Terrestrial Biomes of the Earth

The climate and landscape of the world varies according to.. Latitude – sunlight, seasons Rainfall – how much?, what type?, seasonal changes Geology – soil type, topography Altitude Wind Watersheds and bodies of water A number of fairly distinct biological areas have been identified, these are called Biomes

Tropical Forests Exists around the world between the Tropic of Cancer and the Tropic of Capricorn (~25⁰ N to ~25⁰ S)

Characteristics of Tropical Forests 20 – 34⁰C, lots of sun, lots of rain Seasonal Forests have dry and rainy periods – Found mainly in Africa Rainforests have rain throughout the year (up to 10 m per year). – Found in South and Central America and Asia

50 – 80% of animal and plant species <6% of the Earth’s land area A quarter of our medicine come from tropical forest plants (ex., quinine, curare) The forest has vertical layers, with most of the life to be found in the upper canopy, 100 feet up) Tropical forests produce up to half of the world’s oxygen. (a debatable statistic – why?)

Boreal Forests (AKA ‘Taiga’ forests) Mostly coniferous trees are found in these northern forests which ring the globe from about 50 – 70⁰N.

Seasonal change in sunlight and rainfall but generally cold with little precipitation. Growing season from spring through the summer. Wildflowers, lichen and shrubs also grow in the acidic soil. Many species of animals live here – beavers, bears, deer, wolves, etc.

Temperate Forests Mixed deciduous and coniferous trees throughout this fertile biome.

Cool temperatures (~10⁰C on average) Plentiful precipitation Rich soil that supports diverse plant and animal species. Humans have encroached on this biome (ex., Montreal). Abundant in Canada, USA and Europe.

Food Chain in a temperate forest

Grasslands and Shrublands Grasslands occur where there is not enough rain for trees, but enough rain falls to prevent a desert from forming.

Grasslands include the prairies of Canada and the African savannah, as well as many other areas, both cool and hot.

Savannahs are hot year-round, while temperate grasslands (ex. the Canadian Prairies) have seasonal temperature changes. Man-made grasslands are called ‘derived’. These are used for agriculture and livestock. Many species of animal (coyote, prairie chicken, prairie dog) and plants (grasses, flowers, shrubs). Plants tend to be drought and fire-resistant.

Arctic Tundra

Too cold for trees, only simple seasonal shrubs and lichen (a simple type of resilient moss-like plant). - Permafrost - Short growing season - Caribou, Polar Bears, arctic fox, etc., - Far North

Alpine Biomes Vary from temperate forest through boreal to tundra conditions as the altitude increases

Submontane zone – below 1300 m, deciduous trees Montane zone – 1300 – 1800 m, mixed trees Subalpine zone – 1800 – 2400 m, stunted conifers Alpine zone – 2400 – 3000 m, tough grass Nival zone – Mountain top – snowcaps, no life

Deserts Very little precipitation (less than 25 cm/year) Can be cold (Antarctica) or hot (Sahara) Few plants (ex., cacti) and animals (ex., lizards) Adapted to conserving moisture and losing heat.

A hot desert food chain