seegongsik
Grade 3 (age 8-9)

grade 3 Plant Life Cycle

Plant one kidney bean in a pot and water it, and a few days later two seed leaves push up through the soil. A stem and leaves grow up from between the seed leaves, a flower blooms, and where the flower fades a pod forms with new seeds inside. This journey from a seed sprouting and growing to leaving new seeds behind is a plant's life cycle. Use the slider to step through the five stages from seed to fruit, and compare plants that live one year with plants that live many years in the lower picture.

From seed to fruit

Seed
🌱 The five stages of the life cycle
①Seed: at the right temperature it soaks up water and gets ready to sprout
②Sprouting: the root grows down first, then two seed leaves come up above the soil
③Growing: the stem lengthens from between the seed leaves and more leaves appear
④Flowering: a flower opens at the end of the stem
⑤Fruiting: a fruit forms where the flower faded, with new seeds inside

What a flower does

🌸 What a flower does
①A flower is where seeds are made
②When pollen lands on the pistil, this is called pollination
③Bees and butterflies carry pollen as they visit flowers for nectar, and in plants like corn and rice the wind carries it
④Only after pollination does a fruit with seeds form where the flower faded

Annuals and perennials

🌳 One year or many?
①An annual sprouts in spring, flowers in summer, makes fruit in autumn, and then usually dies
②Annuals get through the winter as seeds
③In a perennial, the roots or stems survive the winter and grow again the next year
④Kidney beans, sunflowers, rice, and corn are annuals; pine trees, apple trees, roses, and lawn grass are perennials

Summary

A plant's life cycle
Seed → Sprout → Stem·Leaves → Flower → Fruit (Seed)
It starts from a seed and carries on by leaving seeds again
Pollination
Pollen lands on the pistil → seeds inside the fruit
Bees, butterflies, and wind carry pollen and help pollination happen
How many years a plant lives
Annual (1 year) / Perennial (many years)
Kidney beans are annuals, and pine trees are perennials
🎯 Key points
①A plant's life cycle goes seed → sprout → stem·leaves → flower → fruit (seed)
②A seed needs water and the right temperature to sprout, and sunlight too to grow
③Seeds are made only after pollination
④An annual finishes its life cycle within a year, and a perennial lives many years
⑤The seeds in the fruit start the next life cycle

Examples and Unit Test

Example 1
Using seed, sprout, flower, and fruit, how do you put a plant's life cycle in order?
1
A seed sprouts, the stem and leaves grow, and then a flower blooms.
2
A fruit forms where the flower faded, and the seeds inside it carry on to the next life cycle.
▸ Seed → Sprout → Flower → Fruit (Seed)
Because the fruit holds seeds again, the life cycle repeats over and over.
Example 2
What has to happen for a flower to make seeds, and what do bees and butterflies do?
1
Pollen has to land on the pistil, which is called pollination, before seeds can form.
2
Bees and butterflies fly from flower to flower for nectar and carry the pollen stuck to their bodies.
▸ Pollination / bees and butterflies carry the pollen
Insects are not the only helpers: sometimes the wind or birds carry the pollen.
Unit-test style
Which statement about a plant's life cycle is correct?
①A plant's life cycle starts from the fruit
②Seeds are made only after pollination
③An annual plant lives for many years
④A seed does not need water to sprout
⑤A pine tree is an annual plant
▸ ② Seeds are made only after pollination
1
Seeds form only after pollination, when pollen lands on the pistil.
2
The life cycle starts from a seed (①), an annual finishes its life cycle within a year (③), a seed needs water to sprout (④), and a pine tree is a perennial (⑤).
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Animal Life Cycles
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Earth's Appearance

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