Ecology Exam 1

What are the key factors that affect the physiology of terrestrial organisms?

• precipitation and temperature

  • also can look at pH, salinity, etc. but not as important

What are the key factors that affect the physiology of aquatic organisms?

temperature, salinity, oxygen content

What factors influence climate and precipitation patterns globally?

tilt and orbit of the earth in relation to how sun hits it and temperature, Hadley cells & other circulation cells in relation to atmosphere and wind patterns, trade winds, water patterns

How does the tilt and orbit of the Earth affect its surface heat?

• at the equator, sunlight hits earth at a direct angle which allows for direct penetration of rays through the atmosphere and hotter areas

• closer to regions of the poles, sun rays hit earth at an angle which means they are spread over a larger area surface and how to travel through more atmosphere,

  • means less sun reaches the surface of earth in these regions and are less hot

How does earth’s orbit and tilt cause seasonal changes?

as the north or southern hemisphere is tilted toward the sun, seasonality occurs since the other side isn’t point in direct sunlight

How is air circulated in the atmosphere?

through atmospheric circulation cells

What is a Hadley cell?

largest circulation cell that determines large-scale patterns of precipitation and moisture, creates bands of desert at 30 degrees N and S of the equator

How do atmospheric circulation cells work?

air warms due to solar heating and rises, it then cools and rain falls, as more air rises it pushes dry air toward the poles, dry air then cools and sinks, the dry air flows toward the equator and the cell cycles once more

What are ferrel cells?

atmospheric circulation cell below the equator but above the poles, driven by connective forces of both ferrel and polar cells

What are polar cells?

atmospheric circulation cell close toward the poles that are similar to Hadley cells but are less intense since less sunlight is hitting them therefore there’s less heat to drive evaporation

What is the inter-tropical convergence zone?

area that lies between where the 2 Hadley cells converge, between the bands of desert formed at 30 degrees north and south

What is the Coriolis effect?

phenomenon in which the rotation of earth causes winds to be deflected right in the northern hemisphere and left in the southern hemisphere

What are trade winds?

winds that blow from east to west at 30 degrees latitude and along the equator, occur due to the deflection in atmospheric circulation cells in response to the Coriolis effect

What are westerlies

winds that blow from west to east at 60 degrees latitude, occur due to the deflection in atmospheric circulation cells in response to the Coriolis effect

What are biomes?

communities based on life forms of species that tend to dominate in a given climate

What is lake turnover?

mixing of warm and cold waters, helps oxygenate water and disperse nutrients, occurs usually in fall and spring

What happens when lake turnover is infrequent?

can result in dead zones/areas of depleted oxygen

What are communities?

species found in a defined area that interact with each other

What is a Whittaker biome diagram?

diagram that shows categorized ecosystem types according to precipitation and temperature, suggests a locations average temperature and precipitation have a large impact on types of vegetation

What is evaporation?

conversion of liquid water to water vapor, drives the global hydrologic cycle

What is the global hydrologic cycle?

continuous movement of water on earth

What are the two ways in which water can be lost from terrestrial ecosystems?

evaporation from soil surface and transpiration

What is transpiration?

process in which water vapor exits the leaves of a plant after water is pulled up from the soil into the plant

What is an evapotranspiration rate?

combination of evaporation and transpiration, total rate at which an ecosystem loses water to the atmosphere

What is potential evapotranspiration (PET)?

max evapotranspiration rate if/when a system has abundant water, driven primarily by temperature, indicative of evaporative demand

What is evaporative demand?

how much energy is available to do work of converting water to vapor

What is the equation for PET?

PET (mm/month) ~ 2 T (in celsius)

What is actual evapotranspiration (AET)?

rate at which water actually evapotranspires

What are climate diagrams?

diagrams that overlay precipitation and temperatures and can be used to estimate AET and PET

When precipitation is greater than or equal to PET, what is the rate of AET?

