Ecology Chapter 4 Mastering Biology

Rank from slowest chemical weathering to fastest

(Slow) Granite, with very few or no cracks Granite, with abundant cracks Basalt, with very few to no cracks Basalt, with abundant vesicles(holes) (Fastest)

Oxidation

- red color of rocks in Arches National Park -Yellow stained rocks that used to contain pyrite before it is weathered

Dissolution

- the salty taste of ocean water - caves formed in limestone

Mechanical Weathering would predominate

-A cold, dry environment experiencing uplift, in which material is being removed by erosion from an underlying pluton/intrusive igneous rock. -A cold, wet environment at high elevation, in which freezing and thawing is common

Chemical weathering would predominate

-A hot environment with many short but intense rainstorms. -A hot, humid climate with heavy precipitation that occurs all year. -A warm, wet environment with above average yearly rainfall and several stormy seasons each year.

Enhances Weathering

-Consistent grazing by a herd of cattle. -A forest fire destroys vegetation without regrowth. -A tree is growing on the side of a rocky hill, and its roots are growing into a crack in the rock. -Animals burrow into the ground, loosening the soil -Humans remove trees and other vegetation in order to develop an area of land. -Lichens, which secrete acids, encrust the surface of a rock

Inhibits Weathering

-Rows of trees are planted on the border of a field to slow the wind and deflect it upward. -A once bare field is planted with trees and shrubs.

Traditional Agriculture

-controls pests with natural pesticides and planting of multiple crops -many crops grown together on small plots of land -relies on human and animal power

Industrial Agriculture

-single crops grown on large plots of land -controls pests with synthetic pesticides -heavy use of synthetic fertilizer -relies on fossil fuel-powered machinery

What is salt weathering?

the formation of minerals in rock cracks during the evaporation of salty water, forcing rock apart

Potassium feldspar weathers in the presence of water containing -----

carbonic acid

Given that annual crop yields in each of the study plots were approximately 4 metric tons/ha, what is the ratio of soil lost to crop yield under conventional tillage?

4,000 kg soil/1 ton crop yield

If the area contaminated with heavy metals contained 10,000 kg of soil, after 5 years of phytoremediation one would expect alpine penny-cress to have removed:

10 kg zinc.

If plants continue to remove zinc at the rate shown, it would take _____ years to remove all the zinc.

15 years

Prior to phytoremediation the concentration of Cd in the soil was:

19 mg/kg soil.

After 1 year of phytoremediation, alpine penny-cress removed ____ mg/kg soil of zinc.

200

What percentage more nitrogen would be saved annually by using reduced tillage rather than conventional tillage?

37%

Approximately how much more soil was lost using conventional tillage rather than reduced tillage?

5,000 kg/ha

How much more organic carbon would be saved annually by using reduced tillage?

70 kg/ha

What do freeze-thaw and salt weathering have in common?

Both freeze-thaw and salt weathering require rain and force rocks apart physically.

------ weathering alters the internal structure of rock materials.

Chemical

You are designing an experiment to test methods to prevent soil erosion in agricultural production. Which of the following are NOT good experiment ideas? A. Compare the planting of grass strips between rows with traditional planting (no grass between rows). B. Compare traditional planting with crop rotation. C. Compare fields left with dead plant cover and fields with living plant cover to determine which is better at reducing erosion. D. Compare tillage of a wheat field with tillage of a corn field. E. Compare traditional tillage planting with contour planting.

D. Compare tillage of a wheat field with tillage of a corn field.

Which of the following statements is FALSE? A. Plants can stabilize the soil and thus influence its formation. B. Plants can add organic material to the soil and thus influence its formation. C. Plants can physically fracture rocks and thus influence the formation of soils. D. Plants remove water from the soil, influencing soil formation. E. Plants can redistribute soil nutrients and thus influence the formation of soils.

D. Plants remove water from the soil, influencing soil formation.

You want to investigate the difference in available water capacity of local farms. Which of the following would be an appropriate hypothesis?

Farms with intermediate particle size will have the highest available water capacity.

Hydrolysis

Feldspar in granite rocks weathering to clay

With the addition of water, the minerals in granite rocks chemically weather into other minerals, known as products. Test your knowledge of the by-product of each mineral as a result of chemical weathering by labeling the minerals below with their respective products.

Feldspar- clay Quartz- No chemical Change Olivine- Limonite

Predict how the results of this experiment might vary if repeated in a less mountainous region with lower annual rainfall.

Lower soil loss for both conventional and reduced tillage treatments

The surface layer of soils is referred to as the

O horizon.

What process is the source of the CO2 that root hairs release into the soil?

respiration

Why does water frozen in the cracks of a rock help to break down the rock?

Water expands when frozen and physically forces the rock apart.

In temperate regions dominated by deciduous forests, seasonal changes result in __________

a larger leaf area index during summer months

A greenhouse gas called ------ influences the rate of chemical weathering.

carbon dioxide

What name is given to the process seen in this animation?

cation exchange

Which of these ions is most likely to be leached from the soil?

chlorine ions

Acid precipitation _____.

decreases soil fertility

The amount of light at any depth in a forest canopy is affected by the leaves above. The best way to measure the impact of those leaves on light availability is to __________.

determine their total area

How do cations enter root hairs?

diffusion

The binding of H+ ions to soil particles _____.

displaces mineral cations

In comparing the removal of cadmium with the removal of zinc, the alpine penny-cress removed a _____ % and a ____ mass of cadmium than of zinc.

higher, lower

The release of CO2 into the soil results in the formation of _____.

hydrogen ions and carbonate ions

Terrestrial organisms typically __________

must cope with a much wider range of temperatures than that found in aquatic systems

Iron weathers through the process of ----

oxidaton

Under which conditions are the processes of weathering, leaching, and input of organic material from plants into soil maximized?

warm temperatures and abundant water

The mechanical destruction and/or chemical modification of rock into smaller particles is called

weathering.