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Unit Breakdown

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Unit 8

Plant Reproduction Scientific Basis

This unit examines the processes of plant reproduction,through which the perpetuation of species is achieved.

The study centers on the morphology of the organsresponsible for plant reproduction—stamen, pistil, and thelike—and on ordering the processes involved—pollination,fertilization and germination.

Contents

Concepts

Types of plant reproduction.

The flower as a reproductive organ.

Fruits and seeds: types, functions and dissemination.

Stages of reproduction.

The life cycle of plants. Seasonal changes in plants.

Cultivation of plants.

Procedures

Solution of problems related to plant reproduction.

Interpretation of diagrams, sequences and graphs.

Chronological ordering of the processes involved in plantreproduction.

Attitudes

Interest in learning more about plants.

Appreciation of the importance of plants and interest incaring for them.

Development of habits associated with the protection andconservation of ecosystems.

Unit Breakdown

Students have covered the morphology of plants and theirclassification as trees, bushes and grasses in previous booksof the series. This unit focuses on plant reproduction. Thestudy of sexual reproduction is limited to flowering plants.

In the first lesson, students will investigate the differencesbetween sexual and asexual reproduction.

In the second lesson, students will review the parts of aflower and learn characteristics of fruits and seeds.

In the final two lessons, students will explore pollination,fertilization and germination—fundamental steps in plantreproduction.

Unit Outline

Plant Reproduction

HealthEducationWash Fruitbefore You

Eat It

Society/Investigate

Greenhouses/Animal

Pollination

Types ofPlant

Reproduction

Flowers,Fruit and

Seeds

FromFlower to

Fruit

Germinationand Growth

Test YourKnowledge

LookHave students look at and describe the photo. In pairs, have them answerthe questions. Ask some pairs to report their answers to the class.

What do you know?Ask students if they have plants at home and where they keep them. Invitethem to describe their plants and to talk about where they came from, whotakes care of them, what they need to live, and so on. Have studentsanswer the questions. Encourage them to take care of a geranium orsimilar plant in the classroom.Answer KeyLook: 1. • Two (trees and grasses). The trees are tall with a brown trunk and greenleaves. The grasses are short with green stems and leaves and pink flowers. • The treesare taller and have thicker stems. • The grasses. 2. • Yes. No. • The evergreen trees inthe background would look the same. The deciduous tree in the foreground would nothave leaves.What do you know? 1. • To grow new plants. • The fruit or the cone. • No (the potatois a tuber, or underground stem). Yes. 2. • Soil, water, air and light. We should water itoften, fertilize it, put it in a suitable place and replant it in a bigger pot as it grows.

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8Plant Reproduction

1. Plants.

• How many different types of plantscan you see in the photograph?Describe them.

• How are they different?• Which of the plants have flowers?

2. This photograph was taken in spring.Imagine the landscape in winter.Draw it.

• Would you see the same plants inwinter? Would there be any flowers?

• What would the trees look like?

LOOK

1. Answer the questions.

• Why do we plant seeds?• What part of a plant contains seeds?• Is a potato a type of fruit? What

about a tomato?

2. Taking care of a plant.

Bring a geranium in a flowerpot toclass. Answer these questions.• What do plants need to grow? How

should we take care of thegeranium?

Take care of the geranium for a year.Check your answers to the questions.

WHAT DO YOU KNOW?

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Notes

Types of Plant ReproductionShow photos of plants and ask students to identify the parts (root, leaves,stem, flowers). Have students read the text and answer Questions 1 and 2.

Sexual ReproductionAsk students how animals and plants are similar (e.g., they grow, feed,breathe, reproduce and die). Then have them review the process offertilization in humans (a male and a female sex cell unite in a fallopiantube). Explain that plants also have male and female organs that producemale and female sex cells. Unlike most animals, which are either male orfemale, most plants have both male and female organs in their flowers.

Ask students to read the text and answer Question 3. Explain that sexualreproduction is so called because the process involves sex cells.

