Transcript Species Distribution Adaptation & Acclimation

Physiological
Ecology
Species
Distribution
The Fundamental Tasks of
Living
 Physiology
work.


is the study of how organisms
How nutrients are acquired & transported.
How wastes are eliminated.
 Ecology
is concerned with how species
deal with their environments and how the
environment limits distribution.

Both directly affected by physiology.
Do Species Distributions form
Patterns?
 Each
place has a unique assortment of
plants and animals.
 Animals and plants are adapted to their
environments.
Do Species Distributions form
Patterns?
 Which
two
pictures were
taken closest to
each other?
A&B
 A& C
A&D
B&C
Do Species Distributions form
Patterns?
 Many
factors influence the distribution of
organisms:
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Land or water
Amount of nutrients available
Amount of sunlight available
pH
Other species present
Do Species Distributions form
Patterns?
 The
two most important factors in a
terrestrial environment:
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Moisture
Temperature
 From
the way
the Valdivian
forest looks
compared to
the other
locations, which
labeled point on
the graph would
you expect to
represent its
annual
temperature
and
precipitation?
Whittaker Diagrams

The Whittaker
Diagram
suggests that the
average
temperature
and
precipitation of
a particular
location controls
what type of
vegetation may
grow there.
Temperature vs Water
 Temperature
and precipitation combine
to control the amount of water available
to plants and hence, its overall health.

Physiological tolerances describe what a
plant can tolerate.
 Max/min
temperatures
 How much water is required
Temperature vs Water

Water enters a plant
through the roots.
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Travels up through the
plant
Is lost at the leaf
surfaces –
Transpiration
Water is also lost
through evaporation
from the soil surface.
The total amount of water available to plants in
any ecosystem is a balance between incoming
precipitation and outgoing evapotranspiration.
Potential Evapotranspiration
 The
amount of water loss from an
ecosystem at a given temperature is
known as the Potential
Evapotranspiration (PET).
 To avoid desiccation, a plant will need to
access an amount of water that is equal
to or greater than PET.
Climate Diagrams
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
The PET can be read from
the temperature line on
the climate diagram,
because, as you saw,
potential
evapotranspiration (in
mm) is approximately
twice temperature (in °C).
Where the precipitation
graph line lies above the
temperature line,
precipitation is greater
than PET. If precipitation
lies below temperature,
precipitation is less than
PET.
Tolerances Define Species
Ranges
 Every
species has a limited tolerance to
different environmental variables that
determine its geographic range, including
not only temperature and precipitation,
but also the many other variables we
mentioned earlier. The sum of these
conditions is sometimes referred to as a
species’ niche.
Tolerances Define Species
Ranges

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The speed of a
desert night lizard
increases up to
35 °C, then drops.
Physiology plays
a large role in
determining the
range of areas
where you will
see any given
species.
Tolerances Define Species
Ranges
 Temperature
and precipitation are very
important, but sometimes they don’t tell
the whole story.
 For example spruce require an
environment where precipitation is above
PET throughout the year.

In Georgia, precipitation is above PET, but
spruce don’t occur.
 Competition?
Soil drainage? Nutrients?
Law of the Minimum
 Liebig,
working in the 1800’s, suggested
that growth and reproduction are limited
by the rarest resource.
Shifts in Species Ranges
 The
geographic range of a species can
change over time.

As the ice receded after the last ice age,
organisms moved back into the area.
 Measured
using pollen in core samples.
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Spruce tree distribution over the past 21,000 years. Ranges were
reconstructed from depth-specific pollen grain counts in lake sediments.
Blue indicates glaciated areas. Green indicates spruce range, with darker
green suggesting higher spruce density. Data courtesy Williams et al.
2004 and the National Climatic Data Center.
Physiological Ecology
 Each
species has an optimal environment
and tolerance to a variety of conditions.
 If conditions change a species can
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Migrate with climatic conditions
Go extinct
Adapt to the new conditions
Physiological Ecology
 Adaptation
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to new conditions can occur:
As individuals acclimate or
As populations evolve
Adaptation &
Acclimation
Adaptation and Acclimation
 Dams
result in
warmer water
downstream.
 Temperature is an
important factor
for many species.
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Will it affect the
trout living in the
stream?
Trout Physiology
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Enzymes are proteins that catalyze reactions.
Change shape during the process.
Affected by temperature.
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High temps denature enzyme – doesn’t work.
Low temps decrease flexibility – doesn’t work.
Trout Physiology

Trout living
above the dam
(cool) and
below the dam
(warm) have
enzymes that
have different
optimal temps.
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Genetic
adaptation or
individual
acclimation?
Acclimation
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Experiment to
determine if
individual fish
acclimate.
The optimal
temperature for the
enzyme adjusts
upward over a few
weeks.
No reproduction
involved – not
genetic.
Adaptation through Evolution
 Acclimation

No reproduction
 What

occurs in the short-term.
happens over several generations?
Each generation of fish receives a new mix
of alleles.
 Some
may be better for high temperatures.
 They may adapt to high temperatures
through natural selection.
Managing Dams
 Large
dams pull
water from deeper
under water
resulting in cooler
summer
temperatures and
warmer winter
temperatures.
Managing Dams
 Mixing
deep and
shallow water
alleviates the
problem, but
doesn’t eliminate it.
 Still working to
restore native
fishes.
 Small dams can
often just be
removed.
Homeostasis
Homeostasis
 Homeostasis
occurs when an organism
maintains relatively constant internal
conditions.
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Temperature
pH
Salinity
 Some
organisms can tolerate a wide
range of conditions, some narrow.
Surface Area to Volume Ratio
 Organisms
interact with their environment
through the surfaces of their bodies.
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Much of the exchange of heat and water
occur across the skin.
The amount of skin, or surface area, is a key
to homeostasis.
Surface Area to Volume Ratio
 Surface
area –
exposed surface.
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Sphere: πd2
Cube: 6w2
 Volume
– internal
capacity.
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Sphere: π/6 d3
Cube: w3
Surface Area to Volume Ratio
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A thermoregulating
kangaroo rat gains
and loses heat via
several processes
which we account
for using the heat
balance equation.
These heat inputs
and outputs must
balance (summing
to near zero) for the
animal to maintain
homeostasis.
Surface Area to Volume Ratio
 Heat
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can be gained an lost through:
Radiation from sun
Metabolic heat
Re-radiation
Conduction
Convection
Loss of heat with water (latent heat)
Surface Area to Volume Ratio
 Ectothermic
animals rely on the
environment to
regulate their
temperature.

