LEC17

Question 1

What are the problems with the current changes in ecosystems?

Answer 1

The rate and scale at which humans modify them has drastically increased

Question 2

What are some examples of changes humans have brought to ecosystems?

Answer 2

• Habitat modification
• Nutrient and chemical flows (fertilizers, heavy metals)
• Moving species around the world
• Changing the atmosphere

Question 3

Define

Anthropogenic changes

Answer 3

Major changes to populations, communities and
ecosystems caused by human activities

Not limited to climate change

Question 4

Define

Global Change Biology

Answer 4

The study of rapid and ongoing anthropogenic
changes that have “global scale” consequences

Question 5

Why is it hard to predict effects of
human actions on the world?

Answer 5

1. Multiple drivers and natural variation
2. Lagged effects
3. Feedbacks

Question 6

Give an example of positive feedback

Answer 6

Added CO2 causes the air to absorb more heat, heat creates water vapour, water vapour then traps more heat

Question 7

Give an example of negative feedback

Answer 7

• More vapour creates more clouds
• Clouds reflect light
• Air absorbs less heat

Question 8

How are we changing the environment?

Answer 8

1. Climate change
2. Land-use change
3. Nutrient cycling
4. Chemicals added to the environment

Question 9

Describe the lags and feedbacks affecting climate change

Answer 9

• Lags: ocean heating
• Feedbacks: formation of water vapour, emission of CO2 from biomes, changes in ocean circulation

Question 10

Describe the lags and feedbacks affecting land-use change

Answer 10

• Lags: recovery of plants after the last ice age, extinction debts
• Feedbacks: Fire, water infiltration

Question 11

Describe the lags and feedbacks affecting nutrient cycling

Answer 11

• Lags: plants and algae take time to increase in population, nutrients can cycle in ecosystems for a long time
• Feedbacks: eutrophication can lower oxygen and kill predators (positive); algae/plants dying can remove nutrients

Question 12

Describe

The effects of chemicals added to the environment

Answer 12

• Pharmaceutical drugs enter freshwater ecosystems through humans sewage and agricultural runoff

Question 13

Describe

Acid precipitation

Answer 13

• Creation of acid precipitation, contains sulphuric acid and nitric acid from the burning of wood and fossil fuels
• Air pollution from one region can result in acid precipitation downwind

Question 14

Define

Mitigation

Answer 14

Slowing rates of change/reducing the magnitude of overall change, to give ecosystems and species time to adapt

Question 15

Define

Adaptation

Answer 15

Finding ways to help ecosystems and people adapt to changes