Displaying items by tag: tropical

Tuesday, 21 September 2021 09:37

Vegetation - Class 6 Social Studies Revision Notes

What is Vegetation?

  • Vegetation refers to all plant cover on the surface of the earth It cosists of grasses,trees,bushes,thickets and shrubs
  • Vegetation can either be natural or planted

Types of Vegetation in Eastern Africa

  1. Tropical rainforest vegetation
  2. Savannah woodland
  3. Savannah grassland
  4. Mountain vegetation
  5. Swamp vegetatio
  6. Desert and semi-desert
  7. Mangrove vegetation

 

  1. Tropical rainforest vegetation

    • Also called equatorial vegetation
    • Found in equatorial climatic region

      Characteristics
      1. Tall trees that form canopies
      2. Vegetation is evergreen
      3. Trees have straight trunks
      4. Trees have broad leaves
      5. Trees have buttress roots
      6. Forests are thick and dense
      7. Trees are mainly hardwood e.g.oak, teak, mvule, mahogany, ebony, camphor,obeche, iroko, heartwood, ironwood, rosewood, sapele, limba, okoune

  2. Savannah woodland

    • Comes immediately after tropical rainforests
    • Mainly consist of trees

      Characteristics
      1. Trees are of medium height
      2. Trees are widely spaced compared to equatorial
      3. Trees are decidiuos
      4. Tall grass between the trees
      5. Tree tops are umbrella shaped
      6. Common trees are acacia and baobao
      7. Trees are deep rooted and have thick barks
    • Examples of woodland savannah
      1. Miombo woodland in central tanzania
      2. Shimba hills forests in kwale county
      3. Southern sudan
      4. Karamoja district of uganda

  3. Savannah grassland

    • Mainly consist of grass and few scattered trees
      Characteristics
      1. Drought resistant vegetation
      2. Grass may grow upto 2m
      3. Tall elephant grass
      4. Few scattered trees
      5. Trees have thick barks
      6. Trees have thorny leaves
      7. Main trees are baobab,acacia, cacti, euphobia
  4. Swamp vegetation

    • Common in swampy regions
    • Mainly grows in poorly drained areas
    • Main vegetation are;a. Papyrus reeds
    • Water lilies
    • Found in
      1. South sudan Bahr-El-Ghazal-Sudd swamp
      2. L. kyoga in Uganda
      3. Malagarasi swamp in Tanzania
      4. L.amboseli swamp in Kenya

  5. Mangrove vegetation

    • grows in the mudd salty waters along shores of Indian Ocean
    • They have breathing roots(aerial roots)
    • Trees are mainly hardwood
    • Is found along the shores of idian ocean and mouths of R.ruvuma, R.juba

  6. Mountain vegetation

    • grows on the slopes of mountains
    • is widespread on the winward sides of the mountains
    • vegetation changes as altitude increases
    • vegetation is mainly influenced by the altitude
    • is also called alphine or montane vegetation

  7. Semi-desert vegetation

    • Found in ares with rainfall between 250mm-500mm

      Characteristics
      1. Short scanty thorny bushes
      2. Short tough and scattered patches of grass
      3. Vegetation is drought resistant with modified for thorns
      4. Common plants cactus, baobab and euphorbia

  8. Desert vegetation

    • Found in areas with rainfall less than 250mm

      Characteristics
      1. Stunted plant
      2. Plants have thorny or needle-like leaves
      3. Ground is bare
      4. Plants have thick fleshy stems
      5. Plants are deep rooted
      6. Spinky scanty grass
      7. Found in true deserts e.g.
        1. Kaisut and chalbi and taru deserts
        2. Nubain desert
        3. Ogaden desert

Factors that influences vegetation distribution

  1. Climate
  2. Soils
  3. Relief
  4. Drainage
  5. Human activities
  6. Government policies
Tuesday, 21 September 2021 06:21

Climate - Class 6 Social Studies Revision Notes

What is Climate?

