What is physiology?
branch of biology concerns with understanding the function of tissues, organs, and organ systems
physiological ecology
the study of how organisms are physiologically adapted to their environment; an organism's ability to carry out it's vital functions (or the efficiency with which it performs these function; depends on environmental conditions
What are the limitations of life?
energy, water, and temperature
What is the source of carbon from which life is constructed?
the atmosphere
Plants are...
autotrophs; make their own carbon
Humans are...
heterotrophs; have to eat their carbon
Photosynthesis
light energy from the sun fuels a series of reactions that result in the fixation of CO2 and the release of O2
cellular respiration
plants use this in order to convert the energy in sugars and other molecules into ATP; producing CO2
net photosynthesis
photosynthesis - respiration
What happens in shaded environments?
low light limits the rate of photosynthesis; leaf respiration is lower
shade intolerant plants vs shade tolerant plants
adaptations to sun and shade environments; show fundamental difference in patters of photosynthesis in response to different levels of available light
What happens when you move a shade-tolerant plant to a high light environment?
its maximum rate of photosynthesis is limited
specific leaf area (SLA)
ratio of surface areas in cm2 to weight in g; the surface areas of leaf produced per gram of biomass allocated to leaf production
Shade tolerant plants have...
greater SLA; shorter
Shade intolerant plants have...
lower SLA; longer
stomata
openings on the leaf surface that allows CO2 to enter; gas diffuses from higher concentration in the air to lower concentrations in the leaf
Stomata is found in...
terrestrial plants
How is diffusion controlled in terrestrial plants?
the stomata opens and closes
stomata are usually closed when...
photosynthesis and the demand for CO2 are reduced for any reason
stomata are open when...
the concentration of CO2 in the air outs the leaf is greater than that inside the leaf
transpiration
when the stomata are open, water vapor in the leaf diffuses out
transpiration rate depends on..
the diffusion gradient and stomatal conductin of H2O
How is the water in plants replaced?
plants take up water form the soil by the roots and transport that water to their leaves
What kind of transport happens in plants?
passive; does not require energy
Water loss through transpiration will continue as long as...
light energy striking leaf supplies enough heat for evaporation, moisture in available in the soil, and the roots are able too maintain a more negative water potential than the soil
What affects the water potential of the soil?
rain
water use efficiency
the ratio of carbon fixed per unit of water loss
What plants have the least water use efficiency
plants in the rainforest; because there is a lot of rain
What plants have the most water use efficiency?
plants in the desert; b/c there isn't as much rain
CO2 concentrations in the atmosphere are increasing. Should this lead to an increase or decrease in the amount of time a plant must leave its stomata open?
decrease
CO2 concentrations in the atmosphere are increasing allowing plants to keep their stomata closed more of the time. Is this change accompanied by an increase or decrease of the water use efficiency of the plant?
increase
Temperature effects...
photosynthesis and cellular respiration
Does photosynthesis increase or decrease as temperature increases?
increase
The max temperature for photosynthesis is higher or lower than the max temperature of respiration?
lower
Tmin =
min. temperature
Tmax =
max. temperature
Topt =
range of temperatures over which net carbon uptake is highest
As air temperature rises...
the rate of transpiration rises
plant acclimation
reversible changes to different environments
Topt lower
for plants grown under cooler conditions
Topt higher
for plants grown under warmer conditions
How do most plants acquire energy?
through the sun & photosynthesis
How do animals acquire energy?
through different types of organisms
What impacts structure/function relationships in animals?
size
Surface area of a cube
6 x Ls²
Volume of a cube
L x W x H
Why does the relationship between surface area and volume impose a critical constraint on the evolution of animals?
Many basic physiological and biochemical processes require the transfer of materials and energy between the exterior (environment) and interior of the organism
producers
plants that make their own food
Herbivore
A consumer that eats only plants.
Studied by 101 People