Topic 10.4 Human effects on ecosystems

Question 1

How have humans influenced ecosystems?

Answer 1

• Increased carbon dioxide and other pollutants causing climate change
• Depleted biological resources e.g. overfishing
• Destruction of habitats for buildings, farmland, resources, etc

Question 2

Define global warming

Answer 2

The gradual increase in the average temperature of the Earth’s atmosphere and surface.

Question 3

How might global warming effect the natural world?

Answer 3

• Temperature, rainfall, light levels etc. all affect survival.
• Habitats may be destroyed by deforestation or flooding.
• Species may need to change their habitat or face extinction

Question 4

Name a treaty and discuss its aims

Answer 4

Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). Regulates trade of living organisms depending on thier classification from vunerable to endangered.

Question 5

Discuss the effect of treaties such as CITES on global biodiversity

Answer 5

Some success at conserving biodiversity by limiting trade of species on the brink of extinction. However many countries haven’t signed up, there are no legal sanctions and the market is still in high demand.

Question 6

What are the main principles behind sustainable living?

Answer 6

Balancing human needs with conservation. Maintaining biodiversity of a habitat while allowing use of the resources there. Minimising effect of human activities.

Question 7

Suggest changes that can be made to improve sustainability

Answer 7

• Reducing global warming; limit carbon dioxide levels by using biofuels and reforesting depleted areas.
• Conserving species such as fish for economic, social, and ethical reasons.

Question 8

How is evidence related to climate change validated?

Answer 8

Papers sent out to other experts for peer review to check for validity. If data and conclusion seem reasonable, results are published in scientific journals. May also be presented at conferences.

Question 9

What evidence has been used to show the global climate has changed?

Answer 9

• The fossil record shows how often the world has gone through ice ages
• Dendrochronology studies trees to estimate climate
• Peat bogs preserve evidence from pollen to show how vegetation has changed
• Ice cores reveal preserved evidence of historical gas compostition and species present
• Temperature have been recorded over the last hundred years