Fifth Grade - Science - March - Overview

This month in science, fifth graders study life cycles and reproduction. For many of them, the information on life cycles will be a review of material covered in Second Grade. This unit also deepens knowledge of some forms of reproduction previously studied. By the end of the unit, students should be able to describe the difference between sexual and asexual reproduction. Additionally, they should be able to give examples of asexual reproduction and name the types of reproduction found in plants. Through the use of a flower, students will examine the reproductive parts of a flowering plant and learn the role that each part plays in the plant's reproduction. Finally, students will cover sexual reproduction and reproductive organs in animals. Some of the lessons require materials that you may wish to begin obtaining and preparing as soon as possible.
 

Fifth Grade - Science - Lesson 34 - Life Cycles

Objectives
Define "life cycle."
Recall and sequence the life cycle of a chicken, human, covered-seed plant and frog.
Compare and contrast the life cycle of two of the above organisms.

Materials
One transparency or copy on chart paper of the each of the four graphic organizer wheels (attached)
Answer key for each wheel (attached)

For each cooperative team:
One copy of each of these three graphic organizer wheels: human; covered-seed plant; frog
One copy of the list of life cycle terms (Note that the lists have been printed so that when copied, they may be cut apart to save paper.)

Teacher Background

This lesson acts as a review for material covered earlier in the curriculum, and in it, students are reminded of content they learned in Second Grade regarding the life cycle. In Second Grade, they learned about the life cycle of a plant, chicken, frog, darkling beetle, silkworm and butterfly. This lesson incorportates the life cycle of a human and introduces two terms with which students may not be familiar: fetus and adolescent.
 

Procedure

Tell students that the new science unit they are beginning today is, in part, about a type of cycle. Have students brainstorm different types of cycles with which they are familar. Ask: What do all of these cycles have in common? (Make sure that students note the circular activity of a cycle.) What does the word "cycle" mean? (Answers will vary. Students should, however, understand that the definition has to do with a complete round or recurring series.) What type of cycle do you think the class will be studying?

Write the term "Life Cycle" on the board and tell students to think about its meaning. Then, direct students to briefly discuss with a partner the meaning they give to this phrase. Ask for pairs to share their ideas, then tell students that for the purposes of this lesson and the upcoming unit, "Life Cycle" will be defined as "the development of an organism from birth, to growth, to reproduction, to death." (Write this definition on the board as well.)

Display the transparency or chart of the graphic organizer wheel for the life cycle of a chicken. Tell students that to get them thinking about life cycles, together you will fill out the wheel for the life cycle of a chicken.

Ask: What do you call the tiny organism found within a fertilized egg? (an embryo) Write "embryo" inside the top rectangle of the wheel. Remind students that as the embryo develops, it grows a beak, eyes, feathers and all the other parts that make it look like a tiny chicken. When it is fully developed, it hatches. Ask: What do we call the animal at this point? (a chick) Write this in the second rectangle of the wheel. What is the next stage in the life cycle? (The chick becomes a chicken.) Tell students that the life cycle of the chicken consists of three stages. The chicken, if it's a hen, may or may not have eggs fertilized by a rooster, and go on to lay eggs that will become chicks. Eventually, though, the chicken will die, and this is always understood as the final stage in the life cycle for all organisms.

Ask: Can you think of another creature whose life cycle consists of more than three stages? (Answers will vary.) How many stages do you think humans go through in our life cycle? (Allow for disucssion, but do not provide a definitive answer.) Tell students that they will be completing life cycle puzzles in cooperative teams. Divide the students into groups of three or four, then pass out the group supplies (see Materials). Tell students that the list contains all of the terms they need to correctly fill in the life cycle of a human, a covered-seed plant, and a frog, but these terms have been mixed up. In teams, they will use the terms to fill in each of the three life cycle wheels. They will use every term and will not have any terms left over, so encourage them to draw a line through the terms as they use them. Another strategy students may want to use is to first designate (using letters or symbols) each of the terms as belonging to the human, frog or plant life cycle. Then, they can work from the list with its designations to fill in each wheel. Though one or two of the terms may be unfamiliar to them, if they discuss the possibilities with one another, they should be able to solve the puzzles. Tell them that embryo is on the list three times because it does go in all three life cycles (Hint, hint!). Instruct students to remember to work together to fill in each wheel.

When groups have completed this task, ask them to share their responses. Correctly fill in each of the large wheels on chart paper or the overhead, using students' responses. (Note that students may not have been previously familar with the difference between a human embryo and a human fetus. If they are not, simply explain that within the womb, when the embryo is nine weeks old, it graduates from being an embryo and is called a fetus until born.) Ask: What is the stage of the human life cycle between child and adult called? (adolescence) What is a term that is used more frequently for humans in this stage? (teenagers) Ask students to show by raising their hands if they completed one wheel correctly, two wheels correctly or all three wheels correctly. Congratulate students and thank them for their effort.

Next, leaving the large wheels on display, ask students to think about how these life cycles are alike and different. Direct them to select any two of the three life cycles, and to write two paragraphs: one comparing the life cycles they selected and one contrasting them. They may want to consider the number of stages in each life cycle, the similarity of any stages, the terms for the stages, and the sizes of the organisms and how they change as each goes through the stages. Remind students of the purpose behind comparison and contrast and of proper paragraph form. When students are finished, if time permits, you may wish to have them read their paragraphs aloud as other students complete Venn Diagrams on the board, using the information that is being read. Collect all paragraphs for grading purposes.

Suggested Follow-up Activities

Distribute blank organizer wheels to the class and ask them to draw the organisms within the rectangles as they appear in each of their stages. Under each rectangle, students should write the name of the stage.