Asexual ReproductionHave students read the text and look at the photos on page 82. Ask themwhat the main difference between sexual and asexual reproduction is (sexcells are not involved in asexual reproduction).

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82

1. Types of Plant Reproduction

Types of Plant ReproductionThere are two kinds of plant reproduction: sexualreproduction and asexual reproduction.• The part of the plant responsible for sexual

reproduction is the flower.• Asexual reproduction occurs when a new

plant grows from the stem or leaves of anexisting plant.

All plants can reproduce by sexual reproduction.Some plants can reproduce by both methods.

Sexual ReproductionFlowers are responsible for sexual reproduction inplants. A male sex cell and a female sex cell uniteinside a flower. The fruit and seeds develop fromthe flower. Later, a new plant develops from a seed.When a plant reproduces by sexual reproduction,there are differences between the parent plantand the offspring plant. For example, the color of their flowers might be different. The fruit of onemight be smaller than the fruit of the other. One might be more resistant to certain illnessesthan the other. Some plants, like ferns, do not have flowers.However, these plants also produce sex cells andare capable of sexual reproduction.

1. How do plants reproduce?

2. How can a new plant growfrom an existing plant?

3. What do flowers do?

Questions

The tuber and flowers of a potato plant.

The bulb and leaves of an onion. The flowers and stolons of astrawberry plant.

stolons

bulb

tuber

Expressing Concepts

Focus on Science

Human and Plant Reproduction

Review students’ knowledge ofhuman reproduction: What organsare there in the male and femalereproductive systems? What occursduring fertilization? (A male and afemale sex cell unite.) How does a babychange as it grows?

Explain that flowers also have maleand female organs, which producemale and female sex cells. Theoffspring of many plants are verysimilar, but not identical, to the parentplants. The offspring of some plants(those that can reproduce asexually)are identical to the parent plants.

Elicit the names of the parts of a plantand the functions they perform(leaves—nutrition and respiration;stem—support for the flower andleaves, transportation of sap; roots—absorption of water and nutrientsfrom the soil; flowers—reproduction).

This lesson may be used to reviewthe following language:

Might

The fruit of one might be smaller thanthe fruit of the other.

1. Types of PlantReproduction

ConceptsTypes of plant reproduction. Theflower as a reproductive organ.

VocabularyAsexual reproduction, bud, bulb, cutting,female sex cell, flower, leaf/leaves, malesex cell, seed, sexual reproduction, stem,stolon, tuber.

MaterialsPhotographs of a variety of plants.

In pairs, have students make illustrated charts with the three types ofasexual reproduction and their characteristics.

Point out that some animal groups also reproduce asexually. A starfish (anechinoderm) can grow from a single arm of an adult starfish.

Have students do the Activities in pairs. Have some pairs report theiranswers to the class.

ActivitiesAnswer Key: 1 • asexual reproduction. • asexual reproduction; sexual reproduction;sexual reproduction. • Sexual reproduction. • Asexual reproduction. 2 Sample answer:Sentence a) is correct. All plants can reproduce sexually; some plants, like the onion,the potato and the strawberry, can also reproduce asexually.

Compare and Analyze: CuttingsAsk students what decorative plants they have at home. Have them readthe text. In pairs, have them discuss and do the activity.Answer Key: • Take an existing plant and cut off a branch with several leaves on it.Plant the branch. • No. A branch cannot fall off and plant itself voluntarily.

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Parks and Gardens

Have students write a detaileddescription of a public park theyknow well, where there are a varietyof trees, shrubs, flower beds, and thelike. Alternatively, have them writedetailed descriptions of the trees andplants in their yards or gardens.

Language Skills: Writing

Environmental Education:Deforestation and Reforestation

Materials: Construction paper (1 sheet per pair).

Discuss the problem of deforestationin many parts of the world, wheretrees are cut down for lumber or tomake way for road construction orfarmland. Deforestation can result indesertification of some areas, causingdrought, reduction of food suppliesfor many animals and destruction oftheir habitats.

