Sustaining Ecosystems

Question 1

How plants adapt in polar region

Answer 1

• grow slowly because soil lacks nutrients in a cold climate
• grow close to ground because it is too cold and windy for trees to grow
• have a short growing season
• have small leaves and little moisture

Question 2

Soil profile in a tropical rainforest

Answer 2

• the very thin litter layer rapidly decomposes in heat
• shallow top soil is a mixture of decomposed organic material
• the sub-soil is deep due to the weathering of rocks below
• underlying rock weathers quickly at high temperatures to form sub-soil
• the soil is low in nutrients as theyre quickly taken up by trees

Question 3

Shifting Cultivation

Answer 3

1) small area of trees are cleared by chopping and burning
2) seeds are grown in the new clearing and ash from burning trees adds nutrients to soil
3) initially the crops grow well but after a few years the soil loses its fertility
4) people move onto another part of the forest and the trees grow back in that area