Download Objective: Students will investigate how plants

Objective: Students will investigate how plants produce seeds. They will compare techniques used in plant
pollination. Through physical demonstration they will role play a pollinator.
Curriculum Links: Grade 7 Interactions within Ecosystems
Grade 10 Sustainability within Ecosystems
Biology 20 Interactions among living things
Method/Approach: Lecture, brainstorming, U-tube video (5:23 mins.), & role play activity
Materials needed:
Handouts provided in the lesson
Yellow and Black pipe cleaners, enough for each student
A bowl, a bag of cheesy, and a bag of gummy bears (black preferred)
Access to the internet and screen to show the youtube video
If possible have a lily plant as a visual aid or artificial plant showing parts of a flower
Explore:
As part of our orchard project this class we wish to examine how seeds and fruits develop. Our hope is that one
day we can harvest fruit from the orchard we are planning to plant here at Beardy’s. So once we plant the trees
and shrubs what happens for the plants to grow fruit?
All living things are meant to reproduce. Animals reproduce through sexual acts, and plants also have sexual
cells. Unlike animals, plants are literally rooted to the spot, so they cannot move to combine sex cells from
different plants; for this reason, species have evolved effective strategies for accomplishing cross-pollination.
What is pollination and cross-pollination?
Ask the students to come up with a definition. (Write this definition on the board - Pollination is the transfer of
pollen from the anthers of a flower to the stigma of the same flower (pollination) or of another flower (crosspollination). It would be great to have a plant such as a lily to show the class the anthers with its yellow pollen
and the sticky stigma. Continue to explain pollination is the first stage in the process whereby the male cells of
the flowering plant gain access to the female egg-cells in order to form seeds. The second part of the process is
fertilization.
Write on the board: Pollination leads to
Fertilization and this leads to the development of
Seeds.
Most plants need help moving pollen from one flower to the stigma (top of the pistil) of another. Wind moves
the pollen from some plants such as grasses like corn. Animal pollinators move pollen for many other
flowering plants. Animals (which includes the largest group we call insects) are known to be good pollinators
of flowers. Have the class brainstorm what insects they think are good pollinators.
(The insects include bees, butterflies, moths, some flies and some wasps.) Explain that the insect group are
invertebrates with exoskeletons and jointed limbs. Next ask them if they know of any birds that pollinate
flowers. (Hummingbirds are also great pollinators.) Lastly what mammal is the best pollinator? (nectar
feeding bats).
Pollination Pictures (handout one)
In the next picture the number one and two show self-pollination. Here the pollen for the same flower is
transferred to its stigma and also from a different flower on the same plant. This type of pollination will result
in fertilization but it often results in weaker plants. Most flowers have some way of avoiding self-pollination
and encouraging cross-pollination.
Number three shows cross-pollination. The pollen from one plant is brought to the stigma of another plant. In
this case stronger and more successful offspring are produced. In cross-pollination the plants must be of the
same species. For example, only pollen from a daisy can pollinate another daisy.
Fruits refer to the plant structure having sweet, edible portions and generally consumed raw. Its main functions
are to enclose and protect the seed and to help in its dispersal.
The pollinators are simply going to the flowers to get nectar and /or pollen to meet their own energy needs.
During this search for themselves they provide an important service to the flowering plants.
All parts of the flower may play a part in pollination but the main organs are the stamens (which hold the
anthers) and the stigma. Each stamen (male organ) consists of a filament and a pair of anthers (pollenproducing sacs). When the pollen grains are ripe the anther walls split and expose them. The stigma is the
receptive surface of the female part of the flower. (Handout the picture sheet of pollination to the students and
go over the pictures with them.)
Since flowers can’t move, they need to be able to attract pollinators or be built so that wind is able to pollinate
them. Flowers attract pollinators like bees, butterflies, insects, and birds with sweet nectar, bright colors, and
shapes and structures. Many flowers are unspecialized and can be pollinated by almost any insect, but more
specialized flowers can be pollinated by only a few species of insect.
Over 90% of all flowering plants and over three-quarters of the staple crop plants that feed humankind rely on
animal pollinators. Bees are the most pollinating insects. In their search for pollen and nectar they visit large
number of flowers – usually all of the same species – and pollinate them.
Get the class to brainstorm some fruits they think are pollinated by bees. After getting a few examples hand out
the sheet showing the great number of fruit, vegetable, spices, nut and oilseed crops.
On one side of the sheet have the food list that bees pollinate and on the other side photocopy the maze that
shows a hummingbird pollinating a flower. Go over the list of plants that are pollinated by bees. Emphasize
how important bees are and that there are many species of bees. To help remember and honour bees get them to
make a model of a bee with pipe cleaners. The instructions are on the handout food list sheet. Demonstrate and
let them do it.
Next they can turn the sheet over and complete the maze. It can be promoted as a race to see which
hummingbird gets to the flower first.
Activity: To remember the importance of the bee in pollination we are going to create our own bee out of pipe
cleaners. Each person needs one yellow and one & ½ black pipe cleaners, and a pencil. Twist the yellow pipe
cleaner and the full black pipe cleaner around each other. Next wrap the twisted pipe cleaners around the pencil
very tightly for the bee’s body. Now slide the bee’s body off of the pencil. Take the other black pipecleaner
and twist it around the bee body to make wings. The students can take their bees home to help them remember
today’s lesson on the importance of pollination in producing food. Students will have to glue on their own eyes
later.
Get the students to put the bee models away. To get their attention back to the pollination topic show the short
video “The bug chicks vimeo” on pollination. (right click on title and open hyperlink to connect) You want the
video episode 5 that lasts 5:23 minutes.
Remind the students the goal of having a productive orchard. Explain to them that most fruit trees need crosspollination for good fruit set, thus you must carefully plan what varieties need to be planted near each other to
allow bees to pollinate the flowers. For us we are lucky that the orchard planning will be done by experts in the
plant world. It is important that we understand that fruit does not just appear magically but needs many factors
to happen correctly. If after a few years we are not getting the fruit we expected then we must bring in experts
to study the problem and explain what may be missing.
Lastly this class we will participate in a simple pollination exercise. Everyone will be given a cheesy. You are
to pick it up with one hand and roll it around in your fingers. Next I will come along with a bowl of gummies.
With your hand that held the cheesy pick out one gummy from the bowl. Place it on your other hand. Does it
have the cheesy powder on it? This quick exercise it to emphasize how pollinators pass on the pollen to
different flowers in the wild. (Let the students know they may eat the gummy and cheesy if they wish now.)
Conclusion:
This class started with us asking how we get fruit from our plants in our orchard. We examined pollination and
discovered that it is essential to produce seeds and fruit in plants. We learned about different types of
pollinators and that flowers have developed ways to attract them. Once the orchard is planted and the flowers on
the plants come into bloom we will know the process that happens for the fruit to develop.
Next class we will learn about the types of plants we are looking at placing in the Beardy’s orchard.