Elicit the meaning of the wordreforestation. Discuss how ourknowledge of plants and theirreproductive processes (e.g., the timeof year they are fertilized or if theycan reproduce asexually) makes itpossible to grow new trees whereolder trees used to be.

In pairs, have students make posterspromoting reforestation.

Cross-Curricular Connection

Asexual Reproduction The stem or leaves of a plant are involved in asexualreproduction.Tubers, bulbs and stolons are types of stem.• Tubers are stems in the soil. Buds sprout from the

tubers. The buds produce new plants.• Bulbs are also underground stems. Bulbs have a

bud inside them. The bud produces a new plant. • Stolons are stems above the ground. New stolons

produce new plants.When a plant reproduces by asexual reproduction,the new plant is identical to the original plant.Plants that reproduce by asexual reproduction canalso reproduce by sexual reproduction.

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CuttingsCuttings allow us to grow new plantsfrom existing adult plants. To grow aplant from a cutting, first take anexisting plant. Cut off a branch withseveral leaves. When you plant thebranch, roots will grow out of it. Theroots take hold in the soil and thebranch begins to grow and develop.This kind of asexual reproduction doesnot happen naturally. It is a techniquewe use to produce specific plants, likegeraniums and roses.

• Explain what you must do to grow ageranium from a cutting.

• Do plants reproduce from cuttings naturally? Why or why not?

Activities

Complete the sentences.

• Bulbs, tubers and stolons are involved in .

• The potato plant can reproduce by and by .

Flowers are responsible for in .

• involves the sex cells.

• involves stems and leaves.

Which of the following sentences is correct? Explain.

a) Some plants can reproduce sexually and asexually. b) If a plant reproduces sexually, it cannot reproduce asexually.

2

1

Compare and Analyze

Tulips have flowers and bulbs.

Geranium

sexual reproduction asexual reproduction

The Parts of a FlowerShow photos of flowers and ask students to identify the different parts,using The Parts of a Flower diagram.

Explain that some parts of a flower, such as the pistil and the stamen, arerelated to reproduction, while others, such as the calyx (the collective termfor the sepals) and petals, protect the other parts. Petals also attract animals,which play a role in plant reproduction. Point out that there are a greatvariety of flowers: some have fused petals, such as the bellflower; some havemany stamens, such as the honeysuckle; others have few, such as the orchid.

Have students read the text. Encourage them to locate on the diagram theparts mentioned in the text. Then have them answer Question 1. Askstudents to copy the diagram in their notebooks and label the parts withshort texts describing their functions. Then have them do Activity 1.

SeedsExplain that some fruits, such as the strawberry, have their seeds on theoutside, but other fruits have their seeds on the inside. Have students readthe text and answer Question 2.

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84

2. Flowers, Fruit and Seeds

The Parts of a FlowerThe flower is the reproductive unit of floweringplants. The parts of a flower include the following:corolla, calyx, pistil and stamen. • The corolla is the colorful part of the plant. Petals

form the corolla.• The calyx is at the bottom of the flower. Sepals

form the calyx. The sepals are small green leavesthat protect the flower before it opens.

• The pistil has three parts: a stigma, a style andan ovary. The ovary produces the female sexcells, called ovules. The style is usually shapedlike a bottle. The tip of the pistil is called thestigma.

• The stamen has two parts: a filament and ananther. The anthers produce pollen. The male sexcells, or sperm, are in the pollen. Flowers usuallyhave several stamens.

1. Describe flowers.

2. Describe seeds.

3. What kinds of fruit and nutsare there?

Questions

The fruit of a strawberryplant.

The fruit of a blueberrybush.

Fleshy Fruits

Nuts

Almond nuts on an almond tree. Chestnut

protectivecasing

nut

Chickpeas

pistil

corolla

stamen

sepalpetal

The Parts of a Flower

calyx

stigma

style

ovary

anther

filament

Seeds

Expressing Concepts

Focus on Science

Plant Reproduction

Materials: Flowers, scalpels (perpair); paper.

