Ecology Lessons 4-7

Question 1

When is algal bloom most likely to occur, & why?

Answer 1

It is mot likely to occur in the summer, because it is the season when there is the most sunlight & the bodies of water warm up.

Question 2

How can human health be affected by disturbed nitrogen cycling?

Answer 2

Drinking water containing toxic algae from an algae bloom can cause an upset stomach & diarrhea.

Question 3

Can you identify human activities that should not be taking place in waters in which an
algal bloom is occurring?

Answer 3

1. Swimming because it can expose someone to algal toxins or cause them to ingest the toxic water.
2. Fishing because the fish might be contaminated.

Question 4

Why are backcountry campers advised to bury their feces in the ground & to avoid washing pots & dishes in the bodies of water?

Answer 4

Burying feces will prevent it from being washed into lakes & rivers, & river/lake water might contaminate the pots & dishes.

Question 5

What is bioaccumulation?

Answer 5

Bioaccumulation is when a non-biodegradable substance increases in concentration within each successive trophic level.

Question 6

Bioaccumulation Facts:

Answer 6

-DDT is a pesticide.
-The use of DDT was restricted in Canada in 1969. DDT causes peregrine falcon eggshells to
thin and break.
-By the 1970s, the peregrine falcon population in North America was almost wiped out.

Question 7

How can DDT enter a food web?

Answer 7

DDT can enter a food web when insects eat plants which have been doused with DDT. These insects will absorb DDT from the plants they’ve consumed, & the organism which eats them will amass even more DDT.

Question 8

How does the concentration of DDT change with each successive trophic level?

Answer 8

As DDT moves up the trophic levels in food chains or food webs, its concentration increases. This happens because DDT is fat-soluble and so it accumulates in the bodies of organisms which come into contact with it.

Question 9

A slogan of the environmental movement is “Think globally. Act locally.” How does this
slogan apply to the increasing atmospheric carbon dioxide levels and to changing your
lifestyle to help reverse this trend?

Answer 9

-People can plant more trees & shrubs in their yards.
-They can also recycle paper & building materials.
-Make homes more energy-efficient (insulation, fix house)
-Use public or manual transportation

Question 10

Why might it be difficult to change some of our actions that disturb the carbon cycle? Give
specific examples.

Answer 10

-We rely on forests for building supplies & land for farming
-We rely on fossil fuels to produce energy
-Some people are reluctant about changing their lifestyle

Question 11

What natural events can disrupt the carbon cycle?

Answer 11

-Forest fires can burn trees & release CO2
-Volcanic activity can destroy rocks containing carbon, releasing CO2 into the atmosphere

Question 12

What human activities can disrupt the carbon cycle?

Answer 12

-Deforestation reducing the number of plants to perform photosynthesis
-Burning fossil fuels releases CO2 into the atmosphere

Question 13

Sources of nitrate & ammonia

Answer 13

-human sewage,
-pet and livestock feces (solid waste)
-lawn and garden fertilizers
-eroded soil

Question 14

How can sewage & waste water enter bodies of water?

Answer 14

-Septic fields & holding tanks can leak, releasing waste & sewage into the ground

-Water treatment plants may malfunction and release raw sewage into lakes & rivers.

-Heavy rainstorm can overwhelm the capacity of a water treatment plant, requiring its water to be released into a lake or river

Question 15

In what materials is carbon found in the following: the
soil, the atmosphere, a plant, an animal, bedrock?

Answer 15

-In soil carbon is found in dead and decaying plants and animals. It is also found in the living organisms that inhabit the soil.

-In the atmosphere, carbon is found in carbon dioxide.

-In plants, carbon is found as glucose in cellulose and starch.

-In animals, carbon compounds from plants are converted back into glucose to be used in cellular respiration. Carbon is also found in the tissues of animals.

-In bedrock, carbon is found in oil, gas and
coal.

Question 16

Why do farmers alternate planting clover and alfalfa with their wheat and canola crops?

Answer 16

Alfalfa and clover plants contain bacteria in their roots that can “fix” atmospheric nitrogen into compounds that plants can use.

Question 17

In what form is nitrogen found in the following: the soil,
the atmosphere, a plant, an animal?

Answer 17

In soils, nitrogen can be found in nitrates, nitrites and ammonium ions.

In the atmosphere, nitrogen is found as nitrogen gas and nitrogen oxides.

In a plant, nitrogen is found in proteins.

In animals, nitrogen is found in animal protein in tissue.

Nitrogen compounds are also found in animal waste.

Question 18

Describe the relationship between nitrogen fixation and denitrification.

Answer 18

Nitrogen fixation turns atmospheric nitrogen gas into nitrogen compounds which plants can use, whilst denitrification turns nitrogen compounds into nitrogen gas.

Question 19

What role does each of the following play in the nitrogen cycle: bacteria, lightning,
decomposers, animals, plants?

Answer 19

Bacteria in the roots of legumes turn nitrogen gas into nitrogen compounds which plants can use.

Lightning turns nitrogen gas into nitrates which are washed into the soil by rain.

Decomposers break down nitrogen compounds like proteins into other compounds.

Animals use nitrogen to produce animal protein, & produce a lot of nitrogen compounds in their waste.

Plants remove nitrogen compounds such as nitrates and
ammonium ions from the soil. These are made into plant proteins.

Question 20

Include the process that changes one carbon
compound into another. Your journey should include at least four stops.

Answer 20

-Plant uses carbon atom to produce glucose during photosynthesis

-Glucose is used to form starch in the plant

-Plant is eaten, & glucose is used by the animal for cellular respiration

-Some carbon atoms are joined with O2 & released as CO2, and some carbon atoms remain in tissue.

-When the animal dies, its remains become fossil fuels.

Question 21

Tanks which collect & store sewage & waste water.

Answer 21

Holding tanks

Question 22

A buried tank into which waste water & sewage are pumped.

Answer 22

Septic Field

Question 23

How might fertilizers & manure be found in rivers & lakes?

Answer 23

Manure & fertilizers might be washed into lakes & rivers during snowmelt or heavy rainstorms as runoff.

Question 24

What happens when there is an excess of nitrate & ammonia in bodies of water?

Answer 24

Algal bloom will accelerate, & the algae will produce dangerous toxins.

Question 25

Why do farmers use fertilizer?

Answer 25

It contains nitrate & ammonia to improve plant growth.

Question 26

What can we do to prevent nitrate & ammonia in bodies of water?

Answer 26

1. Ensure that holding tanks & septic fields are working properly.
2. Limit use of fertilizers near bodies of water.

Question 27

The buildup of nitrogen produces this:

Answer 27

Eutrophication

Question 28

Competition among members of same species

Answer 28

Intraspecific

Question 29

What is produced when nitrogen-containing gases dissolve in atmospheric water vapor?

Answer 29

Acid Precipitation

Question 30

Total area of land required to support a human population at a given level if resource consumption

Answer 30

Ecological Footprint