Agroecosystems 1 Flashcards
Agroecosystem
The living organisms, physical processes and their intersections in a farming system
Selective breeding
Producing offspring from chosen parents, usually to produce desirable characteristics
Genetic modification
The method of altering an organism’s genetic makeup by artificially introducing genes from another organism, often of another species
Limiting factor
An environmental factor present in insufficient amounts to allow a process to occur at a faster rate. E.g. a nutrient being the limiting factor for plant growth
Biota
Living organisms
Évapotranspiration
The combined movement of water into the atmosphere from evaporation from surface leaves and transpiration form surface leaves
Solar insolation
Sunlight landing on a surface
Hydrological growing season
The length of the year that there is sufficient water to sustain growth
Temperature range
Difference between the minimum and maximum temperatures experienced during the year
Thermal growing season
It’s the season of the year that is warm enough for plant growth
Topography
The 3D shape of the land surface
Aspect
The direction something faces in terms of sunlight
Tenant farmer
A farmer that rents land from owners
Quota
A limit on the number or quantity of items e.g, milk production
Harber process
A chemical process used to manufacture ammonia from which nitrate fertilisers can be made
F1 hybrid
The first generation of offspring produced by breeding varieties. All the offspring have the same combinations of characteristics
True breeding variety
A variety of selectively bred organism where all members are genetically almost identical and produce similar offspring
Asexual reproduction
Production of new organism using genetic material from a single individual. The offspring are genetically identical to the parents
Vegetative propagation
Asexual reproduction. Shoots grow out from parents plant. Where they touch the ground, roots and leaves start to grow and a ´daughter’ plant develops
Micropropagation
Involves growing plants from small pieces of plant tissue in a sterile nutrient medium under carefully controlled conditions
Cross breeding
Producing offspring by mating parents of 2 different breeds or varieties
Cloning
An artificial form of asexual reproduction. Taking the genetic material from a body cell of one individual and implanting it into the egg cell from a different individual so that it develops like a normal fertiliser egg
Hybrid vigour
The good health achieved by breeding between breeds that are not closely related, this reduces the risk of inbreeding and recessive gene diseases
Heterosis
The hybrid vigour produced by breeding between two organisms that are not closely related
Artificial insemination
A form of selective breeding where semen is collected from a chosen male and is inserted artificially into the chosen female to cause her to become pregnant
Embryo transfer
The transfer of fertilised eggs or embryos from a female of rare species into females of a closely related species, this enables more young to be produced than could be achieved through normal breeding. It is also used in livestock breeding
IR8
A Green Révolution rice variety
Green Revolution
The agricultural change since the mid 20th century, in the 1969s, where high yielding cereal varieties were bred to increase food production
Transgenics
The process of artificially transferring genetic material from one organism into an individual of another species
Genetic engineering
The method of altering an organism’s genetic makeup by artificially introducing genes from another organism, often from another species
Cutting (method of asexual reproduction)
Putting the cut end of a stem into damp soil. Roots develop from the current and a new plant is produced that is genetically identical to the original plant