Challenge students to research the life cycle of an organism that interests them and to create their own life cycle wheel for this organism. The wheel may be done using terms, pictures or both. Be sure that students title the wheel with the name of the animal they researched, and display completed wheels on a bulletin board entitled "Life Cycles."
 

Fifth Grade - Science - Lesson 34 - Life Cycles
 
 


Life Cycle Terms for the Life Cycle of a Human, Frog and Covered-Seed Plant


 



 
 
 
 
 
tadpole 

plant 

seed 

child 

embryo 

flowering 

frog 

adult 

germination 

embryo 

froglet 

fetus 

fertilization 

embryo 

infant 

adolescent


 

Fifth Grade - Science - Lesson 35 - Asexual Reproduction
 

Objectives
Read to be informed about asexual reproduction.
Correct false statements to make them true.
Propagate a potato to observe asexual reproduction.

Materials
Illustration of a potato plant for transparency (attached and optional)
One copy for each student, or pair of students, of the excerpt from What Your Fifth Grader Needs to Know (attached)
One copy for each student, or pair of students, of the false statement worksheet (attached)
One copy for each student or pair of students, of the answer key (attached and optional)

For each cooperative group:
One section cut from a potato, to include a white growth frequently called an "eye" (see Teacher Background)
A jar
Enough potting soil to fill the jar to a level 1 to 2 inches from the rim
Approximately cup water (just enough to make the soil moist)
A large food storage bag (optional)
Masking tape (optional)

Suggested Books

Student Reference

Coldrey, Jennifer. Discovering Fungi. New York: The Bookwright Press, 1988. Chapter 3 is all about the reproduction of fungi and has lots of information about spores as a form of asexual reproduction.

The Visual Dictionary of Plants. New York: Dorling Kindersley, Inc., 1992. On page 48 there is a detailed description of asexual vegetative reproduction. The photographs on pages 48 and 49 allow students to see plenty of examples of this process.
 

Teacher Reference:

Hirsch, E.D. What Your Fifth Grader Needs to Know. New York: Doubleday, 1993. Contains background for today's lesson.
 

Teacher Resource:

VanCleave, Janice. 201 Awesome, Magical, Bizarre & Incredible Experiments. New York: John Wiley & Sons, Inc., 1994. A variation of potato propagation is on page 27.

Wood, Robert W. Science for Kids: 39 Easy Plant Biology Experiments. Blue Ridge Summit, PA: TAB Books, 1991. A variation of potato propagation, with excellent illustrations, can be found on pages 87-89.
 

Teacher Background

In this lesson, students are reminded that all living things reproduce themselves. There are two forms of reproduction: sexual (involving the use of male and female cells) and asexual (without the use of male and female cells). In today's lesson, students learn about forms of asexual reproduction and through an activity, observe a form of asexual reproduction, propagation.

In preparation for the students to propagate the potatoes, about a week prior to this lesson, place the potatoes in a dark closet. The potatoes should grow small white spots ("eyes") within a week. You may also want to put the potting soil for each cooperative group into a large food storage bag prior to the lesson to make its distribution easier.

Procedure

Ask students to recall the life cycles they completed in Lesson 34. Each life cycle started at the top of the page and moved in a clockwise direction around the various stages in each organism's life. In between the last stage and the first one, on each life cycle, there were three words. Ask: Does anyone remember what those words were? ("creates a new") What did these words mean? (that the adult organism made a new organism) What would happen if no new organisms were created? (All of a species would die and the species would become extinct.) In order to prevent this from happening, all living things reproduce themselves. Ask: What does it mean to reproduce (write on board)? (to make again, or to copy) Reproduction is the process by which organisms create new organisms like themselves. Organisms have different means of reproduction. Students already know about some types of reproduction: plants make seeds, chickens lay eggs, and in the last unit, they learned how cells divide to reproduce themselves. Tell students that in the next several lessons, they will be learning more about different types of reproduction.

Ask students to recall the most recent time they took a test or filled out a form that required them to fill in their name, age or birthday, and sex. Ask: What did you write under "sex?" (whether you were male or female) Tell students that in today's lesson, they will be learning about asexual reproduction. "Asexual" means without sexes, in other words, reproduction that does not use male or female cells. To learn about types of asexual reproduction, they will first do some reading, then complete an activity.

Pass out copies of the excerpt from What Your Fifth Grader Needs to Know and the false statements to pairs or individuals. Direct them to read the passage, then to correct each false statement by rewriting it to make it correct. When students are finished, review their answers with them, and allow students who had time to do the extra credit to read their false statements out loud and to call on classmates to correct them.

Next, tell students that they will be participating in an activity that will allow them to witness asexual reproduction in action. Take out the potatoes and ask: What type of asexual reproduction do you think a potato plant completes? (budding) Tell students that in nature, as a potato plant grows, its root system also grows. Underground tips of the roots grow into large food storage centers called tubers. (Show students the transparency of the potato plant, or draw its likeness on the board.) The tuber of the potato plant is the part we call a "potato" and eat, though the plant was planning on using it as a food storage center not for us, but for new potato plants. On each tuber, there are small dented spots, out of which new potato plants can grow. These small spots are the stem and leaf buds. These buds are spread out over the surface of the tuber, and each section of the tuber that has one contains enough stored food to keep the bud growing until its green leaves are large enough to take over food production for the new plant.

