Biodiversity and the effects of human interaction on ecosystems.

What is biodiversity?

a measure of all the different species of organisms on Earth or within an ecosystem.

Why is biodiversity necessary to maintain a stable and healthy ecosystem?

It reduces the dependence of one species on another for food, shelter and the maintenance of physical environment.

Why is it important to protect biodiversity for the future survival of humanity?

Wider balance of ecosystems that supports all the life, that we depend on.

Our knowledge of the ecosystems in the world is still surprisingly limited.

We risk not being able to reverse and repair ecosystem that benefit us as we loose more species, and each new species has a bigger impact.

List the main causes of the loss of biodiversity.

Habitat loss Population Growth

Diseases Introduced species

Climate Change Pollution

Over-consumption

What problems are associated with the increasing human population?

More land is needed for homes and farming - destroys habitats of other living organisms, natural animals and plant populations are destroyed.

Harvesting Rescources - eg mining, quarrying, drilling for oil. Most of these resources are non-renewable and lead to pollution, such as:

1. Air pollution, smog, sulphur dioxide.

2. Unrecyclable rubbish - landfill sites cause habitat destruction.

3. Global warming caused by CO2

4. Sewage and fertilisers entering rivers and lakes

5. Chemical spills such as oil, heavy metals, pesticides.

Describe and give examples of land pollution.

Sewage, household waste, industrial waste, radioactive waste, chemicals used in faming such as pesticides and herbicides.

Radioactive fallout frm the Chernobyl nuclear reactor accident was carried by the wind across Europe and deposited on the hills of North Wales. Lambs from the area couldn't be safely consumed by humans until 2012 as the concentration of radioactive materials in grass and soil found in the DNA of sheep grazing the land had remained high enough to be dangerous to humans.

Describe and give examples of water pollution.

Sewage, runoff from land use of fertilisers (cause algal blooms) and herbicides and pesticides.

Farmers apply nitrate fertilisers to plants to increase growth - the nitrates combine with sugar to make amino acids to make protein. Farmers dony want to put too much fertiliser on their fields because they are expensive, and may cause eutrophication.

Describe and give examples of air pollution.

Sulphur dioxide (burning fossil fuels and smelting mineral ores for metals). Nitrogen oxides (agriculture and vehicle engines). Particulates (carbon) from incomplete combustion.

Such particulates block or reflect unlight causing global dimming and also decreases global temperatures.

What is eutrophication and what is it caused by?

The artificial enrichment (with nitrates/phosphate from fertilisers/sewage) of waterways that leads to changes that encourage growth of organisms in the water that eventually starve and die.

Describe the process of eutrophication.

1. Sewage (manure) and fertilisers are intentionally spread over land

2. Due to rainfall, these chemicals runoff to waterways.

3. Increase in growth of algae and other aquatic plants due to excessive minerals from runoff.

4. Algal blooms - the abundance of nutrients for their growth - occur.

5. Algae live at the top of the water and block sunlight reaching organisms under the surface

6. Plants that live under the surface die, becoming detritus

7. Decomposition increases, bacteria decompose dead plants and algae. More bacteria, more detritus use more oxygen when carrying out aerobic respiration.

8. Lack of oxygen causes death or forced migration of aquatic animals.

What are the causes and consequences of acid rain?

Causes: sulphur dioxide from burning of fossil fuels that contain sulphur. Nitrogen oxides from car exhausts when N2 burns due to high temperatures and high pressure in engines.

Consequences:

1. Kills trees and damages roots or leaves.

2. Corrodes limestone building and statues by chemically reacting with them.

3. Makes lakes acidic and kills fish by damaging their gills.

Describe how acid rain forms.

1. Burning of fossil fuels such as coal.

2. This releases sulphur dioxide (or, eg nitrogen oxides) into the atmosphere.

3. Sulphur dioxide also dissolves into the moisture in clouds.

4. The cloud blows to another country

5. Acid rain pours from the clouds.

What are the causes and consequences of smoke pollution and smog?

Sulphur dioxide, nitrous oxides, and ozone.