AET is equal to the PET

When precipitation is less than PET, what is the AET?

AET is equal to the amount of precipitation

What is physiologic tolerance?

range of environment parameters over which an organism can survive

What is a niche?

constellation of environmental conditions under which a species can survive

What is Liebig’s Law of the Minimum?

states that growth and reproduction is limited by the most scarce resources, this is specific to each species in each environment at a particular time

What is an optimal environment?

set of conditions for which growth and reproduction is greatest

What are the two ways in which physiological changes occur?

individual level and population level

What would happen if Earth’s axis rotation were tilted at a greater angle toward/away from the sun? Why?

seasons would be more pronounced since the Earth would have less area that is being directly hit by sunrays

What is the best estimate for PET in Down Under during August, when the temperature is 15 C and precipitation is 40mm? Why?

30mm, this is because precipitation at 15 C is 30mm and since precipitation is less than the PET, AET equal amount of precipitation

What are the 3 ways in which species respond to a changing environment?

range shift, acclimation, adaptation

What is range shift?

when a population shifts in response to environmental changes, move to new locations that match their physiological tolerances

What is acclimation?

change in morphology or physiology in response to environmental change, occurs at the individual level, DNA doesn’t change

What is adaptation?

occurs on the population level, genetically determined trait that increases and individuals fitness, improves the chances of surviving and reproducing when an environment changes

How does enzyme activity reflect physiology?

since proteins respond to temperature in different ways, we can look at an organisms proteins to see how they respond to temperature

How does acclimation work?

an organism may have more than one gene in a genome to code for different enzymes optimized for different environments, organisms may also be able to vary the cellular environment within itself by creating proteins to help with environmental change

How can adaptation be confirmed?

difficult, need to know that a populations average phenotype[e changed in response to environment and is driven by genetic change

What is irreversible acclimation?

permanent acclimation, not reversible, changes usually occur during early development and become fixed once mature

What is a common garden experiment?

allows researchers to ascribe differences in phenotype to determine whether a change is due to acclimation or adaptation, individuals or a population is collected from distinct geographic locations and reared under controlled conditions

What is a water budget?

tracks state of water by comparing inputs and outputs

What is a net water balance?

inputs-outputs in amount of water in an organism, W_net = W_ing - W_met ± W_osm - W_evap - W_sec

If W_net = 0, what is happening?

an organism is maintaining homeostasis in relation to water

If W_net > 0, what is happening?

organism is gaining water

If W_net is < 0, what is happening?

organism is losing water

What is ingestion?

input to water budget, water is ingested through drinking or from free water in food

What is metabolic water?

form of ingestion of water, water is produced when macromolecules are broken down by an organism, this is important for organisms in arid or salty areas

What is osmotic exchange?

input and output of water budget, water is gained or lost via osmosis with the environment, common in aquatic organisms

How does osmotic exchange occur in aquatic organisms?

through skin or gills, due to differences in solute concentration in water and within the organism osmosis differs in freshwater and saltwater orgnaisms

What is secretion?

output of water budget, water is lost as an organism secretes urine, feces, or mucus, can be problematic to both terrestrial and aquatic organisms

What is evaporative loss?

output of water budget, terrestrial organisms lose water to evaporation by moistening air through inhalation or through panting/sweating

What is the surface trend for salinity?

• at the equator, near poles, and near coastlines there is less salinity, this is due to rain, ice, and river runoff proving freshwater

• everywhere else is salty because in dry areas evaporation has removed freshwater, more solutes in water

What is the surface trend for oxygen?

lower oxygen at the equator and higher oxygen at the poles, this is because colder water holds more oxygen since the solubility of oxygen increases at decreased temperatures

What is heat balance?

rate at which an organism accumulates or loses heat

What is a poikilotherm?

organism whose body temperature fluctuates

What is a homeotherm?

organism that maintains a relatively stable, constant body temperature

What is an ectotherm?

