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
What is chlorophenoxy?
Type of pesticide
Herbicides
Chemistry resembles that of plant auxins
Broken down in soil in a few days
What are organophosphates?
Type of pesticide
Highly toxic to humans
Biodegradable and non-resistant, readily broken down
What is biomagnification?
Occurs when an element or chemical compound moves form one compartment to another and occurs at a higher concentration in the second
Occurs when concentration factor >1
What is the concentration factor?
concentration of the pollutant in the consumer / concentration of the pollutant in the diet
Why is plastic pollution an issue?
Slow to degrade
Affects lands, waterways and oceans
Marine animals: entanglement, direct ingestion, chemicals causing interruptions to biological functions
Humans: disrupts thyroid levels
What are microplastics?
Small particles less than 5mm in diameter
Come from variety of sources like cosmetics, clothing and industrial processes
What are primary microplastics?
Manufactured, direct result of human material and product use
What are secondary microplastics?
Fragments derived from the breakdown of larger plastic debris
How many times greater than the background rate is the current rate of extinction?
100 to 1000 times greater
What are the main causes of extinction?
Habitat fragmentation Agriculture Human over-population Deforestation Poaching and hunting
Define biodiversity.
The variability among living organisms from all sources including terrestrial, marine and other ecosystems
This includes diversity within species, between species and of ecosystems
What is genetic diversity?
Total number of genetic characteristics in the genetic makeup of a species
What is genetic variability?
Tendency of genetic characteristics to vary
What is species diversity and its two components?
Number of different species
Species richness and species evenness
What is species richness?
Count of species
What is species evenness?
Quantifies how equal the abundances of the species are
Define ecosystem/ ecological diversity.
Variation in ecosystems found in region or variation in ecosystems over the whole planet
How is total species diversity in a landscape determined (gamma diversity)?
The mean species diversity in sites or habitats at a more local scale (alpha diversity) and the differentiation among habitats (beta diversity)
What is a biodiversity hotspot?
An area of high species richness and of high level endemism : area of high conservation value
Define endemism.
Term used to describe the usually limited geographical distribution of a taxonomic group, usually at family, species or genus level
