BIO 150 Lecture Notes 04 and 05 (Week 1) ABIOTIC FACTORS: Energy Relations (Light and Temperature) and ABIOTIC FACTORS Water and Nutrients

Light

visible electromagnetic radiation (400-700 nm); primary energy source for the biosphere

Intensity

____________ of Light (how much?) – strength of light; measured in lux or footcandles; depends on distance from source, other factors (e.g. season, weather, cloud cover, time of day, plant cover, air particles)

Intensity

____________ of Light - depends on the angle of incoming light (low angle-low intensity; high angle-high intensity), variations in Earth’s orbit such as eccentricity (how elliptical the orbit is), obliquity (degree of tilt) and precession (direction of tilt), and variations in solar energy output (solar cycle)

• Quality

• Periodicity

• Directionality

• ______________ (what wavelengths?)

• ______________ (for how long?) – duration of day length; function of latitude and season

• ______________ (from what angle?

• Transmitted, reflected, absorbed

• reflected, absorbed, transmitted

Fate of incoming solar radiation

• ______________, __________________, refracted, _________________, scattered

• In plants – _________________ (without change in wavelength), _________________ (raise plant temp., contribute to transpiration, drive photosynthesis), _________________ (after some wavelengths have been filtered out; change in both quality and intensity of light)

• Condition

Light as an environmental factor

• As a ______________ – involved in circadian rhythms, photoperiodism, phototropism, phototaxis

• Resource

Light as an environmental factor

• As a _______________ – involved in phototrophy, photosynthesis (utilizing Photosynthetically Active Radiation, PAR wavelengths which depend on the primary pigment used for photosynthesis)

resource depletion zone (RDZ)

Shade is a ___________________ because shading reduces the intensity of light and changes which particular wavelengths are transmitted across

Heliophytes (a.k.a. Sun Plants)

Sciophytes (a.k.a. Shade Plants)

The two types of plants based on light utilization?

Heliophytes (a.k.a. Sun Plants)

Types of plants based on light utilization

• needs full sun for growth

• efficient use of high light intensity

Heliophytes (a.k.a. Sun Plants)

Types of plants based on light utilization

• never reach photosynthetic saturation

• small, angled leaves

Sciophytes (a.k.a. Shade Plants)

Types of plants based on light utilization

• Inhibited under full sun

• More efficient Ps at low light intensities

Sciophytes (a.k.a. Shade Plants)

Types of plants based on light utilization

• often reach saturation levels at 20% full sunlight

Sciophytes (a.k.a. Shade Plants)

Types of plants based on light utilization

• Large, horizontally oriented leaves w/ lots of chlorophyll and accessory pigments

Temperature
Heat

______________ - a measure of the average kinetic energy of the atoms or molecules in the system

______________ - thermal energy transferred from a hotter system to a cooler system; 0 heat flow if in thermal equilibrium

macroclimate; microclimate

Part of the descriptions for _________________ (what weather stations and what we represent with climate diagrams) and _______________ (climatic variation on a scale of a few km, m, cm; measured over short periods of time)

altitude; latitude; continental/maritime; surface

Temperature & Heat

Affected by _____________, ____________, _________________ location, ____________ features (Vegetation, ground color, water

features, boulders, burrows, etc.)

• hyperthermophiles

• thermophiles

• mesophiles

• psychrophiles

In microorganisms –

• _______________ (thrive at very high temp),

• _______________ (live at high temp),

• _______________ (moderate temp),

• _______________ (low temp)

Poikilotherm (‘pokilo’ = varying)

Types of organisms based on - Stability of body temperature

_____________ (varying)

Homeotherm (‘homeo’ = same)

Types of organisms based on - Stability of body temperature

_____________ (same)

Ectotherm

Types of organisms based on - Source of energy for regulating body temperature

________________ – heat from outside (environment)

Endotherm

Types of organisms based on - Source of energy for regulating body temperature

______________ – heat from inside (organism’s own metabolism)

ectotherms; endothermic; pokilothermic

Many poikilotherms are _______________ and many homeotherms are _____________, BUT some animals that exhibit facultative endothermy are _______________

endotherms; ectotherms

Endotherms and ectotherms co-exist – High cost-high benefit strategy of _______________; Low cost-low benefit strategy of ________________

• Chilling injury

• Freezing

Effects of extreme temperatures on organisms

Low temperature

• ________________

• ________________

• Denaturation of proteins

• Dehydration

Effects of extreme temperatures on organisms

High temperature

• _____________________

• _____________________

• Insulation

• Evaporative cooling

• Countercurrent hea

Some adaptations to extreme temperatures

• _______________ (e.g. blubbers)

• _________________ (e.g. panting, sweating)

• Adjustment of supercooling points

• __________________t exchangers (e.g. blood vessels in bird’s feet)

• Freeze-avoidance

• Freeze-tolerance

Some adaptations to extreme temperatures

• __________________ (ice crystals are prevented from forming)

• __________________ (encourage formation of extracellular ice to minimize intracellular damage)

• Other morphological, anatomical, and behavioral features

Some adaptations to extreme temperatures

To high temp.

