Back to AI Flashcard MakerBiology /LGS A-Level OCR Biology - Unit 6 - Ecosystems Part 3
LGS A-Level OCR Biology - Unit 6 - Ecosystems Part 3
This flashcard deck covers key concepts from Unit 6 of the OCR Biology A-Level syllabus, focusing on ecosystems. Topics include crop rotation, primary and secondary productivity, the carbon and nitrogen cycles, and human impacts on these cycles.
How does crop rotation increase primary productivity?
Stops reduction in soil levels of inorganic ions e.g. K^+ or NO3^-
Tap or swipe ↕ to flip
Swipe ←→Navigate
1/25
Key Terms
Term
Definition
How does crop rotation increase primary productivity?
Stops reduction in soil levels of inorganic ions e.g. K^+ or NO3^-
Crop rotation
Growing a diff. crop in each field on a rotational cycle
How does use of pesticides increase primary productivity?
Prevents loss of biomass and lowering yield of plant
Why do plants need NH4+?
Maintains pH
Why do plants need NO3-?
Part of the nitrogen cycle
Function of K+ in plants
Improves growth of leaves
Related Flashcard Decks
Study Tips
- Press F to enter focus mode for distraction-free studying
- Review cards regularly to improve retention
- Try to recall the answer before flipping the card
- Share this deck with friends to study together
| Term | Definition |
|---|---|
How does crop rotation increase primary productivity? | Stops reduction in soil levels of inorganic ions e.g. K^+ or NO3^- |
Crop rotation | Growing a diff. crop in each field on a rotational cycle |
How does use of pesticides increase primary productivity? | Prevents loss of biomass and lowering yield of plant |
Why do plants need NH4+? | Maintains pH |
Why do plants need NO3-? | Part of the nitrogen cycle |
Function of K+ in plants | Improves growth of leaves |
Function of PO4 3- in plants | Improves growth of roots |
Increasing secondary productivity | Harvesting animals before adulthood; Selective breeding; Animals treated w/ antibiotics; Zero grazing; Keeping environmental temp constant - prevents energy loss through homeostasis |
How does harvesting animals before adulthood increase secondary productivity? | Minimises loss of energy as younger animals invest a larger proportion of energy into their growth |
How does selective breeding increase secondary productivity? | Produces improved animal breeds w/ faster growth, increased egg production and increased milk production |
Zero grazing | Bringing food directly to animals | Maximises energy allocated to developing muscle by reducing need to move |
Processes in the carbon cycle | Photosynthesis; Respiration (animals and plants); Anaerobic respiration (dead organic matter and excreta); Fossilisation; Combustion; Diffusion and carbonic acid formation; Diffusion; Decomposition; Feeding; Sedimentation |
Processes adding to atmospheric CO2 | Respiration; Combustion; Diffusion frm the sea to the air |
Processes removing atmospheric CO2 | Photosynthesis | Diffusion and carbonic acid formation in the ocean |
Sedimentation | CO2 is used by plankton to produce calcium carbonate shells. When these die, their shells sink to the ocean floor and are buried by sediment |
Fossilisation | Organic matter is buried and compressed over millions of years forming gas, coal and oil |
Human interferences that affect the carbon cycle | Combustion; Population size (respiration and waste); Deforestation; Farming |
Effects of human interferences w/ the carbon cycle | Global warming/enhanced greenhouse effect; Ocean acidification from carbonic acid; Warmer sea - less CO2 absorbed; Removing photosynthesisers; Releasing more CO2 through combustion of trees |
Processes in the nitrogen cycle | Nitrification; Assimilation; Denitrification; Nitrogen fixation by organic and non-living processes; Ammonification |
What is nitrogen fixing? | Conversion of atmospheric nitrogen (N2) into nitrogen containing compounds |
Nitrogen fixing | Carried out by denitrifying bacteria (Azobacter) and mutualistic bacteria (Rhizobium) in plant root nodules. Nitrogenase reduces N2 to NH3 to form amino acids; Atmospheric fixation; Haber process to make chemical fertilisers |
Atmospheric fixation | Converting nitrogen gas into nitrates by lightning. The energy from lightning breaks the N2 into atoms which combine w/ oxygen and dissolve in rain |
Ammonification | Converting nitrogen containing compounds (e.g. urea from urine) to NH3. Carried out by decomposers |
Nitrification | Conversion of ammonium ions to nitrites (by Nitrosomonas) and then into nitrates (by Nitrobacter) by nitrifying bacteria (chemoautotrophs) |
Assimilation | Nitrates in the soil are absorbed from the soil by plants and algae. Animals then eat plants and assimilate nitrogen compounds too |