Explain that, like all other livingthings, plants eventually die. Toensure the perpetuation of the species,they have to reproduce themselves.Emphasize that a flower has male andfemale parts, and that, as in othertypes of sexual reproduction, bothmale and female sex cells arenecessary to create new plants.

Focus students’ attention on TheParts of a Flower diagram on page 84of their books. Divide the class intopairs and distribute materials. Haveeach pair cut a cross section of theirflower, draw it and label the parts.Display students’ diagrams aroundthe classroom. Encourage students tocompare the parts of different kindsof flowers.


Adverbs of frequency

Flowers usually have several stamens.

2. Flowers, Fruit andSeeds

ConceptsThe flower as a reproductive organ.Fruits and seeds: types, functions anddissemination.

VocabularyAnther, calyx, corolla, filament, fleshyfruit, nut, ovary, petal, pistil, sepal,stamen, stigma, style, sunflower.

MaterialsPhotographs of a variety of flowers.

FruitsExplain that some seeds are often mistaken for nuts (e.g., brazil nut,almond, pistachio). The term fruit refers to the container for the seeds; thismay or may not be edible. Have students read the text, look at the photosof fruits and answer Question 3. In pairs, have students do Activity 2.

ActivitiesAnswer Key: 1 Clockwise from top left: petal, stigma, filament, anther, ovary; petal, stigma,anther, ovary, filament. The stigma is part of the pistil. The petals protect other organs andattract animals. The anthers produce the male sex cells. The filaments support the anthers.The ovary produces the female sex cells. 2 One Seed: peach, apricot, plum. Several Seeds:melon, apple, cucumber, pear. Thin Covering: green pepper, apple, melon, tomato,cucumber, pear. Thick Covering: peach, apricot, plum.

Look: The Sunflower Is Not a FlowerExplain that sunflowers turn during the day so that their flowers alwaysface the sun. Have students read the text and answer the questions.Answer Key: • It looks like a single flower, but it is made up of many small flowers. Thestigma has two parts. The stamens are short. The anthers are joined. • The daisy.

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The Colon

Ask students to find sentences withcolons in the text (The parts of a flowerinclude the following: corolla, calyx,pistil and stamen. The pistil has threeparts: a stigma, a style and an ovary.).Ask what function the colon has (tointroduce a list of related items).

Write the following notes on theboard and have students turn theminto complete sentences using acolon in each:

reproduction—sexual, asexualthe stamen—filament, anther

Language Skills: Reading

Art: Paper Flowers

Materials: Paper, construction paper,green paper, tissue paper (variouscolors), modeling clay, thin andregular wire.

Ask students to study carefully TheParts of a Flower diagram on page 84of their books. Then, using thediagram as a guide, have them designand make three-dimensional modelsof flowers. Show them how to usewire wrapped in green paper for thestem, construction paper for thesepals, tissue paper for the petals,thin wire for the style and thefilaments, and small balls of modelingclay for the stigma and anthers.


Activities

Read the key words. Look at the pictures. Put the key words in the correct box. Explain what each part of the flower does.

Draw the following fruit with their seeds in your notebook. Complete the tables.

peach, melon, apricot, plum, tomato, cucumber, apple, pear, green pepper

2

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SeedsSeeds form inside fruit. Some fruit, like the peach,only have one seed. Other fruit, like the apple, have several.Seeds have a protective covering. The covering ofsome seeds, such as peas, is very thin. Other seedsare harder, like watermelon seeds. The covering ofsome seeds is hard and thick, like the apricot seed.

FruitsAfter fertilization, part of a flower develops into a fruit. • Fleshy fruits accumulate water. Grapes,

cucumbers, apples, oranges, strawberries,peppers, etc. are all fleshy fruits.

• Nuts do not accumulate water. Acorns,chestnuts, almonds, peanuts, etc. are all nuts.

The Sunflower Is Not a FlowerAlthough the sunflower looks like aflower, it is not a single flower. Asunflower is a group of many flowers.

