Ecosystems of the planet (OCR Geography A)

Ecosystems of the planet

An ecosystem has two parts: abiotic, where non-living things (rocks etc) live; and biotic, where living things live and includes the consumers and producers of the food chain. Biomes are largescale ecosystems.

Ecosystems need energy which comes from sunlight, which the plants take in which is used to make their own food and are producers of the food chain. Then, the animals consume the plants or each other. Fungi and bacteria feed on dead and waste material and make things break down or rot (decomposers) - they recycle nutrients for the plants to use again.

Tundras are located north and south because in polar areas the Sun's rays are less concentrated and the lack of heat limits vegetation growth, so plants are stunted and low-growing.

Tropical rainforests are located north and south of the Tropics (of Capricorn and Cancer) since the Sun's rays are at a high angle in the sky for the whole area and are concentrated over smaller areas than the poles, providing low heat, so vegetation is dense and there are high-growing plants.

Tropical grasslands

• Tropical grasslands are located between the latitudes 5 and 30 degrees north and south of the equator, within central parts of continents, including most of central Africa surrounding the Congo basin, parts of Venezuela, and parts of Mexico.
• The climate can change from tropical wet to tropical dry, with temperatures high throughout the year and cloud cover limited for most of the year which allows daily temperatures of 25 degrees C. There are 2 seasons: a longer dry season and a shorter wet one.
• With the summer rain, the grasses grow very quickly to over 3m in height. The length of the growing season depends on how long the rainy seasons last. Many trees are drought- or fire-resistant to survive the dry season. There are 40 species of hoofed animals and it is home to herbivores, as well as carnivores, grazing species, and antelopes.
• The baobab tree's bark is thick to retain moisture, has root-like branches holding a small amount of leaves to reduce water vapour loss, and is adapted to the climate by growing large swollen stems long enough to tap into water supply deep into the ground.

Temperate grasslands

• They lie in the centre of continents between the latitudes of 40-60 degrees north and south of the equator; the most major temperate grasslands are the steppes of Eurasia and veldts of Africa.
• The climate is cooler than tropical grasslands (Savannah) and an ecosystem of extremes, summers are very hot and winters very cold. Summers can reach 38 degrees C and winters -40 degrees C. Rainfall yearly can vary from 250mm-750mm, 75% of which occurs during summer, which brings drought and occasional fire to maintain the grasslands.
• The length of the growing season depends on temperatures, but don't grow as fast as those of the Savannah. Trees and shrubs struggle growing, but some grow along valleys where water is available. River grasses grow more evenly…