Unit 10- Human Factors On The Ecosystem

Question 1

What international agreement has been set up to conserve biodiversity?

Answer 1

CITES- convention on international trade in endangered species

Question 2

What is the purpose of CITES and how does it work?

Answer 2

To promote conservation of species, and avoid extinction by banning the international trade of products from endangered animals and the animals themselves (eg ivory)
Governments now have to grant a license for the trade of animal products and licenses aren’t granted if the species is endangered

Question 3

What is extinction

Answer 3

The permanent loss of all members of a species, either in a localised area or off the earth

Question 4

The population of cod was nearly wiped out due to over fishing in 1970-1990, what measures can be taken to limit the impact of commercial fishing? 5

Answer 4

• setting quotas to limit the number of each fish species caught per year
• limiting more destructive types of fishing (bottom trawling)
• limiting size of mesh on the nets so young fish aren’t caught so can reproduce
• limiting fishing during breeding seasons
• banning fishing of endangered species

Question 5

Fish farms are a good alternative to over fishing, however what are the negatives of fish farming?

Answer 5

• pollution to the local environment from the amount of waste
• large commercial fish are carnivores and need small fish to eat

Question 6

Fish farming was not banned until there was enough evidence and scientists to back up the petition, how are scientific findings accepted? 4

Answer 6

• peer review of findings by scientists in similar fields
• assessment and testing of techniques used to find the data
• scientific agreement that the paper is valid and reliable
• publication in a reputable scientific journal
• presentations at conferences
• publications on websites

Question 7

Why do so many steps need to be taken to ensure scientific findings are accepted?

Answer 7

The process of peer review etc removes bias and misleading conclusions showing that the data is genuine and significant

Question 8

What are the difficulties involved in implementing policies to protect species?

Answer 8

Not everyone involved is able to modify their behaviour and maintain an adequate living standard
International agreements are hard to monitor
Evidence about problems may not lead to a consensus

Question 9

What are the main green house gases?

Answer 9

Water vapour, Methane, carbon dioxide, ozone, CFCs

Question 10

What evidence is there that the worlds climate has increased?

Answer 10

• fossil records show the frequency of ice ages
• dendrochronology, the study of tree rings is used to estimate the climate for past years
• peat bogs preserve evidence from pollen to show the change in vegetation
• ice cores reveal preserved gas bubbles in the ice and gives us the composition of air hundreds of years ago
• temperature has been recorded using thermometers for years now

Question 11

How do tree rings (dendrochronolgy) give us evidence for climate change?

Answer 11

• trees have annual rings due to seasonal growth
• big cells in summer then small cells in winter
• a narrower ring tells us that growth was slow that year suggesting temperature was colder

Question 12

How do ice cores give us evidence for global warming and a change in the air composition?

Answer 12

• the thick ice in certain areas like Antarctica is thousands of years old
• by drilling ice cores many kilometres deep, ice from the past can be collected
• ice cores have rings much like trees which reflect annual rainfall
• also each layer contains tiny gas bubbles of the air at the time the ice was frozen, which can be analysed to see the composition

Question 13

Where are the most accurate recordings of carbon dioxide concentrations recorded?

Answer 13

Mona Loa observatory in Hawaii

Question 14

How can the increasing annual volume of CO2 going into the atmosphere be reduced?

Answer 14

• reducing the production of CO2 from factories
• stopping deforestation
• ## use renewable energy sources

Question 15

What is an anthropogenic change?

Answer 15

A change due to human activities

Question 16

What are the main sources of global warming? And how?

Answer 16

• burning if fossil fuels, releases CO2
• deforestation, increases carbon dioxide conc by reducing photosynthesis
• agriculture, methane is produced by bacteria respiring anaerobically in farm herbivores like cows and in rice farms, since both have increased, methane production has increased
• landfills, the anaerobically respiring bacteria that produce methane also occupy landfills

Question 17

What changes are arising from global warming?

Answer 17

• ice caps melting
• glaciers are retreating as their lower ends are melting
• sea level rising
• ocean currents are changing
• weather

Question 18

What biological factors are affected by global warming.

Answer 18

• increased metabolic rate
• the distribution of species, animals may relocate to a new area to find a climate that’s better suited
• seasonal cycles, plants in certain areas flower early
• farming, temperate regions may be able to grow more tropical crops
• disease, diseases that could once only survive in warmer conditions ave been found in south of England

Question 19

How can the increasing volume of methane being pumped into the atmosphere be reduced?

Answer 19

• recycle waste to reduce landfill waste (providing less energy for bacteria producing methane)
• change livestock diet to reduce methane release
• reduce meat consumption, reducing demand for meat stock