Fertilization

Fertilization is the act of bringing male and female gametes together to create a new life (zygote). Gametes are single strands of unpaired chromosomes.


In the animal world, a female egg comes together with a male sperm for fertilization. Because we are so familiar with that process, many people assume that pollen is the same thing as sperm, but it isn’t. Instead, plants use a method called double fertilization to create seeds for future generations. Before double fertilization can occur, the pollen must make it to the flower.


Pollination

Pollination is the movement of pollen from an anther (male) to a stigma (female). This can occur within a single flower, between flowers of the same plant, or between different plants. Approximately 90% of pollination occurs with the help of other living things, usually beneficial insects. Once a flower is pollinated, the really amazing stuff starts to happen!


Double fertilization
Without getting too technical, flowering plants (angiosperms) use one female cell (gametophyte), also called an embryo sac, and two male cells (sperm) to create a seed. Conifers and other gymnosperm plants work pretty much the same way, but without creating flowers or fruit.

 Did you know that pine cones are actually modified branches?

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Double fertilization (UC Davis)

Once attached to an appropriate flower, the pollen granule germinates, sending a tube down to the female sex organs, or ovum. This tube is used to move male gametes (sperm cells) to the egg cell. One pollen grain fertilizes an egg that becomes the baby plant, or embryo. Another pollen grain fertilizes a different cell, which becomes starchy food for the embryo, called endosperm. So, forget your 6th grade sex ed movie. Flowering plants do it doubly!