The Birds and the Bees
When your parents used the euphemistic term "the birds and the bees," they may have actually been talking about human reproduction, but the phrase is synonymous with reproduction for a reason. The birds and the bees are an important part of flowering plant life cycles. To understand how birds and bees fit into plant life cycles, you need to understand how plants work.
Not all plants sprout from seed through sexual reproduction. Some plants reproduce asexually. A small plant may sprout from a "runner," or a branch that grows sideways from a parent plant. A plant may also grow from a tuber or bulb, which is a kind of root. At the end of a growing season, the plant dies back to the tuber, which remains dormant until the next growing season when it produces a new plant. Bulbs and tubers can multiply by dividing themselves or growing new bulbs from their base. Humans can create a new plant by taking cuttings from the old plant's stems or leaves. The plant cuttings can sprout roots and form the base of a new plant.
The most common way for plants to sprout is through sexual reproduction--in other words, from seeds that have been created by a parent plant. Sexual reproduction begins with a flower. Plants that reproduce sexually create a flower in order to facilitate this reproduction. The flower has both male and female parts. The male part is the stamen, which produces pollen. The female part is the pistil. The top of the pistil is called the stigma. The stigma is coated with a sticky substance that can trap pollen grains. When pollen grains stick to the stigma, the stigma then creates a pollen tube, which connects the sperm in the pollen to the flower's ovary. If the flower is not picked, the ovary will form seeds, dry and split open. Some seeds develop inside of fruit, which may be carried away by birds.
In nature, pollination may happen when wind carries the pollen from one flower to another. However, this is not the only mechanism to deliver the pollen. Frequently, flowers have bright attractive petals and nectar that draw in pollinating insects such as bees. As bees move from flower to flower, collecting nectar, the pollen sticks to their bodies and then is transferred to the stigmas of other flowers.