Transcript This week`s lab: Meet directly in 164D Burrill

This week’s lab: Meet directly in 164D Burrill
Bring completed Homework 4: Excel + ‘t-test’
(Lab I: Does caloric content determine food
choice of small mammals?)
Use all data from 1+5yr; n=16 pairs of dishes
Read Lab III (will complete HW 2B + 5 in lab)
Print, read, bring paper @ SDP-1 topic
(see pg. 105)
Review SDP-1 schedule + due dates
(see pg. 3 or 101)
Next lecture Ch 16: Population Genetics
Population Ecology
Genetics Evolution
Darwin’s finches…
Sample exam question
Each of 3 evergreen tree species is restricted to certain soils in Oregon.
Each is transplanted to grow in soils in which it is not-native. Shown
in the table is the growth response of each species grown in each
soil type (acid=high in H+; normal; serpentine= high in Mg++).
1.
2.
3.
Develop an ‘if…then’ hypothesis…prediction for this experiment.
The growth of which species coincide with the prediction and lend
support to the hypothesis?
Propose an ecological factor that may be restricting growth of
Pygmy cypress in its native acid soil.
Soil Type
Lodgepole Pygmy
Cypress
pine
Sargent
Cypress
Acid
5*
3*
3
Normal
3
25
12
Serpentine
3
10
20*
* = native to this soil type
Sample exam ? Given these components
of a heat budget for a desert hare, what is
its heat balance = S? Is it gaining or
losing heat?
Metabolism
8 Kcal/hr
Evaporation
2
Net radiation
-8
Net convection -4
Net conduction +2
What environmental conditions is the hare
likely to be experiencing?
How could it improve its situation?
Ch 9
Adaptation to Life in Varying Environments
Objectives
• Responses to a variable environment
•
Avoidance
•
Alter the environment
•
Change phenotype to match environment
•
Acclimation and acclimitization
•
Developmental response
•
Regulation (vs. conform)
• Responses to variable food
***Sample exam question…
3 species grown in both hot + moderate temp;
then PS rate of both groups of plants was
measured at a range of temperatures.
Red: raised in hot T
Blue: raised in moderate T
1. What is the major question being
addressed in this experiment?
2. Describe how Larrea and Tiderstromia
responded relative to the temperatures at
which it was grown.
3. What is the likely mean temperature (high
or moderate) of Larrea and Tiderstromia?
4. What is the likely temperature range
during the year (high or low) of Larrea and
Tiderstromia? Explain.
5. What is the major conclusion of the
experiment?
What types of environmental variation
demand adaptations of individuals?
• Spatial heterogeneity:
variation in space
• Temporal heterogeneity
variation in time
Activity space: conditions of the environment
in which an organism can live and reproduce.
A) Avoid unfavorable environment by
changing activity space.
Animals can select microhabitats whose
physical conditions fall within their activity
space.
***What are two major results. What explains
the daily pattern of the bird’s selective use of
microhabitats?
When conditions exceed tolerances
B) migration: move to favorable conditions
Migration: a developmental response of
young locusts to high population density.
Migratory path of a female sea turtle
C) Storage: reliance on resources
accumulated under more favorable
conditions.
D) Dormancy: become inactive
• Plants:
Drop leaves
Seeds inactive
• Animals:
Hibernate
Diapause
2) Animals build structures to modify their
microhabitat. ***What is the advantage of
changing the orientation of the nest?
15-20 kph
20 C
15-20 kph
15 C
3) Change the phenotype to better match the
new environment.
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•
•
•
•
•
•
The phenotype is the expression of the genotype:
structure
function
behavior
of the individual organism.
Phenotype = Genotype + Environment
If variable environment  variable phenotype?
Phenotypic change in
pigmentation in a
species; not genetic
difference.
***What accounts for
change?
Phenotypic plasticity:
• Environmentally-induced variation in the
phenotype
• Capacity for plasticity may itself be an
evolved trait
Populations may differ in
extent of phenotypic plasticity.
Possible phenotypic (physiological)
responses to a variable environment:
• Acclimation:
• Acclimitization:
• Developmental response
1) Acclimation (reversible):
• short-term change in structure or
function (biochemical pathways)
• shift in range of physiological
tolerances of an individual
• requires longer periods (days or weeks)
than behavioral or metabolic changes.
*** What is this fish’s response to a
variable environment? Is it adaptive?
Would fish have acclimation ability if lived
in constant, narrow temperature range?
Changing phenotype to match prevailing
conditions often involves changes in
enzyme structure.
Upper critical (lethal) temperature
depends on acclimation temperature.
2) Acclimitization:
• change in response to seasonal
(predictable) environmental changes
• plays a prominent role in responses
of long-lived organisms to seasonal
change
• E.g….
3) Developmental responses (nonreversible):
• permits organism to respond to
varying environments during its
growth
• changes in response to persistent
variation in the environment
Developmental responses are irreversible.