Tell students that you have kept these potatoes in a dark closet to make them "think" they were underground. These tubers, thinking they were in soil, have begun to bud. (Show students the small white spots.) Tell students that to observe budding, a form of asexual reproduction, they will receive, in teams, one of the buds and the material they need to make it grow into a mature potato plant. Ask: What do you think the bud will need to grow? (soil, water, sunlight)

Tell students you will now divide the potatoes up into sections so that each team will get a bud. As you cut the squares containing at least one eye out of the potatoes, ask: Why do I need to cut a large section out of the potato in order for the bud to grow? Why can't I just slice the thin layer of skin that contains the bud itself? (The cut section of the potato needs to contain enough food for the bud to allow it to survive until it has enough green leaves to take over food production for itself.)

Divide the class into groups of three or four, and assign one person in each team to be in charge of materials. This materials person should come to you to collect a jar, enough potting soil to fill the jar, and a section of the potato. Instruct teams to fill the jar with the potting soil, then to bury the potato section, with the bud facing up. The bud should be about 1 inches below the surface of the soil. Teams should then moisten the soil with water. The soil should continue to be kept moist, not wet. Students in each group may want to write their initials on a strip of masking tape and affix it to their jar to keep track of whose jar is whose.

Once students have cleaned up and placed their jars out of the way in an area that receives either sunlight or fluorescent light, summarize the lesson by asking the following questions. What do you think will happen over the next several weeks to the bud? (It should grow and become a potato plant.) Why is this an example of asexual reproduction? (No male or female cells were used.) What are some other examples of asexual reproduction? (fission, spores, regeneration, cloning) Which one of these forms describes the cell division you learned about last month? (fission, which means "splitting") Compliment students on the knowledge they acquired in today's lesson, and tell them that they will need to continue to make sure that the soil within their jars stays moist. Together, you will watch their jars for any changes that may occur.
 

Suggested Follow-up Activity

Obtain a mushroom for each small group. Point out the gills on the underside of the cap and tell students that this is where the spores are produced. Direct students to carefully break the stem of the mushroom off of the cap. The cap should then be laid, gill side down, on a sheet of white paper in an out-of-the-way place, and covered with a glass. The cap should be left like this overnight. The next day, have students carefully lift the glass and the cap. What do they see on the white sheet of paper? (There should be evidence, in the form of a light dust-like material, that the mushroom cap has dropped spores.) Point out to students that this is another example of asexual reproduction.
 
 



Asexual Reproduction

(From What Your Fifth Grader Needs to Know by E.D. Hirsch)


 










One way that organisms copy themselves is through asexual reproduction. "Asexual" means nonsexual; that is, reproduction without using males and females. The organism simply makes copies of itself through cell division.

Asexual reproduction can be very simple. Monerans (the simplest of all organisms) and many protists reproduce by fission, which means splitting. After duplicating their genetic material, monerans like bacteria simply split their single cell in half. This allows them to grow colonies very quickly. Under the right conditions, bacteria colonies can double their numbers every twenty minutes!

Mildews, molds and mushrooms are fungi that reproduce by forming spores. Spores are single cells often protected by a hard covering. Spores drop off the parent, and become new organisms if there is enough water and food for them to live. Most yeasts, on the other hand, reproduce by budding. A "bud," or enlargement, forms on one side of the cell, and eventually breaks off to form a new yeast cell.

Some plants and animals can reproduce themselves asexually in a process called regeneration, meaning to make or generate again. These organisms make new body parts to replace lost ones. In plants, the most familiar example of regeneration is called cloning, in which a piece of the plant--a leaf or stem cutting--is put into some moist material, and a whole new plant forms. Many garden plants like roses are reproduced by cloning, because you can be sure that the new plant is exactly like the parent.

The amount of regeneration that can occur in asexual reproduction depends on the type of organism. You regenerate skin cells when you cut your finger and the wound heals. But for the most part, the human body has little ability to regenerate.

Other animals have a much greater ability to regenerate. A starfish can grow a whole new arm if one is cut off. The lost arm, if it still has a piece of the center of the starfish, can even grow into a new starfish. When certain worms are cut in half, each half grows into a new worm. Salamanders can regenerate a leg if they lose one. The leg can't regenerate a new salamander, though. More complex animals like salamanders and humans have a more limited ability to regenerate.
 
 




False Statements


 









Name(s)______________________________________________
 

Directions: Each of the statements below is false. Using the reading on asexual reproduction, cross out the error in each of the statements below. Then, rewrite each false statement to make it true on the lines provided.
 

1. Monerans and many protists reproduce by regeneration, which means splitting.
 

_________________________________________________________
 

_________________________________________________________
 

2. Mildews, molds and mushrooms are fungi that reproduce by forming buds.
 

_________________________________________________________
 

_________________________________________________________
 

3. Spores are single cells which drop off the parent and become new organisms no matter what the conditions are.
 

_________________________________________________________
 

_________________________________________________________
 

_________________________________________________________
 
 

4. Most yeasts reproduce by budding, in which an enlargement forms on one side of a cell and eventually kills the cell.
 

_________________________________________________________
 

_________________________________________________________
 

5. Some plants and animals can make new body parts to replace lost ones through a process called recreation.
 

_________________________________________________________
 

_________________________________________________________
 

6. In plants, an example of regeneration is cloning, in which a piece of a plant is put into moist material where it forms mold or mildew.
 

_________________________________________________________
 

_________________________________________________________
 

7. If a salamander loses a leg, it can't regenerate a new one.
 

_________________________________________________________
 

_________________________________________________________
 
 


********EXTRA CREDIT********

In the space below, write your own tricky false statement based on the science reading done today. Then write the correction you would expect classmates to provide for it.
 

