Main question

What is the interrelationship between climate, plants, animals and soils in the Arctic tundra biome?

• Resource A

  
  
  
  
  

• Resource B

  
  
  

  Near the surface is a layer which is frozen in Winter but melts in Summer. Below this is the permafrost that prevents water infiltration. Plants contribute very little organic material and this decomposes very slowly into a thin layer of acidic humus. The soil is not mixed much. The top layers of the soil are often saturated and blue-grey in colour. The soils have a low nutrient content.

  
  
  

  

  
  

  Source - https://en.wikipedia.org/wiki/File:Gelisol_profile.jpg -
  This image or file is a work of a United States Department of Agriculture employee, taken or made as part of that person's official duties. As a work of the U.S. federal government, the image is in the public domain.

  
  
  

• Resource C

  
  
  

  Vegetation

  
  
  

  The tundra contains only about 1700 different plant species - mostly grasses, sedges, shrubs, mosses and lichens. There are about 400 types of flowering plants. Very few trees are present, with the exception of a few birch and dwarf willows in lower latitudes.

  
  
  

  Adaptations

  • Majority are short and dark coloured. They grow in clusters.
  • Shallow roots, often spread laterally in a dense network.
  • Many are evergreen.
  • Waxy leaves to reduce transpiration losses.
  • Perennial plants. Rapid completion of their annual cycle - flowering and producing seeds within a few weeks..
  • Are able to survive ice and snow. Some have hairy leaves.

  
  
  

  Lichen. Able to survive dry periods. Able to photosynthesise even when it is cold and with little sunlight. Cells are not damaged by frost.

  
  
  

  Bearberry. Grows in poor dry soils – does not need a great deal of nutrients. Short - 10-20 cm, to avoid the wind. Hair on its leaves to conserve heat. Also leathery leaf surfaces to protect them against frost.

• Resource D

  
  
  

  Only 48 species of terrestrial mammals are found in the Arctic tundra but the number of individuals present from some species may be large. Hares, mice, rabbits, lemmings are examples of these mammals. There are also caribou and musk ox. Predators include wolves, Arctic foxes, and polar bears.

  
  
  

  In Summer there are many insects and mosquitoes. The mosquitoes have chemicals in their blood that prevent it from freezing.

  
  
  

  Many migrant birds, e.g. ducks, fly to the tundra in Summer. Others e.g. grouse and owls remain permanently in the tundra region.

  
  
  

  Adaptations

  • Thick fur to keep warm.
  • Hibernation, e.g. brown bears.
  • White fur, e.g. polar bears, snow hares, Arctic foxes.
  • White feathers, e.g. grouse and snow owls. The grouse have thick feathers on their feet.
  • Rapid breeding cycle. Large litters, e.g. lemmings.
  • Migration.
  • Digging under the snow to keep warm and reach food.
  • Deer have sharp horns and hooves to cut through snow and ice.

  
  
  

  Deer. Strong short legs. Coats of thick fur. Sharp horns and hooves to break through the snow and ice. Wide hooves. Good swimmers. They can reduce their metabolic rate if circumstances are difficult. Migrate of up to 750 kilometres a year in search of grazing. Graze a large variety of tundra plants. Their calves grow very quickly.

  
  
  

  Arctic fox. Stores food, e.g. eggs for Winter. Sometimes they follow larger predators, e.g. bears, and steal their scraps. Hairy tails which they use cover themselves when it is cold. A coat of long fur - dark in Summer, white in Winter. Omnivores – eat eggs, fish, insects, mammals and birds as well as berries, seaweed.