What is interspecific competition?
Competition between different species
What is intraspecific completion?
Competition between the same species
What is biodiversity?
Variety of species in an ecosystem
What is the process of eutrophication?
- water leaches into a river/lake
- this increases algae growth
- this covers the surface of the water, blocking sunlight
- this means plants can’t photosynthesise and die
- these are decomposed by bacteria
- bacteria respire, using up oxygen supply
- animals die because of low water concentration level
What are the greenhouse gases?
Water vapour, carbon dioxide, nitrous oxide, methane and CFCs
What is the effect of nitrous oxide and sulfur dioxide?
Acid rain, damages trees, habitats, and lakes
Causes corrosion
What are the issues with selective breeding?
Reduction in genetic variety - vulnerability in some diseases
Genetic defects
What are phosphates important for?
Making DNA & cell membranes
What is magnesium important for?
Making chlorophyll
What are nitrates important for?
Making protiens
What is potassium important for?
Respiration and photosynthesis
What are the advantages of organic fertilisers?
Cheap
Have a greater range of minerals
Releases the minerals over a shorter period of time
What are the disadvantages of organic fertilisers?
Bulky
Slow acting
May contain pests
What are the advantages of inorganic fertilisers?
Fast acting, mineral ions released immediately
Easy to apply
Easy to transport
Have the exact quantities of each mineral ions
What are the disadvantages of inorganic fertilisers?
Expensive, they require constant reapplication
Bad for the enviroment, can be leached and cause eutrophication
What is bioaccumulation?
Build up of toxins in a food chain
What are the advantages of biological control?
Don’t need to reapply
No bioaccumulation
Won’t damage the crop
The pest wont become resistant
What are disadvantages of biological control?
Takes time
Not all the population will be killed
What is diffusion?
Movement of particles from an area of high concentration to an area of low concentration
What will speed up diffusion?
High temperature
Short distance
Large SA: V ratio
High concentration gradient
How do you test osmosis using a lettuce?
- add distilled water to one watch glass and a concentrated salt solution to the other
- take the two separate lettuce pieces and weigh before adding to the watch glasses
- leave for an hour then measure the mass after
How do you test osmosis using visking tubing?
- put the solutons in two separate visking tubings
- weigh them both
- place one in distilled water and the other in a concentrated sugar solution
- measure mass gained / lost
What is the test for glucose, what do you need to do and what is a positive test result?
Benedict’s
Heat in a water bath
Blue -> brick red
What is the test for protiens and what is a positive test?
Buiret
Blue -> purple
