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ABHAYS A-LEVEL BIO FLASHCARDS > M6, C24 Populations and Sustainability > Flashcards

M6, C24 Populations and Sustainability Flashcards

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Biology 101 flashcards
1
Q

define conservation

A

the maintenance of biodiversity through human action or management

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2
Q

define preservation

A

protection of an ecosystem by restricting or banning human interference

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3
Q

define sustainability

A

Using the Earth’s natural resources in a
way which preserves the environment and
ensures the resource is available for future generations.

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4
Q

what are the benefits to being sustainable

A

It helps to prevent finite resources being used up too quickly

Aims to allow humans in all societies to live comfortably, creating a balance between MEDCs and LEDCs

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5
Q

what is coppicing

A

Tree trunk is cut close to the ground

New shoots can form from the cut surface and mature

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6
Q

what is rotational coppicing

A

Woodland divided into sections.
One small area is coppiced at a time.
You move on to different areas until the first area has re-grown and ready to be re-coppiced

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7
Q

what is pollarding

A

Trunk cut higher than in coppicing

Prevent animals eating new shoots

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8
Q

how can large scale timber production become more sustainable

A 
Involves clearing large areas
Can be made more sustainable by…..
Selective cutting - only cutting largest trees
Replanting trees
Planting trees at a good distance apart
Killing pests + pathogens
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9
Q

describe the ecosystem of Masai Mara

A

Savannah (grassland)
Divided by the Mara river
-Fertile regions close to the river = rich grassland + woodlands
-Further from the river = open plains, with scattered scrubs and trees
Famous for the annual zebra and wildebeest migration
The region was dominated by the acacia bush
Also home to the tsetse fly which carries African trypanosomiasis (sleeping sickness)
Many acacia bushes have since been removed to stop the spread

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10
Q

how does cultivation work in Masai Mara

A

Grassland converted to cropland
Natural vegetation is removed
Nutrients in the soil are used up
Leads to a reliance on fertilisers to grow crops

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11
Q

what is ecotourism

what does it aim to do

A

tourism directed towards natural environments, to support conservation efforts and observe wildlife
It aims to
-reduce the impact tourism has
-Ensure tourism doesn’t exploit the environment
-Consult + engage local communities
-Ensure infrastructure benefits locals + visitors
Repeated use of hiking trails, mechanical transport is contributing to soil erosion and habitat change

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12
Q

how is conservation and research being used in Masai Mara

A

An active conservation and protection programme was established
They’ve employed reserve rangers and provided communication equipment, vehicles and infrastructure
This has deterred the poachers from entering

eg. Black rhino are endangered due to poaching for the horn – they are on the IUCN critically endangered list

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13
Q

What balance is created in Masai Mara between the growing population and conservation

A

Elephants trample on crops and grazers feed off them so land is fenced off but this threatens natural migration

Legal hunting culls excess animals which maintains the population but numbers have to be constantly monitored to balance the ecosystem

Migratory wildlife threatens livestock as they compete for food but disease spreads as both species eat the vegetation

Human population is increasing which means more land is needed for housing but this leaves less land for wildlife

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14
Q

what are virgin caves

A

an example of preservation
humans can’t enter these newly discovered caves
they’re sensitive so humans walking around them would affect them

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15
Q

how is grazing controlled in Masai Mara

A
  • tribes used land for livestock grazing
  • tribes move depending on climate or presence of tsetse fly
  • allows vegetation to recover
  • grazing is limited to the edge of the reserve as local tribes can’t enter park
  • populations have grown in size so herds are larger and more trees have to be removed for fuel
  • vegetation is removed, risk of soil erosion increases
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16
Q

what are the pros and cons of ecotourism

A

pros: educational, profit, employment, aesthetically pleasing, protection of areas and sustainable
cons: soil erosion, damaging environment, expensive

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17
Q

give two reasons why a population would increase and two reasons why it would decrease

A

increase: births, immigration
decrease: deaths, emigration

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18
Q

define limiting factor

A

an environmental resource that limits population growth

19
Q

what are abiotic factors of population size and give some examples

A

non-living factors that affect population size

air
water
light
wind
humidity
inorganic nutrients
soil
pH
temperature
salinity (salt)
20
Q

what are biotic factors

give some examples

A

living factors that affect population size

other organisms
competition
predation
symbiosis - mutualism and parasitism
disease
21
Q

how do you work out population growth as a percentage

A

(population change during period / population at the start of the period) X 100

22
Q

what is the percentage increase of the world population from 5,306,425,000 habitants to 6,895,889,000?

A

(6895889000 - 5306425000) / 530642500
X100

= 30.0%

23
Q

describe the features of a graph showing the population growth (3 parts)

A

1) slow growth (lag) - there are few widely dispersed individuals. limits sexual reproduction as mates are hard to locate
2) rapid growth (exponential) - population grows at its maximum rate, its biotic potential. birth rate is higher than death rate and there is little competition
3) stable/no growth - population reaches maximum size that its ecosystem can sustain. This is called the CARRYING CAPACITY (k) where the population remains roughly stable

24
Q

define carrying capacity

A

maximum population size of the species that the environment can sustain indefinitely, given that food, habitats, water and other necessities are available in the environment

25
Q

define ecosystem

A

A biological community of interacting organisms and their physical environment

26
Q

describe the Tarai region of Nepal

A
  • Hot and humid
  • Fertile soil, rich in plant nutrients
  • High biodiversity
  • Many plants such as pipal and bamboo
  • Large areas of thick forest
  • Contains the Bengal tiger, sloth bear, Asian Elephant and Indian Rhinoceros
27
Q

how does the Tarai region in Nepal use sustainable forest management

A

national legislation
local groups which set harvesting rules, set rates and prices and determine how income is distributed

aims to provide livelihood for local people, conserve forest and provide income for development