Air pollution can also be caused by tiny particulates from smoke which can cause smog.

They can damage the tissue of lungs.

What are the causes of bioaccumulation?

Chemicals added by farmers to plants, such as:

1. Herbicides: kill unwanted pants like weeds and leaves the crop unharmed.

2. Fungicides: kills fungus and their spores that cause disease.

Chemicals dissolve in rainwater and run off the land to waterways and other land areas.

Kills unintended animals, plants and insects.

This reduces biodiversity and also pollutes the environment and can eventually pass to humans via bioaccumulation.

Describe the process of bioaccumulation.

1. Toxins eg insecticides can accumulate in food chains

2. Crops are sprayed with insecticides

3. Crops may be eaten by grasshoppers/ other insects. The insecticide chemicals that are harmful are often stored in the fatty parts of the body.

4. Blackbirds, eg, feed on more than one grasshopper to survive, so digest multiple doses of toxins.

5. This process occurs again, for example sparrows hawks eat many blackbirds, digesting even more toxins. It is often a lethal dose, and can kill them.

How can scientists measure oxygen levels in a river?

Oxygen probe - a device you put in water.

How does analysing water samples monitor pollution?

You can analyse the amount of fertilisers, pesticides, herbices, oil and sewage.

How could you measure acid rain pollution?

Using a pH probe - more acidic results tend to reflect less oxygen dissolved.

What is a bio-indicator?

a species whose population can reveal the quality of the environment.

Bio-indicator case study: What is lichen?

Lichens are organisms that grow in exposed places such as rocks or tree bark.

They need to be very efficient at absorbing water and nutrients to grow there.

Rainwater contains just enough nutrients to keep them alive.

The relationship between lichen and what it grows on is a symbiotic relationship - 2 organisms living together for mutual benefit

How is lichen used as a bio-indicator?

Air pollutants dissolved in rainwater, especially sulphur dioxide, can damage lichens and prevent them from growing.

This makes lichens natural indicators of air pollution as in places where no lichens are growing, it is often a sign that the air is heavily polluted with sulphur dioxide.

It is easy to see if an area is unpolluted as lichens are visible without testing.

Describe another species (not lichen) that can act as a bio-indicator.

Tubifex worms - can survive in water with low oxygen levels as haemoglobin in tails absorbs the little oxygen that's present.

How can you reduce the effects of land pollution?

Fertilisers/Eutrophication - use manure instead of fertiisers

Household waste/landfill - reduce, reuse, recycle

Pesticides/Bioaccumulation - don’t dump waste, manually remove weeds.

How can you reduce the effects of water pollution?

Fertilisers/Eutrophication - using manure instead of fertiisers, don't dump in rivers (change the law) (also stops spread of water-borne diseases)

Pesticides/Bioaccumulation - manually remove weeds, don't dump waste

How can you reduce the effects of air pollution?

Nitrogen oxides/acid rain and smog - burn less fossil fuels, use electric cars, use renewable energy.

Particulates/ breathing problems - public transport, walk, cycle

Sulphur dioxide / acid ran and smog - catalytic converters, electric cars.

Define deforestation.

Removal of forests by felling of burning.

Define slash and burn.

Metho of deforestation where trees are being felled and burned to clear land.

Define biodiversity.

The measure of the variety of species.

Why is deforestation occuring? (Land uses)

Land is useful for:

1. Agriculture so as grazing cattle and planting crops

2. Building towns

3. Contructing dams

4. Trees can be sold as timber and pulp

5. Trees can be used as fuel.

Why is deforestation occuring? (Accidental reasons)

Forest fires (natural)

Animals damage (elephants or disease spread by animals)

Bullet point the effects deforestation has locally.

1. Loss of habitats

2. Reduces biodiversity

3. Effect on food webs and number of organisms

4. Erosion of soil

5. Leaching of minerals

6. Flooding

Bullet point the effects deforestation has globally.

Less CO2 removed from the atmosphere.

More CO2 added to the atmosphere when trees are burnt or decay

Flooding.

Land used for eg cattle ranching or rice farming which both produce methane, and accelerate global warming.

