SCIENCE 7 UNIT B Topic 3: Cones, Pollination, and Flowers

Cones A dry fruit of a conifer that contains seeds Conifers produce male and female cones Female cones Contain ovules (eggs) Small bumps at the end of the scale in a cone Male cones Contains pollen grains containing sperm

Pollination Wind carries pollen grain to ovule Pollen tube grows down from the pollen grain to the ovule Sperm enters pollen tube and makes its way to the ovule The fertilized seed starts to grow Female cones then mature, open, and release seeds (fall/winter months) Takes up to 2 years for this process to occur Once seeds are released they go into a dormant state until perfect conditions arise and then they germinate

Flowers Can be large, small, bright coloured, dull fragmented or fowl smelling depending on its method of pollination

Parts of a flower There are male and female parts on a flower The male part is referred to as the stamen The female part is referred to as the pistil Both the stamen (male) and pistil (female) are surrounded by petals and leaves Petals- brightly coloured parts that aid in advertising the nectar/pollen Sepals- usually green and are underneath flower, protects the flower before it opens

The Pistil Has 3 parts Stigma Sticky tip that pollen grains land on Style The tube connecting the style to the ovary Where the pollen tube grows down to reach the ovary Ovary Contains ovule (eggs)

The Stamen The stamen has 2 parts Filament A stalk that supports the anther Anther Produces pollen

Pollination (self vs. cross pollination) Self pollination Sperm fertilizes the eggs in the same plant Example: wheat, barley Cross pollination The eggs of one plant are fertilized by the sperm of a different plant of the same species Occurs with help of wind or animals (pollinators) Example: bees, deer, bats, hummingbirds, water, butterflies

Artificial Pollination Artificial pollination is the dusting, often by hand, of fertile stigmas with the pollen from plants with desired characteristics. Pollen from the male stamens is collected and used to dust the stigmas. Again, plants with the most desirable characteristics are selected for breeding in this way. Both techniques can result in rapid and widespread change within populations of organisms.