Types of Ecosystem

Quick Summary

• Ecosystems are classified into terrestrial (land) and aquatic (water) types
• Terrestrial ecosystems include forests, grasslands, deserts, and tundra
• Aquatic ecosystems include freshwater and marine environments
• Nigeria has rainforests, savanna grasslands, mangrove swamps, and freshwater systems
• Each ecosystem type has special plants and animals adapted to its conditions

What is an Ecosystem?

An ecosystem is a community of living things (plants, animals, microorganisms) interacting with non-living things (air, water, soil, sunlight) in a specific area. Ecosystems can be as small as a pond or as large as a rainforest.

All ecosystems work through energy flow and cycling of matter. Plants capture energy from the sun. Animals eat plants or other animals. When living things die, decomposers break them down and return nutrients to the soil. This cycle continues endlessly.

Scientists classify ecosystems into different types based on their physical environment. The two main categories are terrestrial (land) and aquatic (water) ecosystems.

Terrestrial Ecosystems

Terrestrial ecosystems are found on dry land. They cover about 30% of Earth’s surface. The type of terrestrial ecosystem in an area depends on climate, rainfall, temperature, and soil type.

Major Types of Terrestrial Ecosystems

1. Forest Ecosystems

Forests have many trees growing close together. They receive high rainfall and have fertile soil. Nigeria’s tropical rainforest covers the south, including Cross River, Edo, and Delta states. Trees include mahogany, iroko, and oil palm. Animals include monkeys, parrots, and forest elephants.

Forests produce oxygen, store carbon, and protect soil from erosion. They provide timber, medicines, and food. The Cross River National Park protects one of Nigeria’s last intact rainforests.

2. Grassland Ecosystems

Grasslands are areas covered mainly by grasses with few trees. They receive moderate rainfall. Nigeria’s savanna grassland covers the middle belt and northern regions, including Plateau, Kwara, and parts of Kaduna states.

The savanna has tall grasses during the rainy season. Common animals include antelopes, lions (in protected areas), and various birds. Grasslands are good for grazing cattle and farming grains like millet and sorghum.

3. Desert Ecosystems

Deserts receive very little rainfall (less than 250mm per year). They have extreme temperatures – very hot during the day and cold at night. The Sahara Desert touches Nigeria’s far northeast in Borno State.

Desert plants like cacti and acacia trees have special features to survive with little water. Animals include camels, lizards, and scorpions. They come out at night when it is cooler.

4. Tundra Ecosystems

Tundra is found in very cold regions near the Arctic. The ground is frozen most of the year. Only small plants like mosses and lichens grow. Nigeria does not have tundra because it is in the tropics.

Aquatic Ecosystems

Aquatic ecosystems exist in water bodies. They cover about 70% of Earth’s surface. Water temperature, depth, salt content, and light determine what lives there.

Major Types of Aquatic Ecosystems

1. Freshwater Ecosystems

Freshwater ecosystems have water with very low salt content (less than 1%). They include rivers, lakes, ponds, and streams.

Rivers: Nigeria has major rivers like the Niger, Benue, Cross River, and Kaduna River. Rivers have flowing water that carries nutrients. Fish like tilapia and catfish live in rivers. People use rivers for drinking water, irrigation, fishing, and transport.

Lakes: Nigeria has natural lakes like Lake Chad (shared with Chad, Niger, and Cameroon) and Oguta Lake in Imo State. Lakes have still or slow-moving water. They support fish, water plants, and birds.

Ponds and streams: These are smaller water bodies. Many villages have ponds for fishing. Streams flow into larger rivers.

2. Marine Ecosystems

Marine ecosystems are found in oceans and seas. They have high salt content (about 35%). Nigeria has a long coastline along the Atlantic Ocean.

Coastal areas: Nigeria’s coast includes the Niger Delta, Lagos Lagoon, and Calabar estuaries. These areas mix freshwater from rivers with saltwater from the ocean. Mangrove trees grow in coastal swamps. They protect the shore from erosion and provide breeding grounds for fish and shrimp.

Open ocean: Beyond the coast is the open ocean. Large fish like tuna and sharks live there. Nigeria’s fishing industry operates in coastal and ocean waters.

Coral reefs: These are underwater structures made by tiny animals called corals. Nigeria has some coral formations off the coast. Reefs support many species of colorful fish and sea creatures.

Comparison of Terrestrial and Aquatic Ecosystems

Ecosystems in Nigeria

Nigeria has diverse ecosystems due to its location in West Africa. From south to north, the ecosystems change based on rainfall and temperature.

Southern Nigeria: Tropical rainforest with high rainfall (over 2000mm per year). Dense trees and diverse wildlife. Major forests in Cross River, Edo, Ondo states.

Middle Belt: Guinea savanna with moderate rainfall. Mix of trees and grassland. Found in Plateau, Benue, Kwara states.

Northern Nigeria: Sudan savanna with lower rainfall. Fewer trees, more grass. Found in Kaduna, Kano, Katsina states.

