Final Flashcards
Enviromental Factor:
Light
A form of electromagnetic radiation
-radiant energy
Light quality
determined by type of wavelengths
(shorter the wavelength the higher the energy)
Photosynthesis is driven by specific wavelengths of light
roughly equivalent to visible light (red thru violet)
- long wavelengths do not excite chlorophyll (e.g. infrared light)
- short lengths can break molecular bonds (e.g. ultraviolet light)
Light-Quality:
Intensity
of photons per unit area per unit time
Light- Quality:
Duration
length of time light is recieved
Light Intensity
Sunlight is more intense near the equator, and less intense the the closer you get to the poles. Also affected by cloud cover and elevation (higher latitude more change).
(more angle= less intensity)
Light Duration
Days are longer in the summer than in the winter.
Change in day length is greater near the poles and very small at the equator.
Total Radiation =
daylength x intensity
Rate of Photosynthesis
Increases with increasing light intensity but species differ in their adaption to light level.
Non-photosynthetic reactions are…
- flowering due to photo-period
- seed dormancy
- etiolation
Non-photosynthetic reactions are…
- flowering due to photo-period
- seed dormancy
- etiolation-competition for sun- marshal energy to elongation to reach the sun
Responses to light
- phototropism
- stomatal opening
- sleep movements
Water
water availability is one of the key indicators of plant species adaption to a region
Water Funtions
- solvent of plant chemistry
- turgor -the pressure applied to have enough water in the plant
- transport (nutrients and sugars)
- cooling/ temperature buffer
- reactant/ source of H and O
Water Properties
Cohesion- attraction of like molecules to one another
In Xylem- water molecules move in units
Water Properties
Diffusion- movement of a substance from high concentration of low concentration by random motion
Water Properties
Osmosis- diffusion of a liquid across a selectively permeable membrane until the concentration of the fluid is equal on both sides of the membrane
(water has random molecular motions)
Osmosis
the ratio and the solute molecules is the same on both sides of the membrane -osmosis balances the number of water and solute molecules, regardless of size or weight
Water Potential
tendency of water molecules to move
- diffuse
- evaporate
- be absorbed
Water Potential
expressed in terms of pressure
- positive values indicate push
- negative values indicate suction
Water Potential
water moves from higher potential to lower potential ie. \+3 to +1 \+1 to -1 -2 to -4
Plant water potential
Composed of osmotic and pressure components
Osmotic Potential
the portion of water actively constrained by interaction with dissolved substances -potentials are negative (a tension or pull on water)
Pressure Potential
the portion of water actively contributed by compression of stretch surfaces- pressure potentials are positive (a pressure or a push on water)
In cells due to positive push of cell wall and negative xylem due to the pull of the atmosphere.
Water Potential
water potential at any point in the plant is the algabreic sum of it’s components.
ie. (-4)+(+2)= -2
Water Potential
water potential at any point in the plant is the algabreic sum of it’s components.
ie. (-4)+(+2)= -2
Water Potential = osmotic potential + pressure potential
Homeostasis
maintanence of a constant physical and chemical environment within an organism
Transpiration
release of water vapor through the stomata
-water pulled from the plant by atmospheric demand and the plant can only control the opening, the stomata, not the pull
Evapotranspiration
a loss of soil moisture to the atmosphere by transpiration and evaporation
Potential of Evapotranspiration
-measure of atmospheric demand
Demand increases with:
- lower moisture content in air
- higher air temp.
- higher wind speed
Temperature
heat is a form of energy -intensity of head
Determining Factors of Temperature
- Radiation- transfer without connecting medium
- Convection- transfer in a moving agent (air mass)
- Conduction- flow of heat through a substance
Location Factors of Temperature
Latitude- affects intensity of light
Season- affects duration and intensity of light
Elevation- affects amount of atmosphere present
Cardinal Temperatures
- Maximum temperature
- Minimum temperature
- Optimum Temperature- (grows the best)- ie puts on the most weight.
Developmental Responses
Plants mature faster at higher temperatures
-relationship does not hold under severe stress
High Temperature Stresses Can Cause…
- Dehydration
- denature of proteins
- metabolic imbalance (conversion of sugars into usable energy)
Low Temp Stress Can Cause…
- Chilling injury
- Winter injury
- Freezing injury
Chilling injury is..
