B7.4 Learning from nature

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Cambridge IGCSE Biology Flashcards on B7.4 Learning from nature, created by franimal on 13/06/2014.
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Flashcards by franimal, updated more than 1 year ago
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Question Answer
What kind of system do we have of using resources and what nickname is often applied to this? Our linear system is often called 'take-make-dump'.
What kind of system does nature use and what other word for this is there? A closed-loop system is also called an ecosystem.
Name four examples of ecosystems. There are rivers, lakes, grasslands, coral reefs, woodlands, beaches, caves...
What effect does energy have on closed-loop and linear systems? Energy can't be reused - so it's always linear. However a closed-loop system can obtain energy from a sustainable source (aka the sun).
Name two examples of waste materials from microorganisms that are then taken up by plants? nitrates and phosphate
What group of people still live a closed-loop lifestyle? the Maasai
What are things that used to be part of a living organism called? dead organic matter (DOM)
What is released by some microorganisms to break down DOM? digestive enzymes
What three things do different kinds of bacteria do to nitrates/nitrogen? Some bacteria break down the proteins/amino acids into ammonium ions, some break down the ammonium ions into nitrates and in anaerobic soil, other bacteria change nitrates into nitrogen gas.
What two carbohydrates do bacteria break down? cellulose and starch
What is the transfer of pollen called? pollination
What other word is there for bumblebees? pollinators
What is an area that renews itself and doesn't change called? A stable ecosystem.
Name three ways in which ecosystems often aren't perfect closed loops. Birds migrate for the winter and not all of them come back, rivers carry nutrients etc downstream and deposit them there and coral reefs grow larger as they take minerals from the water.
What are life-support systems that we depend upon for our survival called? ecosystem services
In what four ways does the forest above Mexico City help regulate water and what happened that effected this? The soil is full of DOM from the leaves and holds water like a sponge which means the water gradually flows into the rivers, tree roots reduce 'soil erosion' by holding the soil together, leafy branches means water drips onto the soil instead of cascading onto it, and water evaporating off the forest canopy generates cloud and rain. Deforestation meant this happened less, because there were less trees.
What new method is there of protecting earthworms whilst planting new crops? direct drilling
Earthworms are incredibly useful creatures. In what five ways do they help make soil fertile? They digest leaves and eject fine soil onto the surface as worm casts, more DOM ends up in the soil for plant nutrients, air gets into the soil through their burrows, their burrows mean water can drain easily and their actions bury stones.
If a substance doesn't rot, what is it called? non-biodegradable
What two effects can plastics that end up in the sea have? They can be eaten by fish, turtles or sea birds and their guts can become blocked, whilst wave action can make plastics into fine granules that are eaten by small animals instead of their normal food. These small animals then die, causing starvation for the bigger fish that eat them.
What are poisonous chemicals called? dioxins
What material has been liked to birth defects and cancer in humans? heavy metals
What is it called when chemicals are passed up the food chain and how does it work? Sometimes bioaccumulation occurs, where small amounts of non-biodegradable products are passed up the food chain in higher and higher quantities until they become toxic to the predators at the top.
What is plant and animal material and waste that can be used as a fuel called? biomass
What two reasons are there why human waste is very rarely used as fertiliser? It could cause bioaccumulation and transmit infectious diseases.
Describe and name what happens when nutrients from non-organic fertilisers flow into lakes. It causes algae to grow and algal bloom occurs, covering the whole surface of the lake and killing the plants that can no longer photosynthesise. The algae then dies and bacteria use the oxygen in the water and the DOM to respire, making the water deoxygenated. This process, called eutrophication, therefore kills both plants and fish.
What is crop rotation? Changing the crop grown in a field each year to preserve fertility.
What does clover have in it's roots and what kind of crop is it? Clover has nitrogen-fixing bacteria in it's roots and is a fallow crop, a crop that isn't harvested.
What is the Californian system of producing almonds called? intensive agriculture
Name four of the problems with the system California has for producing almonds. Fertilisers have to be added, there's very little biodiversity, pest insects and fungi have few natural enemies, (pesticides that kill pests also kill bees so) bees must be transported to the almond sites.
What system is in place for North Sea cod but what five problems does this cause? There are quotes in place, but politicians don't want to set them low enough, fishing has to be monitored and policed, many boats just dump fish if they catch too many or the wrong species, fishing fleets move to poor countries and cause devastation to the local people, and there's trawling for deep-sea fish instead which effects their ecosystem and damages the sea bed.
Why do fishing bans have to be set now, rather than when the stocks have crashed? Other species of fish move in and take the place of whatever has become extinct in that area, so the fish can never return to their original space in the food chain.
What is it called when dry land becomes a desert? desertification
What five techniques have the local people living in the Sahel dry-zone developed to avoid desertification? Herds are moved around a lot, trees aren't cut down, acacia trees are planted as windbreaks, thorny branches and rocks are used to reduce erosion in stream beds, and hundreds of small pits are dug to make seedbeds for crops.
What's happening in the Sahel area right now? There's overgrazing, traditional skills are being lost, intensive farming is beginning to occur and the population has risen.
Why do want to conserve seeds in the Sahel area? Because the native species are adapted to dry conditions and therefore grow best.
What are forests that have never been cut down called? primary forests (or old growth forests)
Why five reasons are there for forests to be cut down? For timber, for grazing space for cattle, to grow palm oil, to grow soya and to grow biofuels.
What nine problems does cutting down the forests cause? Soil erosion, mud slides, silting of rivers, flash floods, loss of cloud colour, drought, polluted water, no fish, and the removal of a sustainable source of timber.
What possible solution is there to illegal and unsustainable timber production? eco-labelling
What is it called, when a forest stores carbon in it's trees? Being a 'carbon sink'.
What is sunlight stored as chemical energy in a fossil fuel called? fossil sunlight energy
What happens when carbon dioxide dissolves in water? A weak acid is formed and the seas become more acidic, harming wildlife.
What two things mean we can't rely on traditional farming methods? They take up huge amounts of time and couldn't feed the millions of people who live in cities.
What is it called when an object becomes a material for another product? It's a technical nutrient.
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