2016 Flashcards
What are pheromone traps
Layers of straw used to conserve soil water, suppressing weed growth and keeps the crop above soil level
What is crop rotation
plants changing soil types for nitrogen-fixing bacteria to be cultivated to improve soil fertility
what is an introduced pathogen
plasmid containing small amounts of DNA code for the plant to develop resistance
what is mulching
Turning soul over to disperse the nutrients (top soil tends to be less fertile)
Factors that should be standardised in investigating the nutrient content of water (and it’s algae)
- light intensity
- same time length (a week)
- same temp
- same water source
- same species of algae
- same volume of water same time of the year/ season
How can the growth of aquatic algae be measured
Spectrophotometer (immediately after taking the sample and after it’s settled)
Why is biodiversity higher in a larger uncleared area of woodland
- abiotic factors (light, temp, humidity)
- difficult to colonise other areas
- loss of intersperses relationships (predator/prey food chain)
How does the canopy layer affect the plants growing on the woodland floor
- lower light levels
- more humid
- reduced wind velocity
- less strong rain
- dead organic matter
- specialisations to abiotic factors (chlorophyll concentration and pigments- wavelength)
Short term fluctuations in the water table
- precipitation
- weather changes
- abstraction changes
Long term fluctuations in the water table
- climate change
- greater average abstraction rate (more than the recharge rate)
Why is abstracted water not always suitable for irrigation
- if the water table is below the sea level (salt water intrusion)
- salinity above range of tolerance (osmotic dehydration)
Why is aquifer water better for irrigation than rivers
- more reliable/ predictable supply
- less turbid (needs less processing)
- consistent mineral content
- fewer pathogens
Endemic definition
A species that is only found in one area
Why is an eDNA sample better than trapping organisms
- don’t need to capture organisms (less risk of harm)
- no disturbance to the habitat
- gene pool studies are possible
What are some issues with eDNA use as a method
- delayed results
- no population dynamic data
- more complex equipment (requires training)
Why are ground- based surveys used
- ground growth rates monitored
- food data collected
- DNA samples
- blood samples
- can follow organisms with tracking devices
How does global climate change affect polar species populations
Reduced ice means less species that rely on it e.g penguins or polar bears
How does the decrease in one species affect another
- more food resource
- change in predator patterns
- less competition for breeding sites
Why is polyculture more productive than monoculture
- higher yield per area
- more than one product
- reduced risk of species loss from pests/ disease
- more interspecies relations (ecological stability)
Why is manure used in farming
- replace lost nutrients
- increase plant growth (productivity)
How is ph measured
Shaken up in distilled water and left to settle and measured with a calibrated ph meter
How do microorganisms and invertebrates increase agricultural food yields in waterlogged soil
- more aerobic activity (aeration)
- increased decomposition (nutrient cycling)
- more mycorrhizal fungi
- more denitrification
- increased nutrient uptake
Define keystone species with features
- disproportionate effect of a community relative to their abundance
- seed dispersal
- create niches for other species
- increased mineral and nutrient availability
- control abiotic factors
Evidence of overfishing
- the growth/ regeneration rate is low
- smaller mean mass
- younger mean death
- low genetic diversity
How could good net design reduce by-catch
A maximum size limit means that larger species eg dolphins can escape
How do no take zones increase long term catches
- protects the breeding population
- surplus’s repopulated the overfished areas
How do minimum catchable size regulations increase long term catches
- uncaught/ rereleased organisms survive to grow and reproduce
- larger mass when caught (economically profit)
What could cause the decline of bee populations
- changed farming practices
- pesticide use
- climate change/ weather patterns
- changes to interspecies dependence
