B14 - variation and evolution Flashcards
what is the definition for a species
organisms with similar characteristics that can produce fertile offspring
what is natural selection
where the organism most suited to the environment is more likely to survive and pass on it’s advantageous traits to it’s offspring
what is the process of evolution by natural selection
all populations have variation
some variation leads to advantageous alleles
the organisms with the advantageous alleles for their environment survive
they breed and produce offspring with the advantageous allele
the frequency of the advantageous allele increases each generation
what is selective breeding
humans breeding animals with desired characteristics (e.g. large cows) to produce offspring with those characteristics
what are the pros and cons of selective breeding
pros - produces better food / desirable traits
cons - less variation, physical problems, disease can wipe out whole population
what is genetic engineering
where you insert a gene from one organism into another to give it a certain trait
steps for genetic engineering
1 - cut gene from donor cell, and cut open bacteria plasmid
2 - insert gene into plasmid
3 - put new plasmid back into bacteria
what is a plasmid
a circle of DNA in the cell that can replicate separately from chromosomes
what is a marker gene
a gene that tests if the gene has been inserted properly
what is recombinant DNA
DNA that has been formed by combining genes from different organisms
pros and cons of genetic engineering
pros - can make insulin, proteins or stop diseases
cons - can’t release into wild population, ethical issues
what is plant tissue culture
taking a small sample of cells from a plant and growing it into a full clone of the original plant
what is embryo transplantation
animal with desired characteristics is given hormones to make eggs which are fertilised, eggs are split into single cells and put into surrogate mother
how does adult cell cloning work
putting the nucleus of an adult cell into an empty egg
