CHAPTER 14 Flashcards
what are the two types of variation
environmental and genetic
what causes genetic variations
the fusion of two sets of dna - one from mother, one from father
examples of characteristics influenced only by genes 3
eye colour
inherited diseases
blood group
what causes environmental variation
the conditions and environment organism lives and grows in
definition of environmental variation
differences between organisms of the same species due to differences in their surroundings
definition of genetic variation
the combination of two sets of dna leading to different characteristics in the offspring
examples of characteristics caused by environmental variation 3
suntan
education
height in plants
what are most characteristics caused by
both environmental and genetic variation
what is natural selection
the organisms with the most suitable characteristics for the environment survive and pass on these successful alleles
what is a mutation
a change in genetic code
what does evolution through natural selection suggest
only the most well adapted to an environment will survive and pass on their alleles, leading to changes in the characteristics of organisms
4 key steps in natural selection
mutation of a gene
advantages of survival
breed
pass on genes
what will mutation very rarely lead to
a new phenotype
example of mutation in action
giraffes having long necks to be able to reach leaves
what is the phenotype caused by
genes
what is speciation
development of a new species
how does speciation occur
the phenotype of an organism changes so much that a completely new species is formed
what is extinction
no individuals of a species remain
3 reasons for extinction
new predator
new disease
catastrophic event eg natural disasters
what is selective breeding
breeding two specific parents to produce offspring with a desired characteristic
examples where selective breeding is used 3
cows producing more milk
crops with disease resistance
pets with good temperament
basic process of selective breeding
select parents with desired characteristic breed them together
select the offspring with the best characteristic and breed these continue until all offspring have trait
problems with selective breeding 2
inbreeding causing health problems
new diseases/ changes in the environment - no variation to adapt
what is inbreeding
when two animals that are closely related are bred
what is genetic engineering
altering the genetic material of an organism by transferring a gene so it has a desired characteristic
what is used to cut out a gene in genetic engineering
an anzyme
what is the removed gene inserted into
a vector
what does the vector do in genetic engineering
it is used to insert the gene into the organisms
process of genetic engineering
the gene is isolated and cut out from one organism
it is inserted into a vector
the vector inserts the gene into the desired cells
the organisms grow with the characteristic
examples of vectors used in genetic engineering 2
bacteria
viruses
examples of where genetic engineering has been used 3
bacteria making insulin
gm crops for a higher yield
gene therapy
what is gene therapy
swapping faulty genes in ill people with working ones to cure the disease
why are crops genetically modified
they have increased yields
frost and pest resistant
main advantage to increased crop yields
can feed growing population
advantages to gm crops
increased yield
more nutrients
can grow in difficult climates
problems with gm crops 3 `
can affect wildflowers
we don’t fully understand health impacts
transplanted genes may mix into environment too form herbicide resistant weeds
what is a clone
something that is genetically identical to its parents
main way of cloning plants
tissue culture
process of cloning by tissue culture
plant cells are put in a growth medium and grow into clones of their parents
advantages to tissue culture 3
made quickly
preserve rare plants
grown all year round
alternative way of cloning plants
cuttings
process of cloning by cuttings
cutting are taken form parent plant and grown to make clones
main way of cloning animals
cuttings are taken form parent plant and grown to make many clones
main way of cloning animals
embryo transplants
process of embryo transplant
sperm cells taken from animals
egg cells taken from another animal
the two are combined to form an embryo
these cells are unspecialised so can become a whole animal
the embryo is split apart and the cells transplanted into the surrogate mother
what is adult cell cloning
when a whole new animal is produced from one cell if an adult animal
process of adult cell cloning
taking unfertilised egg cells and remove nucleus
another nucleus is taken form an adult body cell
the nucleus is inserted into the empty egg cell
the egg cell is stimulated to divide
this created an embryo which is then implanted into the adult female to grow
benefits of adult cell cloning 3
animals that are already producing used proteins in their milk can be cloned
save animals from extinction
bring back extinct species
problems with adult cell cloning
reduced variety in an population - unable to adapt to change
loss of embryo life
‘designer babies’
benefits of genetic modification in medicine 3
potential to cure inherited diseases
insulin and growth hormones can be made from bacteria or fungi
genetically modified mice used to develop cure
benefits of genetic modification in agriculture 3
crops can grow in difficult climates
increase yield pest of frost resistance
