B14: Variation & Evolution Flashcards
What is selective breeding?
The process by which humans breed animals for particular genetic characteristics.
How long has selective breeding been going on for?
Thousands of years since they first bred food crops from wild plants and domesticated animals.
What is the process of selective breeding?
Choosing parents with desired characteristics from a mixed population which are bred together.
What are 4 examples of reasons to selectively breed?
Get disease resistance in foods, animals that produce more milk, domestic dogs with gentle nature and large or unusual flowers
What is the main disadvantage of selective breeding?
It reduces the collection of different alleles of the population. It can also lead to inbreeding where some will be prone to diseases as their gene pool is small
Why have plants been genetically engineered?
To be resistant to diseases or produce bigger and better fruit
Why have bacterial cells been genetically engineered?
To produce useful substances such as insulin to treat diabetes
What happens in genetic engineering?
Genes from the chromosome of humans and other organisms can be cut out and transferred to cells or other organisms
What are some concerns about GM foods?
It effects the population of wild flowers and insects. They also think that the effects on human health has not been explored
What are 3 main steps in genetic engineering?
Enzymes are used to isolate the required gene which is inserted into a vector. The vector is used to insert the gene into required cells and genes are transferred to the cells of animals, plants or microorganisms at early stages to they can develop desired characteristics
What is usually a vector in genetic engineering?
Bacterial plasmid or virus
What are disadvantages of gene therapy?
The faulty gene will be in all cells, so putting the healthy gene in all cells would be difficult.
What would be a solution to the disadvantage of gene therapy?
Transferring the gene at an early stage of development, e.g. egg or embryo stage
What are advantages of GM crops?
Used to make crops with more desirable crops (resistant to disease)
What is tissue culture?
Using small groups of cells from part of a plant to grow identical new plants
What is tissue culture important for?
Preserving rare plant species or commercially in nurseries
What are cuttings?
An older, but simple method used by gardeners to produce many identical new plants from a parent plant
What are embryo transplants?
The process of splitting apart cells from developing animal embryo before they become specialised, then transplanting the identical embryos into host mothers
What are the 5 steps of adult cell cloning?
Nucleus is removed from unfertilised egg, nucleus from adult body cell is transferred to egg, electric shock stimulates cell division to embryo. This is then placed into the uterus of the surrogate
What are 3 advantages of cloning via embryos, rather than selective breeding?
Faster, no need for 2 parents and more offspring produced
What are 2 benefits of cloning via cuttings, rather than micropropagation?
Faster and no need for professional expertise or equipment
What is evolution?
The process by which the inherited characteristics of a population change over time due to natural selection
What provides evidence for evolution?
Antibiotic resistance and fossil records
What are disadvantages of inbreeding?
Population is more prone to disease, reduces size of gene pool and rare inherited diseases are more likely to appear
