Ecology Ch. 6

Measuring the relative abundance of the non-radioactive isotopes of elements in materials is known as stable isotope analysis

Match the algebraic symbol with its definition.

W_i – water inside the organism; W_d – water consumed; W_S – water urinated; W_o – water pf diffusion

To compensate for osmotic water loss, fish drink seawater. How do fish deal with the salts in the seawater? They excrete Mg and SO4 through their kidneys; they secrete Cl and Na from their gills

The tension produced by the evaporation of water from the plant’s leaves reduces the water potential within the entire plant

Rank the following sources of water intake (greatest to least) for the Onymacris beetle, with the greatest at the top. Fog, metabolism, food

The movement of water vapor from the land to the atmosphere is known as evaporation

Match the isotopic pair to the source of the reference material.

D: ¹H – Standard Mean Ocean Water

¹⁵N: ¹⁴N – atmosphere

¹³C: ¹²C – PeeDee limestone

³⁴S: ³²S – Canyon Diablo meteorite

Which of the following are strategies used by plants to conserve water in arid environments? Reduced leaf area; dormancy; thicker leaves

The magnitude of soil matric potentials are inversely related to soil grain size, with coarse soils having lower matric potentials than fine grained soils

For organisms in aquatic environments, the water balance equations include a term for osmosis, W_o. The sign of W_o changes depending upon the organism and environment

Camels conserve water by insulating itself from high temperature and reducing exposure to the sun

The relative humidity is 39% when: water vapor density is 7 g/m³, saturation vapor denity is 18 g/m³

A shallow root network allows the saguaro cactus to rapidly take up water during rare rain events

Which of the following would be regulated by an organism through the process of osmoregulation? Cations, water, anions

The ability of water to do work is dependent on the free energy content, moving from a position of higher free energy to a position of lower free energy

Water flows from the soil to the plant when plant < soil

In general, plants growing in drier climates tend to have roots that grow deeper and make up a greater proportion of the plants biomass than plant in moister climates

In their study of kangaroo rats, Tracy and Glenn found differences between the three sites they looked at. Rank the sites in order of evaporative water loss from greatest to lowest. Moist, intermediate, dry

Which of the following are ways that scorpions conserve water? Burrowing into moist soil; reducing their metabolic rate

What is the benefit to aquatic animals of being isosmotic with the surrounding water? Energy conservation

In aquatic environments, water moves down it’s concentration gradient

Because freshwater fish are hyperosmotic, they compensate by drinking large amounts of water. FALSE

The water balance equation for animals is basically water entering equals water exiting. Indicate whether the following are inflows (“in”) or outflows (“out”): in – W_d and W_f; out – W_e and W_S

In a hypoosmotic organism, water will tend to flow out of the organism, while salts will tend to flow into the organism

Which of the following is a source of water intake for Kangaroo rats? Food moisture, metabolic

Like animals, the water balance for plants is water entering equals water exiting. Some flows are unique to plants and there are several flows that are common to both plants and animals. Indicate which of the following are common to both plants and animals (“true”) or not common (“false”): false – W_e and W_r and W_t; true - W_a

Plants growing in the rain shadow of a mountain range will have more roots than individuals of the same species growing at the same elevation on the windward side of the mountain range.

We can think of aquatic organisms and their environment as two aqueous solutions separated by a selectively permeable membrane

Pure water has a potential of zero, while most environmental water has a potential that is negative

A fish, with few solutes in its body fluids, swimming in the ocean near the mouth of a river would experience lower osmotic pressure as compared to swimming in the open ocean

In response to increasing the humidity of the experimental chambers, Toolson and Hadley found that the internal temperature of cicadas increased to the ambient temperature

The presence of hydrocarbons helps to improve the waterproofing of the cuticle of scorpions

In drier soils, water will remain in the smaller soil pores. TRUE

As a result of being hyperosmotic to the surrounding seawater, sharks gain water through osmosis

Reducing evaporative water loss is an important component of water balance for organisms found in arid environments

Ehleringer found that plants using deep ground water tended to have DeltaD closer to winter precipitation, while plants with shallower roots were closer to summer precipitation

Within the vascular tissues of plants, hydrogen bonds between adjacent water molecules hold the column of water together

The matric (in MPa) will be -0.2 given: plant -1.2 MPa, pressure -0.7 MPa, solutes -0.3 MPa

Being hyperosmotic, freshwater invertebrates must expend energy to release water and absorb salts

Park was interested in studying the response of Digitaria and Eleosine to water stress in sand dunes

For the fluid in plants, the water potential plant = matric + solutes

A decrease in air temperature will result in a decrease in the saturation water vapor density

The maximum quantity of water that air at a specific temperature can hold is known as saturation water vapor density

In order to offset the water loss from evaporative cooling, the cicadas increase their water intake by sucking water from their host plant

In order to maintain their water balance and compensate for water loss through osmosis, saltwater mosquitoes will consume large amount of seawater, up to 240% of their body volume. Which term in the water balance equation would reflect this inflow of water? W_d

Several desert beetles have evolved ways to acquire water by collecting water from fog

Animals predominantly eating C4 plants would have a lower ratio of 12C:13C than those eating C3 plants

The name of the SI unit of pressure defined as 1 N/m². Pascal

Solutes is a positive number. FALSE

During Park’s experiments with Digitaria and Eleusine, the drought period was twice the time between waterings in under the well-watered conditions

The pressure exerted by water vapor in air is the water vapor pressure

The amount of energy an organism expends upon the magnitude of the osmotic pressure and the permeability of their bodily surfaces

Toolson and Hadley’s experiment showed a that there was a “threshold effect” for evaporation. Until the temperature had increased to 39 degree C, there was little change in the evaporation rates of the scorpions

Using the figure, at an air temperature of 23 degree C, the measured vapor pressure of 1.9 kPa represents a vapor pressure deficit of 0.9 kPa

Schenk and Jackson found that, in general, root lengths increase when moving from 80 degree to 30 degree latitude

Water’s tendency to adhere to soil particles creates matric forces

An increase in the vapor pressure deficit in the air around an organism would result in an increase in the rate of evaporation from the organism

Strategies for water conservation are limited to plants growing in arid environments. FALSE

The function of specialized cells on the anal papillae of mosquito larvae is to absorb ions

A plant is placed in a clear, sealed chamber. Over time you would expect the evaporation rate from the plant to decreases

The saturation water vapor pressure increases when air temperature increases

In Hadley and Schultz’ experiments with tiger beetles, they measured water loss by weighing the beetles before and after the beetles were placed in chambers of dry air

Toolson and Hadley found pores in the cuticle of the cicadas that permit water to move through the otherwise water-impermeable cuticle

As a result of their experiments on the water loss in tiger beetles, Hadley and Schultz hypothesized that difference in experiments were related to the amount of hydrocarbons in their cuticle

Park conducted his experiment with Digitaria and Eleusine in the laboratory

When Toolson and Hadley placed a humidity sensor just above the cicadas, they found the evaporation rates increased when the temperature of the environmental chamber was increased

In his experiments, Park found that differences in root growth between the two species were greatest in deeper soil layers

14N is differentially excreted during protein synthesis compared to 15N. We would therefore expect the ratio of 14N:15N to decrease when moving up a food web

The difference between the saturated vapor pressure and the measured vapor pressure is the vapor pressure deficit