Capter 8 Flashcards
What is Physiology?
The study of the functions of organisms and
their parts
What is physiological ecology?
The study of how organisms function in their environment
What is Ecophysiology?
Ecophysiology is an
integrative field that strives
to unite multiple
subdisciplines of biology to
solve ecological problems
- Ecophysiology: “Ecology
provides the questions, and
physiology provides the
tools to determine the
mechanisms.”
Thermobiology
The physiological mechanisms and
behavioural choices that are used to achieve a favourable energy balance
Metabolism
Heterotrophic organisms need other
organisms to fulfill energy and nutritional
requirements
* Metabolism: the
chemical processes
within living organisms
that maintain life
Aerobic metabolism
oxygen is involved in
converting carbohydrates,
lipids, proteins to ATP in
mitochondria
Anaerobic metabolism
lower efficiency production
of ATP without oxygen
* Measure metabolic rate as
oxygen consumption
(aerobic) or heat production
(anaerobic)
Ectotherms
organisms
that rely on the external
environment as the
primary source of heat
* They have slower
metabolic rates
* They can survive long
periods with little food
Endotherms
organisms that rely on their own
metabolism for warmth
* They have faster
metabolic rates, and can
remain active in cool
environments
* Retain heat by insulation
and circulatory system
* Use considerable energy
for thermoregulation
* Typically also homeotherm
Homeotherms
Organisms that maintain constant body
temperature
Heterotherms
(poikilotherms):
organisms that cannot
maintain a steady body
temperature
Heterotherms often bask
to maintain body
temperature
Endothermy/homeothermy in insects
Sphynx moths can
raise their thorax
temperature within
minutes, by muscle
contraction
Heat production
Three quarters of
metabolized energy is
released as heat
* Some mammals have
brown adipose tissue
(fat), which releases all
energy as heat without
producing ATP
Insulation
Effective
thermoregulation
requires ability to
conserve heat: insulation
* Hair and feathers work by trapping stagnant air
* Fat is also a good
insulator (mostly in
aquatic organisms)
Counter-current exchange
A counterflow mechanism that enables fluids at different temperatures flowing in channels in opposite directions to exchange their heat content without mixing.
Responce to cold
Rapid muscle
contractions (shivering)
produce heat
* Vasoconstriction reduces
heat loss
* Muscles contract to fluff
up feathers or fur when
cold (e.g. goose bumps)
Respponses to heat
- Sweating and panting
(evaporation cools) - Vasodilation, especially
in large-area organs
such as ears - Reduction of metabolic
rate - Seeking shade Warm animals may sweat,
pant, vasodilate, become
less active, and seek shade
Torpor
- Relatively short-term condition of
decreased activity - bats do this
- heart rate temperature breathing all drop
Hibernation
Long-term condition of decreased
activity in cold temperatures
(months or weeks long)
- heart
rate and
breathing slow
down and body
temperature
lowers to near
freezing
Estivation
decreased activity in hot temperatures
sleep
- no pysiological change
Antifreeze
Antifreeze proteins:
substances which
reduce the freezing
point
* Polar marine fish can
live in waters <0°C
* Ice crystals would
normally destroy cells
* Dehydration to
concentrate the
cytoplasm and avoid
crystals
Acclimatization
Acclimatization is the
physiological
adjustment of
organisms to abiotic
factors outside of their
normal zone
* Change in physiological
function smaller than
expected if organisms
have time to acclimate
Gas exchange
Oxygen is required for
mitochondrial
respiration, and CO2
must be removed
* Oxygen transport
system is required,
except in very small
organisms (e.g. insects)
* Organs for gas
exchange: lungs and gills
Gills and gas exchange
Gills: The gas
exchange surfaces of
aquatic animals
* Water is more viscous
than air; more energy
is needed to move
water over exchange
surface
* If water is cold, heat
loss is considerable
Gas exchange in air
- Lungs and tracheal
systems are gas
exchange surfaces in
terrestrial animals - Some amphibians
exchange gases through
skin - Water loss due to
evaporation is a problem
in dry climates Aquatic mammals and
reptiles also breathe air
Respiratory pigments
Respiratory pigments
(e.g. hemoglobin) allow
more gas transport in
body fluids
* Blood plasma carries
3mL O2/L without
hemoglobin; 200 mL O2/L
with hemoglobin