Damaged due to about freezing temps.
- tropical and subtropical plants
- reduces enzyme and membrane function
Chilling injury is..
Damaged due to about freezing temps.
- tropical and subtropical plants
- reduces enzyme and membrane function
- loss of fruit quality
Freezing injuries..damage from temps below zero
- dehydration (b/c ice outside cells)
- puncture by ice forming inside cells
- discoloration and loss of turgor
Winter injuries…damage from cold weather cond.
- desiccation (warm air/ frozen soil)
- smothering (ice crust)
- heaving (shrink and swell of freeze thaw cycles)
Mineral Nutrients (plants are matter and energy)
- mineral nutrients (inorganic compounds)
- largely supplied from the soil
Plants are Synthesizers
Meaning their material needs will be the simplest form of matter.
17 essential elements: Macronutrient
Carbon-organic compound
Hydrogen- charge transfer
Oxygen- respiration
Nitrogen- proteins, nucleic acid
Phosphorus- energy transfer
Potassium- charge/osmotic balance
Also Calcium, Magnesium, Sulfer
Nitrogen- proteins, nucleic acid
Phosphorus- energy transfer
Potassium- charge/osmotic balance
Also Calcium, Magnesium, Sulfer
Sources of Plant Nutrients
Atmosphere: C,H,O,+
Soil Minerals: dissolved
Organic Matter: Degradation of previously living matter
Manufactured fertilizers
Manufactured Fertilizers
-regardless of the source, plants absorb essential elements in the same exchangeable or soluble form
commercial fertilizers tend to have higher nutrient concentrations and be more readily available (soluble forms) then organic forms
Ecology
the science dealing with the relationships among living things and their environment
Ecosystem
a complex of all living organisms of a habitat and their physical enviroments
Habitat- where organisms live
Identified by:
- tropic structure
- biotic diversity
- materials cycle
Food Wed
Nutrients and energy move through the food web
Energy Flow through an ecosystem
Ultimate fate: energy is dissipate as heat and must be replaced. The sun is the source of new energy is the sun. Plants convert solar energy into chemical energy required by animals.
Energy flows through leves
Primary producers -> herbivore -> primary carnivore -> second carnivore.
Nutrient Cycle
Elements are lost but not recycled. Organisms pass among organism and the environments. Plants convert elements to organic forms used by animals
Nutrient Cycle
Elements are lost but not recycled. Organisms pass among organism and the environments. Plants convert elements to organic forms used by animals.
Community
all species of an ecosystem, collectively
Niche
a micro-environment suited to particular plants or physiology
Succession
the orderly change in the balance of species resulting from modification of the physical environment
Climax Vegeatation
the ultimate, more or less stable stage of succession when certain species dominate an ecosystem
Ecological Footprint
the bio-productive area required to maintain current consumption and absorb wastes generated
(can be calculated for a individual, geographic area, sociopolitical group, or all humanity.)
DNA fingerprinting allows identification of different
Genotypes based on differences in size of DNA fragments.
If environment had no effect on phenotype, then in a given species the number of genotypes would be
more than or equal to the number of phenotypes.
Meiosis is a process by which the number of chromosomes in a nucleus is
reduced at a specific stage in the plants life
For a cultivar to be classified as a hybrid, it must:
result from the mating of different species
A gene that directs the production of root hairs would be found in
All cells throughout the plant. Because all cells carry the same instructions.
Scientists use the technique known as RNA interference to
Prevent expression of a naturally occurring gene
In photosynthesis, an ATP molecule produced by the:
Photo-chemical reactions stored less energy per molecule than sugar
In a zygote, genes outside the nucleus are
acquired only from an egg
A product of respiration’s electron transport system (chain) is:
water
The rate of respiration which an enzymatic reaction proceeds is
a faster with higher concentrations of enzyme and substrate.
Inbreeding depression results when typically
self-fertilizing species achieve a high degree of homo-zygosity.
As a result of double fertilizatio, a seed’s embryo and endosperm have…
different chromosome numbers but always the same kind of alleles
Lipids have a key role in
cell membranes
When crossing-over occurs in a plant, changes are observed in
some trait combinations of that plants progeny
Linkage
alleles that are located close together on a chromosome to be inherited together during meiosis
