sustainability and interdependence Flashcards
(52 cards)
importance of biodiveristy
to maintain a wide variety of genetically diverse species
3 ways to measure biodiversity
species diversity
genetic diversity
ecosystem diversity
3 threats to biodiversity
human exploitation (overexploitation)
bottleneck effect
habitat corridors
explain over exploitation
when resource stock is placed under too much pressure leaving too few mature individuals that could produce the next gen.
explain the bottleneck effect
a sharp reduction in population due to a natural disaster resulting in a change in the frequency of alleles and a decrease in genetic variation
explain habitat corridors
a natural or man-made area of habitat that connects two habitat fragments allowing individuals to move between populations and helps to restore biodiversity
what is a naturalised species
a species which was originally invasive but has become established within the community
Annual weeds
Short life cycle
Rapid growth
High number of seeds produced
Dormant seeds remain viable for a long time
Perennial weeds
Long life cycle
Vegetative reproduction
Storage organs
Cultural control of weed growth (3)
Ploughing- top soil is turned over to bury perennial weeds
Removal of weeds- removed early in life of the crop, allowing the crop to get a head start
Crop rotation- different crops are grown each year to prevent the build up of pathogens
Chemical control pesticides (4)
Insecticides
Fungicides
Molluscicides
Nematocides
2 types of herbicides
Selective- stimulates growth until the plant exhausts its food resource and dies
Systematic- absorbed by the weeds vascular system where it’s transported around the plant and therefore prevents growth
Bioaccumulation
A build up of a chemical in an organism
Biomagnification
An increase in the concentration of a chemical moving between the trophic levels
Biological control
The control of a pest by the introduction of a natural predator
Integrated pest management
A strategy for controlling pests by combing the use of biological, cultural and chemical practices
Selective breeding is used to improve for,
Higher food yields
Higher nutritional value
Pest and disease resistance
Ability to thrive in particular environments
Why are plant field trials used for?
The see the difference in plant cultivars in the same conditions
To see the effect of environmental conditions have on a cultivar
When designing field trials you have to take in account for,
The selection of treatments-used to make a valid comparison
Number of replications- take account for the variability
Randomisation of treatments- to eliminate bias
Consequence of inbreeding
Decreased yield and decreased size
By what means can new alleles be introduced to a plant cultivar that is beginning to show inbreeding depression?
Crossbreeding
What does the Bt toxin do?
It gives plants a greater resistance to pests
factors effecting metabolic rate
Ph
salinity
temperature
why is it important to regulate temperature in the body?
so enzyme controlled reactions occur at their optimum
