Studied by 0 peopleWhat is a mutation?
a change in the genetic material of an organism
What is natural selection?
the process by which evolution takes place. Organisms produce more offspring than the environment can support. Only those that are most suited to their environment will survive to breed and pass on their useful characteristics to their offspring
What is selective breeding?
speeds up natural selection by selecting animals or plants for breeding that have a required characteristic
Describe the process of selective breeding:
1. Choose the parents with the desired characteristics from a mixed population
2. Breed them together
3. Continue with the best of the offspring
4. This continues over many generations until all the offspring show the desired characteristic
What features are desirable in selective breeding?
Disease resistance in food crops or garden plants, animals that produce more meat or milk, domestic dogd and farm animals with a gentle nature, large / unsual coloured or heavily scented flowers
What are the benefits of selective breeding?
new varieties may be economically important by producing more or better quality food, animals can be selected that cannot cause harm eg. cattle without horns
What are the risks of selective breeding?
reduced genetic variation can lead to attack by specific insects or disease which could be extremely destructive, rare disease genes can be unknowingly selected as part of a positive trait leading to problems with specific organisms, can create physical problems in specific organisms
What is a gene?
segment of DNA that codes for a protein that carries genetic information
What is variation?
differences between individuals of the same species
What is adaptation?
a characteristic that helps an organism survive and reproduce in its environment
What is inheritance?
Passing of characteristics from parent to child
What does nature variation depend on?
Genes
Give examples of nature variation:
Blood groups, eye colour, nose shape, sex
What does nurtue variation depend on?
Environment you live in and the conditions an organism develops in
Give examples of nurtue variation:
Hair length, scars
What is genetic engineering?
The transfer of a piece of DNA from one organism to another organism
How is the gene transferred in genetic engineering?
human cell containing the insulin gene in its DNA & a bacterium with ring of plasmid is collected. 2. Insulin gene is cut out of the human DNA using an enzyme. 3. Plasmid is removed from the bacterium and cut open using an enzyme. 4. Insuline gene is inserted into the plasmid by another enzyme. 5. plasmid with insulin gene is taken up by bacterium 6. bacterium multiplies. 7. Bacteria now starts producing insulin which is collected
Give reasons why a crop may be genetically modified:
if crops are grown in areas with many weeds they can be GM to produce herbicides, if crops are eaten by locusts they can be GM to produce pesticides, if crops are located in a dry area they can be GM to become drought resistant, if crops are not productive they can be GM to produce a high yield
What are the benefits of genetic engineering?
Can mass produce desired proteins, can modify crops to be resistant to pests
What are the limitations of genetic engineering?
Expensive process, resistant genes could be transferred to natural populations
What is gene therapy?
Treatment of an inherited disorder by giving the patient a healthy copy of a faulty gene
Give an example of a disorder that can be treated by gene therapy
cystic fibrosis
What is survival of the fittest?
Fittest individuals selected to survive and reproduce and therefore useful traits passed on
What is evolution?
Inheritance of certain characteristics in a population over multiple generations which display the best phenotypes for the environment which could lead to a change in the whole species or the development of a new species
What is speciation?
Formation of new species
What is a gene pool?
All genes and alleles in a population
What is inbreeding?
breeding of closely related individuals
What are the drawbacks of inbreeding?
rare inherited diseases are more likely to appear, reduces the size of the gene pool, population as a whole is more at risk of disease
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