Observations and results
Did some types of fruit clearly have more seeds than others? Did the cucumbers, squash, tomato and pepper have a lot of seeds, easily over 100 each? Did the apple only have a few seeds, no more than 10?

Fruits are divided into three general groups, with the "simple fruits" group making up the majority we encounter. They're formed from one ovary in one of the plant's flowers. As the ovary turns into fruit, different ovary parts become different fruit parts; when fertilized, small structures called ovules become the fruit's seeds—and more fertilized ovules means more seeds! The other two fruit groups are more complex. In "aggregate fruit"—such as raspberries—multiple ovaries fuse on a single flower. In the third group, called "multiple fruit," many ovaries and flowers unite. A pineapple is a good example of a "multiple fruit."

Cucumbers, melons and squash are simple fruits (they are part of a fruit type called pepo, which are berries) with a firm rind and softer, watery interior. And, as you probably saw, these fruits make many seeds! A zucchini or cucumber can easily have a couple hundred neatly patterned seeds.

Tomatoes, grapes, kiwifruit and peppers are also simple fruits (technically true berries) with fleshier walls and usually very fluid insides—think of how watery a ripe tomato is! Some, like tomatoes and peppers, can have a couple hundred seeds, whereas others, like kiwifruit, can have several hundred! Citrus fruits are berries (a type called hesperidium), too, with leathery rinds and usually only a few seeds.

Similarly, apples and pears also only have a few seeds (10 at most) but are not berries—they belong to a different fruit type, known as pomes, which have some fruit flesh not made from the flower's ovary, but rather from plant tissue near the ovary, which is the same for strawberries.

Cleanup
Dispose of the seeds from your fruit or, if you're motivated and curious, look into how you could grow plants from your seeds. You can eat the rest of the fruit or save it for a tasty, healthy snack later!

More to explore
Plant Structures: Fruit from Colorado State University Extension
How do seedless fruits arise and how are they propagated? from Scientific American
Cache Crop: Rodents May Have Replaced Extinct Megafauna as Seed Dispersers [Video] from Scientific American
Lab 5: Fruits and Flowers from Kellogg Community College
Seed Saving Tips from West Virginia University Extension Service
How Many Seeds Do Different Types of Fruit Produce? from Science Buddies

This activity brought to you in partnership with Science Buddies

4 Comments

1. 1. tommyoctober 05:04 PM 7/20/12

   Interesting stuff but I think the more germaine question is WHY Nature needs so many of certain types of seeds to insure that a fruit or veggie will reproduce? I suspect that if you examine the conditions and environments where these items grow you will find that the ones that grow in the more hostile areas (dry, hot, insects, birds, etc) will produce more seeds. It's similar to humans whereby the average sperm count/ejactulation is 200,000,000 and only one, if that, gets to the endzone. One wonders what is so hostile about the "scenery" along the way to the fallopian tube wherein lurks such danger? If you think those numbers betray quite a foe, consider the horse (2 billion/E) or the pig (4 billion/session). Those are the armies trained for land mines, electrified fences, broken glass or Summer's Eve! Great topic!

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2. 2. Steve3 05:23 PM 7/20/12

   "But, in fact, different plants have different strategies for seed production and dispersal. Some fruits produce many, .... Other fruits put all of their resources into producing and protecting one very large seed."
   
   I think at point smart kids (like me) are wondering why? ¿WHY?
   And are there just two strategies? Lots of small seeds or one big one? Is it a sliding scale? Do long fruits have consistently more and round fruit fewer. Does tree fruit have more or less than bush fruit?
   
   I see that Mr October has beaten me to the question; good on you sir.

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3. 3. Steve3 in reply to tommyoctober 05:30 PM 7/20/12

   There are 365 x 24 opportunities a year for sexual intercourse (er perhaps you could multiply that by 12) but the window of opportunity for a sperm to fertilise appears (opens?)about 13 times a year.
   You could multiply 365x24x12x200,000,000 and realise just 13 of those sperm (+/-) will come to fruition.

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4. 4. donnawanna 11:42 AM 7/21/12

   The vegetable plants purchased at Home Depot and Lowe's this year did not produce vegetables w seed. hmmmmm

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