Paper 1a15
You have been answering m.c. questions for a long time and do not need much introduction to them. Their disadvantage is that reading them can take up quite a bit of time, but at least you won't make spelling mistakes in your answers. Some examination texts are quite hard, but remember that you don't have to get every detail or recognise every word. Concentrate on the big meaning and the parts you are asked questions about.
A Vanishing World
Read the passage and then choose the correct options
The number of different types of animals and plants is decreasing sharply. This loss in biodiversity is receiving a lot of attention from scientists and environmentalists for what it implies about the health of our planetary ecosystem.
First of all, to see if this is a serious problem we need to discover what the normal rate of extinction is. The margins of error are large but these figures are the best we can come up with as there is very limited data from any parts of the world. The accepted figure is that one species of mammal or bird can be expected to vanish every 500 to 1,000 years. However, we know of 38 birds and mammals that died out from 1600 to 1810, and 112 from 1810 to 1995. The current rate of loss is nearly one hundred times what it normally was, and by 2020 it is predicted to be from one to ten thousand times the original rate. This vast increase is the result of threats to entire categories of ecosystems. For example, all the world's coral reefs are at risk and their disappearance would remove a very large number of species we hardly know.
Another figure puts the loss of all types of living organisms at 784 since 1500: 582 on land, 226 from rivers and lakes and 15 from the sea. The United Nations reckons that 11,046 more are at immediate risk.
