At the 4-cell stage, the EMS cell requires a signal from its neighbor (and sister cell), the P2 blastomere.

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#Unit 10. Ecological Principles

Temperate forests 

Temperate forests are largely found between 40° and 60° N of the equator. 

Temperate rain forest (Evergreen): Temperatures are a little cooler, 5–25°C on average, and winters are mild, but there is abundant rainfall, usually exceeding 200 cm a year

Temperate Deciduous Forest (lose their leaves in winter):  Temperatures fall below freezing each winter but not usually below –12°C, and annual rainfall is generally between 75 and 200 cm. Soils are rich in organic and inorganic nutrients, and quite fertile. 

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#Id: 6051

#Unit 10. Ecological Principles

Grasslands   Grasslands are found on every continent except Antarctica, and cover about 16 per cent of the Earth’s surface.  They develop where there is not enough precipitation to support forests, but enough to prevent deserts forming.

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#Id: 6052

#Unit 10. Ecological Principles

Tropical Grassland or Savanna 

These are hot, tropical areas, averaging 24–29ºC with a low or seasonal rainfall of between 70 and 130 cm per year.

As with grasslands, the predominant mammals are the grazers. 

 In Africa, the large herds of grazing animals provide food for many different kinds of large carnivores (lions, hyenas, leopards). 

The world’s greatest assemblages of large mammals occur in the savanna biome.

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#Id: 6053

#Unit 10. Ecological Principles

Temperate Grassland  Temperatures in the winter often fall below –10ºC, while summers may be very hot, approaching 30ºC, and summer droughts are not uncommon.  Annual rainfall is generally between 25 and 100 cm, too low to support a forest but higher than that in deserts.  Prairie soils are among the richest in the world, having a nutrient content much greater than that of a typical forest soil.

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#Id: 6054

#Unit 10. Ecological Principles

Location        Grass land 

Eurasia Steppes 

North America  Prairie

Argentina  Pampas 

South Africa  Veldts

Australia and Newzeland          Tussocks 

Australia                              Down 

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#Id: 6055

#Unit 10. Ecological Principles

Taiga, Northern Coniferous Forest, or Boreal Forest  The climate is one of short, cool summers and long winters with abundant snowfall. Precipitation is generally between 40 and 70 cm, often occurring in the form of snow.

Most of the trees are evergreens or conifers with tough needles, hence its similarity to temperate rain forest.