardigrades can survive in a dehydrated 'cask'
state called a 'tun'. The process is
cryptobiosis, and they then rehydrate and
survive. Several times a day, and survive for
years...
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Evolution and Ecology I. Responses to
Environmental Change A. Habitat Selection
B. Store Resources - tubers
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Evolution and Ecology I. Responses to
Environmental Change A. Habitat Selection
B. Store Resources - tubers - fat
(steatopygia in humans)
Andamese pygmy
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Evolution and Ecology I. Responses to
Environmental Change A. Habitat Selection
B. Store Resources - tubers - fat
(steatopygia in humans) - cache
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Evolution and Ecology I. Responses to
Environmental Change A. Habitat Selection
B. Store Resources - tubers - fat
(steatopygia in humans) - cache
Many desert ants in Australia have a worker caste
called 'repletes' that hang from the roof of the
nest and are fed sugar... they are the colony's
storehouse.
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Evolution and Ecology I. Responses to
Environmental Change A. Habitat Selection
B. Store Resources C. Forage Efficiently 1.
Optimal Foraging Theory predicts that selection
will maximize energetic efficiency rate of
energy acquisition/travel, search, and handling
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1. Optimal Foraging Theory predicts that
selection will maximize energetic efficiency
rate of energy acquisition/travel, search, and
handling Typically, this relationship is NOT
constant
Energy Acquired
Time Investment
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1. Optimal Foraging Theory predicts that
selection will maximize energetic efficiency
rate of energy acquisition/travel, search, and
handling Typically, this relationship is NOT
constant. Rather, there are "diminishing
returns"
Energy Acquired
Time
Travel
Search/Handling
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1. Optimal Foraging Theory predicts that
selection will maximize energetic efficiency
rate of energy acquisition/travel, search, and
handling Typically, this relationship is NOT
constant. Rather, there are "diminishing
returns"
Same payoff in long time
Energy Acquired
big payoff in little time
Time
Travel
Search/Handling
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1. Optimal Foraging Theory predicts that
selection will maximize energetic efficiency
rate of energy acquisition/travel, search, and
handling Typically, this relationship is NOT
constant. Reduce travel time, spend less time
searching ....
Energy Acquired
Time
Travel
Search/Handling
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1. Optimal Foraging Theory predicts that
selection will maximize energetic efficiency
rate of energy acquisition/travel, search, and
handling Typically, this relationship is NOT
constant. Increase travel time, each try better
be worth it .... greater search time
Energy Acquired
Time
Travel
Search/Handling
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Evolution and Ecology I. Responses to
Environmental Change A. Habitat Selection
B. Store Resources C. Forage Efficiently 1.
Optimal Foraging Theory predicts that selection
will maximize energetic efficiency rate of
energy acquisition/travel, search, and
handling 2. Energetic reward can be balanced by
other costs, too like risk of predation.
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2. Energetic reward can be balanced by other
costs, too like risk of predation.
Risk-Sensitive Foraging If you are going to risk
death, the payoff better be huge. Juvenile Creek
Chubs will forage in the presence of a predator
(adults) if their prey density increases, too.
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2. Energetic reward can be balanced by other
costs, too like risk of predation.
Risk-Sensitive Foraging If you are going to risk
death, the payoff better be huge. Juvenile Creek
Chubs will forage in the presence of a predator
(adults) if their prey density increases,
too. And as the density of adults increase, the
chubs will only forage in this space if their own
prey is ALSO increased... suggesting that they
are responding to the ratio of potential risk to
potential reward.
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Evolution and Ecology I. Responses to
Environmental Change A. Habitat Selection
B. Store Resources C. Forage Efficiently 1.
Optimal Foraging Theory predicts that selection
will maximize energetic efficiency rate of
energy acquisition/travel, search, and
handling 2. Energetic reward can be balanced by
other costs, too like risk of predation. 3.
Prey Choice Invest more for higher quality
reward. Avoid low quality, because the return
rate is poor. you waste time gathering low
quality food, and pass up opportunity to invest
time in high quality food.
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Evolution and Ecology I. Responses to
Environmental Change A. Habitat Selection
B. Store Resources C. Forage Efficiently 1.
Optimal Foraging Theory predicts that selection
will maximize energetic efficiency rate of
energy acquisition/travel, search, and
handling 2. Energetic reward can be balanced by
other costs, too like risk of predation. 3.
Prey Choice Invest more for higher quality
reward. Avoid low quality, because the return
rate is poor. you waste time gathering low
quality food, and pass up opportunity to invest
time in high quality food. Specialists will tend
to forage on higher quality food...
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Evolution and Ecology I. Responses to
Environmental Change A. Habitat Selection
B. Store Resources C. Forage Efficiently 1.
Optimal Foraging Theory predicts that selection
will maximize energetic efficiency rate of
energy acquisition/travel, search, and
handling 2. Energetic reward can be balanced by
other costs, too like risk of predation. 3.
Prey Choice Invest more for higher quality
reward. Avoid low quality, because the return
rate is poor. you waste time gathering low
quality food, and pass up opportunity to invest
time in high quality food. Specialists will tend
to forage on higher quality food... 4. Prey
Density
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4. Prey Density a. Type I functional response
captured is a constantly function () of of
prey available or of predators.
L-V
   
 
Prey Captured
Prey Density
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4. Prey Density a. Type I functional response
captured is a constantly function () of of
prey available or of predators. b. Type II
functional response success rate declines at
higher prey density either as a result of pred
handling time, satiation, or failure to focus on
single prey item (the benefit of
flocking/schooling behavior).
L-V
   
 
Prey Captured
Prey Density
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4. Prey Density a. Type I functional response
captured is a constantly function () of of
prey available or of predators. b. Type II
functional response success rate declines at
higher prey density either as a result of pred
handling time, satiation, or failure to focus on
single prey item (the benefit of
flocking/schooling behavior). c. Type III
functional response At low densities of prey,
the predator does poorly because they do not
develop a good search image or an efficient
strategy.
L-V
   
 
Prey Captured
Prey Density
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Evolution and Ecology I. Responses to
Environmental Change A. Habitat Selection
B. Store Resources C. Forage Efficiently
Largely Behavioral and Very "Plastic"
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Evolution and Ecology I. Responses to
Environmental Change A. Habitat Selection
B. Store Resources C. Forage Efficiently D.
Acclimation - reversible, physiological change in
tolerance range
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D. Acclimation - reversible, physiological
change in tolerance range
The relationship between Goldfish swimming speed
at different temperatures correlates with
acclimation temp.
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More likely for species that experience a
variable environment
Larrea - desert plant that experiences hot
summers and cold winters, and can acclimate to
both
Atriplex -Inhabits cold coastal habitats and
can't acclimate to hot temps.
Tidestromia - heat adapted species that ccan't
adapt to cold temps.
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More likely for species that experience a
variable environment
Atriplex -Inhabits cold coastal habitats and
can't acclimate to hot temps.
Tidestromia - desert species that can't adapt to
cold temps.
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More likely for species that experience a
variable environment
Larrea - desert plant that experiences hot
summers and cold winters, and can acclimate to
both