Lecture 28

Question 1

Ways that humans take resources from their environment

Answer 1

Biosphere (hunting, gathering, logging, agriculture), hydrosphere (water, fishing, salt), geosphere (minerals, fuels, building materials), atmosphere (oxygen)

Question 2

Waste products are returned by humans when taking resources from the earth

Answer 2

to lithosphere (solid waste), to hydrosphere (dissolved material), and atmosphere (gases and aerosols)

Question 3

Renewable resources

Answer 3

those replenished by growth each season

Question 4

examples of renewable resources

Answer 4

crops, wood, running water, fisheries

Question 5

Non-renewable resources

Answer 5

those replenished only on longer timescales

Question 6

examples of non-renewable resources

Answer 6

minerals and fossil fuels

Question 7

Open system (old resource management)

Answer 7

Resource use was viewed as a process of extraction from the environment from seemingly limitless resources, used by humans, and disposal wastes and by-products back into the environment.

Question 8

Human population and resources

Answer 8

Technological advances have allowed for dramatic increases in the human population, putting increased strain on Earth’s resources and environment

Question 9

Closed-system earth

Answer 9

Earth itself is a closed system, so wastes and by-products (pollution) returned from extraction, production, manufacturing, and consumption directly impact the human economy. Earth’s resources are not unlimited and that conservation, efficiencies in extraction, manufacturing, and transportation of goods, and recycling / reuse are needed leads us to the modern resource cycle

Question 10

We can extend resources through:

Answer 10

conservation, reuse, recycling, or substitution.

Question 11

Stock is depleted if the resource is withdrawn at a rate ___ than the rate of replenishment.

Answer 11

faster

Question 12

Responsible resource management

Answer 12

use resources at a rate that does not exceed the replenishment rate

Question 13

If a renewable resource is severely depleted, it will not be able to _____.

Answer 13

regenerate

Question 14

Forest harvesting techniques:

Answer 14

clear-cutting (non-sustainable), cut blocks, and selective harvesting

Question 15

Clear-cutting forest harvesting

Answer 15

This resulted in the loss of root systems that hold soils together causing widespread soil erosion, nutrient loss, and accumulation of debris in rivers and streams.

Question 16

Cut-block forest harvesting

Answer 16

small clear-cut areas surrounded by forest are harvested.

Question 17

Selective harvesting

Answer 17

(thinning) where only trees of a certain maturity are removed to a level that prevents ecosystem damage.

Question 18

Deforestation negative effects

Answer 18

• forests are a carbon sink, and deforestation leads to losses in carbon sequestration from the atmosphere
• loss of habitat biodiversity, habitat, and soil worldwide
• tropical forests are susceptible to deforestation because tropical soils are nutrient-poor, and experience greater erosion with shallower root systems

Question 19

Fisheries

Answer 19

useful for: animal protein consumption, oils, or fishmeal for animal consumption.

Question 20

Methods of fisheries harvesting

Answer 20

capture fisheries and aquaculture

Question 21

Capture fisheries harvesting

Answer 21

those in which fish are caught in the wild, and this contributes nearly 100 million metric tons/year

Question 22

Aquaculture

Answer 22

the raising of fishery resources in captivity – is used primarily to raise high-value products (shrimp, salmon), and contributes an additional 50 million metric tons/year.

Question 23

Cons of capture fisheries

Answer 23

can lead to overexploitation

Question 24

Cons of aquaculture

Answer 24

may cause the loss of natural coastal environments, requires considerable resources to run, and can lead to the spread of disease in the fish population

Question 25

Continued overuse of fishery resources can lead to _______

Answer 25

commercial extinction – so few organisms remain that it is not economically feasible to continue to harvest them

Question 26

Estimates are that ___ of global fisheries are overexploited, with another __ fully exploited

Answer 26

50%

25%

Question 27

Soil Resources

Answer 27

Arable soil is essential to the global food supply (human supply and production of feedstock and cattle). Soil supplies essential nutrients for plant growth and takes hundreds to thousands of years to develop.

Question 28

The soil profile is comprised of ___, starting with: and ending with:

Answer 28

horizons

weathered parent rock and ending in organic oxygen-rich O-horizon at the surface

Question 29

Soil horizons:

Answer 29

O (organic matter), A (mixed mineral and organic matter), E (removal of soluble material), B (accumulation of clay), C (weathered parent rock)

Question 30

Threats to soil resources

Answer 30

loss of nutrients due to overproduction, contamination from agricultural practices, herbicides, industrial activities, over-fertilization, and compaction.

Question 31

Soils form on timescales that are _____ of years, while global soil loss is occurring at __ per decade

Answer 31

thousands years versus 7% per decade

Question 32

How to minimize soil erosion

Answer 32

employing proper crop rotation techniques (including allowing fields to be fallow periodically), preventing soil pollution, terracing on sloped land, and optimizing irrigation, pesticide, herbicide and fertilizer applications

Question 33

Over-fertilization causing Eutrophication

Answer 33

When excess nutrients – especially phosphorous and nitrogen – leach from agricultural fields to freshwater bodies, algae, plankton, and aquatic weeds grow. As these organisms die, the process consumes oxygen in the water, causing the water to go anoxic. This, in turn, kills other organisms living in the water

Question 34

Water resources are needed in:

Answer 34

food production (animal and plant), energy generation, transportation, recreation, and industrial processes

Question 35

Irrigation is by far the largest consumer of water globally, comprising more than __ of use, with industrial uses comprising an additional __.

Answer 35

75% and 20%

Question 36

How water can be lost:

Answer 36

industrial contamination, the overuse of groundwater aquifers (causing their compaction), and increased evaporation due to climate change or deforestation

Question 37

Costs of damns

Answer 37

habitat loss, the modification of river ecosystems, modifications to seasonal discharge rates and patterns, and a reduction in sediment transport downstream (which can cause deltas to retreat).

Question 38

Arak Sea in Kazakhstan

Answer 38

a classic example of overuse. Beginning in the 1960’s, water was diverted from rivers that feed the sea for irrigation projects. A once thriving fishing industry collapsed, and all that remains of the ‘sea’ is a thin strip of saline water.

Question 39

Ogallala aquifer in the central part of the United States

Answer 39

water levels have dropped by well over 90 meters and the land surface has dropped 10’s of meters due to agricultural and industrial consumption exceeding the rate of recharge.