Global Enviro Change :) Flashcards
Hefin timeeee
What are some main drivers of global change historically?
Solar variation Plate tectonics Volcanism Proliferation and abatement of life (rapid changes in population levels) Meteorite impact Resource depletion Changes in Earth's orbit
What does the overwhelming evidence suggest is the cause of current global change?
Growing human population
Demand for energy, food, goods, services and information, and its disposal of waste products
What has global change caused in the past 250 years?
Climate change
Species extinction (also fish-stock collapse)
Desertification and ocean acidification
Ozone depletion and pollution (or Poh-llution am I right? )
What is pollution?
Introduction of contaminants into the natural environment that cause adverse change
This can be foreign substances or naturally occurring
How many people did pollution kill in 2015?
9 million people
How do we measure how toxic pollution is?
Lethal concentration
Lethal dose
What is the lethal concentration?
Lethal concentration is the concentration of the chemical in the air or water that will kill 50% of the test animals with a single exposure
What is the lethal dose?
Lethal dose is the single dose of a chemical that, when fed to a group of test animals or applied dermal, will kill 50% of all the animals.
What does it mean if the effects of pollutants are additive?
Effects of each may simply be added together to indicate overall effect
What does it mean if pollutants have an antagonistic effect on each other?
One pollutant may cancel out or reduce the impact of another
What does it mean if pollutants have a synergistic effect together?
Pollutants combine in such a way that the environmental effects are greater than would be expected additively
What are the four sources of pollution?
Point source (e.g. Poh)
Multi source (e.g. if Poh was cloned and there was loads of Poh’s)
Seeping (if Poh was liquidised)
Spreading (if Poh was a gas)
When does acute pollution occur?
When a large amount of waste matter enters the environment usually from a point source after a one-off accidental event
What does acute pollution generally have a toxic affect on?
Biota
What happens to an ecosystem after an acute pollution event?
After event the ecosystem begins to recover and return to resemble the original situation
What is an example of a common acute pollutant?
Crude oil, which is a blend of many chemical compounds
What are the affects on biota by acute pollution?
Around 90% of sunlight is intercepted
Division of algal cells is inhibited even at very low levels of oil
Food chains are directly and indirectly
What is chronic pollution?
Low-level input into the environment that occurs either more or less continuously or as frequent pulses
What effect does chronic pollution have on its environment?
The environment is constantly under stress, albeit light stress
Ecosystem doesn’t have time to recover and often there is a cumulative effect
What is an example of chronic pollution?
Pesticides
What are pesticides?
Highly toxic chemical substances deliberately introduced into an ecosystem to kill or reduce population size or growth of particular pests or weeds
What are the benefits of pesticides?
Caused major increase in food and other organic products over past 50 years
Reduction in impact of weeds and pests
Improved harvest
Fewer storage losses
Control of human, livestock and crop diseases
What is a negative affect of pesticides and an example of this?
Can unintentionally reduce populations of species not being targetted
In the 60s, DDT was commonly used as a general pesticide
Peregrine falcon population was falling dramatically
High residues of DDT found in the fatty tissues of peregrine carcasses and eggs
What are organochlorines?
Type of pesticide
Broad-spectrum toxins
Remain in environment for a long time
