5.1.3 Agriculture Flashcards
Selective Breeding
Genetic Engineering
The process used to produce animals and plants with desired characteristics. Humans achieve this using cloning, recombinant DNA techniques, gene editing and transgenic technologies (transferring genes from one species to another).
It includes four basic steps:
- Determine the desired trait
- Interbreed parents who show the desired trait
- Select the offspring with best form of the trait and interbreed these offspring
- Continue this process until the population reliably reproduces the desired trait
Genetic Engineering
The molecular technologies used to alter the characteristics of organisms in a targeted/specific way.
Selective Breeding in Plants (+ Three Examples)
Selective breeding is often performed in plants to produce higher-quality food. This includes being larger, more nutritious or having more aesthetically pleasing food products. It is done by collecting seeds from individuals with the desired qualities and cross-pollinating the resulting plants. Wild plants are a resource for genes that may later be used for crop development. In order to conserve this genetic variation, they are collected and stored in seed banks.
Wheat (Triticum aestivum)
- Selected for traits such as high yield, high gluten content and heads that do not shed seeds easily
- One of the first plants to be selectively bred, by William Farrer who used his wife’s hairpins to transfer pollen.
Orange-Fleshed Sweet Potatoes:
- Selectively bred to be rich in provitamin A to prevent malnutrition.
Mung Beans (Vigna radiata)
- Cultivated to be double the size of their wild form and grow upright.
Selective Breeding in Animals (Four Examples)
Sheep have been selectively bred to have a favourable quality and quantity of wool.
Cows have been selectively bred for their quality of milk and cattle for muscle mass.
Poultry have been selectively bred for their body weight and egg-laying.
Domestic dogs are all descended and selectively bred from a wolf species, causing questionable outcomes on their health and welfare.
Australia black tiger prawns were developed by CSIRO and partners to improve growth, survival and pond yields by 50%.
Artificial Insemination (IVF)
Reproductive Technologies
- A process by which a human egg is fertilised with sperm in a laboratory and then implanted in a uterus, resulting in pregnancy if the fertilised egg successfully implants.
- Can be used to treat infertility, prevent certain genetic problems and help members of the LGBTIAQ+ community start a family.
- Can be expensive and success rates vary.
Genetic Modification and Cloning
Reproductive Technologies
An organism’s genome can be altered by transferring the genes from one organism to another.
- In plants, this can increase crop productivity and provide crop resistance to insects and prevent disease.
- In animals, this can improve fertility, and the quality and yield of meat, milk, eggs and wool.
Cloning is a method of producing genetically identical organisms.
Health
Issues with Technologies
Crops usually appear unaffected by a transgene, but animals may experience adverse effects that affect growth rates.
Uncontrollable Pest Plant Species
Issues with Technologies
This is only a concern if the transgene promotes rapid growth and there was a selective advantage to having the genes in a wild environment.
Loss of Biodiversity
Issues with Technologies
The reduction of genetic variation may be harmful with environmental changes. However, genetic modification technology may accelerate the trend of used to re-introduce characteristics into the population specifically with seed banks.
Reduced Genetic Variation
Issues with Technologies
Reducing genetic variation increases the likelihood of detrimental homozygous recessive traits in offspring.
