Ecosystem Characteristics | Geography for GCSE/IGCSE - Year 11 PDF Download

Tropical Rainforest Ecosystem Characteristics

• The Tropical rainforest (TRF) biome is primarily located in a region between 15 degrees north and 15 degrees south of the equator within the equatorial climate zone.
• Occupying just 6% of the Earth's surface, the key tropical rainforest areas are situated in various countries, including:
  • The Amazon, the largest remaining rainforest globally, commonly linked with Brazil but extending into parts of seven other nations.
  • Central America, encompassing sections of Belize, Costa Rica, El Salvador, Guatemala, Honduras, Nicaragua, and Panama.
  • Central Africa, covering Cameroon, the Central African Republic, the Republic of Congo, the Democratic Republic of Congo (DRC), Equatorial Guinea, and Gabon.
  • Indo-Malaysia, which includes Malaysia, Indonesia, and several other countries in Southeast Asia.

Biodiversity in Tropical Rainforests

• Tropical Rainforests (TRFs) host the highest biodiversity of plants and animals globally.
• Biodiversity in TRFs:
  • Estimates suggest that TRFs are home to over 50% to 80% of the world's plant and animal species.
  • In a mere 10km² area, one can find up to 1,500 flowering plants, 750 tree species, 400 bird species, and 150 butterfly species.

Nutrient Cycle

Tropical Rainforests (TRFs) exhibit a unique nutrient cycle due to their climatic conditions:

• The TRFs experience a perpetual growing season characterized by consistent high rainfall and temperatures throughout the year.
• The nutrient cycle in TRFs is rapid, facilitated by the continuous shedding of leaves by trees and plants.
• The abundant moisture and high temperatures accelerate decomposition and recycling of nutrients in the ecosystem.
• Rapid plant growth in TRFs results in swift nutrient uptake from the soil.

Layers of the Tropical Rainforest

The tropical rainforest consists of five distinct layers:

• Ground layer (0m)
• Shrub layer (3-4m)
• Under canopy (15m)
• Canopy (30m)
• Emergents (45-55m)

Adaptations

• The tropical rainforest (TRF) hosts plants and animals well-suited to its unique climate.

Food web

The TRF sustains a complex food web comprising Producers, Primary consumers, Secondary consumers, and Tertiary consumers.

• Producers
• Primary consumers
• Secondary consumers
• Tertiary consumers

Hot Desert Ecosystem Characteristics

• Hot desert biomes are predominantly located around the Tropic of Cancer and Tropic of Capricorn.
• Roughly 20% of the Earth's surface comprises hot desert ecosystems, encompassing regions such as:
  • North America - encompassing the Mojave and Sonoran Deserts in the USA and Mexico.
  • South America - including the Sechura Desert in Peru and the Atacama Desert in Chile.
  • Africa - consisting of the Sahara, Kalahari, Namib, and Somali Deserts.
  • Middle East - featuring the Arabian Desert.
  • Asia - housing the Dasht-e Lut in Iran, the Gobi, Turkestan, Thar, and Taklamakan Deserts.
  • Oceania - hosting the Australian Desert.

Biodiversity

• Hot deserts exhibit one of the lowest levels of biodiversity on Earth.
• The biome supports around 5000-6000 plant species, numerous invertebrates, and up to 20 bird species.

Nutrient cycle

• Plant growth in hot deserts is restricted by extreme temperatures and water scarcity.
• The nutrient cycle is slow, with most nutrients being retained in the soil.
• Hot desert nutrient cycle:

• The soils in hot deserts are sandy, coarse, and low in nutrients due to the lack of organic matter.

Adaptations

• Plants and animals in these regions have evolved remarkable adaptations to endure the harsh conditions of extreme temperatures and minimal rainfall.

Food Web

In hot deserts, the food web is intricate, involving:

• Producers
• Primary consumers
• Secondary consumers
• Tertiary consumers

Hot desert food web: