WEEK 8: SS2 BIOLOGY THIRD TERM (SAVANNAH & ARID LAND)

                                 

Photo Credit: Wikipedia, sourced on 17th June, 2025 17:34PM

KEY VOCABULARY WORDS: Savanna, Baobab, Shrubs, Campos, Ilanos, Steppe, Prairies, Pampas, Veld, Downs, Deciduous trees.

                                       

GRASSLAND OR SAVANNAH

Grassland OR Savannah is a type of ecosystem characterized by wide open spaces with tall grasses, scattered trees, and shrubs, commonly found in tropical and subtropical regions with seasonal rainfall.  Examples of grasses found in tropical grassland (Savanna) include Alfalfa, Bluegrass, and Buffalo grass, trees include the Baobab tree and the Acacia tree.                                                                                 

 TYPES OF SAVANNA

1. Tropical Grassland/Savanna is found in Africa, Brazil (where it is called Campos) and in South America (where it is called Ilanos). 

5 examples of grassland savannahs in Africa:

1. Serengeti Savannah – Tanzania and Kenya

2. Sudan Savannah – Spanning across countries like Nigeria, Chad, and Sudan

3. Sahel Savannah – A transitional zone across countries like Mali, Niger, and Burkina Faso

4. Miombo Woodland Savannah – Found in Zambia, Angola, and Mozambique

5. Guinea Savannah – Common in central Nigeria, Ghana, and parts of West Africa

Temperate Grassland is found in Asia, North America, South America and South Africa where the grasses appear uniform.

CHARACTERISTICS OF GRASSLAND

1. Dominated by grasses – Grasses are the main vegetation, with few trees or shrubs.

2. Seasonal rainfall – Grasslands receive moderate rainfall, often with distinct wet and dry seasons.

3. Wide open spaces – Large, flat or gently rolling areas without dense forests.

4. Rich soil – Fertile soil, especially in temperate grasslands, supports farming.

5. Fire-adapted ecosystem – Natural or man-made fires help maintain the grassland by preventing tree overgrowth.

6. Home to grazing animals – Supports large herbivores like antelopes, zebras, and cattle.

ADAPTIVE FEATURES OF PLANT SPECIES IN GRASSLAND/SAVANNA

1. Deep root systems – To reach underground water during dry seasons.

2. Narrow or rolled leaves – To reduce water loss through evaporation.

3. Thick bark and fire-resistant seeds – To survive frequent grassland fires.

4. Storage organs (e.g., bulbs or tubers) – To store water and nutrients during drought.

5. Fast growth during rainy season – To take full advantage of short periods of rainfall.                                                                                                                                                                         Here are examples of plants species in savannah or grassland Baobab Tree (Adansonia digitata), Acacia Tree (Acacia senegal and Acacia tortilis), Elephant Grass (Pennisetum purpureum), Whistling Thorn (Acacia drepanolobium), Candelabra Tree (Euphorbia candelabrum), Spear Grass (Heteropogon contortus)

ADAPTIVE FEATURES OF ANIMAL SPECIES IN GRASSLAND/SAVANNA

1. Speed and agility – Animals like antelopes and cheetahs are fast to escape predators or catch prey in open spaces.

2. Camouflage – Fur or skin color blends with the dry grass, helping animals like lions and zebras avoid detection.

3. Migration and water conservation – Many animals, such as wildebeests, migrate in search of water and fresh grass during dry seasons, and some can survive long periods without drinking water directly.

FOOD CHAIN IN GRASSLAND/SAVANNA

1. Grasses → Grasshoppers → Lizards → Snakes

2. Grasses → Zebras → Lions

CLIMATIC FACTORS AFFECTING GRASSLAND/SAVANNA

1. High temperature

2. Moderate rainfall

3. Low relative humidity

4. High light intensity

ARID LAND (DESERTS)

                                       Source : https://education.nationalgeographic.org/resource/desert/

                                                sourced on 17th June, 2025 17:48PM

Aridlands are dry regions with very low rainfall, sparse vegetation, and extreme temperatures, making them prone to drought and limited plant and animal life.

TYPES OF ARIDLANDS

1. Hot or Tropical Deserts found in North Africa (Sahara desert), South Africa and Australia.

2. Cold or Temperate Deserts (Tundra) found in North America, Canada and Europe

CHARACTERISTICS OF HOT DESERTS

1. Scarcity of water

2. Hot temperatures- daily temperature fluctuations

3. Presence of sandy soil

4. Predominance of strong wind

5. Poor vegetation

ADAPTIVE FEATURES OF PLANT SPECIES IN ARIDLANDS

Examples of plants Species in Hot desert include

1. Bulbous Cacti

• Absence of leaves

• Possession of prickles or thorns to reduce transpiration

• Presence of thick, succulent stem and side branches to store water for long periods of drought

2. Dwarf Acacia

• This is a drought resistant plant which possess deep roots to absorb underground water present deep down in the soil

3. Wiring grasses

4. Date palm

5. Baobab tress e.t.c

ADAPTIVE FEATURES OF ANIMAL SPECIES IN ARIDLANDS

Examples of animals found in aridlands include

1. Camel

• Possesses the ability to drink lots of water which sustains the animal for several days hence able to withstand a wide range of body temperature up to 40°C during the day.

• It can walk for several days without drinking water.

2. Rodents (e.g Rats)

• Kangaroo Rats possess the ability to remain in burrows during the day thereby avoiding excessive heat thus reducing evaporation from its body.

3. Lizards

4. Snakes

5. Toads

6. Zebras

7. Locusts

8. Desert tortoises e.t.c

FOOD CHAIN IN ARIDLANDS

1. Plants --> Desert Rats --> Snakes

2. Plants --> Ants --> Scorpions --> Snakes

FACTORS AFFECTING ARIDLANDS

Major Abiotic factors affecting aridlands are

1. Temperate

2. Rainfall

3. Sunlight

4. Wind

5. Low relative humidity