The Biome Of One Tropical Region Flashcards
1
Q
What is the tropical biome that we have studied
A
Tropical savanna grasslands
2
Q
What are Savannas and give some facts
A
- areas of tropical grasslands that can occur with or without trees and shrubs
- cover 1/4 of the worlds land surface
- found between rainforests and desserts
- depend on an inter-relationship between plants, animals and the physical environment
- these areas are under increasing pressure from human activity
3
Q
Features of a savanna grassland
A
- associated with continental interiors and develop where temperatures are high
- precipitation is low
- seasonal drought is common
4
Q
Location of savanna grasslands
A
- occur in a broad band 5-15* north and south of the equator
- found between tropical rainforests and hot desserts
- occupy 65% of Africa’s land area
- other locations include Australia, South America and India
5
Q
Climate of a savanna grassland
A
- lies close enough to the equator to experience high temperatures throughout the year
- climate varies across the Savanna
- towards the rainforest belt there is more rainforest to support tree growth
- towards the dessert belt only grasses occur
6
Q
What is the mean temperature in a savanna grassland
A
- about 20* throughout the year
- highest reaching 36*
- 11-13 hours of daylight
7
Q
What is the rainfall like in a savanna grassland
A
- total rainfall can range between 600mm-2000mm
8
Q
How long is their prolonged drought and what does it do
A
- Lasting at least 5 months
- increases potential for seasonal outbreaks of fire
- creates a cycle of water surplus/deficiency
- linked to annual wet/dry seasons
- drier cooler season has high temperatures and evapotranspiration
9
Q
Formation of the ITCZ rainfall belt
A
- inter- tropical convergence zone
- forms as a result of intense solar heating
- warm air can hold more water vapour than cool
- when air on the surface is heated it can hold large quantities of water vapour that has been evaporated from the surface
- as air rises and cools it’s less able to hold water vapour
- some of that water vapour condenses to form water droplets
- if the air continues to rise condensation continues to add to the size of the water droplets
- thick clouds form leading to rain
- called convection rainfall
10
Q
ITCZ continued
A
- the heating is so intense and the convection currents are so strong
- dominate the climate of the whole tropical region
- air rises and cools and brings rain
- cooler air flows pole wards away from the equator
- at 30* from the equator the cooled air starts to sink back to the surface
- as the air sinks it warms again due to compression
- be chase the air has lost its moisture the warming process is more rapid than the cooling
- areas of hot , high-pressure air formed at about 30* north and south of the equator
11
Q
Movement of ITCZ
A
- sun appears overhead at the equator on the 21st of March and September
- during summer in the northern hemisphere the sun appears to migrate north of the equator
- northern winter appears to migrate south
- overhead sun migrates and so does the ITCZ
12
Q
Example of movement of ITCZ
A
- Kano
- ## one season a year when the sun is overhead and the ITCZ dominates the area and brings intense rainfall
13
Q
What is the soil moisture budget
A
- the combined pattern of rainfall and temperature
14
Q
What happens during the wet season in the soil moisture budget
A
- may to September
- usually an excess of rainfall
- over evaporation
- plenty of water available for plant growth
15
Q
What happens during the dry season in the soil moisture budget
A
- excess of evaporation from over precipitation
- so little water percolates down through the soil
- some is drawn back to the surface where it then evaporates so little percolates
- evaporation combined with water being used by plants, steadily reduces the soils store of moisture until it is dry
- from this point on there is no moisture so plants stop growing and enter a dormant period
16
Q
The situation in East Africa
A
- West Africa has two areas of tropical grassland
- one north and south of the equator
- the grassland spreads right across the equator and there is no area of rainforest
17
Q
Savanna grassland soils
A
- closely linked with climate and tend to reflect the local seasonal rainfall pattern
- soils in the savanna are commonly leached
- similar to soils of the rainforest but are not as intensely weathered
18
Q
What happens to the soils during the wet season
A
- excess of precipitation
- over potential evapotranspiration
- this results in leaching of soluble materials and small particles will be taken down through the soil
- these soils are deposited deep within the soil
19
Q
What happens to the soil during the dry season
A
- evapotranspiration is less than precipitation
- silica and iron compounds are carried up through the soil and precipitated close to the surface
20
Q
What is another word for horizon in soils
A
Layer
21
Q
What are the layers in savanna grassland when it comes to soil
A
- thin dark humus layer
- hard cemented layer
- layers then merge
- re-deposited silica
- rapid chemical weathering
- bedrock
22
Q
What is geomorphology and how does it play an important role in affecting soil type
A
- the way that the land looks
- landforms and the process that form them
- important role- areas have different conditions so it can affect the way that the land looks
23
Q
What soil type is at the base of slopes and river valleys
A
- enriched by clay, minerals
- woods are likely to be found
24
Q
What soil type is found on the top of slopes
A
- fewer nutrients due to erosion
- grasslands are likely to be found
25
What do the different types of soil create when it comes to vegetation
- thick clay based soils created woodland
| - leached sang soils created grasslands such as savanna grasslands
26
Where are grasslands found
- on tectonically stable geological shields which have been weathered and are lacking in nutrients
27
Which vegetation is adapted to drought and what are the adaptions
- xerophytic ( looks like your eye when you die (drown))
- deep tap roots to reach water table
- partial/total loss of leaves