• Describe a sunflower.What are its flowers like?

• What other plant has flowers ingroups but looks like a singleflower?

Fruit with One Seed Fruit with Several Seeds Seeds with a Thin Covering Seeds with a Thick Covering

Look

special leaves that protect the flowers

flowerspetals

stigma

anthers

A Single Flower

stigma petal anther filament ovary

PollinationHave students look at and describe the photo. Explain that the powder ispollen, which contains the male sex cells. For reproduction to take place,these sex cells have to come in contact with the female sex cells, producedin the ovary. Plants have adapted in different ways to ensure that the malesex cells come in contact with the female sex cells (pollination). Pollinationoccurs only in plants of the same species. In some species, wind andanimals transport the pollen between plants that are far from each other.

Have students read the text and answer Question 1.

Explain that the appearance of a flower is related to its method of pollination:flowers that rely on animals for pollination are often brightly colored orstrong smelling; wind-pollinated flowers often do not have petals and are notimmediately recognizable as flowers. Sometimes certain colors attract specificanimals, such as yellow and blue for bees, and red and yellow for birds.

FertilizationIn pairs, have students study the Fertilization of a Pea Plant diagram anddescribe the process. Have them read the text and answer Questions 2 and 3.

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3. From Flower to Fruit

PollinationPlants with flowers reproduce sexually. Thishappens when pollen from the stamen reaches thepistil. Pollination is the transfer of pollen from themale part to the female part of flowers.Some plants self-pollinate. The pollen comes from the stamens of the same plant. Other plants cross-pollinate. The pollen comes from the stamenof another plant of the same species.The wind and certain animals can transfer pollenfrom one flower to another. • For example, the wind transports the pollen of

wheat flowers. The pollen can reach the flowersof many different wheat plants.

• Some animals and insects, like hummingbirdsand bees, also transport pollen. When bees landon flowers to feed, pollen sticks to their bodies.They then carry the pollen from one flower toanother. Bees pollinate rosemary flowers, for example.

Plants that rely on animals for pollination havebrightly-colored flowers or strong smells to attractthe animals. Other plants have small green flowers,so animals do not notice them. The wind transportsthe pollen of these plants.

1. What is pollination?

2. How are plants fertilized?

3. What do the seeds do?

Questions

The wind pollinates this bulrush.Fertilization of a Pea Plant

1

3

2

4

stamenwith pollen

The pollen grains openand the male sex cellsappear.

pollengrains

stigma

stigma

fertilization

The fertilized cellswill turn into seeds.

Parts of theovary will turninto fruit.

petal

ovary

male sex cell

female sex cellsExpressing Concepts

Focus on Science

Pollination

Materials: Photos of a variety offlowers.

Ask students if they (or members oftheir families) are allergic to pollen.Ask at what time of year theirsensitivity tends to increase and toexplain why (during spring andsummer, when flowers producepollen for fertilization).

Explain that pollen is a fine powderproduced in the anthers (the maleparts of the flower). Pollen containsthe male sex cells. For fertilization totake place, these male sex cells haveto come in contact with the femalesex cells of the same or a differentflower.

Many plants, especially grasses, usewind to transport their pollen. Theflowers of these plants often havesmall green petals.

Other plants rely on animals totransport their pollen from oneflower to another. The flowers ofthese plants are usually large andcolorful, to attract the animals.

Display photos of flowers and havestudents say if they are wind-pollinated or animal-pollinated.


Conjunctions: so, because

Other plants have small green flowers,so animals do not notice them.This happens because the wind oranimals transport the seeds.

3. From Flower to Fruit

ConceptStages of reproduction.

VocabularyBlossom, cross-pollinate, fertilization,fertilize, germinate, pollen grain,pollination, self-pollinate, wind.

Have students do the Activities in pairs. Have each pair compare answerswith another pair. Then have several pairs report their answers to the class.