* Pigments are especially
important for animals
with high metabolic rates
Physiological ecology of plants
Plants are autotrophs
rooted in a fixed place, requiring:
* Light
* CO2
* Water
* Mineral nutrients
* Suitable temperature
What is the formula for photosynthathis
Sunlight + 6CO2 + 6H2O → C6H12O6 + 6O2
Stomata
Where carbon dioxide enters and oxygen and water vapour leaves
Light reactions
- Absorption of sun’s
energy produces ATP and
NADPH (required to turn
the carbon dioxide into
glucose), and O2 is
released from H2O - This reaction requires
light
Dark reaction
- ATP and NADPH is used to
fix CO2 as sugars in the
Calvin cycle - The first product is a
molecule with 3 carbon
atoms (3-phosphoglyceric
acid), and the process is
called C3 photosynthesis - Process is independent of
light (but it can occur
during daytime)
Photorespiration
Photorespiration: Some
plants can use O2 as a
substrate for
photosynthesis, instead of
CO2
* This reaction is pronounced
when CO2 is low, O2 is high,
or temperatures are low
* C4 plants evolved to avoid
photorespiration because it
is an energy-wasting
reaction
Corn, a warm climate
plant, uses C4 path to
avoid photorespiration
C4 photosynthesis
C4 photosynthesis is an
alternative chemical pathway,
allowing plants to avoid
photorespiration
* C4 plants fix CO2 in mesophyll
cells as a molecule with 4
carbon atoms (malate) then
transport it to bundle sheath
cells where O2 is absent
* This also increases water
efficiency
- C4 plants fix CO2 in mesophyll cells as malate, transport it to bundle sheath, where O2 is absent
- fixation of
CO2 is done in different location
than the Calvin cycle
Co2 - h2o tradeoff
To acquire CO2 for
photosynthesis, plants
have to open their
stomata
* This leads to increased
water loss
* Under dry conditions,
plants close their
stomata
* This is a problem for
photosynthesis under
dry conditions
cam photosynthesis
Crassulacean Acid
Metabolism (CAM)
photosynthesis evolved
to reduce loss of water
* Stomata open at night
when air humidity is high
* CO2 is fixed as malate,
stored in vacuoles
* Stomata close during day
* CO2 is released from the
malate for Calvin cycle
CAM plants are often
succulents, such as cacti.
- dry environments
- fixation of
CO2 is done at a different time
than the Calvin cycle
What equation describes pop size in an open pop
N(t+1) =Nt+ (B-D+(It-Et)
Which one of the following statements about thermobiology is TRUE?A. Bears don’t hibernate; they have extended sleep.B. Shivering allows organisms to warm up.C. Counter-current exchange allows animals to keep feet warm in cold environments.D. Antifreeze chemicals are important in the overwintering physiology of some frogs.E. All of the other statements are true.
e
Which one of the following sequences about vocal learning behaviour is in the CORRECT ORDER?
A. Crystallization > silent phase > sensory phase > sensorimotor phase
B. Sensory phase > silent phase > sensorimotor phase > crystallization
C. Sensory phase > sensorimotor phase
D. Sensorimotor phase > sensory phase
E. None of the sequences are in the correct order
b
Which of the following statements about nutrient cycles is TRUE?
A. Carbon is commonly found in Earth’s atmosphere, and is not common within Earth’s crust.
B. Nitrogen is commonly found in Earth’s atmosphere, and is not common within Earth’s crust.
C. Sulfur is commonly found in Earth’s atmosphere, and is not common within Earth’s crust.
D. Phosphorus is commonly found in Earth’s atmosphere, and is not common within Earth’s crust
E. All of the other statements are true
b
What are autotrophs?
- plants
- synthesis food using exsternal source of energy (sun) to create simple sugars from inorganic compounds
What are heterotrophs?
- animals
- survive by feeding on biomass
Vasoconstriction
Vasoconstriction is accomplished by smooth muscle surrounding the arterioles that supply the skin. It slows the flow of blood to the
surface, which reduces the heat lost to the environment
Counter-Current Heat Exchange
The artery and vein supplying the limb are in proximity, so heat is exchanged between the two. As warm blood passes down the artery, heat is lost to the cooler venous blood returning from the distal end, thus reducing the amount of
heat lost in the limb.
Are CAM and C4 cycle the same?
C4 photosynthesis: fixation of CO2 is done in different location than the Calvin cycle
CAM photosynthesis: fixation of CO2 is done at a different time than the Calvin cycle