- sunken stoma on the leaves to reduce moisture loss
28
What type of vegetation is adapted to fires and what are the adaptions
- pyrophytic (the p looks like a long tree)
- thick bark which can resist burning
- bulk of biomass being below ground level to aid rapid regeneration after a fire
- growth of tissue in grasses is located at the base shoot
29
What happens during the warm wet summers in a savanna grassland
- there is much photosynthesis and there is a large net primary productivity of 900 g/m2 per year
- 1,500 g/m2 near the rainforest
- 200 g/m2 near the savanna scrub
30
What are the typical species in Africa
- acacia tree
- baobab tree
- elephant grass
31
Elephant grass- explain the characteristics
- can grow to a height of over 5m
- the seeds lie dormant until the season rains then grow vigorously in large tuffs
- dry season- grass turns a pale straw colour (from normal yellow colour)
- they die back to remain dormant again
- store food in their roots
- they are adopted to fire as growth occurs from the base
- following a prolonged drought the grass can absorb water droplets faster
32
Explain the characteristics of the xerophytic tree
- acacia
- deep tap roots to reach the water table
- wide root spread near surface to absorb water
- able to maximise water uptake through adapted root network
33
What are the characteristics of the pyrophytic tree
- baobab tree
- stumpy branches
- touch up to 10m in diameter
- water stored in spongy wood of trunk
- short stumpy roots
34
Nutrients cycle between climate soils and vegetation
- nutrients store is less than the rainforest because of the shorter growing season
- litter store is small because of fire
35
Animals in the savanna grassland- what they are
- largest variety of herbivores with more than 40 types of grazers- giraffes, zebras and elephants
- these animals often form in large herds to protect the herbivores
- especially for the the predators: cheetahs, lions and Eagles
- food chains are very short- often stopping at the secondary consumer level
36
How have herbivores evolved
- highly specialised eating patterns
- browsers- nibble twigs and leaves- the white rhino
- grazers- eat grass and herbs- the black rhino
37
What is selective grazing
| Give examples of animals and why is it effective
- allows for a categorisation depending on the height at which they eat
- giraffes feed from the top of the canopy
- rhinos from the bottom
- gazelles on the grass alone
- animals eat different types of day/night and some different types of the year
- this minimises competition
38
What happens during the dry season with the animals and how Ro animals respond to prolonged drought
- competition for water is intense
- they respond to prolonged drought in two ways:
- small animals hibernate
- birds and most large animals will migrate
- elephants can do this but their size and strength allows them to tear open the trunks of baobab trees
- carnivores (lions) are supported and prey on the migration herd
- fauna creatures (locusts) destroy large areas of grassland
39
Why is human activity an impact on savanna grasslands
- savanna grasslands depend on complex and fragile interrelationships
- if any are destroyed/modified the whole community is placed at risk
40
Describe overgrazing and what happened in the 20th century
- done by cattle
- this trampling results in increased soil erosion, decrease in soil fertility and extensive desertification
- this leads to permanent loss of thousands of hectares of land
- traditional pastoralism was nomadic, they followed the migration routes
- 20th century shifted from nomadism to a more settled pattern of farming
- this resulted in overgrazing
- savanna soils are not well suited
41
Describe how fire has an impact on savanna grasslands
- some is from natural causes but most are from human activity
- fire has been used to aid hunting
- early growth of grass is used to start fires in the dry season to attract game animals - easier to find and hunt
- can spread quickly and damage soil
42
Why have animals been hunted in savanna grasslands
- valuable body parts
- elephants for there ivory tusks
- lions for there fur
- bison for there meat
43
Why is the introduction of arable farming a threat
- threat to world climate
- burning of grassland proir to ploughing can release huge quantities of carbon dioxide
- contributed to global warming
44
Why is deforestation a problem in savanna grasslands
- lush vegetation Is being denuded (striped)
- the area is home to rare flora and fauna such as rare orchids
- they are cutting down the tress, wood for fuel and opencast mining
- also being cleared for agriculture for growing cash crops such as sugar cane and soya beans
45
Why is urbanisation a problem in savanna grassland
- urban sprawl
| - results in traditional savanna wildlife becoming isolated into pockets of natural vegetation
46
How does international tourism pose a threat to savanna grasslands
- east Africa
- people rooming about where the animals live and bred can disturb them in their breaking pattern or where they live
- this happens even though there are game reserves where they conserve the indigenous wildlife
47
What is biodiversity
- the variation of plants, animals, and other life forms, the genetic material they contain and the ecosystems they form
- genetic: genetic variation in a species
- species: variation of species emerging from evolution
- ecosystem: different communities of plants and animals
48
Value of biodiversity
- been recognised by locals who make use of it on a diary basis for traditional medicine, food, building materials and clothing
- locals have long relied on the diversity an ecosystem can provide
49
What reduces biodiversity
- combined pressure of rapid population growth, commercial agriculture, urbanisation and industrial growth
- species are lost from this fragile ecosystem as the completion for space and food becomes greater
50
What is the evidence for the more sustainable model of development
- nature-based tourism
- the scenic beauty and wildlife attracts lots
- the incomes used can preserve the health and beauty of the area and help to preserve the wildlife
- examples: Serengeti
