B17 Biodiversity And Ecoystems

Question 1

What is biodiversity?

Answer 1

Biodiversity is a measure of variety of all the different species of organisms on Earth, or within a particular ecosystem.

Question 2

Why is biodiversity

important?

Answer 2

Biodiversity is important for wellbeing as it provides food, potential foods, industrial materials and new medicines.

Question 3

Why does an increased
human population reduce the
land available for other plants
and animals? (give 4 reasons)

Answer 3

It reduces land for others because of : Human buildings, quarrying ,farming and dumping waste these are the reasons there are less land for others

Question 4

Give three examples of
resources that humans are
using up.

Answer 4

Water, Oil and coal

Question 5

What are the main causes of pollution

on the land? (give 4 examples)

Answer 5

• Sewage. Sewage is a cause of land pollution because when human waste is not treated properly the soil becomes polluted with unpleasant chemicals and gut parasites.
• Landfill sites , which can take up room and destroy natural habitats. Toxic chemicals can spread from the waste into soil
• Industrial Wastes can poison the soil for miles around. After Chernobyl in 1986 the soil was contaminated for thousands of miles away from the original accident.
• Farming can cause pollution because Weeds compete with crops plants for light,water and mineral ions. Animal and fungal pests attack crops and eat them. Farmers increasingly use chemicals to protect their crops however the chemicals are poisons.

Question 6

Why are pesticides a problem for

foodchains?

Answer 6

Pesticides are a problem because :

• They get into the food chain because the toxins get into organisms that feed on the plants or live in the soil.
• Bioaccumulation happens when toxins build up in the organisms.
• They can be washed out jnto rivers and streams.

Question 7

How does farming and the release of

sewage cause pollution in the water?

Answer 7

• Minerals in fertilisers especially nitrate are washed from the soil into local streams , ponds and rivers.
• Untreated sewage that is washed into waterways out into the sea causes high levels of nitrates in the water.
• Nitrates and other minerals stimulate growth of Algae and water plants.
• Increase in decomposers leads to a fall in the levels of dissolved oxygen in water. Meaning there is not enough oxygen to support some of fish and other aerobic organisms living in it.
• Toxic chemicals such as pesticides and herbicides or poisonous chemicals from landfil sites can also be washed waterways.
• The largest carnivores die or fail to breed because of the build - up of toxic chemicals in their bodies

Question 8

Why are there strict controls on the use of

chemicals on farms?

Answer 8

• Toxic Chemicals such as pesticides and herbicides can have the same bioaccumulation effect on aquatic food webs as they on life on land.
• Large carnivors die or fail to breed because of the build-up of toxic chemicals in their bodies.
• The more nitrates that are in the ocean the more levels of dissolved oxygen decrease meaning there isn’t enough oxygen to support fish

Question 9

Outline the steps involved in the

formation of acid rain

Answer 9

• Fossil fuels are burnt in vehicles and factories, acid gases are formed. Carbon dioxide is released into the atmosphere.
• Fossil Fuels often contain sulfer impurities which react with oxygen when they burn to form sulfer dioxide gas.
• Sulfer dioixde can cause serious breathing problems for people if the concentration get too high.
• Acidic sulfur dioxide and nitrogen oxides also dissolve in rainwater and react with oxygen in the air to form dilute sulfuric acid and nitric acid
• Acid rain has been measured with a pH of up to 2.0

Question 10

Explain why some countries that have strict
controls on sulphur emissions still suffer acid
rain damage to their buildings and ecosystems.

Answer 10

• The sulfur dioxide and nitrogen oxides are carried high in the air by the winds. As a result, relatively ‘clean’ countries can receive acid rain from their ‘dirtier’ neighbours
• Acid rain directly damages the environment. If it falls onto trees, it can kill the leaves, buds ,flowers and fruit.
• In some countries , such as Finland, the acid rain falls as ‘acid snow’. This can be damaging as all the acid is released in the first meltwater of spring causing an ‘acid flush’

Question 11

What are
particulates? Give two
effects of particulates
on the planet/humans

Answer 11

• Particulates are tiny sold particles
• Particles reflect sunlight so it can cool down the temperatures at the surface of the Earth.
• Particles are breathed in and can damage the lungs and the cardiovascular system.