ActivitiesAnswer Key: 1 a) the transfer of pollen from the stamen to the pistil. b) wind;animals. c) stigma; same. d) stigma; different. e) male; female. f) ovary. 2 Sampleanswers: a) Pollination is the transfer of pollen from the stamen to the pistil.Fertilization is the union of a male and female sex cell. b) Female sex cells (ovules)are produced in the ovary and male sex cells (sperm) are produced in the anthers. c) Pollen contains the male sex cells. d) Seeds form after the female sex cells unitewith the male sex cells in the ovary. 3 The pistil and the stamens.

Look: Traveling FruitExplain that dandelions have yellow petals; after fertilization, they looklike the one pictured in the book. Have students read the text and answerthe questions.Answer Key: • No (the blossom allows it to float in the wind). • No.

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Stages of Fertilization

Materials: Paper (1 sheet per group).

Divide the class into small groups.Have each group copy theFertilization of a Pea Plant diagramon a sheet of paper and writecaptions describing each stagearound it.

Display students’ diagrams aroundthe classroom.


Health Education: Medicinal Plants

Explain that a number of plants canbe used for medicinal purposes, suchas chamomile, aloe vera, lime,rosemary, willow and arnica. Askstudents if they have ever takenmedication derived from a plant and,if so, what it was, what it was for andwhich plant it was derived from.Point out that not all plants aremedicinal and that, on the contrary,some are highly poisonous.

Have students look in their homesfor medicinal products derived fromplants. Ask them to present reportson what the products contain andwhat ailments they treat.


Activities


a) Pollination is .

b) The and are involved in pollination.

c) In self-pollination, the pollen from a flower's stamen falls on the of the

plant.

d) In cross-pollination, the pollen from a flower's stamen falls on the

of a plant.

e) During fertilization, a sex cell and a sex cell unite.

f) Fertilization takes place in the of a flower.

Explain the differences between:

a) pollination and fertilization. c) pollen and male sex cells.b) female sex cells and male sex cells. d) seeds and female sex cells.

Which parts of a flower are involved in fertilization?3

2

1

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FertilizationMost plants do not have flowers throughout theyear. They flower during their reproductive season,usually in spring. A mature flower produces sex cells: male sex cells, or sperm, in the anthers andfemale sex cells, or ovules, in the ovary. During reproduction, a female cell unites with amale cell. The reproductive process is as follows:1. The anther produces a lot of pollen grains.

The pollen grains contain the male sex cells. 2. The pollen grains fall on the stigma.3. The pollen grains open and the male sex

cells come out. The male sex cells penetrate the pistil.

4. Fertilization occurs inside the ovary. That is wherethe male and female sex cells unite.

After fertilization, the fertilized cells become seedsand part of the ovary turns into a fruit.The seeds fall to the ground and germinate. Thisproduces new plants. Some seeds germinate a longway from the plants they come from. This happensbecause the wind or animals transport the seeds.

Traveling FruitThe fruit of a dandelion is very light.Its seed is very small. The seed isattached to a stem with a blossom atthe top. When the wind blows, itcarries the fruit with it. For this reason,dandelion seeds can germinate a longway from the plants they come from.

• Could the fruit be transported bythe wind without its blossom?

• Could it be transported by the windif the seeds were big and heavy?

Look

a lot of fruit

a single fruit

blossom

seedstem

GerminationAsk students what plant parts are involved in asexual reproduction(tubers, bulbs, stolons). Clarify that seeds are produced only in sexualreproduction. Explain that some seeds require special conditions togerminate. The case of a mistletoe seed needs to be cracked inside a bird’sdigestive system and then fertilized by its excrement in order to germinate.

Have students study the Bean Germination diagram and read the text. Thenhave them answer Questions 1 and 2 and do Activity 1.

GrowthAsk students what plants need to live (nutrients, water, suitable light, soiland temperature).

Mention that annual plants grow from seeds and die in the same year,biennial plants in two years and perennial plants in many years. Someplants live much longer than the longest-living animals. For example,there are bristlecone pine trees in the western United States that are nearly5,000 years old.

Ask students to read the text and answer Question 3.

