Second Grade NGSS
Plants, Growth, Pollination

 

Discovering the parts of a flower.

 
SECOND GRADE
FLOWERS AND POLLINATION

OBJECTIVES:
•Exploring the parts of flowers.
• Learning about pollination.  
        

VOCABULARY:
•flower
• organ
• plant

MATERIALS:
worksheet on flower parts
information on pollinators
• magnifying glasses or microscope
• video (lots on u-tube)

BACKGROUND:

Insects, and some other animals, regularly visit flowers for the sugary nectar and protein-rich pollen they produce. This act of pollination is the first step in fruit and seed production. Any insects, birds, and bats act as pollinators. Both the plants and their animal pollinators have developed unique relationships and structures that allow them to successfully interact. For example, the long tongue (proboscis) of moths and butterflies allows them to reach nectar produced deep inside of flowers. In many cases both the animal and the plant benefits from this interaction as the animal obtains food and the plant is pollinated. However, some animals may steal nectar or pollen without pollinating the plant, and some plants can trap and kill pollinators.

Humans also are dependent on insect-pollinated plants for foods, medicines and clothing. Worldwide three-fourths of all food and feed crops require pollinators to reproduce. We can even thank a species of fly for pollinating the cocoa plant that we use to make chocolate!

Successful pollination depends on pollinators finding the right flowers at the right time.

Pollinators locate appropriate flowers by visual and chemical cues. Since the structure of the mouthparts of pollinators differ greatly as do flower structures, the pollinator also has to locate the right type of flower.

Key Points

·         Adaptations such as bright colors, strong fragrances, special shapes, and nectar guides are used to attract suitable pollinators.
·        
Important insect pollinators include bees, flies, wasps, butterflies, and moths
·         Bees and butterflies are attracted to brightly-colored flowers that have a strong scent and are open during the day, whereas moths are attracted to white flowers that are open at night.
·        
Flies are attracted to dull brown and purple flowers that have an odor of decaying meat.
·        
Insects and flowers both benefit from their specialized symbiotic relationships; plants are pollinated while insects obtain valuable sources of food.

PROCEDURE:

Flowers contain many structures.  Not all flowers have all the idealized parts and some are hard to see.  In this activity students will discover the parts of a flower that is available.  We will describe the stamen, style, sepals and petals.

1.     Go over the powerpoint (only three slides).

§  Slide 1.  First review that flowers make seeds using pollen.  Pollenators get food as they travel from plant to plant.

§  Ask them to name a few pollenators they know.

§  Flowers are bright to bring the pollenators to the flower.

§   Slide 2.  Go over the parts of a flower.  Tell them the main four to remember are pistil, stamen, petal and sepal.  Ask them at the end what those four do.

§  Slide 3.  Pass out handout.  Tell them they are going to make a color guide for flowers.  Ask them to color the word petal and then color the petals in the drawing the same color.  It doesn’t matter what color they choose as long as the name and object are the same.  Repeat for other words.

 

2.    Collect flowers that children will dissect.  Use meat trays for the students to perform their dissection. 

3.   
You may want to use a plastic knife or scissor, depending on what plant you have found to dissect.   Ideally it would be good for each child to have their own flower.  You also may want to get 2-4 different flowers and have the students compare amongst.

 

4.    Carefully cut the long way and set them side by side.

 

5.    Compare with the diagram on next page and have them try and take each of the components from the flower.   Petals are modified leaves that surround the reproductive parts of flowers. They are often brightly colored or unusually shaped to attract pollinators. Together, all of the petals of a flower are called a corolla. Petals are usually accompanied by another set of special leaves called sepals, that collectively form the calyx and lie just beneath the corolla.  Sepals protect the flower before it opens and can support the petals when the flower is in bloom

 

6.    You can have the students try to draw their flower and its parts on the sheet.  Flowers are different so the 4 structures can be quite different depending on the species.  Some flowers do not have all parts.

 

7.    Stamens produce the pollen and pistils house the future seeds.  A pistil typically consists of an expanded basal portion called the ovary, an elongated section called a style and an apical structure that receives pollen called a stigma.

 

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