Ecosystems Flashcards
What is an ecosystem?
A functional unit that tends to be fairly sustaining
What is a habitat?
The place with a distinct set of conditions where an organism lives
What is a community?
Various populations sharing a habitat or ecosystem
What is a population?
A group of interbreeding individuals of the same species in the same area
What can ecological factors be broken down into?
Biotic and abiotic factors
What is an abiotic factor?
Give three examples
Non-living or physical and chemical factors
- Solar energy input; affects plants, length of days
- Climate; such as rainfall, winds and temperature
- Topography; types of landscape such as high altitude which would affect climate
- Oxygen exposure
- Edaphic factors; soil pH and mineral ion concentration
- Pollution
- Catastrophes; earthquakes, floods, volcanic eruption and fires
What is a biotic factor?
Give three examples
Living factors that effect a habitat
- Interspecific and intraspecific competition
- Predation
- Disease
- Mutualism; a relationship where both species benefit
‘Biotic factors are usually density dependant’
Explain this
The effects are related to the size of the population relative to the area available
What are density independent factors?
- Factors whose effects does not change proportionally when the population increases or decreases
- This are more typically abiotic factors
What are anthropogenic factors?
Abiotic and biotic factors that are caused by human activity
Why do species survive in a habitat?
They have adaptations that enable them to cope with both the biotic and abiotic conditions in their niche
What is primary succession?
Colonisation of a newly formed habitat where there has never been a community before
Give an example of a pioneer species
- Lichens
- Algae
Another name for population size
Abundance
‘The population sizes of Predator and prey are linked’
Explain this
- As prey population increases, there’s more food for predators so their population increases
- As the predator population increases, the prey population decreases
- Theres now less prey so the predator population decreases
What affects distribution as well as abundance of a species?
Biotic and abiotic factors
ie where a plant can grow and how well it can grow
What is a niche?
The role of a species within its habitat
Includes biotic interactions and abiotic interactions
What happens in primary succession?
- Pioneer species grow because they’re specialised to cope with the harsh conditions of the environment at this stage
- They die and microorganisms decompose the organic material, forming a basic soil
- They soil helps to retain water which allows new species to grow there
- These then die and microorganisms decompose them, making the soil deeper and richer in nutrients
- This allows even more species to grow and the overall conditions less hostile
How does secondary succession differ from primary succession?
- Secondary succession is land that has been cleared of all plants but soil is remains
- Therefore it starts at a later seral stage; starts with the bigger plants instead of the pioneer species
What is climax community?
- The ecosystem is supporting the largest and most complex community of plants and animals it can
- Its in a steady state
What is deflected succession?
A community that remains stable only because human activity prevents succession
What is another name for producers?
Autotrophs
What are tertiary consumers?
Consumers that eat other consumers
Sometimes called top carnivores
What is trophic level?
The position a species occupies in a food chain
What are detritivores?
Primary consumers that feed on dead organic material called detritus
Why isn’t all sunlight absorbed into a plant?
Chlorophyll can only adsorb certain wavelengths
Why are there different pigments in a chlorophyll?
Each pigment absorbs a different wavelength of light so more pigments means a greater amount of light is absorbed
Give the equation and units for calculating gross primary productivity
GPP = NPP + R
KJ m-2 year-1
What is gross primary productivity?
The rate at which energy is incorporated into organic molecules
What is net primary productivity?
The rate of which energy is transferred into the organic molecules that make up new plant biomass
NPP = GPP - R
What are primary consumers?
Consumers that eat plant material
What are heterotrophs?
Organisms that obtain energy as ready made organic matter by ingesting material from other organisms
Why does only 2-10% of energy get passed on from produces to primary consumers?
- Not all available food gets eaten
- Some undigested food is lost in faeces
- Energy used in respiration