_________________________________________________________


 








Fifth Grade - Science - Lesson 35 - Asexual Reproduction
 
 


Answer Key: False Statements


 









1. Monerans and many protists reproduce by fission, which means splitting.
 

2. Mildews, molds and mushrooms are fungi that reproduce by forming spores. Students may have also written: Most yeasts reproduce by forming buds.
 

3. Spores are single cells which drop off the parent and become new organisms if there is enough water and food for them to live.
 

4. Most yeasts reproduce by budding, in which an enlargement forms on one side of a cell and eventually breaks off to form a new yeast cell.
 

5. Some plants and animals can make new body parts to replace lost ones through a process called regeneration.
 

6. In plants, an example of regeneration is cloning, in which a piece of a plant is put into moist material where it forms a whole new plant.
 

7. If a salamander loses a leg, it can regenerate a new one.
 

Fifth Grade - Science - Lesson 36 - Sexual Reproduction in Plants
 

Objectives

Describe the difference between asexual and sexual reproduction.

Examine reproductive parts of a non-seed, naked-seed and covered-seed plant.

Listen to the process by which non-seed, naked-seed and covered-seed plants reproduce.
 

Materials

The life cycle of a fern, for transparency or drawing on chart paper (attached)

The pollination of a pine cone, for transparency or drawing on chart paper (attached)

For each cooperative group

A mature fern frond with spore caps on its leaves' undersides (can be obtained from a florist)

One pine cone (can either be obtained commercially or found outdoors)

One pea pod with peas inside

A magnifying glass (optional)
 

Suggested Books

Student Reference

Burnie, David. Eyewitness Books: Tree. New York: Alfred A. Knopf, 1988. Cones are addressed comprehensively on pages 44-45 with lots of photographs to clarify the concepts covered.

The Visual Dictionary of Plants. New York: Dorling Kindersley, Inc., 1992. Though the vocabulary pertinent to today's lesson is a bit sophisticated for fifth graders, the photos of the reproductive parts of naked-seed plants on pages 16-17 are outstanding.

Wexler, Jerome. From Spore to Spore: Ferns and How They Grow. New York: Dodd, Mead & Company, 1985. This book has lots of photographs showing the reproductive process of ferns, and the text is appropriate for fifth graders.

Teacher Reference

Hirsch, E.D. What Your Fifth Grader Needs to Know. New York: Doubleday, 1993. Contains background for today's lesson.
 

Teacher Background

In today's lesson, students learn about sexual reproduction within the plant kingdom. They are given materials that contain reproductive parts of a non-seed (fern), naked-seed (pine) and covered-seed (pea) plant. After examining each, students listen to a description of its role in the reproduction of the plant.

In Second Grade, students dissected a seed and looked at the plant embryo contained within. Through this activity, they became familiar with various parts of a seed. The Second Grade curriculum also taught them that egg cells must be fertilized by pollen to grow into seeds, and allowed them to compare a chicken egg to a seed.
 

Procedure

Begin today's lesson by asking students to tell you what the subject of the last science lesson was. (asexual reproduction) Ask: What is asexual reproduction? (the creation of a new organism without the use of male or female cells) Knowing this, then, how would you define sexual reproduction? (the creation of a new organism using male and female cells) Tell students that indeed, sexual reproduction requires the joining of male and female cells before reproduction can occur. These special male and female cells are called gametes. (Write on board.) The male gamete is typically called sperm, and the female gamete is typically an egg. (Write both on the board, under gametes.) When the sperm and egg come together, we say that fertilization (also write on board) has taken place; the egg is now fertilized.

Tell students that today, they will be learning more about sexual reproduction in plants. Put the students into groups of three or four and tell them that you will be giving them a section of a plant that contains its reproductive parts. Their job is to carefully examine the plant section to try to find the parts that play a role in reproduction. (You may want to write this task on the board.) They may take apart any pieces of the plant that they would like to, but should do so carefully, so as not to destroy the reproductive parts. Pass out the fern fronds and allow students to begin to examine them. If magnifying glasses are available, pass these out as well to aid in the students' investigation. After a minute or two, ask if any groups have found what they believe to be the reproductive parts of this plant. If no group suggests the spore caps on the undersides of the leaves, show them to the students, and tell them that these are the reproductive parts of a fern.

Display the transparency or chart of the life cycle of a fern. Tell students that although the reproductive parts of a fern are called spores, they are different from the spores they learned about in the last lesson, which were a form of asexual reproduction. Direct students' attention to the drawing of the fern frond at the top of the cycle. Tell them that the picture shows a mature fern frond which has created spore caps, just like the ones they have. The next picture shows the spore cap releasing its tiny spores. Each one of these spores is a single cell! When the fern spores get wet, they germinate, or begin to grow, and become tiny heart-shaped plants that produce both male and female gametes (continue to point to the appropriate stages on the life cycle wheel). When these male and female gametes come together, the fertilized egg grows into a new stage of the fern life cycle in which it is called a gametophyte. This tiny plant will grow into the large fern you may find growing in the woods. When the fern is mature, it will produce spore caps and the whole cycle will begin again.

Tell students that although they can see the spore caps, the spores themselves are very tiny and hard to see. For a long time people thought that ferns grew from seeds that were invisible. It was said that if a person ever found an invisible fern seed and carried it around, they too would become invisible! Tell students that we now know that ferns come from spores, not seeds at all. Scientists therefore call ferns and mosses that reproduce without the use of seeds non-seed plants. The next two forms of sexual reproduction that students will learn about will be within plants that use seeds, not spores.

Tell students that each group will now be receiving another reproductive part of a plant. This time, their group task is to examine what they are given and to try to generate an explanation for how the plant part acts in its role in plant reproduction. In other words, how does it work? The fact that they were just told that it has something to do with seeds should be a hint. Collect the fern fronds as you pass out the pine cones and give groups a few minutes to examine them.

