B8 Flashcards
define asexual reproduction
process resulting in production of genetically identical offspring from one parent
type of reproduction in bacteria, yeast, sea anemone
asexual
- cell division (binary fission)
- budding
- split in half, grow to form individual
define sexual reproduction
- process involving fusion of nucleus of two gametes to from a zygote
- production of offspring that are genetically different from each other
define species
group of organisms that can reproduce to produce fertile offspring
is nucleus of gamete complete?
no, it is haploid
is nucleus of zygote complete
yes, it is diploid
what is haploid
haploid cell only has one set of chromosomes
what is diploid
diploid cell carries two sets of chromosomes, one from each parent
advantages of asexual reproduction
- less energy used
- easier production of new plants
- species able to populate area quickly
- desired characteristics retained
- reproduction is faster
- only one parent needed
disadvantages of asexual reproduction
- more susceptible to disease
- more vulnerable to environmental change
- any non-beneficial trait will be passed on
- only suitable to one type of environment
advantages of sexual reproduction
- genetic variation, allow adapt to changes in environment
- disease less likely to affect population
disadvantages of sexual reproduction
- lots of energy to ensure successful reproduction
- takes long time
function of sepals
- protect growing flower
- help stop from drying out
function of petals
- attract pollinators to carry out pollination
function of stamens
- produce male gametes (pollen)
- provide correct structures & conditions necessary for transfer of pollen
function of filaments
- hold anther in position
- where it is able to transfer pollen to pollinator
function of anthers
- produce pollen grains
- contain plant’s male gametes
function of carpels
- produce female gametes
- provide correct structures & conditions necessary for fertilisation
function of style
- support & present stigma
- in position where it can receive pollen from other flowers
function of stigma
- trap pollen from other flowers
function of ovary
- contain ovules (contain female gametes)
- develop into seeds after fertilisation
function of ovules
- female gametes produced & contained
what is pollination
transfer of pollen grains from an anther to a stigma
what is fertilisation
occurs when pollen nucleus fuses with a nucleus in an ovule
structural adaptations of insect pollinated plant
- large flower
- colourful, conspicuous petals
- large, sticky pollen
- shorter style ensure stigma enclosed within flower
- shorter filaments ensure anther is enclosed within flower
structural adaptations of wind pollinated plant
- smaller flower
- inconspicuous petals, absent in some species
- smooth, light pollen
- large quantity of pollen
- stigma exposed to air, feathery
- long filaments expose anther beyond flower parts into air currents