Ecology Lessons 4-7 Flashcards
When is algal bloom most likely to occur, & why?
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.
How can human health be affected by disturbed nitrogen cycling?
Drinking water containing toxic algae from an algae bloom can cause an upset stomach & diarrhea.
Can you identify human activities that should not be taking place in waters in which an
algal bloom is occurring?
- Swimming because it can expose someone to algal toxins or cause them to ingest the toxic water.
- Fishing because the fish might be contaminated.
Why are backcountry campers advised to bury their feces in the ground & to avoid washing pots & dishes in the bodies of water?
Burying feces will prevent it from being washed into lakes & rivers, & river/lake water might contaminate the pots & dishes.
What is bioaccumulation?
Bioaccumulation is when a non-biodegradable substance increases in concentration within each successive trophic level.
Bioaccumulation Facts:
-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.
How can DDT enter a food web?
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.
How does the concentration of DDT change with each successive trophic level?
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.
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?
-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
Why might it be difficult to change some of our actions that disturb the carbon cycle? Give
specific examples.
-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
What natural events can disrupt the carbon cycle?
-Forest fires can burn trees & release CO2
-Volcanic activity can destroy rocks containing carbon, releasing CO2 into the atmosphere
What human activities can disrupt the carbon cycle?
-Deforestation reducing the number of plants to perform photosynthesis
-Burning fossil fuels releases CO2 into the atmosphere
Sources of nitrate & ammonia
-human sewage,
-pet and livestock feces (solid waste)
-lawn and garden fertilizers
-eroded soil
How can sewage & waste water enter bodies of water?
-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
In what materials is carbon found in the following: the
soil, the atmosphere, a plant, an animal, bedrock?
-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.