Living world Flashcards
(90 cards)
1
Q
What is an ecosystem?
A
An ecosystem is a natural system that is made up of plants, animals and the environment in which they live
2
Q
Two types of component in an ecosystem
A
Biotic- eg plants, animals, bacteria, fungi
Abiotic- eg climate water and soils
3
Q
What is a food chain?
A
Shows the direct links between different organisms that rely on each other as a source of food
4
Q
What is a food web?
A
The complex hierarchy of plants and animals that rely on each other as a source of food within an ecosystem
5
Q
Two main sources nutrients are derived from
A
- rainwater washing chemicals out of the atmosphere
- weathering of rocks, releasing chemicals into the soil
6
Q
Natural changes of an ecosystem
A
-extreme weather events
-fire caused by lightning
-climate change/ global warming
- spread of invasive species or introduction of alien species
7
Q
Human induced change of an ecosystem
A
-land use change eg- deforestation and hedgerow removal
-alteration to water and soils, such as land draining or adding fertilisers
- hunting or trapping animals
-introduction of alien species
8
Q
how changes effect pond ecosystem
A
-climate change and extreme weather events can dramatically effect water levels. low water levels put organisms in danger
-fertilisers on farmland can result in an influx of nutrients into a pond, causing algal bloom, which effectively deprives the pond of oxygen
-introduction of alien species could reduce food supple for other organisms
9
Q
how changes affect deciduous forests?
A
-Chalara- disease that affects many ash trees, causing bark loss and tree damage. Lack of ash trees affects the ecosystems food supply for primary consumers
-controlled hunting for species such as deer can be important to maintaining balance within an ecosystem, as it will keep food supply for other consumers higher
10
Q
What factors affect the distribution of global ecosystems (biomes)?
A
-climate (primary factor)
-warm/ cold ocean currents
-distribution of land and sea
-pattern of surface winds
11
Q
Characteristics/ location deserts
A
-roughly 30 degrees N and S of equator, close to tropics of Cancer and Capricorn
-sinking air suppresses rain formation- arid conditions
-hot in daytime but cooler at night- no cloud cover, heat cannot be contained
- plants and animals well adapted
12
Q
Location/ characteristics of tropical rainforests
A
- close to equator, widespread across Asia, Africa and South America
- high sun insolation
- low pressure due to rising air
- high rainfall
- high biodiversity
13
Q
What are the 3 nutrient stores
A
-biomass (trees, plants etc)
-soil
-leaf litter
14
Q
Tropical rainforest facts
A
-cover about 2% of earth’s surface
-home to over 50% of the worlds plants and animals
-experience high temperatures (about 27 degrees throughout the year)
-high rainfall (over 2000 mm per year)
Typically have ‘wet season’ from June to october
15
Q
Rainforest soils characteristics
A
-not very fertile
-red coloured and iron rich
-nutrients concentrated in upper topsoil- very quickly taken up by plants as they grow
16
Q
Rainforest Plants and animals characteristics
A
- highest level of biodiversity
-birds live in canopy high above flood feeding off seeds and nectar
-mammals such as monkeys and sloths well adapted to life in trees
-snakes use trees as vertical highways
-animals like deer and rodents browse on vegetation on forest floor
17
Q
Characteristics of people in rainforests
A
-tradition tribes live in harmony with natural environment-hunting only what is needed to survive- sustainable
-People from outside local area exploit rainforests for commercial gain- extremely harmful to rainforest
18
Q
Nutrient stores in rainforests
A
- vast majority of nutrients in biomass
- soil contains few nutrients, as they are quickly absorbed by plants or leached into soil by rainfall
- few in litter store, as decomposed quickly break down dead leaves due to perfect conditions
19
Q
Plant adaptations in rainforests
A
- buttress roots help anchor trees in shallow rainforest soil
- lianas- woody vines which grow around and between tree trunks
- tallest trees punch their way through the main canopy to exploit maximum sunlight
20
Q
Animal adaptations in rainforests
A
- Toucans and parents have strong breaks for cracking hard nuts which other birds cannot break
- three toed sloths have long claws allowing them to climb trees. also algae grows on their fur, acting as camouflage
21
Q
how biodiverse are rainforests?