After several minutes, ask each group to share their ideas about how a pine cone may act in its role as the reproductive part of a pine tree. Tell students that there are actually two types of pine cones, and display the transparency or drawing depicting this. Explain that if they were to go into the forest and look on a mature pine tree, they would probably see both small cones that carry the males gametes and larger cones that carry the female gametes. Ask: What type of pine cone did your group have? Tell students that the male cones are smaller because the male gametes are tiny, and do not take up much room. These male gametes are stored in tiny grains of pollen that are blown by wind from the male pine cone to the female pine cone. They stick to the eggs found inside the female pine cone and fertilize them. The fertilized eggs grow into seeds, and when the female pine cone is full of seeds, it opens its scales and drops the seeds onto the ground, where they will grow to become pine trees if food and water are present. Ask: If your groups had a female pine cone, how open were its scales? Was anyone able to find a seed in their female pine cone? What does this tell you about the stage of the pine cone when it was found?

Tell students that the seeds from a pine tree are called "naked" because there is nothing covering them except their own skin. Ask students to recall from the animal classification unit that most living organisms have been given a scientific name that is Latin or sounds Latin. The scientific name for the group of plants that includes pines is "gymnosperms," which means "naked-seeds."

To recap what has been learned so far in today's lesson, tell students that they know now that plants are capable of sexual reproduction. Two examples of plants that reproduce sexually are the fern and the pine. The fern manufactures spores to reproduce, and the pine creates cones, which contain "naked" seeds. So, they have heard about sexual reproduction in non-seed and naked-seed plants. Tell students that each group will now be receiving a third reproductive part of a plant. Tell them that they will recognize it immediately. Their task, within groups, is to propose ideas for how the plant grew it and what type of seed it might be. They will want to examine it as they did the other plant parts, as this will help them in their task. Pass out the pea pods and allow groups several minutes to examine them. While students do so, collect the pine cones.

After several minutes, ask: How do you think that the pea plant manufactured the pea pod? Allow groups to share their ideas, then tell them that the pea plant started its creation of a pea pod with a flower. When the flower was fertilized, its fertilized eggs became the peas contained within the pods. Tell students that they will learn more about flower fertilization in the next lesson. Ask: What type of seed might the pea be? Tell students that if a pine seed is naked, the pea seed can be considered clothed. Most plants "clothe" their seeds with some type of covering--think about an apple, an orange, a cucumber and a tomato as examples. Ask: How is the pea seed clothed? (within a pod) These plants with "clothed" seeds are called "angiosperms." What do they think this name means? (covered-seeds) All angiosperms have at least one thing in common: they produce seeds from a flower. Angiosperms, like gymnosperms, drop their seeds onto the ground, and if conditions are right, the seeds grow to become plants.

Collect the peas (and magnifying glasses, if they were used) from the students and summarize the lesson by asking the following questions. What is sexual reproduction? (the creation of a new organism using male and female cells) How is it different from asexual reproduction? (In asexual reproduction, male and female cells are not used.) Can you name three types of plants that sexually reproduce? (non-seed, naked seed and covered-seed plants) What were the examples of each that you examined in class today? (the fern, the pine and the pea, respectively) What are all covered seeds produced from? (a flower) Compliment students on the knowledge they gained in today's lesson, and tell them that in the next lesson, they will learn more about the role of the flower in reproduction.
 

Suggested Follow-up Activity

Students would benefit from seeing the content covered so far in this unit organized in outline form. With the students, complete the following outline on the board. (You may also choose to give the outline format, with blanks inserted in the place of some names, to students in groups, and challenge them to complete it.)
 

REPRODUCTION
 

I. Asexual

A. Fission

1.Bacteria

B. Spores

1. Mushroom

C. Budding

1. Yeast

D. Cloning

1. Rose

E. Regeneration

1. Starfish
 

II. Sexual, in Plants

A. Non-seed

1. Fern

B. Naked-seed

1. Pine

C. Covered-seed

1. Pea

Fifth Grade - Science - Lesson 37 - Parts of a Flower and Flower Pollination

Flower dissection activity adapted from "Flower Power." The Mailbox, February/March 1995, p. 39.
 

Objectives

Dissect a flower and classify its parts.

Complete a sequence chain describing the pollination of a flower.

Construct a flower model. (optional)
 

Materials

Transparency or drawing on chart paper of a cross-section of a flower (attached)

Key for cross-section of a flower (attached)

Transparency or drawing on chart paper of the series of illustrations showing flower pollination, fertilization and seed development (attached)

For each student

One copy of the sequence chain (attached)

One copy of the cross-section of a flower (attached)

For each cooperative group

One flower (This can be obtained from a local florist; ask about the donation of drooping or slightly damaged flowers. Tulips and daffodils are good choices because they are plentiful at this time of year and have parts large enough for students to see and handle.)

One copy of the flower chart (attached)

A sheet of dark, preferably black, construction paper

Tape
 

Suggested Books

Student Reference

Aldrich, Arthur. Flowers and Flowering Plants. New York: Franklin Watts, 1976. This book would prove an easy read for fifth graders, but it does describe all of the flower parts they study in today's lesson, as well as pollination. There are helpful illustrations of a cross- section of a flower and of flower parts on pages 12-13.

Ganeri, Anita. Nature Detective: Plants. New York: Franklin Watts, 1992. Flowers, their parts and pollination are addressed on pages 16-19.