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4. Germination and Growth

GerminationA seed produces a new plant through the process ofgermination. A seed must fall to the ground andhave water to germinate. A bean germinates in various stages. First, the bean becomes buried in the soil. Later, a small rootgrows downward. Then the stem starts to grow.Finally, the leaves grow. Some seeds need special conditions to germinate.For example, some need to spend the coldmonths of winter in the soil to be able togerminate in spring.

GrowthA plant grows gradually after germinating. It keepsgrowing until it becomes an adult plant. Someplants, like trees, keep growing throughout their lives.The life span of plants varies a lot. In general, treescan live for many years. Other plants, like poppies,live for only one year.The seasons of the year affect the life of plants.Plants flower in spring. Their fruit and seeds growand mature in summer. Some plants lose theirleaves in autumn. Their branches are bare during winter.

1. What is germination?

2. How does germinationhappen?

3. How long do plants live?

4. How do trees change duringthe year?

Questions

1. The root comes out. 2. The root and the stemgrow.

3. The leaves form. 4. The root and the stemcontinue growing. Theexisting leaves grow.New leaves come out.

Bean Germination

Expressing Concepts

Focus on Science

Germination in Different Seeds

Materials: Different seeds (e.g., beans,corn), blotting paper, glass jar, sand.

Have students line the inside of aglass jar with wet blotting paper andfill it with sand. Tell them to keep the paper moist throughout theexperiment. Have students placedifferent seeds between the paper andthe glass and watch them germinate.

Ask students to measure the growth ofthe seeds over a few weeks and drawline graphs of their development.

Have students compare how theseeds germinate: Which seedgerminates the fastest? Are theredifferences in the kind or number ofleaves? Which appears first, the root orthe stem? Are all the leaves the same?


Adverbs of sequence

First, the bean becomes buried in the soil. Later, a small root grows downward.

4. Germination andGrowth

ConceptsStages of reproduction. The life cycleof plants. Seasonal changes in plants.

VocabularyCross section, deciduous, evergreen,germinate, germination, life span.

Trees throughout the YearExplain that many plants flower in spring. The fertilized flowers producefruits in the summer, the fruit falls to the ground in autumn and the seedsgerminate the following spring.

Have students read the text and answer Question 4. Ask students to nameevergreen and deciduous trees (e.g., evergreen—pine, spruce, cypress;deciduous—oak, maple, beech). In pairs, have them do Activity 2.

ActivitiesAnswer Key: 1 1. seed. 2. root; downward. 3. stem. 4. leaves. 2 Sample answer: Appletrees flower in spring. The fruit ripens in summer. In autumn, the fruit falls to theground and is eaten by animals or rots. The seeds are exposed. The seeds germinatethe following spring, producing a new plant.

Look and Compare: How Can We Measure the Age of a Tree?In small groups, ask students to read the text and to discuss and answer thequestions. Clarify that one year’s ring comprises a dark and a light ring.Answer Key: • Because a new ring appears every year. • In general, plants live longer.

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If Trees Could Talk

Invite students to imagine that treesare able to talk and recount all thethings they have seen in their longlives. Divide the class into pairs andhave each pair choose a local tree.Then have each pair write aninterview in which the tree describeshow it looked when young, how itgrew over the years and the changes ithas seen throughout its life. Havepairs act out their interviews.

Language Skills: Speaking

Language Arts: The Changing Seasons

Ask students what season it is. Havethem describe the landscape, focusingon the stages of life of the plants.

Elicit observations about how thetrees change throughout the year.Have students describe the treesaround the school and ask them to predict what changes they willundergo in subsequent seasons.Remind them that not all trees losetheir leaves in autumn.

Invite students to write poems on thesubject of the changing seasons.


Stages of Plant Reproduction

Preparation: Photocopy page 140 (1 per student).

