B14 - Variation Flashcards
variation
differences in the characteristics of individuals in a population
variation due to
inherited
-environment
-or both
Natural selection
organisms are in competition with members of the same species
-ones that are at an advantage survive and breed
Variation within a species
genes are inherited
new variants
result of mutation
-Change in dna code
mutations when gametes are formed
affect phenotype
-new variants into genes
mutations rarely
produce an adaptation for the organism
theory of evolution by natural selection
all species have evolved from simple life forms
-produces a change in inherited characteristics
better adapted species
process of natural selection + evolution
- genetic variation within species
- better adapted individuals survive + breed
-alleles that are well adapted are passed on
when do two population split and become their own species
when they can no longer interbreed to produce fertile offspring
rapid change in species due to
a new phenotype which is better suited to the environment
selective breeding
speeds up natural selection by selecting animals or plants for breeding that have a required characteristic
Farmers eg of selective breeding
-select ones with desirable characteristics
-forms a breeding stock
Desirabl characteristics eg
-disease resistant crops
-animals that produce more meat/milk
-gentle nature dogs
-heavily scented flower
con of selective breeding
strange combination of genes that wouldn’t have occured naturally
- reduced variation
-inbreeding
pro of selective breeding
useful organisms have been produced
inbreeding causes
pront to disease + inherited defects
-lack of variation
lack of variation means
-reduces number of alleles
-if conditions are unstable and changes
-won’t be able to cope with change
-death of species
geentic engineering
involves modifying genetic material of an organism
process of genetic engineering
enzymes isolate + cut out required gene
-inserted into vector using more enzymes
-genes are transferred at an early stage
-organism grows to develop this characteristic
vector used genetic engineering
usually bacterial plasmid / virus
plants genetic engineering
desired genes inserted into meristemc ells
-used to produce identical clones
GM bacteria/fungi
-cultred on a large scale
-make lots of protein (insulin)
-but there is a limit to hm protein is made
GM crops
-increases yield + size + nutrition
-resistant to disease/ insect
- resistant to herbicide
GM crops - resistant to insects
-make their own pesticide
GM crops - resistant to herbicide
- farmers can kill weed w/o damaging crops
clone
individual produced asexually and genetically identical to parent
tissue culture = cloning
-expensive
-allows many clones to be made from a small piece of tissue
process of tissues culture
-mixture of hormones to group cells that are needed
-produces a callus
-using hormones/right conditions = stimulates growth of cells to be a new plant
callus
big mass of identical plant cells
Tissue culture pros
-high quality w desired qualities
-used commercially in plant nurseries
-preserves rare plant species
taking cutting
-older + simpler
-produces identicalt o parent plant
-used by gardeners
Cloning cattle embryos process
-fertility hormones to top quality cow to produce may eggs
-fertilise egg w sperm
-embryonic cells are split and transplanted into surrogate
-produces identical twins
Cloning cattle embryos process - fertilisation
-inside a cow and embryos are washed out of uterus
-or eggs are collected and fertilised in a lab
pros of Cloning cattle embryos process
-produces more calves
-produces GM embryos = useful
-carried to places in need (dry areas)
cons of Cloning cattle embryos process
-expensive
-highly skilled work
can mamals reproduce asexually
never
adult cell cloning
-new whole animal is produced from the cell of another adult animal
adult cell cloning proces
- nucleus is removed from unfertilised egg
- nucleus is removed from an adult body cell
- nucleus is inserted into egg cell
-electric shock = stimulates division to from embryonic cells
-embryo is inserted into surrogate
pros of adult cell cloning
-produce useful proteins in milk
-produces medically useful animals
-prevents extinction and brings back species
-clones pet = dna lives on but ethical concerns
risks of adult cell cloning
-cloning human babies = ethical concerns
-reduces variation
benefits of genetic tech
- curing inherited disorders by replacing faulty genes
-produce proteins for humans from GM organisms (insulin) - GM mice to mimic human disease = cure
Pros of genetic tech in agriculture
-improved growth rates of plants
-increase food value + yield
-drought resistant
- herbicide resistant + makes own pesticides
Concerns of genetic tech agriculture
-GM food can affect human diet
- GM organisms on nature
- fears human engineering (designer babies)
Concerns of genetic tech agriculture - GM organisms on nature
- they are infertile = farmers repurchase seeds
-if infertile genes spread damage ecosystems
