Impact of human activities on biodiversity

Starter: Recap GCSE

Draw images to illustrate how people affect the

planet

What affects population numbers?• People now live longer• Drought can cause crops to fail and lead to famine

and starvation• Disasters like earthquakes and the Tsunami can kill

thousands of people• HIV-AIDS is spreading rapidly in some countries• Better medical care means more babies survive at

birth• Contraception is now available in many countries• New technology means farmers can now grow more

food on their land• People are now vaccinated against many diseases

How many people are alive on Earth now?

•More or less than 100 years ago?

•In 100 years will there be more or less people alive on the Earth?

•What is the pattern?

Effects of the population explosion

As more people arrive at the party,,,,

• Less drinks

•Less space

•More rubbish

•Less (fresh) air

Can’t see the wood for the trees

• Woods are not just trees!!!!• YouTube - More Than Just Timber - State of the Forest Episode

1

Stark statistics

•Tropical rainforests cover 7% of the Earth’s surface but account for 50% of all its species

•Present rate of species extinction is between 100 and 1000 times greater than at any point before

Context: conflicting needs/desires

• A study in 1989 (obviously the figures will be much different now) of an Amazon rainforest in Peru showed that each hectare of the forest produces fruit and latex (rubber) with an annual market value of $700. If, however, the trees are cut down, the total value of their wood is $1000. Now, trees can only be felled once, but fruit and latex can be harvest every year. This study into sustainable management can allow governments to be persuaded that more money can be made from rainforests by exploiting them on a sustainable basis than by destroying them, therefore it may be worth their while to preserve them.

Deforestation exam questionDeforestation exam questionAlthough rainforests now cover less then 4% of the land surface of

the Earth, they account for more than 20% of the planet’s net carbon fixation. By comparison, temperate forests are about half as productive (per unit area), while boreal forests (forests of northern latitudes) and grasslands are only a quarter as productive.

A 13 km2 rainforest preserve in Costa Rica has 450species of trees, more than 1000 other plant species, 400species of birds, 58 species of bats and 130 species of

amphibians and reptiles.

In this question, one mark is available for the quality of use and organisation of scientific terms.Making use of the information in the passage and the figure, describe the important features of tropical rainforests and explain why their disappearance is a cause of considerable concern (9 marks).

• (b) 1 high, biodiversity / species diversity ;• 2 deforestation, causes extinction / reduces biodiversity ;• 3 decrease in, size of gene pool / genetic diversity ;• 4 act as carbon, reservoirs / sinks ; R carbon fixation• 5 remove carbon dioxide from atmosphere ;• 6 release of carbon dioxide when wood is burnt ;• 7 less photosynthesis also means less oxygen production ;• 8 transpiration contributes to atmospheric water content ;• 9 destruction of rainforests disrupts water cycle ;• 10 rainforests can be used to supply sustainable crops ;• 11 example of crop ; e.g nuts / rubber / fruits / plant oils• 12 drugs / other useful compounds (may await discovery),

that onlyoccur in rainforests ;

• 13 soils are nutrient deficient and cannot sustain agriculture ;

• 14 increased risk of soil erosion ;• 15 moral responsibility to conserve for later generations ;• 16 ref to indigenous populations / tribes ;• 17 AVP ; e.g. provision of habitats

QWC – clear, well organised using specialist terms ; 1

• award the QWC mark if four of the following are used in correctcontext

• biodiversity transpiration

• deforestation water cycle

• carbon reservoirs / sinks sustainable

• photosynthesisnutrient deficient

Why are the Galapagos

islands important?They are

sometimes called ‘evolution’s workshop’

Galapagos Workshop - Biodiversity Photography: Documenting the Diversity of Life with Stock & Fine-art Images and Video#1070274276_RPKQL#1070274276_RPKQL

What are the issues?

• YouTube - Tourist killers - BBC Environment• YouTube - Alien invasion on the islands - BBC

Environment• YouTube - Managing tourism in the Galapagos

islands• YouTube - The Galapagos Conservation Fund• YouTube - Galapagos Conservation Trust talk

about holidays to the Galapagos Islands

What do you think?

1. The Galapagos is an important tourist site

2. Tourism to the Galapagos should be banned

3. Conservation should be prioritised over tourism

4. Tourism is the only problem the Galapagos Islands face