b14: variation and evolution Flashcards
(15 cards)
what is variation
difference in the characteristics of individuals in a population
what can cause variation
genetic causes
environmental causes
combination of genes and the environment
how do new phenotype variants occur
mutations
what is selective breeding
breeding plants and animals for particular characteristics
describe the process of selective breeding
- choose parents with desired characteristics
- breed them together
- choose offspring with desired characteristics and breed again
- continue over many generations until all offspring show desired characteristics
what are the consequences of inbreeding
inherited defects and disease
what is genetic engineering
modifying the genome of an organism by introducing a gene from another organism to have desired characteristics
how have plant crops been genetically engineered
to be resistant to disease, herbicides, pesticides
to produce bigger fruits
to give higher yield
how have bacteria been genetically engineered
to produce useful substances, such as human insulin tp treat diabetes
what are enzymes used for in genetic engineering
cut out the required gene
what is used to transfer the required gene into the new cell in genetic engineering
vector (e.g. bacterial plasmid or virus)
describe the steps involved in adult cell cloning
- nucleus removed from unfertilised egg
2.mnuclus from adult body cell inserted into egg cell - electric shock stimulates egg cell to divide to form an embryo
- embryo develops and is inserted into the womb of an adult female
what is tissue culture cloning
using small groups of cells from plants to grow identical new plants
why is tissue culture cloning important
preserve rare species and for growing plants commercially in nurseries
what is cutting as a cloning method
simple method used by gardeners to produce many identical plants from a parent plant