Large surface area
in contact with
warm ground &
exposed to sun.
Adaptations for Controlling
Internal Temperature
 Change

Seek shade/sun
 Use

behavior
color
Dark to absorb heat, light to reflect heat
 Insulation
Water Balance
 Ingestion

Animals can take
in water by
ingesting it – from
water they drink or
in foods they eat.
Water Balance
 Secretion

Water lost through
excretion of
metabolic wastes
and elimination of
fecal waste.
Water Balance
 Absorption
– most
aquatic animals
can absorb water
through their skin.

Bodies saltier than
the freshwater
they live in so
water enters their
bodies.
Water Balance
 Metabolism

of food
During cellular
respiration, sugar
(glucose) is broken
down into carbon
dioxide, water,
and free energy.
Water Balance
 Evaporation
– loss
of water from the
surface of the
organism.

Provides cooling
Adaptations for Water
Conservation
 Desert
dwelling
tenebrionid beetles
use behavior to
harvest moisture
from fog.
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Abdomen up,
water condenses
and rolls down
grooves to mouth.
Trade-offs in Water Balance
 Kangaroo
rat tradeoff between water
balance and heat balance.
 Plants have a tradeoff between
photosynthesis and water balance.
Why be a Mammal?

Mammals are
endothermic &
homeothermic.
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They produce their
body heat internally
and maintain a
steady temperature.
Requires lots of
energy!
Optimal
temperature for
metabolism is always
available.
Metabolism
Metabolism
 All
organisms require energy to fuel their
metabolism and nutrients to build their
bodies.
Photosynthesis
Energy arrives as
sunlight.
 Plants use
photosynthesis to
make glucose from
carbon dioxide &
water using energy
from the sun.
 Bonds in glucose store
energy.
6 CO2 + 12 H2O + sunlight → C6H12O6 + 6O2 + 6H2O
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Respiration
 When
organisms need energy, they can
break the bonds in glucose during cellular
respiration.
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C6H12O6 + 6O2 → 6 CO2 + 6 H2O + free energy
Photosynthesis
 Light

Reactions
Sunlight hitting
chlorophyll
molecules
energizes electrons
to power creation
of first NADPH, then
ATP.
Photosynthesis
 Light
Independent
Reactions

Rubisco uses the
energy stored in
NADPH and ATP
from light reactions
to carry out
carbon fixation.
Photorespiration
 Rubisco
can bind
to oxygen instead
of carbon dioxide.


Destroys the sugar.
Depends on
concentrations of
carbon dioxide vs
oxygen.
C4 Photosynthesis
 Some
plants that
grow in hot
climates separate
light dependent
and light
independent
reactions into
different cells.
Water Potential
 Plants
take up water through their roots
and lose water through pores in the
leaves.
 Pores in the leaves of plants (stomata)
open to take in carbon dioxide for
photosynthesis.

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Release oxygen and water.
Transpiration
Water Potential
 Water
moves from
an area of higher
water potential to
lower water
potential.
 Increased humidity
in the air will make
water move more
slowly through the
plant.
Cavitation
 At
low humidity,
the tension in the
water column. As
the molecules pull
away, air bubbles
can form.
 Interferes with a
plant’s ability to
take up water.
Soil Type Affects Water
Potential
 Attraction
of water to soil decreases its
mobility.
 Finer particles (clay) of soil have more
surface area for water molecules to
adhere to – lower water potential.

Requires more suction to pull water out of
soil.
Solutes Affect Water Potential
 Adding
solutes to the water decreases
water potential.
Controlling Water Flow
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Water can only flow from
high to low water
potential if there is an
open route.
Add a valve to the top of
the straw.
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Partially closing the valve
allows the plant to avoid
cavitation at lower
humidity.
Closing the valve stops
the flow.
Controlling Water Flow
 Leaves
have a
waxy coating to
prevent water
loss.
 Stomata can
open/close like
valves to
conserve water.
Xylem
 The
xylem is a
series of tubes that
carry water
through the plant.
 Tradeoff between
having narrow
tubes to prevent
cavitation and
wider tubes to
carry more water.
CAM and Water Conservation
 CAM
is a third type of photosynthesis
where light dependent reactions and light
independent reactions are separated in
time.
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Stomata open at night to let carbon
dioxide into the leaf. High humidity at night
reduces risk of cavitation.
Stomata closed during the day. Light
dependent reactions can now occur using
the carbon dioxide taken up at night.
Ingestion by Heterotrophs
 Heterotrophs

can’t make their own food.
Take in food from the environment.
 Herbivores
 Carnivores
 Decomposers

Specialists vs Generalists
 Tradeoff
between availability & efficiency
Plant Nutrient Acquisition &
Mycorrhizae
 Plants
acquire
nutrients from the
soil.
Increased surface
area will help
gather more water
and nutrients.
Plants solve this problem by associating their roots
with fungi in a mutualism called mycorrhizae. The
plant provides the fungus with sugars and in return
the fungus grows out into the soil and transports
nutrients to the plant.
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