Question

Mount Kilimanjaro is a 6,000 -meter-tall (19,685-foot) mountain in Tanzania, Africa, just 320 kilometers (200 miles) south of the equator. Moving from bottom to top, a hiker passed through savanna grasslands, tropical rain forest, treeless moorland, and alpine desert, ending on a glaciated peak. Explain why the climate conditions and biological environments changed as the hiker climbed up the mountain.

Short answer

The climate changes with altitude, affecting temperature, rainfall, and vegetation distinct to each zone from savanna to glaciated peak.

Step-by-step solution

Understand Climatic Zones

Mountains like Kilimanjaro have distinct climatic zones due to changes in altitude. As a hiker ascends, each zone offers different environmental conditions. These zones are shaped by the changes in temperature, precipitation, and oxygen levels at different elevations.

Examine the Base Elevation

At the base of Kilimanjaro, the climate is hot due to its proximity to the equator. The area is covered with savanna grasslands that can withstand the warm temperatures and moderate rainfall typical of this elevation.

Transition to Tropical Rainforest

As the hiker moves upwards, they enter a tropical rainforest. This zone is characterized by higher rainfall and a cooler temperature compared to the savanna, thanks to increased elevation. The dense forest thrives in humid conditions.

From Rainforest to Moorland

Continuing up the mountain, the hiker reaches the moorland zone. This area experiences less rainfall than the rainforest and cooler temperatures. Plants here are adapted to milder climatic conditions and reduced availability of water.

Approach to Alpine Desert

As elevation increases further, the hiker encounters an alpine desert. This region is characterized by harsh, cold winds, limited rainfall, and sparse vegetation. The altitude causes lower oxygen levels and temperatures, hindering plant growth.

Reaching the Glaciated Peak

Finally, at the peak of Mount Kilimanjaro, conditions become extremely cold and dry, similar to a polar climate. Glaciers cover the summit, and biological diversity is minimal due to the harsh environment and thin air.

Key concepts

Altitude and Climate

Mountains create unique climate situations, mainly due to changes in altitude. As you ascend a mountain, like Mount Kilimanjaro, the air temperature generally decreases. This is because the atmosphere becomes thinner at higher altitudes, leading to cooler conditions.

Another factor affected by altitude is precipitation. Moist air that is drawn upward cools and releases its moisture. This is why some regions of mountains can be lush with rainfall, while others have less. Higher elevation often means less precipitation after a certain point, leading to drier zones.

Moreover, altitude changes oxygen levels. As you climb higher, the air contains less oxygen, which can influence both the climate and the types of life forms that can survive. This combination of temperature drop, moisture change, and reduced oxygen significantly impacts how each segment of the mountain environment is structured.

Biomes on Mountains

Biomes are large communities of plants and animals that occupy a distinct region. On mountains like Kilimanjaro, you'd find several changing biomes as altitude increases. These transitions showcase how diverse ecosystems are shaped by the environment.

Starting at the base, you often have warm savanna grasslands. This biome supports a rich mix of grasses and scattered trees adapted to warmer temperatures and moderate rainfall. As you ascend, you enter a tropical rainforest zone. A rainforest biome is teeming with biodiversity and supported by frequent rainfall and cooler temperatures.

Climbing further introduces you to moorland. Moorland biomes have hardier shrubs and bush-grasslands adapted to cooler temperatures and less moisture. Finally, you would reach an alpine desert, characterized by low vegetation due to harsh climates and cold winds. These biomes underscore the adaptability of life to varying climatic conditions.

Ecological Altitude Gradient

The ecological altitude gradient refers to how vegetation and animal communities change with changing altitude. As a hiker climbs a mountain, they experience this shift firsthand, encountering distinct ecosystems at various heights.

Lower altitudes are warm and humid, offering optimal conditions for diverse plant and animal life. As one moves higher, the environment becomes more challenging with reduced temperatures, leading to fewer plant species and simplified ecosystems.

This gradient is crucial for studying how species adapt to different conditions. Understanding these changes helps us see how altitude creates barriers and opportunities for life, allowing diverse habitats to thrive separately even in close proximity.