ESSENTIAL VOCABULARY UNIT 7

ACID RAIN

Rain polluted by chemicals as a result of industrial activity.

BIODIVERSITY

The variety of life forms in an environment. It is a measure of the health of an ecosystem.

CANOPY

The uppermost level of a forest, forming an almost continuous cover.

DECIDOUS TREE

A tree which loses its leaves in the autumn, such as the oak tree.

DEFORESTATION

The destruction of forests when tres are cut down in order to make use of the land.

DESERT

A landscape that receives very little precipitation, and where only a few plans, like cactuses, can grow.

DROUGHT

An extended period of very low rainfall, causing water shortages.

DUNE

A mound of sand found in deserts and oceans, created by the wind.

EARTHQUAKE

The shaking of the Earth’s crust along the boundaries of tectonic plates, when they slide against each other.

FOREST FLOOR

The soil surface of a forest where shrubs, ferns and fungi grow.

GLOBAL WARMING

The increase in Earth’s average temperature.

GREENHOUSE EFFECT

The process in which, due to increased levels of carbon dioxide combining with water vapour in the atmosphere, heat is trapped on the Earth’s surface.

HURRICANE

A very strong wind, accompanied by torrential rain.

MANGROVE FOREST

A coastal seawater habitat in the tropics, where vegetation includes mangrove tres, which have adapted to a seawater environment.

PERENNIAL TREE

A tree that doesn’t lose its leaves in the autumn.

PERMAFROST

Soil that is frozen all year round, found in Polar regions.

RAINFOREST

A dense forest found in tropical areas with high rainfall.

SAVANNAH

A grassland that has very tall grass during the rainy season, as well as shrubs and a few widely spaced tres.

TAIGA

 A biome of coniferous forests found in continental climates, South of the Artic tundra.

TUNDRA

 A vast area near the Artic Ocean in the Northern Hemisphere with permanently frozen subsoil.

VOLCANIC ERUPTION

The sudden expulsion of hot rocks, ash and gases from a volcano.