A
- contain 170,000 of the worlds 250,000 known plant species
-recent survey found 487 separate tree species in a single hectare
22
Q
reasons for high diversity in rainforests
A
- wet and warm climate allows rapid plant growth, providing habitats for animals also
- rapid recycling of nutrients speeds up plant growth
- many parts untouched by people, so can grow and thrive as they please
23
Q
How much deforestation has occurred in brazilian rainforest since 1970?
A
- 18% of total rainforest cleared (3x size of Uk)
24
Q
how does farming lead to deforestation?
A
- land cleared for crop plantations and cattle grazing
- cattle ranching accounts for 80% of deforestation in brazil
-indigenous tribes clear small areas of land to practise subsistence farming
25
how does logging lead to deforestation?
- trees cut down for timber- woods such as mahogany and teak valuable for furniture
- small trees used for fuel
- 80% of deforestation in Malaysia is for logging
26
how does road building lead to deforestation?
- trees cleared to make way for roads
- roads provide access to new mining areas, settlements and energy projects
- Trans- amazonian highway in brazil stretches for 4000 km through rainforest
27
how does mineral extraction lead to deforestation?
- minerals such as gold, bauxite are mined extensively, meaning trees need to be cleared before mining can take place
- also pollutes rivers
28
how does energy development lead to deforestation?
- high rainfall leads to ideal conditions for hydroelectric power dams
- in brazil, Belo Monte dam has flooded over 40,000 hectares of rainforest and displaced 20,000 locals
29
how is economic development an impact of deforestation?
- mining an commercial farming create jobs for locals
- hydro electricity is cheap renewable energy, boosting industrial development
- improved infrastructure opens up new areas for economic development
- loss of biodiversity may reduce tourism
30
how is soil erosion an impact of deforestation?
- without trees to intercept high rainfall, land is exposed, meaning soil is much more vulnerable to the torrential rain
-with no roots to bind it together loose soil can be easily eroded and washed away
31
how is climate change an impact of deforestation?
-high levels of evaporation from plants cools the air, so without this air becomes warmer
- trees are carbon sinks, so when they are burned the carbon is released back into the atmosphere, contributing to the enhanced greenhouse effect-> global warming
32
how are rainforests important resources?
- people use reserves of wood, nuts, fruit and minerals- items such as banana, cocoa and sugar from here
-20% of worlds freshwater comes from amazon basin
33
how are rainforests valuable for medicine
- 25% of all medicines come from rainforest plants, with more than 2,000 plants having anti-cancer properties
- on top of this, less than 1% of plants have actually been tested for medicinal qualities
34
how much of the worlds oxygen is contributed by rainforests?
-28%
35
different management techniques for rainforests?
- selective logging + replanting
- conservation and education
-debt for conservation swaps/ debt reduction
- ecotourism
- international agreements about hardwoods
36
what is selective logging/ replanting?
- trees selected by professionals or machines in order to reduce damage to other trees
- monitored by officials to ensure legal and correct
- new trees planted after
37
what is conservation and education?
- national parks in rainforests mean areas are protected from development, due to large companies supporting conservation projects in exchange for materials or scientific research
- charities such as WWF support these programmes which train conservation officers and scientists, and promote rainforest conservation in school
38
what are debt for conservation swaps or debt reduction?
-countries that have money owed by other countries will write off debts in return for rainforests being protected
- eg a brazilian debt of £13.5m was converted into a fund to protect areas of rainforest
39
what are international agreements about hardwoods?
-involves companies agreeing to only using timber which has been verified by organisations such as Forest Stewardship Council, who make sure timber comes form sustainable sources, reducing illegal felling
-the International Tropical Timber agreement in 2006 restricted the trade in hardwoods by only marking timber with a registration mark if it is form a sustainably managed forest
40
what is ecotourism?
-a sustainable form of tourism that focuses on the natural environment and has a very low impact.
- supports local communities employing indigenous people as guides, and often providing education or social improvements
- offers local people and government a financial return for preserving rainforests
41
What are the physical characteristics of hot deserts?
