All plants that flower
produce seeds, and the seeds are surrounded by fruit. The seeds
are the plant's way of reproducing itself. Different kinds of
plants form different amounts of seeds. Some make only one, while
others make many seeds; some make large seeds, others make very
The three kinds of
fruits are berries, drupes, and pomes. Oranges, grapes and tomatoes
are berries. Their seeds are embedded in the flesh of the fruit.
Peaches and plums are drupes. Drupes have one seed enclosed in
a hard case surrounded by flesh. Apples and pears are pomes. Pomes
have several seeds enclosed in a core surrounded by flesh.
apples, oranges, tomatoes, peaches, plums, pears
sturdy plastic knives
pieces of plastic
Demonstration: Cut each of the fruits in half. Show the students
the half pieces of each of the fruits. Help them observe and identify
the placement of the seeds in each piece of fruit. Then have the
students group the fruits according to how the seeds are enclosed.
You may want to introduce the words berry, drupe and pome to your
students. If you do, explain that many fruits aren't commonly
classified using their correct grouping. For example: most people
wouldn't consider an orange or a tomato to be a "berry."
You can also explain that many "vegetables" that we
eat are actually fruits - tomatoes, squash, beans, peppers, cucumbers
- anything that develops from a flower (things like lettuce and
carrots are not fruits). You could also point out that apples
are in the pome group and that the French word for apple is "pomme."
Exploration: Give each
group three pieces of fruit representing the three groups (tomato,
peach/plum and apple), a plastic knife, and a piece of plastic.
Have students cut apart their pieces of fruit on the plastic.
(It may be helpful to pre-cut the fruit for your students.) Then
have the students count the number of seeds in each piece, make
note of the size of the seeds, and record their observations on
a worksheet. After they have finished, compare the results of
the different groups. See if there is any relationship between
seed size and number of seeds (i.e., there are fewer large seeds,
many small seeds). You may want to discuss why this might be (large
seeds have a better chance of success at germinating; small seeds
are not as successful, so the plants makes lots of them to compensate).
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