Biology
The Major biomes of the world are:
1. Tropical Rainforest
2. Savanna
3. Desert
4. Shrub
5. Afro-alphine
6. Swamp
1. Tropical Rainforest
Location: The tropical rainforest is located around the equator (i.e., within 5 degree North and South of the equator). The forest is found in the Amazon basin of South America, Zaire basin of central Africa, the coasts of West Africa and interior Malaysia.
Characteristics Of Tropical Rain Forest
1. Tropical rainforest has high temperature of between 25 degree census – 37 degree census with a small annual range of 2-3 degree census.
2. Rainfall is throughout the year with two peaks (double maxima).
3. It has an annual rainfall of over 2000mm.
4. It has abundant sunshine.
5. The forest has little undergrowth.
6. Relative humidity within the forest is very high.
2. Savanna/Grassland
Savanna covers very extensive areas of the world, i.e., about 20% of the total land mass. Grasslands are distinguished from the forest by relatively absence of trees and the abundance of grasses. The grassland is a transitional biome between the forest and the desert.
Grassland or savanna is grouped into tropical grassland and temperate grassland.
Tropical Grassland
The tropical grassland is located between 5 degree and 20 degree North and South of the equator. Areas where this grassland are found include Central America, North West part of South America, interior of Brazil, West Africa, part of East Africa, South East Asia and Northern Australia.
Characteristics of Tropical Grassland
1. It has seasonal convectional rainfall with single maximum.
2. The tropical grassland has tall grasses that are fibrous when old.
3. There is presence of short and scattered trees.
4. Popular trees in the community include acacia, baobab and shea-butter.
5. The grasses are called savanna in Africa and Australia, campos in Brazil and ilanos in Orinoco (South America).
Temperate Grassland
Location: Temperate grassland is found in the interior continents in Asia, North America, South America (Argentina), South Africa and Australia.
Characteristics Of Temperate Grassland
1. The vegetation of the temperate grassland is associated with the temperature continental climate.
2. It also has cold winter with temperature below OoC.
3. The rainfall is usually convectional and light.
4. There is abundance of grasses.
5. The grasses tend to have uniform height or a bit short.
6. The grasses are succulent.
3. Deserts
Deserts are areas generally associated with aridity (dryness). The environment is usually very hot with little or no rainfall. There are two types of deserts. These are the hot deserts and cold deserts.
Hot Deserts
Hot deserts include Sahara desert (North Africa), Arabian desert (Arabia), Iranian desert (Iran), Namib and Kalahari desert (South Africa), Great Australia desert (Australia) and Atacama desert (South America).
Characteristics Of Hot Desert
1. Aridity or rainlessness is common.
2. Annual rainfall is about 250mm.
3. Evaporation is high while the relative humidity is very low.
4. The deserts are associated with cold current.
5. Vegetation is sparse or scanty.
6. Common vegetation includes grasses, shrubs and herbs.
Cold Deserts
Cold deserts are found in the interiors of Eurasia, North America and in Patagonia (South America).
Characteristics Of Cold Deserts
1. Cold desert has hot summers and cold winters.
2. Cold desert have short and scanty grasses.
3. Rainfall is about 25cm (low and unreliable due to long distance from sea.
4. It has drought resistant plants with woody stems and needle-like or spiny leaves to reduce rate of transpiration.
4. Shrub
The shrub vegetation is found in semi-arid regions, border land of tropical deserts and the interior of continents. It is found in West Africa close to the Sahara desert, North-Eastern Brazil and Australia.
Characteristics of Shrubs
1. The rainfall is very low.
2. Summers are hot and dry while winters are mild and rainy.
3. It has drought resistant shrubs, aromatic plants and dwarf trees such as maquis, thorny acacia.
4. Low thorny trees/bushes with shrubs and herbs and common.
5. Shrub has patches of grasses which may even be absent in some cases.
5. Afro-Alpine
Afro-Alpine is a kind of vegetation associated with high mountains or Highlands. The Afro-Alpine vegetation as it relates to Africa is found in highlands such as Cameroon mountain, Kenya highland, Kilimanjaro mountain (East Africa).
Characteristics Of Afro-Alpine
1. Temperature and pressure of Afro-Alpine decrease with altitude.
2. The peak of the mountain may experience ice-cap or permanent snow.
3. Vegetation decreases with height of the mountain.
4. The windward side of the mountain may have a luxuriant forest type of vegetation.
5. The leeward side may experience a savanna type of vegetation.
6. Swamp
The swamp forests are usually found in the tropics, along coastal regions and river mouths of West Africa, East Africa and South Africa. Swamps are generally found along the coast all over the world.
Characteristics Of Swamp
1. The dominant plants are the white mangroves, red mangroves, and raffia palm.
2. The trees have stilt roots which grow down ward and branch into the mud surface.
3. It has high rainfall of over 2500mm with no distinct season.
4. Relative humidity in swamp is very high. It is close to 90%.
5. Animals commonly found include mud skipper, crabs, Tilapia fish, etc.