Morgan, Sally. Flowers, Trees and Fruits. New York: Kingfisher, 1996. Though there is not much text on flowers and their parts, students may enjoy trying the flower-related experiments and activities described on pages 23 and 25.

Selsam, Millicent E. and Joyce Hunt. A First Look at Flowers. New York: Walker and Company, 1977. Fifth graders would find this book very easy to read, but it does contain limited information and diagrams of the flower parts discussed in today's lesson.

Unwin, Mike. Science With Plants. Tulsa, OK: E.D.C. Publishing, 1994. Flowers and pollination are described, with lots of colorful accompanying illustrations, on pages 10-11.

The Visual Dictionary of Plants. New York: Dorling Kindersley, Inc., 1992. Though the text is quite sophisticated, the photographs of flower parts and of the pollination process are outstanding.

Walker, Colin. Pollination and Germination. Cleveland, OH: Modern Curriculum Press, 1993. Pollination is covered comprehensively in this text, which includes a helpful diagram of a cross-section of a flower on page 3.

Teacher Resource

Tilgner, Linda. Let's Grow! 72 Gardening Adventures With Children. Pownal, VT: Storey Communications, Inc., 1988. There are lots of suggestions for hands-on activities within this text.
 

Teacher Background

In this lesson, students learn more about the role of the flower in plant reproduction. They were introduced to this topic in Second Grade, when they learned how a flower is pollinated, and for some students, a portion of the content of today's lesson will be review. After students dissect the flower and classify its parts, they are asked to sequence flower pollination.
 

Procedure

Begin today's lesson by asking students: What does it mean to reproduce sexually? (to create a new organism using male and female cells) Who can name the three types of plants, learned about in the last lesson, that sexually reproduce? (spore-producing, naked-seed and covered-seed) Who remembers how every seed made by a covered-seed plant began? (as a flower) So, if we know that covered-seed plants reproduce sexually through the use of a flower, what types of cells would you expect to find in a flower? (male and female sex cells, or gametes) Tell students that today, they will be examining a flower and learning more about its role in plant reproduction.

Put students into cooperative groups (pairs would probably work best if you have enough supplies) and pass out the construction paper and flower chart. Tell students that they will be receiving a flower, and their task will be to carefully take apart the flower and tape its parts into the appropriate boxes on the flower chart. Ask: How do you think you will figure out where to tape the flower parts? (by reading the description in each box and finding a flower part that matches the description) Suggest that students examine all of the flower parts and lay each of them into the box where they think it to belong before they do any taping. That way, they won't risk tearing the paper, which is likely to occur if students tape each part into a box as they go. Instruct students, when dismantling the flower, to do so over the construction paper. Distribute the flowers and as students begin to dissect them, attach pieces of tape to the desk of one member of each group.

When students have completed dissecting the flowers, display the transparency or chart of the cross-section of a flower and distribute student copies. Begin in the upper left corner of the flower chart and ask a student to read the text describing the flower part that belongs in the box (the sepals). Next, ask a volunteer to point out on the flower cross-section on the overhead or chart paper, the sepals of the flower. Students should then label the sepals on their own cross-sections correctly, as you label the part on the transparency or chart paper. Continue to review the flower chart in this manner, having a student read the description of what would go in the box, asking a volunteer to point out the same part on the flower cross-section, then instructing students to label their own cross-sections as you label the transparency. By comparing what they taped in the box to what is being pointed out on the diagram, students should be able to tell whether or not they correctly identified each of the parts of the flower during their dissection. (Have students note that the pistil actually consists of three parts, two of which, the stigma and the style, they were not asked to identify on the flower part chart.)

Once the chart has been reviewed, and all of the flower parts identified, ask students to carefully examine, without lifting or tilting it, the construction paper, over which they dismantled the flower. Ask: What do you see on the construction paper? (It is expected that at least several of the groups will see small grains of pollen, the male gamete of the flower.) Ask: Considering the action that caused the pollen to collect on the construction paper, how do you think this male gamete joins the female gamete, which is inside the pistil? (Frequently an insect, drinking flower nectar, will carry pollen from the stamen onto the stigma or style of the pistil. Pollen may also be moved to the pistil by the wind.) Students may find it interesting to note that flowers that are wind pollinated may be dull and drab because they do not need to attract insects in the role of pollinators. Ask: How would you expect other flowers, that do need to attract pollinators, to do so? (through bright colors and sweet scents) Display the first drawing in the series of flower pollination, fertilization and seed development.

Now show students the second picture in the series and tell them this picture shows what happens next. Pollen landed on the stigma, and from the pollen grain, a tube has grown down the style, leading to the ovary. (The tube is the white line leading from the stigma to the ovary.) The pistil will not let a pollen tube grow unless the pollen comes from the same kind of plant. Ask: Why do you think this is so? (Students should remember from the classification unit that only organisms from the same species will reproduce and create offspring that look like the parents.) The male gamete from the pollen travels down the pollen tube to meet the female gamete in the ovary. When the male gamete joins the egg cell in the ovary, fertilization occurs.

Display the next picture in the series and tell students that once this has happened, the flower petals begin to die and drop off, and the ovary begins to grow.

Allow students to see the fourth picture and point out that the ovary continues to grow. Ask: What do you think is inside of it? (fertilized eggs, which are seeds) Tell students that if there was only one egg in the ovary, there will be only one seed within the covering produced by the plant. Remind students that the seed covering is frequently the part of the plant that humans consider edible--the fruit or vegetable. Ask: Can you think of any fruit or vegetable that has only one seed? (Answers will vary but may include an avocado, peach or plum.) Can you name a fruit or vegetable that has more than one egg cell fertilized in each of its flowers? (Answers will vary but may include a tomato, pea, orange or apple.)

