Draw the life cycle of an angiosperm along with a brief note on double fertilisation

LIFECYCLE OF ANGIOSPERM
  

Double fertilization:  one fertilization juncture produces a zygote and also a trploid cell. 

Fruits: A developed ovary that encloses the seeds

Flowers: The reproductive structures in angiosperms

Ovules: protected in the sporophylls instead of exposed on the surface


Now take a look at the steps involved in an angiosperm’s life cycle.

1)In the flower’s male parts, the anthers, diploid microsporangium undergo meiosis giving rise to microspores.  These haploid microspores will eventually give rise to haploid pollen grains


2)In the flower’s ovules, the megasporocyst undergoes meiosis creating four megaspores.  Only one of these four megaspores survives and undergoes three mitotic divisions to produce an eight-nucleate embryo sac, or mature megagametophyte


3)Next pollination occurs.  The pollen grain travels to the stigma via wind, insects or other transportational devices.  Once on the stigma it generates a pollen tube down the style.


4)Two sperm travel down each pollen tube into the ovary.  One sperms fertilizes the egg to produce  a zygote and the other fertilizes the central cell to form the endospore.


5)The zygote will give rise to an embryo and will be enclosed with the endospore in a seed.  The endospore gives the embryo energy to germinate.


6)Poison ivy’s seeds are typically dispersed by animals.  However the seeds are buoyant which makes dispersal by water possible as well.


7)Once the seed does germinate, the diploid zygote will eventually turn into another sporophyte. This process is about three years in poison ivy


8)The cycle starts over.