D4.2 - stability and change Flashcards
annual horticulture
a plant that grows for one long season and dies during the winter
biomass
mass of an organism, population or community
carbon footrprint
total amount of greenhouse gases produced by a given activity, individual or group of people over a given period of time
biochemical oxygen demand
oxygen needed by bacteria in a body of water
disease vector
an organism that carries a pathogen between hosts, but doesn’t experience symptoms of the disease
herbaceous
a plant that contains xylem and phloem (vascular) but does not have woody tissue
hypoxia
low oxygen concentration that is too low to support life functions
perennial
a plant that survives through winter where the above-ground part dies and growth below the ground occurs in spring
phytoplankton
producers in marine food chains - group of species of bacteria, protists and single-celled plants
primary production
converting inorganic molecules to organic molecules and generating biomass (photosynthesis)
species evenness
measure of relative abundance of a species in a given area
stable ecosystems
ecosystems that have the potential to persist and be sustainable over long period of times, with no changes and no stress on the ecosystem
- allows continued survival of organisms and have high species richness and evenness
what are examples of stable ecosystems?
forest ecosystems and desert ecosystems
what does ecosystem stability depend on?
- supply of energy
- nutrient cycling
- genetic variation of species
- stable climate
what can be a disruption to a stable ecosystem?
- removal of materials
- food availability
- species populations and food chains/webs
- eutrophication
- climate change / global warming
- biochemical processes / rates
tipping point
level of disturbance causes a quick change that is difficult to reverse
how is the Amazon Rainforest an example of a possible tipping point in ecosystem stability?
positive feedback loop
- deforestation causes there to be fewer trees, resulting in decreased transpiration, causing droughts and fires, further decreasing the amount of trees
mesocosms
model ecosystems that allow experimentation of factors affecting ecosystem stability
- can be closed (only energy but not matter is exchanged) or open (matter and energy can be exchanged)