28
Q

in Nepal, what are the successes of community forestry groups (6)

A
  • increased area and improved density of forests
  • improved soil and water management
  • increase in retail price which means greater economic growth
  • employment and income generated through non-timber products produced
  • sustainable wood fuel sources which 3/4 of household energy comes from
  • securing biodiversity
29
Q

in Nepal, how do they promote sustainable agriculture (6)

A
  • promote production of fruit&veg in the hills to avoid further intensification
  • enhance crop production by improving irrigation facilities (moving water from area to area)
  • growing more than one crop on a piece of land (multi-cropping
  • enhance fertility of the soil by growing nitrogen-fixing crops
  • growing crop varieties resistant to various soil, climates or biotic challenges (biotechnology and genetic engineering)
  • enhancing crop yields by improving fertilisation techniques (using manure to improve soil)
30
Q

describe an ecosystem of a peat bog

A

Wet
Spongy ground
Boggy
Mosses, heathers, many insects, so many nesting birds

31
Q

how do peat bogs form

A
  1. An area is wet, acidic and often due to waterlogged soil, the soil lacks oxygen.
  2. Plants that can survive these conditions grow here; eg. Mosses, sedges and shrubs.
  3. When these die, the wet, acidic and anaerobic conditions mean the dead plant material cannot fully decay.
  4. The partly decomposed plant material is called peat.
32
Q

why are peat bogs being destroyed

A
  • to be mixed with soil to improve soil structure and water retaining properties of soil
  • to make space for commercial crops
  • they can be dried and burnt to be used as fuel
33
Q

why is it important to conserve peat bogs

A
  • peat is a carbon store so when you burn it you release carbon dioxide into the atmosphere
  • peat bogs take thousands of years to form so they won’t reappear if you destroy them
  • they are habitats
  • they are a food source for insects which feed nesting birds which feed birds of prey so without them the food chain would be disrupted
34
Q

what methods are being used to conserve peat bogs

A

1) removing trees and tree seedlings from the area to allow the peat bog to have maximum water because the trees require water which would leave the peat bog dehydrated
2) use controlled grazing which ensures diverse wetland surface for structure and species composition. provides a range of habitats for rare insects
3) block any ditches around the peat bog to raise the water table to the bog surface

35
Q

how are humans damaging / have damaged the Galapagos islands

A
  • Explorers/sailors visited in 19th Century affected animal population by eating them
  • Non-native animals introduced and ate the native species (decrease in population) eg. dogs, cats, rats eat young tortoises, pigs destroy nests, goats eat plant life.
  • Non-native plants introduced, compete with native plants
  • Quinine trees taller than native plants, block out sunlight
  • Fishing has decreased population of sea life eg. Sea cucumbers and hammerhead sharks reduced due to over fishing
  • Increases in tourism (41 000 in 1991 to 210 000 in 2014)
  • Population increase due to more opportunities
36
Q

what things have been put in place to stop the human damage to the Galapagos islands

A
  • Galapagos National Park established in 1959
  • Park rangers introduced across the islands
  • Human access limited to specific islands of parts of islands and need a licenced guide
  • Controlling migration to and from islands
  • Eradication of wild goats/dogs
  • Marine protection area established – limits on fishing
  • Quinine trees kept in check by herbicides and uprooting young trees
  • Rules for visitors i.e. no live plants/animals
  • Strict controls on movement of domestic and livestock (introduced animals)
37
Q

how are humans damaging / have damaged Antarctica

A

Some scientists have specialised labs there

  • Tourism has risen in the past 100 years
  • Specifically the Antarctic Peninsula, where the climate is milder and wildlife is present
  • Hunting whales and seals, and depleting fish populations
  • Soil contamination around scientific settlements
  • Human sewage
  • Pollution
  • Rubbish
  • Shipping accidents – oil spills
38
Q

what measures have been put in place to stop human damage to Antarctica

A
  • Antarctic treaty established in 1961 to protect the -Scientific cooperation between nations
  • Conservation of plants and animals
  • Tourist restrictions
  • Waste (food/sewage) must be taken away by ship for disposal
  • Ships using thick oil are now banned
39
Q

define interspecific competition

define intraspecific competition

A

interspecific - competition between different species

intraspecific - competition between members of the same species

40
Q

describe the example of red and grey squirrels for interspecific competition

A

grey squirrels were introduced to Britain from North America
there numbers decreased but red squirrel numbers decreased
grey squirrels can eat a wider range of food so chance of survival increased
food supply for red squirrels decreased as grey squirrel population increased

41
Q

what are the 3 stages on the graph showing intraspecific competition

A

1) population increases as there is a lot of resources but this means more competition for food, space etc.
2) Resources become limiting so population starts to decline
3) smaller population means less competition so population starts to grow again

cycle then repeats

42
Q

what is the competitive exclusion principle

A

more overlap between 2 species’ niches would result in more intense competition
if 2 species have exactly the same niche, one would be out-competed by the other and would die out or become extinct in that habitat

43
Q

define niche

A

the way in which an organism fits into an ecological community or ecosystem

44
Q

how does the predator-prey relationship work? (the 4 stages)

A

1) as prey population increases, there is more food for predators so their population increases also
2) prey population declines as more are eaten. the death rate exceeds birth rate
3) the reduced prey population can no longer support the large predator population. Intraspecific competition for food increases which decreases size of predator population
4) reduced predator numbers result in less of prey population being killed. more prey survive and reproduce, increasing prey population.

cycle repeats

ABHAYS A-LEVEL BIO FLASHCARDS (24 decks)

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