Plant Reproduction: Seed Plants<br />8SCIENCE: Mon. March 14th/Tues. March 15th<br />
Seed Plants<br />Seed plants reproduce sexually <br />Fertilization from male and female sex cells <br />Two types:<br />Gymnosperms<br />E.g. Pine trees with cones <br />Angiosperms<br />E.g. Most have flowers<br />
Gymnosperms<br />Means ‘naked seed’ = needs the cone to protect it!<br />Cones are the reproductive structures on gymnosperms and each species has a different type of cone<br />Male and female cones are produced on the same plant: <br />Female cones have ovules, which contain the egg cells<br />Male cones develop pollen grains, which contain sperm cells<br />
Gymnosperms continued…<br />Male cones release a cloud of pollen<br />Wind usually carries the pollen to the female cone<br />The pollen is trapped by a sticky substance and develops into a pollen tube <br />Grows towards the ovule and sperm can fertilize the egg cell<br />Can take 15 months!<br />
Gymnosperms…there’s more!<br />After fertilization, an embryo forms and develops into a seed<br />When female pine cones mature, they open and release their seeds <br />These can be carried away, or are eaten or buried by animals<br />Buried seeds may grow into new pine trees!<br />
Angiosperms<br />All produce flowers<br />Can be brightly colored or have a nice smell to attract animals<br />Animals like birds (hummingbirds) or insects (bees) can help spread pollen to other flowers <br />When pollen from the stamen lands on the stigma, this is called pollination<br />The same process occurs in gymnosperms, where a pollen tube grows into the ovule and eventually a seed will develop) <br />
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