In the fifth picture, (and sixth picture, which is simply a cross section of the pepper shown in the fifth picture) students can see that the ovary grows into a covering to protect the seed(s). Ask: Now that you can see the covering grown by this plant, can you name the type of plant shown in these illustrations? (a pepper plant) Ask: Depending on the type of plant, what other form might this covering have taken? (Answers will vary, but include fruits and vegetables such as a bean, a berry, a tomato or the hard shell of a nut.) The covering helps to scatter the seeds. Ask: How do you think the covering can help to scatter the seeds? (Animals or people pick the covering, eat it, and either throw or excrete the seed onto the ground, where it will grow. Students may also have seen the seeds of maple trees, which children sometimes call "helicopter seeds." These seeds are each encased in a covering which takes the form of tiny "wings" that can carry the seed for long distances on the wind.)

Tell students that we call the series of events in which a flower is fertilized pollination (write on board). Tell students that the seed which has been created through pollination, if it finds food, water and sunlight, will now begin the life cycle of the plant all over again.

Leaving the series of flower pollination pictures on display, distribute the sequence chain to students. Instruct each student to write his or her name on it, then to use the pictures as clues to fill it in, describing in the boxes the sequence of events that occurs when a flower is pollinated. Students may use their flower charts as references for the part names, and should be encouraged to use the correct names of flower parts when describing pollination. When students are finished, collect the sequence chains for grading purposes.
 

Suggested Follow-up Activities
 

Adapted from Life Cycles: How Living Things Grow and Change. New York: Scholastic Inc., 1993. (p.11)
 

An "anatomically correct" flower
 

Materials

Construction paper

Scissors

Glue

Modeling clay or Play-Dough (about one tablespoon for each student)

Pipe cleaners (four or five for each student)

Talcum or baby powder
 

Using the flower chart as a reference, have students make flowers with the materials above. Petals should be cut from the construction paper and glued together at their bases. The clay or Play Dough should be placed or glued to the base of the joined petals, and will act to hold the stamens and pistil in place. The stamens and pistils should be fashioned from the pipe cleaners, and it would be preferable, if possible, for the pistils to either be longer or a different color than the stamens to distinguish them. (If this is possible, each student will get one pipe cleaner to be the pistil and three or four to be the stamens.) Once the pistil and stamens have been inserted into the clay or Play Dough, the tips of the stamens should be lightly dusted with powder to represent pollen.

Students may enjoy keeping their flowers on their desks as a reminder of the pollination process, or the flowers may be gathered into a "bouquet" for a bulletin board or hallway display.
 

Flower Close-Up
 

Materials

For each cooperative group

Two flowers of the same variety

A magnifying glass
 

Another activity students may enjoy will allow them to examine flowers in a new way.

To complete this activity, cooperative groups will each need two flowers of the same variety and a magnifying glass. First, carefully cut each group's first flower in half, right through the pistil. Allow students to examine the ovary at the base of the pistil with the magnifying glass. What do they observe? Can they see any eggs?

Instruct students to watch as each group's second flower changes, day by day. When the flowers' petals have all dried up and fallen off, give these flowers back to the groups. What changes in the pistil do they observe? (The ovary of the flower should be expanding.) When these ovaries look very plump, carefully cut them in half for each group and allow them to examine them using the magnifying glasses. What do they see? How do these ovaries look different than ovaries of the first flowers? What do they think has happened?
 
 


FLOWER PART CHART


 









Directions:

1. Carefully take apart the flower.

2. Using the descriptions in each box to guide you, match each flower part to the box where it belongs.

3. Once you are sure each part is in the correct box, tape the parts in place.
 
 
 
Sepals are usually green and look like small leaves. They surround the developing flower before it blooms to protect it from hungry insects. They are usually attached to the stem at the base of the flower. 













 

The petals of a flower are usually brightly colored to attract insects, which help to spread the pollen. The petals also provide a protective covering for the plant's reproductive organs.
The stamens are the flower's male reproductive organs. They can be found inside the ring of petals. Each stamen has an anther at its tip, where pollen can be found. Each grain of pollen contains a male gamete. 













 

The pistil is the flower's female reproductive structure. It is near, and may be in the center of, the stamens. At the base of the pistil, in the center of the flower, is the ovary, where seeds are fertilized and formed.

 

Fifth Grade - Science - Lesson 38 - Sexual Reproduction in Animals
 

Objectives

Read content on sexual reproduction in animals.

Complete a crossword puzzle with vocabulary related to sexual reproduction in animals.
 

Materials

For each student

One copy of the excerpt from What Your Fifth Grader Needs to Know by E.D. Hirsch (attached)

One copy of the related crossword puzzle (attached)

One copy of the crossword puzzle clues (attached)
 

Teacher Background

Within this unit, students have now learned that reproduction can be sexual or asexual. They have learned about types of asexual reproduction, and about sexual reproduction within plants. In this lesson, students learn about sexual reproduction in animals through reading and completing a crossword puzzle.
 

Procedure

Begin today's lesson by asking these review questions: What are the two major ways that an organism can reproduce? (sexually or asexually) How do the flowering plants you learned about in the last lesson reproduce? (sexually) What is the difference between sexual and asexual reproduction? (In sexual reproduction, male and female cells, or gametes, are present.) How do you think most animals reproduce? (sexually)

Tell students that they will be learning about sexual reproduction in animals today. Distribute both the excerpt and the crossword puzzle. Tell students that before reading the excerpt, they may want to read the puzzle clues so that they are cued into what is important within the reading. Instruct students to do the reading, then complete the puzzle.

