Ecosystems 6.5 Flashcards
What is an ecosystem and the components of an ecosystem?
-An ecosystem is a group of living and non-living things and the relationships between them
-Habitat: place where the organism lives
-Population: all of the organism of one species that live together
-Community: all of the populations of different species that live and interact together
What is a niche?
-The role of each species in an ecosystem
What are producers,consumers and decomposers
Producers: Plants (and some bacteria) which supply energy to the other organisms
Consumers: Primary consumers are herbivors and secondary consumers are carnivorous etc
Decomposers: feed on waste material or dead organisms
What are abiotic and biotic factors
Abiotic factors: non-living components of an ecosystem that effect other living organisms
Biotic factors: living components of an ecosystem
What are the different types of changes that can happen in an ecosystem?
-Cyclic changes: changes which repeat themselves in rythym for e.g. tides
-Directional changes: Changes which go in one direction and tend to last longer than the lifetime of the organisms in the ecosystem e.g erosion of coastline
-Unpredictable changes: changes which have no rythym or direction e.g effects of a hurricane
What is a trophic level?
-The level at which an organism feeds in a food chain
How is biomass lost between trophic levels?
-Respiration releases energy, which is lost via heat by the organism
-Not the whole animal can be digested like e.g bones
What is the equation to calculate efficiency of biomass transfer?
Efficiency=Biomass at higher trophic level/ Biomass at lower trophic level * 100
What is the primary productivity of a food chain?
- The rate of production of new biomass by the producers
How do humans manipulate environmental factors to increase net primary productivity?
-Increase light levels to plants: growing plants under light banks and planting them earlier so they get exposed to more light
-Irrigation: controlling the amounts of water given to plants
-Growing plants in greenhouses: higher temperature increases rate of photosynthesis and therefore biomass
-Crop rotation: to avoid depletion of inorganic compounds in soils and therefore maximise biomass
-Spraying pesticides and fungicides
How do Saprotrophs contribute to recycling within an ecosystem and what are the steps in their decomposition?
-They digest dead and waste material which would otherwise remain trapped within the organism helping recycle these nutrients
1. Saprotrophs secrete enzymes onto dead and waste material
2. Enzymes digest the materials into small molecules which are absorbed by saprotrophs
3. Molecules are either stored or respired.
What is Nitrogen fixation in the Nitrogen cycle?
-Although nitrogen gas is abundant in the atmosphere it is very unreactive so plants need a supply of “fixed” nitrogen e.g amonium ions or nitrate ions
-Nitrogen fixation can happen when lightning strikes or the haber process when making fertiliser
-However the main supply is from nitrogen-fixing bacteria which have mutualistic relationships with plants supplying them with fixed nitrogen and receiving carbon compounds in return
What is Ammonification, Nitrification and Dentrification?
-Ammonification: when ammonium ions are released through ammonification by bacteria when decaying dead matter
-Nitrification: when bacteria in soil obtains energy by oxidising amonium ions to nitrates and nitrate to nitrates
-Dentrification: Bacteria converts nitrates back into nitrogen gas usually in waterlogged conditions in order to obtain oxygen
Outline the Nitrogen Cycle?
Why do living things need nitrogen?
-Living things need nitrogen to make proteins and nucleic acid
Outline the Carbon cycle
What are the definitions of a climax community, deflected succession, pioneer species and succession?
-Climax community: the stable community that exists after the process of succession has occured
-Deflected succession: happens when succession is stopped or interfered with e.g when a lawn is mowed
-Pioneer species: the species that begins the process of succession, often colonising the area
-Successsion: progressive change in a community of organisms over time
Describe the stages of succession?
1.A pioneer species develops from bare ground, this is known as primary succession
2. Erosion or rock and build up of dead organic material produce enough nutrients for bigger species to develop and replace the pioneer species
3. Larger species succeed smaller ones until a final stable community (climax community) is reached
Does succession allways start from bare ground?
-No succession can also start from damaged habitats for e.g
Why are all the stages of succession visible on Sand Dunes?
-The sea deposits sand on the beach, the sand nearest the beach is deposited more recently.
-This means that sand much further away has undergone more succession, so it is possible to see all the stages of succession
What are factors you need to consider before sampling with a quadrat?
-Where to place the quadrats to gain samples representative of the whole area
-How many samples to take, enough to accurately represent the area but not too much that it is time consuming
What is a belt transect and an interrupted belt transect?
-Belt transect: Continuous samples are taken along a parallel line (belt) using a quadrat
-Interrupted belt transect: Belt transect but instead of continuous samples the samples are at specific intervals