• Modified membranes and proteins

• Protective layers (waxes)

• Reflective surfaces

• Other anatomical features

Some adaptations to extreme temperatures

To high temp.

• Modified membranes and proteins

• Protective layers (waxes)

• Reflective surfaces

• Other anatomical features

• Estivation

• Hibernation

• Torpor

Resting stages under extreme temperatures:

• _______________ – prolonged ‘stasis’ during summer

• _______________ – prolonged ‘stasis’ (months) during winter

• _______________ – state of low metabolic rate (hrs)

Temperature

______________ as a stimulus

• Whether or not an organism starts development (e.g. germination)

• May interact with other stimuli (e.g. photoperiod)

Temperature

______________ as a stimulus

• Growth, flowering, germination, ripening of fruits

• Disease

• Competition

• Humidity

Interaction of temperature with other factors

• ________________ – conditions may favor growth and/or spread of disease agent, or weakening of host defenses

• ________________ – modifies the response to temp because of the presence of a competitor

• ________________ – RH closely tied to Temp

• metabolic

Water and dissolved substances are both conditions and resources.

Water is a critical resource.

• Organisms – composed of ~80% water

• Hydration – necessary for _____________ reactions

• Water content needs continual replenishment

• less

• arid

• food

Water is a critical resource.

• Water incorporated in plant body is _________ than vol. of water that flows through the transpiration stream (importance of root systems)

• Most terrestrial animals drink free water and generate some from the metabolism of food;

• Animals of _________ zones may obtain all their water from their ________.

humidity

Water in the air – ____________

• Moisture content of air relative to an equal volume of saturated air at a given temperature

Water in the air – humidity

• Important source of water

• Affected by temp, LI, and vegetation

• Affects life processes (transpiration, sweating, hydration, etc.)

Rainfall/Precipitation

__________________

• Water condensed from atmospheric vapor and falling in drops

• Allows re-distribution of water; brings water from the oceans to areas over land

Rainfall/Precipitation

__________________

• Water scarcity and abundance determine vegetation type

• Replenishes ground water

• A medium of life in aquatic habitats

condition

• washed away

• pounding; suction

Water as a _____________

• In streams and rivers there is the constant hazard of being _____________

• Repeated ___________ and ___________ of wave action on sea shores

• Holdfasts, flexible bodies, and behavioral strategies of avoidance

• toxicity; osmoregulation; enzyme

pH of water and soil

• Direct effect: __________ – upsetting ____________, ________ activities, gas exchange

• nutrients; toxins

pH of water and soil

• Indirect effect: influence on availability of ____________ and/or concentration of ____________

more

acidophiles; alkaliphiles

Envt with neutral to slightly alkaline pH are _________ hospitable than acidic ones.

Some prok can thrive under very acidic (_______________) or very alkaline conditions (______________)

• 3

Salinity of Water

• Organisms respond to salt like the Response Curve _

Salinity of Water

Creates osmoregulatory problems (same as drought and freezing); Osmotic resistance to water uptake

Halophytes

_______________ – have metabolites for osmoregulation

Others have a way of pumping out excess salt from their tissues to avoid damage

• 3

• soil; water

• food

Mineral Nutrients

• Organisms respond to mineral nutrients like the Response Curve _

• Interactions between foraging for water and nutrients (for plants)

• Plants – from __________ or surrounding _________

• Animals – in organic form, from ________

• Morphological

• Physiological

• Poikilohydry

Adaptations to drought stress

Xeromorphic traits in plants:

• Traits conserve water

• ______________ features (e.g. waxes, sunken stomates, multiple epidermal layers, leaf-folding/rolling, trichomes, etc.)

• ______________ adaptations (e.g. water storage, protective molecules, stomatal closure, CAM, etc.)

• Dormancy

• _____________ (ressurrection plants)

Adaptations to drought stress

Drought tolerance/resistance in animals:

• Structural, physiological, and behavioral adaptations

• Impermeable integuments, reduction in urine flow rate, seasonal migration, estivation, hoarding of food, space choices

Adaptations to drought stress

Drought tolerance/resistance in animals:

• Structural, physiological, and behavioral adaptations

• Impermeable integuments, reduction in urine flow rate, seasonal migration, estivation, hoarding of food, space choices

Adaptations to flooding

• Animals → move out of the flooded area

• Plants (structural and physiological adaptations):

  • Aerenchymatous roots

  • Pneumatophores

  • Capacity to elongate shoot parts upon submergence (hormonal response, ET)

  • Increased porosity (longitudinal transport of O2)

  • Change in timing of reproduction

Adaptations to flooding

• Animals → move out of the flooded area

• Plants (structural and physiological adaptations):

  • Aerenchymatous roots

  • Pneumatophores

  • Capacity to elongate shoot parts upon submergence (hormonal response, ET)

  • Increased porosity (longitudinal transport of O2)

  • Change in timing of reproduction

Solar maximum

Solar minimum

SCHWABE cycle

________________ - the time the sun is active and releases greater amounts of solar energy

________________ - the time the sun is inactive

________________ - Its a cycle, with particular years that sun activity is active and

inactive (11 years - half minimum, half maximum)