Once students have completed the puzzle, either review it together or collect it for grading purposes. (Use the attached key to do either.
 
 


Reproduction in Animals

(From What Your Fifth Grader Needs to Know by E.D. Hirsch)


 






Although some animals can reproduce asexually, as we read earlier, most animals reproduce sexually. Just as plants produce male and female gametes, so do animals. In animals, the gametes or sperm are produced in organs called the testes, while female gametes or eggs are produced in organs called the ovaries. In simpler animals, like earthworms, the sperm- and egg-making organs are both in the same creature. But in most animals, male and female gametes are made by separate male and female creatures.

If sperm and egg join outside the bodies of the parents, the process is called external fertilization. When sperm and egg join inside the body of the female, as with humans, it is called internal fertilization.

Have you ever seen a film that shows fish spawning? Spawning is a form of external fertilization. During spawning, female fish and male fish come very close together in the water. The female releases her eggs into the water and the male releases his sperm. The sperm swim to the eggs and fertilize them.

During spawning season, adult fish release eggs and sperm into the water where fertilization takes place.

Birds and also mammals like horses and humans reproduce by internal fertilization. The female releases an egg from her ovary, and it travels down a tube which leads from the ovary. During mating, the male releases sperm inside the female. The sperm travels to the tube where the egg is, and fertilizes it. If no sperm joins an egg, the egg is unfertilized and leaves the female's body. Other eggs will later travel down the tube leading from the ovary, and one of these may be fertilized.

For birds, fertilization takes place inside the female's body. Whether a bird egg is fertilized or not, it grows larger and gains a shell layer inside the mother's body. Once the mother lays a fertilized egg, she must give it warmth and protection if the chick inside is to develop and hatch.

Once the egg is fertilized, it is called a zygote (ZYE-goat). The zygote begins to divide and grow, and after several days or weeks--depending on the animal--the zygote becomes an embryo. An embryo, remember, is a developing organism. In most mammals, the embryo develops inside the mother's body in an organ called the uterus (YOO-ter-us). The zygote travels down the tube from the ovary, enters the uterus, and attaches itself to the wall of the uterus. In the uterus the developing embryo gets its food and water from the mother. In the later stages of development, the embryo is called a fetus. When it has developed enough to live on its own, the fetus is born.

Horses take eleven months to develop inside their mothers. Sheep take only five months. Do you know how long it takes a human embryo to develop?

Fifth Grade - Science - Lesson 38 - Sexual Reproduction in Animals
 
 


CROSSWORD CLUES


 









ACROSS
 

1. When the sperm and egg join inside the body of a female, it is called ___________ fertilization.
 

2. This organ can be found inside the mother's body and is where the embryo develops.
 

3. This is the female gamete, which is produced in the ovary.
 

4. In the later stages of development, the embryo is called a ____________.
 

5. When the sperm and egg join outside the bodies of the parents, the process is called ____________ fertilization.
 

6. These are the female organs in which eggs are produced.
 

DOWN
 

7. Male gametes, or sperm, are produced in the ____________.
 

8. This is what the egg is called once it is fertilized.
 

9. The zygote continues to divide and grow, and after several days or weeks, it becomes an ____________.
 

10. The egg joins with this during fertilization.

KEY
 
1I N 7T E R N A L
E
S
8Z 2U T E R U 10S
Y 9E E P
3E G G M S 4F E T U S
O B R
5E X T E R N A L M
E Y
6O V A R I E S

 

Bibliography
 

Student Reference

Aldrich, Arthur. Flowers and Flowering Plants. New York: Franklin Watts, 1976.

(0-531-01214-X)

Burnie, David. Eyewitness Books: Tree. New York: Alfred A. Knopf, 1988. (0-394-89617-3)

Coldrey, Jennifer. Discovering Fungi. New York: The Bookwright Press, 1988. (0-531-18170-7)

Ganeri, Anita. Nature Detective: Plants. New York: Franklin Watts, 1992. (0-531-14194-2)

Morgan, Sally. Flowers, Trees and Fruits. New York: Kingfisher, 1996. (0-7534-5032-1)

Selsam, Millicent E. and Joyce Hunt. A First Look at Flowers. New York: Walker and Company, 1977. (0-8027-6281-6)

Unwin, Mike. Science With Plants. Tulsa, OK: E.D.C. Publishing, 1994. (0-7460-0976-3)

The Visual Dictionary of Plants. New York: Dorling Kindersley, Inc., 1992. (1-56458-016-4)

Walker, Colin. Pollination and Germination. Cleveland, OH: Modern Curriculum Press, 1993. (0-8136-2610-2)

Wexler, Jerome. From Spore to Spore: Ferns and How They Grow. New York: Dodd, Mead & Company, 1985. (0-396-08317-X)
 

Teacher Reference

Hirsch, E.D. What Your Fifth Grader Needs to Know. New York: Doubleday, 1993. (0-385-41119-7)

Life Cycles: How Living Things Grow and Change. New York: Scholastic Inc., 1993. (0-590-26140-1)
 

Teacher Resource

"Flower Power." The Mailbox, February/March 1995, 39.

Tilgner, Linda. Let's Grow! 72 Gardening Adventures With Children. Pownal, VT: Storey Communications, Inc., 1988. (0-88266-471-9)

VanCleave, Janice. 201 Awesome, Magical, Bizzare & Incredible Experiments. New York: John Wiley & Sons, Inc., 1994. (0-471-31011-5)

Wood, Robert W. Science for Kids: 39 Easy Plant Biology Experiments. Blue Ridge Summit, PA: TAB Books, 1991. (0-8306-1935-6)