the savanna biome Flashcards

1
Q

where is the savanna grassland located

A

between the tropics of cancer and capricorn
5* - 20* N/S of the equator

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2
Q

what are the distinct features of the savanna

A

-large patches of grassland
-usually found in brazil, africa, australia and india
-periods of drought
-wildfires are common
-mix of tropical forest and desert
-trees, occasional shrubs
- 22-28 degrees celcius
- 20-50 inches of rainfall (1000mm per year)
-rainfall is concentrated in 6-8 months
-fires may occur during drought

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3
Q

what do the fires that occur during a drought result in?

A

the fires kill enough trees to prevent it becoming a forest

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4
Q

describe the environment during the wet season

A

leaves on trees
green elephant grass(3-4m tall)

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5
Q

describe the environment during the dry season

A

no leaves
yellow grass which dies leaving it vulnerable to erosion

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6
Q

properties of the baobab tree

A

-stores water
-thick bark
-grows over 30m in height and 7m in diameter
- shallow roots
- fire resistant
-fewer leaves
- large barell-like trunk

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7
Q

what do the shallow roots on a baobab tree mean

A

it can collect water as soon as it rains

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8
Q

what do the fewer leaves on a baobab tree result in

A

reduces the water lost by transpiration (water droplets not being able to reach the ground as being blocked by the leaves)

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9
Q

how much water does the large barell-like trunk of a baobab tree store

A

up to 500litres of water

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10
Q

properties of the acacia tree

A
  • wide
  • leaves are high up
  • provides shade for animals
  • grows up to 20m in height
    -2m in diameter
    -small leaves with waxy skin
    -thorns on branches
  • long tap roots
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11
Q

how big does the baoban tree grow

A

over 30m in height abd 7m in diameter

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12
Q

what is good about the leaves being high up on the acacia tree

A

cant be eaten by animals

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13
Q

how big does the acacia tree grow

A

up to 20m in height and 2m in diameter

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14
Q

what do the small, waxy leaves on the acacia tree reduce

A

it reduces the amount of water lost through transpiration

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15
Q

what do the thorns on an acacia tree’s branches do

A

deter animals from eating then

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16
Q

whats a benefit of the acacia trees long tap roots

A

during the dry season the roots are able to reach water stores underground, keeping the tree alive for longer

17
Q

what is the soil in the savanna like

A

-porous, drains rapidly
- thin humus layer
- not many plants to provide nutrients
- high rates of decomposition in the wet season
- humus-decomposed leaf litter has lots of nutrients

18
Q

what is desertification

A

degregation of land and vegetation, soil erosion and loss of top soil + fertile land
(turning into a desert)

19
Q

facts about desertification

A

every country is affected by soil degration (desertification)

can take 500yrs to create 2.5cm of soil but only a few years to destroy it, caused by human factors

20
Q

how can farming damage soils

A

soil is vulnerable, chemical fertilasation weaken the living organisms responsible for
soil fertility. regular plowing dries out and comacts the soil

21
Q

how much land is lost through desertification

A

12 million hecter, a third of land threatened and 10 countries affected

22
Q

what is the impact of desertification

A

soil exhaustion reduces food production
20 million tonnes of grain lost through desertification

23
Q

sustainable solutions of desertification

A

-planting trees to slow down wind erosion
- the great green wall in africa
-vegitation fences to anchor the soil
- farming without plowing

24
Q

what is agroecology

A

sustainable farming that works with nature

25
Q

is desertification a human or natural process

A

human

26
Q

how does plowing lead to desertification

A

compacts and dries up soil

27
Q

how does monoculture lead to desertification

A

plants will take all of a certain nutrients

28
Q

how does taking too much ground water lead to desertifcation

A

leaves little water for vegitation

29
Q

how does overgrazing lead to desertification

A

theres no crops or vegitation if farm animals eat them

30
Q

how does using fire lead to desertification

A

releases co2 and destroys vegitation

31
Q

how does poor irrigation lead to desertification

A

bad water, too much salt and chemicals

32
Q

how does over cropping lead to desertification

A

not enough nutrients for all the plants

33
Q

what does the great green wall in africa achieve

A

provides micro nutrients for the soil
provides an income

34
Q

what is happening to lake chad

A

is disapearing due to climate change
- poor irrigation methods removing too much water
-intense farming

35
Q

how can the tranaqua project help lake chad

A

could transfer 50 billion m^3 of water a year to lake chad through a series of dams
- generate up to 15-25 billion kwh of hydro electricity