Reproduction Flashcards
(45 cards)
what is asexual reproduction
a process resulting in the production of genetically identical offspring from one parent
what are the advantages of asexual reproduction
- population can be increased rapidly
- can exploit suitable environments quickly
- time and energy sufficient
- reproduction is completed much faster than sexual reproduction
what are the disadvantages of asexual reproduction
- limited genetic variation in population
- population is vulnerable to changes in conditions and may only be suited for one habitat
- disease is likely to affect the whole population as there is no genetic variation
what is sexual reproduction
a process involving the fusion of the nuclei of two gametes to form a zygote and the production of offspring that are genetically different from each other
what is fertilisation
the fusion of the nuclei of gametes
what is the nuclei of gametes and zygote
haploid for gametes and diploid for zygote
advantages of sexual reproduction
- increases genetic variation
- species can adapt to new environments due to variation- a survival advantage
- disease is less likely to affect population due to variation
disadvantages of sexual reproduction
- takes time and energy to find males
- difficult for isolated members of the species to reproduce
parts of an insect- pollinated flower
sepals, petals, stamens, filaments, anthers, carpels, style, stigma, ovary and ovules
function of sepal
protects unopened flower
function of petals
brightly colored to attract insects
function of anthers
produces and releases the male sex cells (pollen)
function of filaments
holds anther in position
function of style
connects the stigma to the ovary
function of stigma
top of female part that collects pollen grains
function of ovary
produces the female sex cell
function of ovule
in the ovary and it contains the female sex cells
what is pollination
the transfer of a pollen grain from an anther to a stigma
what is self-pollination
the transfer of pollen grains from the anther of a flower to the stigma of the same flower or a different flower on the same plant
what is cross-pollination
the transfer of pollen grains from the anther of a flower to the stigma of a flower on a different plant of the same species
potential effects of self- pollination and cross-pollination on a population
cross- pollination improves genetic variation whereas self pollination reduces genetic variety of an offspring. This is negative because if environmental conditions change it is likely that any offspring will have adaptations that suit the new conditions well.
cross-pollination relies on pollinators whereas wind- pollinated plants do not
what is fertilisation
occurs when a pollen nucleus fuses with a nucleus in an ovule
structural adaptations of insect-pollinated
of pollen grains- moderate- insects transfer pollen grains efficiently with a high chance of successful pollination
petals- large and brightly coloured to attract insects
scent and nectar- present- makes insects visit flower and push stame to get to nectar
# of pollen grains- moderate- insects transfer pollen grains efficiently with a high chance of successful pollination
pollen grains- large, sticky/spiky to attach to insects and be carried away
Anthers- inside flower, stiff and firmly attached to brush against insects
Stigma- inside flower, sticky so pollen grains stick to it when insect brushes past
structural adaptations of wind- pollinated flowers
Petals- small and dull, often green or brown
Scent and nectar- absent- no need to waste energy producing these
# of pollen grains- large amounts- most pollen are not transferred to another flower
Pollen grains- smooth, small and light so they are easily blown by the wind
Anthers- outside flower, swinging loose on long filaments to release pollen grains easily
Stigma- outside flower, feathery to catch drifting pollen grains