Selective breeding And Cloning Flashcards
What characteristics are desirable in plants
Increased yield Durable plants Big flowers Medicinal properties Pest/ disease / frost resistant
How can I do selective breeding in plants
- Decide the characteristics you want your plants to have
- Select individual plants that’s have this characteristic
- Cover the flowers of some of the selected plants
- Use a cotton bud to collect pollen from other selected plants
- Uncover the stigmas . Brush the pollen from the cotton bud onto them .
- Some pollen grains grow tubes . This is fertilisation.
- Wait for the seeds to develop
- Collect the plants and seeds
- Wait for the seeds to grow into plants
- Select individuals that have the characteristics you want .Repeat the process over again .
What is selective breeding
Selective breeding is a process used to produce different breeds of animals or varieties of plants that have useful characteristics
Farmers can improve their crop plants or farm animals by the use of selective breeding
Explain what is meant by selective breeding and give 2 examples of its use (6 marks)
selective breeding is when
~ you choose 2 organisms with useful characteristics (more meat or milk )
~ you breed them together
~ look for characteristics in the offspring
~ selective breeding is repeated over generations
Example 1
Plants , wheat plant - stem length
Example 2
Animals , cattle - milk production
Give 3 advantages of selective breeding
It can produce fitter and stronger animals
It can help eliminate diseases
It can provide a sustainable food chain
Give 3 disadvantages of selective breeding
It leads to decreased genetic variation in the population
The population may not be able to adapt to some things and will be at a risk of going extinct
It reduces the gene pool
What are clones
Clones are genetically identical cells or individuals
Give 2 examples of clones
Bacteria , plants and some animals can reproduce asexually to form clones that are genetically identical to their parent
Identical human twins are also clones ( any difference between them are due to environmental factors )
Explain the process of embryo transplanting
Sperm and egg cells are taken from the best bull and cow
They fuse and the egg becomes embryo
The embryo divides by mitosis( an electric shock)
The embryo is separated into individual cells which go on to form new embryos . These contain the same genes
The embryos are implanted into surrogate cows
The cows give birth to calves , which are all clones of each other
How do you clone animals
Remove the nucleus ( enucleate ) from an unfertilised ovum , keep the ovum
Remove the nucleus from a somatic cell (a body cell) , keep the nucleus
Nucleus is put with the enucleated ovum
Electric current to encourage the nucleus to be taken up by the enucleated ovum
The cell will divide by mitosis
After 6 days the embryo is put into the uterus of a surrogate cow
A clone
State 3 advantages of cloning
Make identical copies of organisms that have useful characteristics
Creation of tissues for medical and cosmetic testing
Prevent extinction
State 3 disadvantages of cloning
Ethical concerns about the use of embryos
All cloned individuals are genetically identical so are susceptible to the same diseases
Many failed attempts - takes time
Allele
Each form of a gene
Characteristic
Distinguishing trait , quality or property
Embryo
A group of specialised cells that will become an organism
