reproduction
- the ability for an organism to produce a new generation of themselves
- asexual : one parent
- sexual : two parents
what is the similarity between asexual and sexual reproduction?
- produce same kind of organisms in order for survival of species
- result in food being produced
what are the differences between asexual and sexual reproduction?
- one parent
- two parents
- one stage : mitosis without fusion of cells
- two stages : meiosis and fertilisation with fusion of two cells
- offspring identical
- offspring genetically different : gametes are formed, alleles are joined in new combinations
- well adapted in unchanging environment
- well adapted to changing environment
- fater reproduction
- slower reproduction
- more energy efficient
- less energy efficient
- no outside agents needed
- pollinators often necessary
- can not adapt to environment
- can adapt to environment
- low possibility of evolution
- good possibility of evolution
what are the advantages of asexual reproduction?
- all individuals can reproduces
- simple and fast process
- very useful in unchanging environment
- favourable mutation can spread rapidly
what are the disadvantages of asexual reproduction?
- no variation
- overcrowding may occur
what are the advantages of sexual reproduction?
- basis of evolution
- better chances at survival
- prevent the spread of disease
- may reduce the chance of inheriting a disease
what are the disadvantages of sexual reproduction?
- high expenditure of energy
- reproduction process is slower
- unfavourable mutations and recessive genes may be expressed
- outside agents may be needed
how does sexual reproduction take place?
- diploid parent produces gametes in gonads by meiosis
- gametes are haploid
- male and female gamete brought together by pollination or mating
- fertilisation takes place
- new zygote is diploid
- mitotic cell division for growth
the gametes
- large and not motile
- male is small and motile
- male : sperm
- female : egg
- male : pollen grain nucleus
- female : egg cell (ovum)
How asexual/sexual reproduction historically has lead to improved food crops
- phenotypic changes
- varieties
- Asexual : no mutations, limitations of bad genes
- grafting : rootstock (good for plants health); scion (superior traits of food production)
how did sexual reproductions improve crops?
- genetic variation
- cross-pollination (variation)
- self-pollination (perpetuate traits)
how can plant breeders use asexual reproduction and engineering techniques to benefit food production and help solve current food crisis?
- asexual propagation limits land size usage
what are the challenges that future food security pose for plant breeders?
- even higher-yielding than at present
- resistant to pests and disease
- drought-resistant and adaptable to different environments
- more efficient soil usage
How could asexual reproduction benefit future crop production?
- propagation is faster
- consistent superior quality
- cheap, easy, quick and in large quantities
- grafting allows for quicker maturity
- micro-propagation is efficient
- commercially important plants mass propagated
- disease-free plants
- all year independent of season
- transgenic plants genetically engineered