- Arid (dry), blow 250mm of rainfall per year
- hot, temps rising well above 40 degrees Celcius
-rocky, desolate places with isolated thorny bushes and cacti
-low biodiversity
42
Where are deserts found?
- between 15 and 35 degrees N and S of equator
43
What is soil like in hot deserts?
- Dry
- not very fertile
- sandy and rocky
- typically about 1m deep
- lack of vegetation
44
in what ways are soils and plants interdependent
- vegetation/ plants provides shade and food for animals- this means stops soil losing water, nutrients also provided when dead matter is broken down
- soil provides the structure for roots to take hold and grow
45
examples of Producers in hot desert
- cacti
- creosote bushes
- thorn acacias
- annual flowers
- rabbit brush
- ocotillo
- sage brush
46
examples of primary consumers in hot deserts
- insects
- lizards
- rodents- eg kangaroo rats
47
examples of secondary consumers in hot deserts
- tarantulas
- scorpions
-lizards
- snakes
48
examples of tertiary consumers in hot deserts
- hawks
- kit fox
49
adaptations of xerophytes (plants that live in dry conditions) that live in hot deserts
- have thick waxy cuticles
- shed leaves to reduce water loss through transpiration
- some have the bulk of their biomass below ground surface where conditions are cooler
- grow very quickly after rainfall
50
examples of hot desert plants
- desert yellow daisy
- prickly pear cactus
- saguaro cactus
51
adaptations of saguaro cactus
-xerophyte
- grows very slowly to conserve energy
- can store up to 9 tonnes of water
- body made of vertical pleats that expand to allow greater water storage
- can lose up to 82% of its water before dying do dehydration
52
examples of adapted hot desert animals
- fennec fox
- peringuey adder
- kangaroo rat
-camel
53
how is fennec fox adapted to hot deserts
- large ears- dissipates excess body heat
-kidneys adapted to restrict water loss
-thick fur insulates them on cold desert nights
- sandy fur helps reflect heat, and acts as camouflage
- thick fur on soles of feet to insulate against hot sand
54
camel adaptations to hot deserts
-can go a week or more without water, can last for several months without food
-can drink up to 46 litres in one drinking session
- store fat in hump which can be metabolised for energy
- body temp fluctuates throughout the day from 34 to 41.7 degrees, allowing them to conserve water by not sweating
- thick lips allows them to eat prickly plants without pain
55
opportunities in hot deserts
-solar energy panels
- tourism
- agricultural farming
- mineral extraction
56
issues of possible opportunities in hot deserts
- expensive to build solar panels
- inaccessibility for tourists
- irrigation needed for farming
- mineral extraction bad for environment
57
which desert is case study
- western desert, USA
58
reasons for tourism in western desert
- visitors get chance to experience wilderness areas
- celebrates culture of natives
- 37 million annual visitors to Vegas
-Lake powell and lake mead create water sports opportunities
59
challenges of tourism in western desert
- artificial lakes eg Mead and Powell, could effect habitats/ change ecosystem
- lack of accessability
60
reasons for farming in deserts
-hot conditions and high sun insolation perfect for growth of many plants
-irrigation supplied by aquifers, which extract water form stores beneath ground
and also by canals
61
challenges of farming in western desert
- canals can cause floods
- high maintenance
62
reason for mineral extraction/ energy generation in western deserts
-rich in minerals- copper, uranium, lead, zinc and coal
- solar energy due to high sun insolation- sonoran solar project projected to provide energy for 100,000 homes
-hydroelectric power created by water in lake Mead
-lots of oil in these regions
63
challenges of mineral extraction and energy generation in western desert
-land conflict
- risk to wildlife
-solar panels expensive
64
explain challenges of extreme temps in western desert
-avg temp of 27 degrees, but can soar up to 50 in the summer
- work very hard outside during the day
- high rates of evaporation leads to water shortages
- western desert expected to warm faster than other regions
65
how is challenge of extreme temp in western desert managed?