Far North: Sahel savanna with very low rainfall. Sparse vegetation approaching desert. Found in Borno, Yobe states.

Coastal areas: Mangrove swamps and freshwater swamps. Found in Lagos, Delta, Bayelsa, Rivers, Cross River states.

How Ecosystems Function

All ecosystems work through energy flow and nutrient cycling.

Energy flow: Energy enters the ecosystem through plants. Plants use sunlight to make food (photosynthesis). Animals eat plants or other animals. Energy passes from one level to another. When living things die, decomposers (bacteria, fungi) break them down.

Nutrient cycling: Important nutrients like nitrogen, carbon, and phosphorus move through the ecosystem. Plants take nutrients from soil. Animals eat plants. Animal waste and dead organisms return nutrients to soil. Decomposers help this process.

Water cycle: Water evaporates from oceans and lakes, forms clouds, falls as rain, and flows back to water bodies. This cycle connects all ecosystems.

Importance of Different Ecosystem Types

Each ecosystem type provides important benefits:

Forests: Produce oxygen, store carbon dioxide, prevent soil erosion, provide timber and medicine, protect water sources.

Grasslands: Support livestock grazing, good for growing crops, prevent soil erosion, store carbon in soil.

Aquatic ecosystems: Provide fish for food, water for drinking and irrigation, routes for transport, regulate climate, support biodiversity.

Threats to Ecosystems

Human activities threaten different ecosystem types:

Deforestation: Cutting down forests for timber and farmland destroys rainforest ecosystems. This is happening in southern Nigeria.

Desertification: Overgrazing and poor farming turn grasslands into desert. This affects northern Nigeria.

Pollution: Oil spills damage mangrove and ocean ecosystems in the Niger Delta. Plastic waste harms marine life.

Climate change: Rising temperatures and changing rainfall patterns affect all ecosystems. Lake Chad has shrunk dramatically in recent decades.

Common Exam Mistakes

WAEC examiners report these common errors:

• Confusing ecosystem with habitat: An ecosystem includes all living and non-living things in an area. A habitat is where one type of organism lives. Students often use these words wrongly.
• Only listing types without explaining: When asked to “describe” ecosystem types, students just write “terrestrial and aquatic.” You must explain characteristics and give examples.
• Missing Nigerian examples: Always use specific Nigerian locations (Niger River, savanna belt, rainforest zone), not just general terms.
• Not mentioning energy flow and nutrient cycling: Questions often ask how ecosystems function. Always include these processes.
• Mixing up freshwater and marine: Freshwater has low salt, marine has high salt. Don’t confuse rivers (freshwater) with oceans (marine).
• Forgetting adaptation: When describing ecosystem types, mention how plants and animals are adapted to that environment.

Practice Questions

Multiple Choice Questions

1. The two main types of ecosystems are:
a) Forest and desert
b) Terrestrial and aquatic ✓
c) Hot and cold
d) Large and small

2. Which ecosystem type covers most of southern Nigeria?
a) Desert
b) Tundra
c) Tropical rainforest ✓
d) Coral reef

3. Marine ecosystems are characterized by:
a) Freshwater
b) High salt content ✓
c) No animal life
d) Frozen water

4. The Niger River is an example of which ecosystem type?
a) Marine
b) Terrestrial
c) Freshwater ✓
d) Desert

5. Ecosystems function through:
a) Energy flow and nutrient cycling ✓
b) Only rainfall
c) Human activities
d) Temperature changes

Essay Questions

1. Describe the two main types of ecosystems with examples from Nigeria. (8 marks)

Tip: Define each type clearly. Explain characteristics. Give specific Nigerian examples for each. Mention typical plants and animals.

2. Explain four differences between terrestrial and aquatic ecosystems. (8 marks)

Tip: Make a clear distinction for each difference. Examples: location, oxygen availability, temperature stability, plant types. Use a comparison format.

3. State three types of terrestrial ecosystems and describe one in detail. (7 marks)

Tip: State three types briefly (forest, grassland, desert). Choose one and describe climate, plants, animals, and location in Nigeria.

4. Explain how energy flows through an ecosystem. (6 marks)

Tip: Start with sun and plants. Explain photosynthesis. Describe food chain. End with decomposers. Use simple steps.

Memory Aids

Remember TA for main ecosystem types:

• Terrestrial (land)
• Aquatic (water)

Remember FGDT for terrestrial ecosystem types:

• Forest (rainforest in southern Nigeria)
• Grassland (savanna in middle and northern Nigeria)
• Desert (Sahara in far northeast)
• Tundra (not in Nigeria – too cold)

Remember FM for aquatic ecosystem types:

• Freshwater (rivers, lakes – low salt)
• Marine (oceans, seas – high salt)

To remember ecosystem function: “Every ecosystem needs Energy and Nutrients” (Energy flow + Nutrient cycling)

Related Topics

• Components of an ecosystem (biotic and abiotic factors)
• Food chains and food webs in different ecosystems
• Vegetation zones of Nigeria
• Adaptation of organisms to their environment
• Conservation of ecosystems and biodiversity