***What’s the morphological response to sun
vs. shade? What’s the advantage?
Regulation (homeostasis): maintain steady
internal conditions against an external
gradient.
Regulators vs conformers
Neutral zone for
regulators
Internal
conditions
Conformer
Regulator
External conditions
Endotherms - thermoregulator
Ectotherms -thermocomformer
What are advantages / disadvantages?
Body temp
Air temp
Homeostasis: what are costs? benefits?
Body
temp
O2 use
Air temp
Partial homeostasis: reset internal
temperature control while in torpor.
O2 use
Air temp
***Compare the total annual energy budget
and energy per unit mass in endotherms vs.
ectotherms.
Which animal would spend the >% of energy
on thermoregulation? Why?
body mass
human
60 kg
penguin
4
mouse
.025
python
4
kcal/yr kcal/kg/da
800,000
36.5
340,000
233
4,000
438
8,000
5.5
Possible responses to a variable
environment:
• Avoid the variable environment
• Alter the environment
• Change phenotype to better match the
environment
• Expend energy to regulate internal
environment
Food supplies vary in space and time,
and in quality of prey items.
• Animals must make choices about
when
where
how long
what
to feed that maximize their fitness.
• Optimal foraging theory
• Behavioral ecology
Dylan’s Hypothesis/Prediction
• If food availability limits the breeding
season of grackles,
• Then the
Faced with variable E, animals forage to:
•
•
•
optimize net capture of resources per unit time
minimize risk
balance nutritional needs  maximize fitness.
Food loads increase with travel times.
Central place foraging:
• when animals are tied to a particular place
• must deliver food to a fixed place 
• tradeoffs (costs/risks vs. size of forage area
• Risk-sensitive foraging:

value of feeding area is reduced by presence of risks,
especially predation.
***Optimal foraging theory vs. actual
foraging…
• 1) Swingtail birds nest on oceanic island; fish food is in
an upwelling 60 km away. What kind of foraging
situation is this?
• 2) Foraging cost is tied to travel time to and from
upwelling.
60 km/hr - no fish
15 km/hr - 2 fish
30 km/hr - 1 fish in bill 5 km/hr - 3 fish
How much time is required for a round trip with 1, 2 and
3 fish?
• 3) Considering only the efficiency of foraging (hrs/fish),
how many fish returned per trip = most efficient use of
bird’s foraging time?
***continued
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At this latitude there are 15 hr time for fishing
each day.
4) For fishing trips with a return of 1, 2, or 3
fish, how many fish per day can they bring to
the nest?
5) How does total catch of fish per day
compare with fishing efficiency?
6) From an evolutionary perspective, which
behavior (return with 1, 2, or 3 fish) would you
expect the bird to use? Why?
7) Most fish return with 1 fish from each trip.
How can you explain this observation when
they catch fewer fish per day than birds
returning with 2 fish per trip?
Avoid high-risk areas unless plentiful food.
Why do foragers consume a mixed diet?
1) Complementarity of amino acids
2) avoid high doses of plant toxins
***Sample exam question…
3 species grown in both hot + moderate temp;
then PS rate of both groups of plants was
measured at a range of temperatures.
Red: raised in hot T
Blue: raised in moderate T
1. What is the major question being
addressed in this experiment?
2. Describe how Larrea and Tiderstromia
responded relative to the temperatures at
which it was grown.
3. What is the likely mean temperature (high
or moderate) of Larrea and Tiderstromia?
4. What is the likely temperature range
during the year (high or low) of Larrea and
Tiderstromia? Explain.
5. What is the major conclusion of the
experiment?
EC…Feedback time…
1) What do you like about teaching of
lecture?
2) What would you like changed/improved?
3) What would make for a better learning
environment?
Summary: Caveats
There are limits to evolutionary responses to
environmental change.
Evolution does not produce perfect organisms for
every suitable habitat.
Not all evolved behavior remains adaptive,
particularly in ecosystems modified by humans.
Populations can’t evolve overnight.
What happens when humans alter the environment
rapidly and in new ways?
Do organisms have the ability to respond
appropriately?
Objectives
• Responses to a variable environment
•
Avoidance
•
Alter the environment
•
Change phenotype to match environment
•
Acclimation and acclimitization
•
Developmental response
•
Regulation (vs. conform)
• Responses to variable food
Vocabulary
Chapte r 9 Adaptation* to Life in Varying Environments
genotype*
fitness*
heterozygous*
recessive*
activity spac e
acclimation
dormancy
proximate factors
complementary
developmental response
endothe rm
partial homeostasis
optimal foraging
evolution *
phenotype *
homozygous*
codominant
microhabitat s
migration
hibe rnate
ultimate factors
reaction norm
regulation
ectotherm
torpor
central place foraging
natural selection*
alleles*
dominant*
phenotypic plasticity
microenvironments
storage
diapause
photope riod
acclimatization
conformer
homeostatis
risk-sensitive foraging