organism who’s body temperature is primarily determined from the heat in the environment, depend on external sources of heat, many are poikilotherms

What are endotherms?

organism whose body temperature is primarily determined by internally-generated metabolic heat, rely on internal heat production, energetically expensive but allows for high performance across a variety of conditions

What is behavioral thermoregulation?

process in which an organism chooses locations with favorable thermal properties

What is the surface trend for temperature?

hotter at the equator due to direct sunlight, the closer we get to the poles the colder it is due to less direct sunlight/sun is spread over larger surface area

What is the pattern of water movements?

upwelling, hot water moves around to mix with colder water, also moves around nutrients, differs depending on the seasons

What is upwelling?

movement of water, drives the circulation of water, there’s a density difference between hot and cold water, mixing of water temp., nutrients, etc.

What is the depth trend for oxygen levels in oceans?

higher oxygen near the surface as we go down there is an oxygen minimum layer, there’s more oxygen as we go back dow

What is an oxygen minimum layer?

layer in depth of water that has the least amount of oxygen, this is due to the presence of organisms that take up oxygen

What is the depth trend of oxygen in lakes?

same as oceans, during winter there’s less of an oxygen minimum layer, during summer more of an oxygen minimum layer, fall and spring there’s the same amount of oxygen throughout due to lake turnover

What is the depth trend for temperature in oceans?

hotter at the surface, then encounter a thermocline due to upwelling, eventually colder at as we go deeper; hotter at top as there’s more sunlight reaching the surface

What is a thermocline?

stratification between hot and cold water (hot on top and cold on bottom), as water heats up kinetic energy increases and hot water mixes with cold to move to the top, creates a transition layer

What is the depth trend for temperature in lakes?

same as oceans, have a thermocline, less drastic than oceans

• in spring and fall temperature isn’t really deviated because of lake turnover

• in winter colder on top and warmer deeper, due to insulation

• in summer hotter on top and colder deeper

What is the depth trend of salinity in oceans?

more salinity up top due to surface evaporation, reach a halocline, get saltier as we go deeper due to density of solutes

What is a halocline?

area where top and deeper layers of salinity in water mix, usually very salty area

What is the depth trend of salinity in lakes?

lower salinity because of fresh water

What is the depth trend of salinity in rivers?

as rivers meet oceans we get more salinity as the two bodies of water mix, closer to the ocean the saltier

What are heat budgets?

rate at which an organism accumulates or loses heat, H_net = H_sr + H_met ± H_tr ± H_cond ± H_conv - H_evap

If H_net = 0, what is happening?

organism is maintaining homeostasis

If H_net > 0, what is happening?

organism is too warm

If H_net < 0, what is happening?

organism is too cold

What is absorbed solar radiation?

input of heat budget, radiation acts as a source of heat based on the exposed surface area of the organism, also depends on amount of radiation absorbed versus reflected

What is metabolic heat?

input of heat budget, heat that’s released when some energy from muscle use, digestion, thinking, metabolized, etc. and released as heat

What is thermal radiation?

input and output of heat budget, how readily an object radiates heat

What is conduction?

heat budget input and output, heat transferred from a hot region, object, or substance to a cooler one through direct contact

What is convection?

heat budget input and output, heat is transferred among moving fluids (water or air)

What is countercurrent heat exchange?

exchange of heat between hot and cold fluids moving in opposite directions, think of an artery of warm blood sandwiched between veins carrying cool blood, forms a temperatures gradient and maintains temperature

What is evaporative cooling?

heat budget output, heat lost from a system when heat is used to evaporate water

What do water budgets in plants look like?

inputs are water from roots and air, outputs are transpiration and secretions

What do water budgets in aquatic organisms look like?

inputs are water from drinking, food, and osmosis, outputs are from osmosis and secretions

What do water budgets looks like in terrestrial organisms?

inputs are water from drinking, food, and air, outputs are from evaporation and secretions