Continents of the world

Transcription

1 Continents of the world

2 Land animals in the Arctic Arctic Fox Arctic Rabbit Arctic Wolf Caribou Moose Arctic Hare Ermine Polar Bear

3 How does a polar bear survive in the cold? Low surface area to volume ratio - shorter legs and a stockier build. This reduces the surface area to lose heat from. Small extremities to reduce heat loss - Polar bears have small ears covered in thick fur, a very short tail and a relatively short nose all of which help to retain heat. Polar bears eat a very high fat diet -It enables them to eat the blubber of the seals that they catch which is the most energy rich and abundant part of the seal. Thick layer of body fat / blubber (anatomical / physiological) - This can be up 10cm (4 inches) thick, it is used both for insulation and also for food storage to help survive when food supply may be intermittent especially in the summer months when bears often go hungry for long periods due to not being able to hunt their preferred food of seals. Up to 50% of a polar bears weight can be fat! It also helps they to float naturally when swimming so avoiding having to use energy to keep their head out of the water. Processing body fat to gain metabolic water (physiological) - Polar bears store a lot of fat which they use for energy in the process combining it with oxygen to release carbon dioxide and metabolic water. They live in a polar desert with little access to fresh water especially in the colder months (which are in the majority) in this way they can get extra fresh water - camels do a similar thing with their stored fat. Thick camouflaged fur The coat of the polar bear is especially thick. There are two kinds of hairs, short soft dense inner hairs and longer stiffer outer guard hairs. The coat is the same colour all year round. The colour of course provides camouflage against an icy and snowy background. Thick fur on the paws to insulate them from snow and ice and also provide for grip on slippery surfaces. The paws are large in size to help spread the bears weight over ice and snow and have blubber under the pads for extra insulation.

4 Falling Penguin Numbers Fishing vessels are traveling to faraway areas to fish. Billions of people around the world rely on fish for their main source of food. Fishing ships are taking more fish than they are allowed in Antarctica. Reduced food availability leads to higher starvation rates and lower breeding success in Penguins. A decrease in the fish population will cause a slow decline in the Penguin population. Antarctic Fish are being sold for hundreds of pounds in top restaurants. 85 per cent of the world s fisheries are currently overfished. Tourist boat wanting to look at the penguins, often visit very close to the Penguin colony. Krill density had dropped by as much as 80 per cent due to the melting of the ice shelves. Dr Dave co-workers are convinced that Global warming is the reason behind the dramatic fall in Penguin numbers. Pollution from increasing tourism and ships visiting the area is damaging the once unspoilt environment.

5

6 Global Warming The earth is naturally warmed by rays (or radiation) from the sun which pass through the earth's atmosphere and are reflected back out to space again. The atmosphere's made up of layers of gases, some of which are called 'greenhouse gases'. They're mostly natural and make up a kind of thermal blanket over the earth. This lets some of the rays back out of the atmosphere, keeping the earth at the right temperature for animals, plants and humans to survive (60 F/16 C). So some global warming is good. But if extra greenhouse gases are made, the thermal blanket gets thicker and too much heat is kept in the earth's atmosphere. That's when global warming's bad.

7 Greenhouse Gases

8 Who causes global warming? USA is the greatest contributor to carbon dioxide (21%). In general the countries are either developed or newly industrialised. In general the larger the country the greater amount of carbon dioxide (population). EU, Japan and Poland do not produce any CO2 from deforestation Brazil is the only country to produce more CO2 from deforestation than fuel burning (300 million tonnes) They are all in the northern hemisphere except for Brazil. The USA creates 7 times more carbon dioxide than India and Poland CIS produces nearly 50% more CO2 than the EU.

9 Some effects of global warming

10

11