INHERITANCE, VARIATION AND EVOLUTION #2 Flashcards
what are the two factors that influence some of our characteristics
genes and environment
natural selection
start with variation is present in the population due to mutations
the change in conditions (in the question) causes the (mutation) to become an advantage
this means the individuals with the mutation are more likely to survive, breed and pass on the allele for that characteristic to their offspring
the offspring inherit the characteristic
the change in condition must be sustained over multiple generations
what is selective breeding
selective breeding is a process where humans breed plants and animals for desired characteristics
what type of features is selective breeding used for to acquire
disease resistance in food crops or garden plants
animals that produce more meat or milk
domestic dogs and farm animals with a gentle nature
large flowers
the process of selective breeding
from existing stock select the ones that have the characteristics you are after
breed them with each other
select the best of the offspring and breed them together
continue this process over several generations, eventually all the offspring will have the characteristics
limitations of selective breeding
selective breeding greatly reduces the number of alleles in the population
there is less variation between individuals in the population
what is genetic engineering
is to transfer a gene responsible for a desirable characteristic from one organism into another organism so that it also has that characteristic
process of genetic engineering
a useful gene is cut from the chromosome of an organism using enzymes and is inserted into a vector
the gene is then inserted into the chromosome of another organism
this gives it its desirable characteristic
how can insulin be made so that patients do not have to use pig insulin
the gene for insulin production is cut from human dna using enzymes
a bacterial plasmid is cut open with enzymes and the human gene inserted
the plasmids are transferred to bacterial cells which then produce the insulin by protein synthesis
how are gm crops useful
they have had their genes modified to improve the size
quality of fruit
or to make them resistant to disease
problem with genetic engineering
maybe changing the organisms genes might accidently create unplanned problems which could get passed on to future generations
cons for gm crops
may not be safe for human health
transplanted genes can get out into the natural environment
pros for gm crops
certain characteristics can increase the yield
people living in developing countries lack nutrients, gm crops could be engineered to contain the nutrients missing.
what are clones
clones are individuals that are identical to their parents
how to clone plants
tissue culture- take small groups of cells from part of a plant and growing them under special conditions
a mass of identical plant cells form called a callus
each callus cell can be grown into a new plant
name a quick and cheap way of cloning plants
tissue culture
two ways of cloning animals
embryo transplant and adult cell cloning
what happens in embryonic cloning
an embryo is divided into several individual cells
each cell grows into an individual embryo in the lab
transfer embryos into their host mothers, which have been given hormones to get them ready for pregnancy
identical cloned calves are born
in adult cell cloning…….
you remove the nucleus from an unfertilised egg cell,
take the nucleus from a skin cell and insert it into an empty egg cell
give the cell an electric shock so it starts to divide to form an embryo
insert the embryo into a host mother to develop
benefits of adult cell cloning
save animals from extinction
risks of adult cell cloning
limits the variation in a population
ethical reasons
benefits of genetic engineering in medicine and agriculture
medical drugs have been produced
gm crops have been developed that they are resistant to herbicides or to insects
other gm crops grow well in hot places in the world
can improve the growth rate of plants and animals
disadvantages of genetic engineering in medicine and agriculture
insects that are not pests may be affected by gm crops
in the long terms insects may become resistant to pesticides
worry about the effect of eating gm crops on human health
ethical reasons
what two factors cause variation between organisms of the same type
genes
the environment