  • Climate is the average weather conditions of a place

Weather instruments

  • Are devices used to measure and record conditions and changes in the elements of weather Weather refers to the atmospheric conditions of a place at a given time
Weather instrument Weather element
Barometer Air pressure/atmospheric pressure
Anemometer Speed of wind
Windvane Wind direction
Hygrometer  Humidity
Windsock Strength and wind direction
Raingauge Amount of rainfall
Sunshine recorder  Sunshine intensity
Thermometer  Temperature

 

Factors that influence climate in Eastern Africa

  1. Latitude
  2. Relief and altitude
  3. Nearness to large water bodies
  4. Prevailing winds
  5. Shape of the coastline

 

  1. Latitude

    • This refers to how far a place is from the equator.
    • Eastern sfrica region is between the tropics
    • The region receives warm temperatures
    • Latitude affects;
      1. Temperatures
      2. Rainfall
      3. Winds
  2. Relief(altitude)

    • Relief refers to the nature of the land
    • Relief refers to the presence of physical features such as hills, mountains, plateau and plains.
    • Altitude is the height of a place above sea level
    • Altitude influences
      1. Temperature
      2. Rainfall
      3. Wind
      4. Air pressure

        Exercise: Draw a relief rainfall diagram

  3. Nearness to large water bodies.

    • Areas near large water bodies receives convectional rainfall
    • Distance from large water bodies affects rainfall,humidity,temperature and winds breeze.
    • Breezes are cool winds meant to lower temperatures of where they blow towards.

      Exercise: Draw convectional rainfall and sea and land breezes

  4. Prevailing Winds

    • Wind is moving air or air in motion
    • They transfer water vapour from one area to another.
    • Winds that have great effects on climatte of Eastern Africa are seasonal(monsoons)
    • North-east monsoons bring short rains
    • South-east monsoon brings long rains

  5. Shape of the coastline

    • Winds blowing parallel to the coast do not cause rainfall
    • Winds blowing directly to the coast causes a lot of rainfall

Climatic regions of Eastern Africa

  • A climatic region is a large area that experiences more or less similar climatic conditions
  • They include:
    1. The equatorial climatic
    2. The modified climatic
    3. The tropical climatic
    4. Mountain climatic
    5. Semi arid climatic
    6. Desert climatic

 

  1. Equatorial climatic region

    • Covers
      1. South Western Uganda
      2. North Western Tanzania
    • Is slightly modified due to altitude and latitude

      Characteristics
      1. High rainfall above 1500mm
      2. Receives convectional rainfall
      3. Rainfall is well distributed throughout the year
      4. High temperatures throughout the year
      5. Annual average temperatures of about 26 ̊ C
      6. High humidity throughout the year
      7. Two rainfall peaks between April-May and November-December
      8. Small range of temperatures

  2. Modified equatorial climatic region

    • is modified because of the high relief(altitude)
    • covers;
      1. Lake region
      2. Coastal region
      3. Western Uganda
      4. Western South Sudan
      5. Rwanda
      6. Burundi

        Characteristics
        1. High rainfall between 1000m-2000m
        2. High temperatures due to low altitude
        3. Convectional rainfall due to nearness to large water bodies
        4. High humidity due to high rate of evaporation
        5. Long rains between March-May
        6. Short rains between October-December

  3. Tropical climatic region

    • Also called savannah climate
    • Is the largest climatic region of Eastern Africa
    • It lies between the tropics
    • covers;
      1. Large parts of Tanzania and Ethiopia
      2. Northern Uganda
      3. South Sudan
      4. Nyika Plateau in Kenya

        Characteristics
        1. Has hot wet seasons and cool dry seasons
        2. Cooler seasons have no rainfall hence remains dry
        3. Hotter seasons receives a lot of rainfall hence they are wet
        4. Rainfall is between 750mm – 1200mm
        5. Has two distinct rainy seasons
          1. Long rains between march-may
          2. Short rains between september-october
        6. Temperature average is 15 ̊ C – 15 ̊ C

  4. Mountain climatic region

    • Experienced on slopes of high mountains and highlands

      Characteristics
      1. High relief rainfall betwee 1100mm – 250mm
      2. Cool/low temperatures due to high altitude
      3. Leeward sides are cool and dry
      4. Peaks of high mountains are permanently covered by snow

  5. Semi-arid climatic region

    • Covers
      1. Eastern and northern kenya
      2. North-Eastern Uganda
      3. Central sudan
      4. Eritrea
      5. Somalia
      6. Djibouti
      7. Central Tanzania

        Characteristics
        1. Low and unreliable rainfall 250mm – 750mm
        2. High temperatures throughout the year 21 ̊ C – 28 ̊ C
        3. Prolonged dry season of over six months
        4. Low humidity
        5. High temperatures at day time and low temperatures at night
  6. Desert climatic region

    • Covers
      1. Sudan
      2. Northern Ethiopia
      3. North-Eastern Somalia
      4. Central part of Northern Kenya
      5. Parts of Eritrea
      6. Parts of Djibouti
        Characteristics
        1. Low/unreliable rainfall below 250mm per year
        2. Rainfall is irregular
        3. High temperatures of upto 40 ̊
        4. Clear/cloudless skies
        5. Very high diurnal range of temperatures