Terrestrial Habitats

Terrestrial habitats refer to life on land and are mainly identified by their vegetation. Key factors affecting terrestrial habitats are rainfall and temperature. These habitats are categorized into four groups: marshes, forests, grasslands, and arid lands.

Marshes

Marshes are low-lying lands that become flooded during the rainy season and are often waterlogged due to poor drainage. They are mainly covered by grasses and shrubs. If trees grow in a marsh, it is called a swamp. Marshes serve as a transition between aquatic and terrestrial habitats.

Formation

Marshes typically form in lowlands with poor drainage, such as floodplains and river deltas. They develop when water overflows its banks or when ponds and lakes fill up with soil and plant material, causing waterlogging. Marshes can be freshwater or saltwater.

Characteristics of Marshes

• Wet, soft, and poorly aerated soil.
• Stagnant water is common during dry seasons, but the area becomes flooded in the rainy season.
• High relative humidity.
• Decomposition of organic matter produces foul-smelling gases like hydrogen sulfide and methane.
• Generally low-lying areas.

Organisms Found in Marshes

Plants in marshes include algae, grasses, water lettuce, water lilies, mangroves, and raphia palms. Animals include crabs, mudskippers, frogs, snakes, crocodiles, and fish.

Adaptive Features

1. Mangroves have cone-shaped roots (pneumatophores) to take oxygen from the air.
2. Salt marsh plants can tolerate high salt levels in the water.
3. Herbaceous plants have strong roots for anchorage and storage.
4. Animals in low-oxygen environments adapt to respire anaerobically.
5. Webbed feet in animals like ducks and crocodiles aid in movement.
6. Camouflage, such as the dark coloration of crayfish, helps avoid predators.

Forests

Forests are large areas dominated by tall trees of various species and heights. Types of forests include tropical rainforests, temperate deciduous forests, and coniferous forests, which are influenced by rainfall, temperature, and humidity.

Characteristics of Forests

• Rich in epiphytes and climbers.
• Trees have broad leaves and buttress roots.
• High humidity and low light on the forest floor.
• Stratification of trees into different layers.
• Thin bark on trees facilitates gaseous exchange.

Forest Layers

1. Emergent Layer: Tallest trees, over 60 meters, with crowns that don’t touch.
2. Upper Layer: Continuous canopy of trees around 40 meters tall.
3. Middle Layer: Shade-tolerant trees under 20 meters tall.
4. Lower Layer: Small trees, palms, and shrubs up to 10 meters tall.
5. Ground Layer: Herbs, fungi, and shade-tolerant plants on the forest floor.

Organisms in Forests

Common plants include mahogany, teak, oil palm, ferns, orchids, and fungi. Forest animals include monkeys, snakes, birds, squirrels, and tree frogs. Many animals are arboreal, and some, like earthworms and beetles, live in the soil.

Adaptations

• Trees have strong taproots and broad leaves for photosynthesis.
• Epiphytes absorb moisture from the air and store water.
• Animals like squirrels have strong limbs and long tails for climbing.
• Camouflage helps animals like chameleons blend into their surroundings.

Savanna/Grassland

Grasslands, or savannas, are dominated by grasses with scattered trees and shrubs. Rainfall in this habitat is insufficient to support dense forests.

Characteristics

1. Dominated by grasses, covering about 70% of the area.
2. High temperatures and intense sunlight.
3. Low humidity and rainfall (60–150 cm annually).
4. Scattered trees with small, drought-resistant leaves.

Organisms in Grasslands

Plants include acacia, baobab trees, and guinea grass. Animals range from herbivores like antelopes and zebras to predators like lions.

Adaptations

• Trees have thick bark to resist fire.
• Plants store water in thick trunks or underground stems.
• Animals like zebras use camouflage to avoid predators.

Arid Lands (Deserts)

Deserts receive less than 250 mm of annual rainfall and experience high evaporation rates, making them the driest habitats.

Characteristics

• Low rainfall and humidity.
• Extreme temperatures.
• Sandy or rocky soils.
• Frequent strong winds and intense sunlight.
• Drought-resistant plants like cacti and thorny bushes.

Organisms in Deserts

Plants include cacti, acacia, and wiry grasses. Animals include camels, foxes, scorpions, and snakes.

Adaptations

• Plants store water in thick stems and have deep roots to access underground water.
• Animals excrete solid waste to conserve water.
• Camels can store water and withstand temperature changes.
• Snakes and frogs camouflage with the sand.