How does cattle ranching and rice farming produce methane?

Cattle release methane as a product of digestion through belching, and when their manure decomposes.

Rice paddies involve flooding the fields with water, preventing oxygen from entering. This creates an anaerobic environment (low/no oxygen) Microbes in the soil thrive in these conditions and decompose organic matter (like dead plant material). This decomposition process releases methane, which then travels up through the rice plants and escapes into the atmosphe

How can deforestation be reduced?

1. Selective logging to ensure sustainability

2. Conservation projects by NGOs

3. International agreements

4. Agroforestry

What is peat?

A material formed over thousands of years from plant material that an decay properly due the the acidic conditions and lack of oxygen.

Why are peat bogs being destroyed?

Peat can be burned as fuel

Its widely used by gardeners in compost to improve the soil conditions.

Why is peat bog destruction bad?

They are enormous carbon sinks, so losing them releases lots of carbon into the atmosphere (when its burnt)

Released CO2 contributes to global warming

Peat is formed very slowly and is destroyed way faster than its formed.

Destruction of peat destroys habitats for plants and animals.

What can be done to prevent peat bog destruction?

Gardeners using peat free compost to reduce CO2 emissions which is made from bark, garden waste, or coconut husks.

List 6 sources of CO2.

Burning fossil fuels

Burning Peat

Using peat as compost

Cars

Deforestation/ burning trees

Decay / respiration

Volcanic erruptions

List 2 sources of methane.

Cattle

Rice paddies

What is the greenhouse effect?

Where energy from the sun reaches the earth’s surface, and much of it is ‘re-radiated’ back out into space.

Some of it is ‘absorbed’ by gases such as carbon dioxide and methane.

As a result, the earth and its surrounding atmosphere is kept warm and ideal for life.

Because CO2, methane etc act like a greenhouse around the earth, they are known as the greenhouse gases.

The way they keep the earth warm is the greenhouse effect, and is vital for life.

Without it, the earth wouldn't be warm enough for life

Describe global warming.

The greenhouse effect is necessary to keep the earth’s surface at a suitable temperature for life.

As the levels of greenhouses gases emitted into the atmosphere increase, the greenhouse effect also increases.

This means more infrared radiation from the sun is absorbed by the gases, making the temperature of the earth’s surface increase.

Describe the consequences of global warming.

Ice caps in the north sea and South poles will melt, and so will many glaciers.

As a result, sea levels will rise.

Water gets warmer so less CO2 can be absorbed by the ocean (the heat decreases the solubility of gases so they cant dissolve.)

Loss of habitat due to flooding

More severe, unpredictable weather events.

How can we reduce the causes of global warming?

Reduce deforestation

Use renewable energy

Don't use peat

Use public transport

How can we reduce the effects of global warming?

Plant more trees

Increase peat bog habitats

Develop crop resistant to droughts or higher temperatures

Conservation activities to prevent reduction in biodiversity

What are SSSIs?

Sites of special scientific interests, areas legally protected from harmful activities.

Why are SSSIs important?

Sites of special scientific interests are important as the have unique species, high biodiversity and sometimes are the home of endangered species.

Where might there be conflict between maintaining biodiversity and human needs?

Maintaining biodiversity fundamentally clashes with land use

We need more land to be natural, but it would mean less land for food production, for example.

Reduction of deforestation limiting land available for food production and downstream uses of wood.

How may a fall in CO2 emissions help to maintain biodiversity?

If emissions are reduced globally, Global warming will be reduced and thus

• Biodiversity in unique habitats and ecosystems like arctic and Antarctica ice can be preserved

• Prevents rise in sea levels that will destroy biodiverse mangrove forests, which are incredibly important regions for yound fish to mature.

• Prevents temp increase that could dry out wetlands and cause bleaching/ death of coral reefs which are very biodiverse.

How can taxes be used to reduce human damage to ecosystem?

Taxes on waste like landfill and industry emissions can be used to offset IE pay for activities that reduce effect of human damage.

Money used to promote research into less damaging alternatives like recycling over landfill.