Biology Revision

Evolution

Theory Natural selection Mutations Endangered and extinct species Fossils Key Words

Human Influence on the Environment

Fertilisers Eutrophication Deforestation Intensive farming Destruction of the land Pesticides Effects on the Environment What can be done Key Words

Pollution

Acid rain The greenhouse effect Pollution Problems Solutions Key Words

Biotechnology

Industrial fermentation Food production Other products Key Words

Gases in our Atmosphere

The carbon cycle The nitrogen cycle Key Words

The Theory, Natural Selection, Mutation and Fossils

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An example is the peppered moth.

They live in woodlands – on lichen-covered trees.

There are two types: light/speckled form and the dark form

The darker moth was caused by a mutation and was usually eaten by predators

In the 1850s the darker moth was rare, but pollution started to blacken the trees

They were not at advantage as they could camouflage

In 1895 most of the population of moths were dark

In cleaner areas the light moth had the advantage, so it survived to breed

(Explanation for theory)

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Generally, mutations in a species is harmful

But in the peppered moth case it was helpful as the environment changed

Over a long time new species can be formed because of small mutations

This relates to the theory of evolution because it means that all species came from one common ancestor that existed billions of years ago

Those species were unable to adapt accordingly go they became extinct.

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Endangered species are in danger of being extinct

E.g. The red squirrel is endangered in the UK

Animals are endangered/extinct because of:

Climate change Hunting Pollution Habitats being destroyed

Some people object to having whales in zoos because some are endangered

Animals that are extinct are species that haven’t survived anywhere in the world

E.g. The mammoth and dodoS

pecies can be protected by: Laws Captive breeding programmes Protected habitats

Conservation programmes help the human race, they protect our food supply, maintain food chains, and saves future medical cures

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Fossils are remains of dead organisms that lived millions of years ago

They are found in rocks, normally sedimentary, amber, peat or ice

Fossils are evidence of evolution

Younger fossils are usually found nearer the surface

Records are incomplete because fossilisation rarely happened and soft body parts aren’t fossilised

Records can be interpreted differently

Fossils can be formed by:

1. The hard parts of an animal form rocks because they don’t decay

2. Minerals which preserve their shape slowly replace the softer parts of the animal that decays slowly

3. Fossils are formed in areas where decay cannot take place

E.g. There’s no oxygen, moisture or warmth(Proof for theory)

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Evolution

Charles Darwin

Lamarck

Natural Selection

Mutations

Endangered

Extinct

Genes

Competition

Breeding

Species

Conservation programmes

Habitat

Organisms

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Fertilisers, Eutrophication, Deforestation, Intensive Farming, Pesticides and Destruction of the Land

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Humans are using the world’s natural resources at an alarming rate

Combustion of fossil fuels contributes to acid rain and the greenhouse effect

Gases such as sulphur dioxide dissolve in rain and make it acidic

Acid rain damages wildlife and pollutes rivers and lakes

Carbon dioxide is the main gases that causes global warming which is caused by the greenhouse effect

It traps heat and makes the Earth warmer

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People need to limit their needs

Intensive farming produces quality food and enough to supply people’s needs in Europe but has its problems – alternative is organic farming

Organic farming produces less food per area of land but is kinder to the environment

Organic farming uses manure as a fertiliser and has land for wild plants and animals to flourish.

Biological control of pests are also used where animals eat the pests, it’s not as effective but it isn’t harmful

Greenhouses can grow food more efficiently and can grow food out of season while deducing harmful effects

Developing alternative energy sources, such as solar power and wind energy, will help conserve the fossil fuel supply and reduce carbon levels

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Acid rain

Greenhouse effect

Sulphur dioxide

Carbon dioxide

Fertilisers

Nutrients

Artificial

Eutrophication

Microbes

Sewage

Deforestation

Soil erosion

Pesticides

DDTI

ntensive farmingO

rganic farmingG

reenhouseB

iological controlF

ood chainF

ossil fuels

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Acid Rain, Pollution and the Greenhouse Effect

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Acid rain kills fish and trees

Acid rain also damages buildings, especially those made from limestone

Acid rain falls into lakes which then poisons fish and the poisoned fish are eaten by birds which poisons them.

Rising temperature causes melting of the polar ice caps. This means that sea levels would rise. This would cause serious flooding

Plants may be killed by the warming

Weeds may thrive because of the extra carbon dioxide which they grow well on.

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People can use alternative energy sources

E.g. Renewable energy such as: Solar power Wind energy

Use unleaded petrol to reduce the lead emissions

Reduce the need for cars overall

Stop large scale deforestation because trees absorb carbon dioxide

Use catalytic converters in cars to reduce harmful emissions

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Pollution

Pollutant

The greenhouse effect

Global warming

Methane

Carbon dioxide

Fertilisers

Pesticides

Sewage

Fossil fuels

Sulphur dioxide

Nitrogen oxides

Acid rain

CFCs

UV rays

Catalytic converters

Deforestation

Alternative energy sources

Flooding

Oil spillages

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Industrial Fermentation, Food Production and

Other Products

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The Carbon Cycle and the Nitrogen Cycle

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Feeding

Decomposers

Death but no decay

Death and Decay

Photosynthesis

Burning and Combustion

Respiration

The atmosphere

Fossil Fuels

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Added Notes:Decomposition

•Decomposers are bacteria and fungi which break down dead material•They help recycle carbon into the atmosphere and recycle nutrients into the soil•Plants use this nutrients dissolved in water during photosynthesis.•Animals eat plants, and both animals and plants die, making the cycle start from the beginning again•Decomposition happens everywhere in nature, in compost heaps and even sewage works•The perfect conditions are:

•Warm•Moist•Plenty of oxygen

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•The atmosphere contains 78% nitrogen gas•Nitrogen is needed to make protein•Plants and animals cannot use nitrogen as a gas – it has to be converted into nitrates•Animals get protein by eating plants which plants make from nitrates•It is a continuous cycle•There are four ways that nitrogen is converted into nitrates and only two ways that nitrogen is taken out of the soil•There are three different types of bacteria involved in this cycle:

•Nitrifying bacteria•Nitrogen-fixing bacteria•Denitrifying bacteria

NitratesNitrates

Nitrogen in the airNitrogen in the air

SoilSoil

Death and Decay

Death and DecayProteins in

Animals

Proteins in

AnimalsFertilisersFertilisers

Proteins in Plants

Proteins in Plants

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Photosynthesis

Respiration

Combustion

Carbon

Fossil fuels

Decomposers/decomposition

Nutrients

Warmth

Moisture

Oxygen

Lightening

Nitrates

Nitrogen

Nitrogen-fixing bacteria

Root nodules

Protein

Detritivores

Decomposers

Nitrifying bacteria

Leaching

Denitrifying bacteria

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