- plants and animals already adapted
- houses have thick walls, which keeps cool during day and keep heat inside during night
- walls white washed to reflect sunlight
- workers eg farmers only work outside during morning or evening- banned throughout day
66
explain challenge of water insecurity in western desert
- increasing population- demand for water increases
- decreasing snowfall in rockies- less meltwater which flows through rivers and canals to
people
67
how is challenge of water insecurity in western desert managed
-storing water in reservoirs such as lake Powell and Mead-large bodies of water reduce evaporation
-flat roofs to collect rainwater
- shade balls in reservoirs to reduce evaporation
68
Explain problem of nevada’s water deficit
- lack of rainfall
-lack of freshwater from colerado river
-struggle to reduce demand for water
- people watering their lawn uses 60% of water
69
how to manage challenge of Nevadas water defeci
- ‘xeriscaping’- gardens which use drought resistant plants
- new developments- no front yard grass, 50% backyard grass only, $2 for every square foot of grass
70
explain challenge of inaccessibility in western desert
- lack of roads due to low population density
- route 60, route 70 only main roads
71
how challenge of inaccessibility managed in western desert
- 4 airports in las Vegas
-118 routes to vegas- 38 millions visitors a year
72
what is desertification
- the process of land becoming drier and degrading in quality, due to both human activities and natural process
73
reasons for desertification
- climate change (global)
- population growth (global)
- removal of fuel wood (regional)
- overgrazing (local)
- over-cultivation (local)
- soil erosion (regional)
74
cycle of desertification
-amount of natural vegetation decreases (due to external factor)
-no plants of leaves can intercept rain and soil is exposed to sun
- sun bakes soil and it cracks
- rain water runs over surface rather than it being absorbed
-soil is easily washed away (leaching)
-soil is degraded, losing fertility and structure
- soil is worn out, poor quality and so it is hard to grow crops and natural vegetation
-cycle repeats
75
Desert fringe case study
- Sahel region (south of Sahara)
76
where is Sahel
- thin band that runs ways to west across 9 countries, such as Chad and Sudan, and is just south of Sahara
77
How does overcultivation cause desertification
- exhausts soils fertility
-more children born into farming families- more crops planted- some aquifers drained dry
-European countries using large areas of Ghana to grow water-hungry cash crops
78
how does overgrazing cause desertification
- if too many animals graze for too long on one site, all vegetation is eaten and may be unable to regrow
-Due to political boundaries, Normandic groups cannot wander freely meaning that they have to stay in the same place- land gets overgrazed
79
how does soil erosion cause desertification
-overcultivation and over grazing both result in soil erosion
- topsoil becomes exposed due to lack of interception or shade, therefore it becomes baked and hard, meaning that rainfall washed over soil, carrying topsoil away and leaching its nutrients
-this makes it impossible for vegetation to regrow
80
methods to prevent desertification
- water and soil management
- afforestation ( planting trees)
- use of appropriate/ intermediate technology
81
how does afforestation prevent desertification
-allows tree roots to bind soil together and prevents it from drying out due to more shade and coverage
- this means soil is not eroded as it cannot easily be washed away by rainfall or blown away by wind
-e.g great green wall across Africa
82
limitations of afforestation
- costs a lot
- with Great Green wall example- lots of countries need to agree to it
83
how does water and soil management reduce risk of desertification
- traps soil that is being transported by wind or by water during rainfall
- meaning that soil isn’t eroded, and less water is lost through surface run off
-leading to an increased crop yield by up to 50%- significantly reduces risk of desertification
- eg Burkina Faso
84
-limitations of soil and water management
- difficult to maintain
- small scale
85
how does appropriate (intermediate) technology (fuel efficient stoves) reduce risk of desertification
- needs 55% less firewood to cook food
- less trees cut down for firewood- less deforestation
-more trees = soil held together by roots and not dried out due to shades, and leaves intercept rainfall- less leaching
- eg Senegal - 86% of aural population depends on biomass for cooking
86
limitations of appropriate technology (fuel effiecient stoves)
- still uses firewood
- hard to give everyone stove
87
How many plant species in amazon rainforest
- 60,000
88
How many live in amazon rainforest
- 20 million
89
What type of forest is epping forest
- Ancient deciduous forest
90
How many species of fungi in epping forest
- 700
