1. Diversity of Life Investigation 7: Plant Reproduction

2. At the end of Investigation 7 you will be able to:
Define and describe the structures and functions of flowers.
Describe sexual reproduction in plants.
Explain how seed dispersal methods contribute to a plants survival.

3. Investigation 7 - Part 1 Flower Dissection

4. Life on Earth comes in many forms
Life on Earth comes in many forms. In an effort to understand the vast diversity of life, scientists have attempted to organize living organisms into groups. The current system has five primary groups called kingdoms: Monera, protists, fungi, animals and plants.

5. One part of our definition of life is that living organisms reproduce their own kind. The protists we studied reproduce by simply splitting in two. Where there was one a moment ago, there are now two. Plants and animals, however, reproduce differently. With few exceptions they use sexual reproduction.

6. FLOWERS
In order to discover how plants reproduce, we will investigate their sexual structures. Many plants produce flowers. You will work with a partner to observe and dissect the flower to study its structure and design.

7. FLOWER DISSECTION
Let’s watch and listen to instructions on FOSS Web to dissect the flower.
If microscopes are available, you may want to let students who finish their flower mounts early use them to observe parts of the flower in more detail.

8. FLOWER DISSECTION View model mount
In pairs, open text to page 40 for use when dissecting, mounting, and describing parts.
Complete dissection with directions on next slide.

9. Directions Remove sepals; mount one or two.
Remove pedals; mount one large piece.
Remove stamens; mount one or two.
Mount remaining part which is pistil and ovary.
View items with a hand lens for a closer look.
Pull index card out from under tape and lay on top. Close up the sides.
Label and describe the parts of the flower.

10. Paste this copy of Parts of a Flower on your page.
Watch your flower
parts as I read the story of pollination.

11. POLLINATION STORY
The ovary of the flower is where the seeds develop. As we know, seeds contain an embryo, which is the living baby plant that has the potential to grow into a new plant. Seeds start as ovules, tiny preseeds in the ovary.

12. POLLINATION STORY
The ovary is located at the base of the pistil in the center of the flower. Inside each ovule is a single, female sex cell, the egg. Some plants have one ovule in the flower, like a peach or cherry flower. Other plants have hundreds of ovules in the flower, like a watermelon or a tomato flower.

13. POLLINATION STORY
Before an ovule can develop into a seed, the egg must be fertilized.
An egg is fertilized when it joins with a male sex cell, the sperm. The sperm cell is inside the pollen grain. Pollen grains are produced by the plant in the anthers at the tips of the stamens.

14. POLLINATION STORY
The process by which pollen gets from the male anther to the female pistil is called pollination.
Pollination is complete when a pollen grain, carried by air or an animal, lands on the sticky tip of the pistil, the stigma.

15. POLLINATION STORY
The pollen grain then germinates and grows a structure like a root that goes down the length of the pistil. It is called the pollen tube. The sperm cell from the pollen grain travels down the pollen tube into the ovule, and penetrates the membrane of the egg cell.

16. POLLINATION STORY
The contents of the two sex cells mix together, forming a single, fertilized cell. The fertilized cell is alive and has the potential to develop into a new plant. Sexual reproduction happens when a female sex cell (egg) and a male sex cell (sperm) merge to form a single cell with information from both the male and female!

17. POLLINATION Well, it doesn’t seem like plants get around much.
So, if an egg must be fertilized by pollen from a different flower, how does that happen?
How does the pollen get from one flower to another?
Let’s watch “The Life Cycle of a Flowering Plant” video clip. During video, write words/phrases that catch your attention or seem important/interesting. Fill your page.

18. Let’s talk…
Share with your partner the words and phrases you wrote down.
Make a mark by the ones that are the same.
Let’s share whole group.
Now…
Please read the Flowers to Seeds article on pp of the Diversity of Life resource book and answer the questions at the end of the reading.

19. POLLINATION
While we are working, I will call on partners to view pollination images and play the Pollinator Game online. You have apx. 5 minutes.

20. Investigation 7 - Part 2 Seed Dispersal

21. FLOWERS AND POLLINATION
WHAT IS THE PURPOSE OF FLOWERS?
reproduction
WHAT IS POLLINATION?
Transfer of pollen from the male anthers
onto the tip of the female pistil.

22. FLOWERS AND POLLINATION
WHY ARE THERE SO MANY COLORS AND SHAPES OF FLOWERS?
To attract different pollinators
WHAT HAPPENS AFTER POLLINATION?
The egg in the ovary is fertilized by the sperm
from the pollen.
WHAT IS A SEED?
The embryo of a new plant encased in a seed coat along with a supply of energy.

23. FLOWERS AND POLLINATION
What is the purpose of a seed? why is it not a good idea for all the seeds to grow directly under the parent plant?
To grow and produce the next
generation of its kind.
Resources might be diverted
or depleted by the parent plant.

24. SEED DIVERSITY
We know quite a bit about seeds, including where they come from, their basic parts, what happens to them when they start to germinate, and the roles played by the parts of the sprouting seed. There is a lot of similarity among seeds. But there is a lot of diversity in seeds as well. In what ways are seeds different from each other?

25. SURVIVAL
The ultimate measure of an organism’s success is its survival until it reproduces. Survival depends on the organism’s ability to acquire the resources necessary to stay alive, including air, water, nutrients, energy, and space. Many organisms can move to find the resources they need for survival. Plants have to use other strategies for acquiring resources.

26. SURVIVAL
One important strategy for survival is growing in a location where there is little competition for resources. In many cases this means starting life some distance away from the parent plant. Seeds are not rooted in the ground. This is the only time in a plant’s life when it can move. Seeds must have ways to get away from the parent plant. The features of seeds that allow them to move are called seed-dispersal features.

27. SEED DISPERSAL Have you seen examples of seed dispersal?
What kinds of features do the seeds have to allow them to move away from the parent plant?

28. SEED DISPERSAL
Does anyone have a dog or cat? Have you ever had to remove stickers or burs fro their fur? What are those stickers and burs?
What do your socks look like after a walk through a field in the fall? What are those things?
What happens to dandelions after they go to seed? What are those little fluffy things that blow away?
What do squirrels do with all those acorns they collect in the fall? What are acorns?
These are all seeds.

29. SEED DISPERSAL
Some examples of seed-dispersal features www. fossweb.com Today we are going to look for seeds in nature to see what kinds of features they have for getting around. We are going to take a mini- field trip around the school to look for seeds on plants that are growing there.

30. SEED HUNT Please look at page 47 in your lab notebook.
Please use paper and tape to create a seed collection envelope.
When we return, you will sort your seeds and tape them into the appropriate boxes on the Seed-Hunt Card.

31. SEED HUNT CARD
Share your card with another group. Do you agree with the way that they classified their seeds?
How many different seed-dispersal features did you observe on seeds in this area?
What dispersal mechanisms are used the most by plants in this area?
You may want to let the students plant some of these seeds.

32. RESPONSE SHEET PLANT REPRODETUCTION SELF ASSESSMENT
Please revisit page 45 of your lab notebook. Please make any changes or additions that you think are appropriate.