What is ecological efficiency?
Ecological efficiency = % of chemical energy transferred from one trophic level to the next.
What is the formular for energy efficiency?
Percentage efficiency=(net productivity of the organism)/(net productivity of previous trophic level)×100
What is an ecological pyramid?
An ecological pyramid is a diagram that shows the relative amounts of energy or matter contained within each trophic level in a food chain or food web
Three types:
- energy pyramids
- biomass pyramids
- pyramids of numbers
What is an energy pyramid?
Shows the relative amount of energy available at each trophic level - with the different widths
What is a biomass pyramid?
- represents the amount of living organic matter at each trophic level
- typically, the greatest biomass is at the base of the pyramid
What is a pyramid of numbers?
Shows the relative number of individual organisms at each trophic level
Why do ecosystems rely on energy?
The amount of energy available in an ecosystem determines how many organisms can live in that ecosystem.
How does energy enter an ecosystem?
Sunlight is the primary source of energy for ecosystems
What is photosynthesis?
Photosynthesis is the process by which plants, algae, and some bacteria use sunlight to produce glucose and oxygen from carbon dioxide and water
What is cellular respiration?
Cellular respiration is the process by which cells break down glucose in the presence of oxygen to release energy in the form of ATP, along with carbon dioxide and water.
What is ATP?
Adenosine Triphosphate - ENERGY
What is ecological succession? (5)
- ecological succession is the process by which the structure of a biological community changes over time.
- each community changes its environment and is later replaced by another community.
- each successive community is called a sere.- (the first sere is the pioneer community)
- each sere replaces the previous one until finally a stable community, the climax community is formed.
- two types of succession:
- primary
- secondary
What is primary succession?
Primary succession is the process in which plants and animals first colonize a barren habitat
What is secondary succession?
- secondary succession differs from primary succession in that it begins after a major disturbance, such as a devastating flood, wildfire, or human activity that wipes away part of a landscape.
- however, the stages of secondary succession are similar to those of primary succession
What are pioneer organisms?
- pioneer organisms have traits that enable them to live in harsh environments that are often exposed and lack nutrients and water.
- they take advantage of the lack of competition in new or disturbed areas
- pioneer plants are often shade-intolerant and do not compete well with larger plants that have more extensive canopies
What features of pioneer species make them effective colonisers? (4)
- ability to fixate nitrogen
- tolerance to extreme conditions
- rapid germination of seeds
- ability to photosynthesise
Solar energy transfer and transformation in an ecosystem?
Solar energy is captured by producers and transformed into chemical energy during photosynthesis, producing biomass. This energy is then transferred through consumers and decomposers in food chains, with most lost as heat through respiration. The carbon cycle underpins this flow, as CO₂ is fixed into biomass and later released back through respiration, decomposition and combustion.
Describe water cycle?
Water evaporates from surfaces and transpires from plants, then condenses to form clouds and falls back as precipitation. It is taken up by organisms and returned through respiration, transpiration and excretion. This transfers water between the atmosphere, hydrosphere and biosphere.
Describe carbon cycle?
Carbon dioxide is fixed by producers during photosynthesis and transformed into organic molecules that form biomass. It is transferred through food webs and released back into the atmosphere by respiration, decomposition and combustion. This cycle links the atmosphere, biosphere, hydrosphere and geosphere.
Describe nitrogen cycle?
Nitrogen-fixing bacteria converts atmospheric nitrogen into ammonia and nitrates, which plants absorb and build into biomass. Consumers obtain nitrogen by eating plants and other organisms, and decomposers return nitrogen compounds to the soil. Denitrifying bacteria release nitrogen gas back to the atmosphere, completing the cycle.
List the ways carbon is transferred and transformed?
Photosynthesis – Carbon dioxide is transformed into glucose (chemical energy) and incorporated into plant biomass.
Feeding – Carbon in biomass is transferred from producers to consumers through food chains.
Respiration & decomposition – Carbon compounds in organisms are transformed back into carbon dioxide and transferred to the atmosphere by respiration of producers, consumers, and decomposers.
List the ways water is transferred and transformed?
Absorption – Water is transferred from the soil into plants through root uptake and incorporated into biomass.
Feeding – Water in plant and animal tissues is transferred to consumers when they eat.
Transpiration/evapotranspiration – through transpiration/evapotranspiration organisms transform liquid water into water vapour and transfer it back to the atmosphere.
List the ways nitrogen is transferred and transformed?
Nitrogen fixation – Bacteria transform atmospheric nitrogen into ammonia/nitrates, which plants absorb and build into amino acids and proteins.
Feeding – Nitrogen compounds in plant biomass are transferred to consumers.
Decomposition & denitrification – Decomposers transform organic nitrogen back into ammonium, and denitrifying bacteria transfer it to the atmosphere as nitrogen gas.
What are the gross inputs and outputs of photosynthesis?
Gross Inputs:
- Carbon dioxide (CO₂) from the atmosphere
- Water (H₂O) from soil/root uptake
- Light energy from the Sun
Gross outputs:
- Glucose (C₆H₁₂O₆) (chemical energy stored in biomass)
- Oxygen (O₂) released into the atmosphere
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Unit 3 - Topic 1 (Biodiversity)39
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Unit 3 - Topic 1 (Classification Processes)42
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Unit 3 - Topic 2 (Functioning Ecosystems)34
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Unit 4 - Topic 1 (DNA structure and replication)23
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Unit 4 - Topic 1 (Cellular replication and variation)25
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Unit 4 - Topic 1 (Gene expression)38
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Unit 4 - Topic 1 (Mutations)26
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Unit 4 - Topic 1 (Biotechnology)19
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Unit 4 - Topic 1 (Inheritance)15
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Unit 4 - Topic 2 (Evolution)31
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meiosis - cellular replication extra7
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gene expression - extra12
