Ecology and Ecosystems Flashcards
Discuss the relationship between atmospheric carbon dioxide levels and global temperatures. (6)
greenhouse effect keeps the earth warm
Over time, the earth’s temperature fluctuates naturally
Changes in human activities have led to increases in CO2 concentration
CO2 absorbs longwave radiation, which traps heat
An increase in atmospheric CO2 (concentration) correlates with the increased global average temperature
The use of fossil fuels increases atmospheric CO2
Autotroph (producer)
(auto = self; troph = feeding) Synthesize their own organic molecules from simple, inorganic substances; MOST through photosynthesis - using energy from sunlight and inorganic substances such as carbon, Some through chemosynthesis - using energy from the oxidation of inorganic molecules; ie phytoplankton, cyanobacteria, plants
Consumer
Heterotrophs that ingest organic matter which is living (or that has recently been killed) ie carnivores, herbivores, omnivores, scavengers
Detritivores
Heterotrophs that ingest non-living organic matter such as detritus (dead/ decaying organic matter, faeces) and humus (dead/ decaying leaves mixed in with topsoil); have INTERNAL digestion - recycle nutrients and improve soil conditions; facilitate decomposition; ie earthworms, woodlice, dung beetles
Saprotrophs
Heterotrophs that ingest non-living organic matter such as detritus (dead/ decaying organic matter, faeces) and humus (dead/ decaying leaves mixed in with topsoil); have INTERNAL digestion - recycle nutrients and improve soil conditions; facilitate decomposition; ie earthworms, woodlice, dung beetles
Autotrophs
Self feeding
Organisms which synthesize organic molecules from inorganic sources
Photoautotroph
Photosynthesis
Makes organic compounds using energy derived from the sun
Chemoautotroph
Chemosynthesis
Makes organic compounds using energy derived from the oxidation of chemicals
Heterotrophs
Other source feeding Organisms which obtain organic molecuels from other organisms Consumers Detritivores Saprotrophs
Explain how energy enters, flows through and is lost from food chains/ food webs (and how this limits the number of trophic levels/ biomass at each trophic level).
Energy enters as light - producers transform light energy into the chemical energy of carbon compounds through photosynthesis; compounds are high in energy
Pass from producers to consumers through feeding
Energy is not recycled within a food chain
Energy enters as light and is dispersed as heat
80-90% of energy is lost at trophic level - due to:
energy being released through cellular respiration
Not all tissues are eaten in a food web (hair, bones) so energy is not available for the next trophic level
Some organisms die before being eaten by an organism at the next trophic level
The amount of energy availble to each successive trophic level is only about 10% of the available energy at the trophic level before it. The inefficiency of energy transfer between trophic levels LIMITS the length of food chains and the amount of biomass of higher trophic levels.
Energy stored in organic molecules can be released by cellular respiration to make ATP
This creates a heat byproduct
Living organisms CANNOT transform this heat in usable forms of energy
So it is released into the environment and “lost” from ecosystems
Explain how increasing carbon dioxide levels in the atmosphere can lead to ocean acidification and coral death.
Increase carbon dioxide levels increase the atmospheric temperature
This causes more frequent extreme weather events
Causing changes to ocean currents
This leads to ocean acidification which can kill coral reefs
This further warms temperatures - melting permafrost which has traditionally trapped methane
What results in the greatest loss of energy from food chains
cellular respiration
Describe cellular respiration and energy loss
Energy stored in organic molecules can be released by cellular respiration to make ATP
This creates a heat byproduct
Living organisms CANNOT transform this heat in usable forms of energy
So it is released into the environment and “lost” from ecosystems
Outline the role of methanogenic archaeans in the carbon cycle.
Methanogens produces methane from organic matter in anaerobic conditions
Some of the methan is diffused into the atmosphere or accumulates in the ground
Methane in the atmosphere is oxidized to form carbon dioxide and water
Outline the formation of peat (including the environmental conditions required for its formation)
Peat forms when organic matter is not fully decomposed because of acidic conditions in waterlogged soils
Explain the movement of inorganic nutrients in ecosystems.
Inorganic nutrients cycle within ecosystems
Decomposers break down waste of dead organisms; recycling inorganic nutrients, and complex molecules are broken down into simpler compounds by fungi and bacteria; then they are returned to the soil to be absorbed by plants and made into complex organic compounds again - which are then passed on to herbivores, carnivores, etc
Outline the general characteristics of an ecosystem.
Ecosystem: a community and its abiotic components
They are sustainable (productive and successful over long periods of time)
Recycle nutrients
Energy flows through them
Contain producers and decomposers