Answer Key: 1. 4—fruits and seeds; 5—germination; 1—flowers; 3—fertilization; 2—pollination. 2. See preceding answer. 3. 1. flowers;flowers form. 2. pollination; insectsand the wind carry pollen from onepart of the flower to another or fromone plant to another. 3. fertilization;pollen fertilizes the ovules of the sameor another plant. 4. fruits and seeds;fruits and seeds develop. 5. germination; new plants form.

Worksheet 15

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Trees throughout the YearTrees change throughout the year. For example,trees flower in spring. Reproduction also takes placein spring.The leaves on trees also change. Evergreen treeshave leaves all year long. For example, pine treesare evergreen. Deciduous trees lose their leaves inautumn. For example, apple trees are deciduous.

How Can We Measure the Age of a Tree?

We can calculate how old a tree is bycounting the rings on a cross section ofits trunk. Each ring represents one yearof growth. The rings generally vary incolor and thickness because treegrowth varies from year to year. The longest-living plant is believed tobe a species of pine tree called thebristlecone pine. Some bristleconepines are 4,850 years old. This meansthat they were alive when theEgyptians were building the pyramids.

• Why does the number of rings on atrunk tell us how old the tree is?

• Which live longest, plants oranimals? Discuss.

These plants grow new leaves

in spring.

A lot of plants have lost their leaves by winter.

Activities


Explain how plants change throughout the year. Give examples. 2

1

Look and Compare

Growth Rings of a Tree

Stages of Germination

1. A is buried in the soil.

2. The grows .

3. Then, the grows.

4. Finally, the grow.

GreenhousesIn groups, have students brainstorm answers to this question: What are theadvantages of growing plants in greenhouses? (Greenhouses provide food atany time of the year, regardless of the environmental conditions outside.)

Have students look at and describe the photos. In pairs, have them readthe text and do the activities.Answer Key: 1 • They are very big. • They are made of metal and glass. • Fruits,vegetables and flowers. 2 Sample answer: We can control the conditions to make theplants grow quickly. We can grow plants all year round. The plants produce flowersand fruits several times a year. 3 Sample answer: geraniums, pansies, daisies, cacti,peppers, tomatoes, strawberries.

Animal PollinationHave students identify the animal in the illustrations. Then have individualstudents describe the process of pollination orally. Elicit the names of otheranimals that transport pollen (e.g., hummingbirds, bees, butterflies). Havestudents do the activities.

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GreenhousesWhat Are Greenhouses?

Greenhouses are enclosed areas where wegrow plants. We grow plants for food inmany greenhouses. We also grow plants todecorate the streets and our homes. A lotof the peppers, green beans, tomatoes,roses and tulips that we see in marketsgrow in greenhouses.

Cultivating Plants

In greenhouses, we can control everything thataffects plant reproduction and growth. We cankeep the temperature and humidity at optimumlevels. We can give each plant the water andfertilizer it needs. We can also give the plantssubstances to keep them healthy.Consequently, the plants grow quickly. Theyproduce fruit several times a year.

The Advantages

Growing plants in greenhouses gives us alot of fruit all year long. Not long ago,each fruit had its season. For example, youcould only buy cucumbers in summer.Now you can buy cucumbers at any timeof the year. This is because we grow themin greenhouses.

Describe the greenhouses in the photographs.

• How big are they?• What materials are they made of?• What plants do we grow in them?

What are the advantages of growing plants in greenhouses?

Find out about the greenhouses in your community. What plants grow in them?

3

2

1

SOCIETY

Monitoring plants in a greenhouse.

We also grow fruit in greenhouses, like these peppers.

We grow decorative plants like geraniums in greenhouses.

Expressing Concepts

Focus on Science

Cultivation of Plants

Discuss the fact that humans havecultivated plants for food forthousands of years; to learn how to do this, ancient peoples had toobserve plants and learn about theirmethods of reproduction.

Divide the class into groups. Set atime limit and have groups make listsof plants that humans can eat. Havethem sort the plants into those thatgrow locally and those that do not.

Name different plant foods and havestudents say if they are available allyear round or only at certain times of the year.

Ask students if it is possible tocultivate plants not native to an areaor out of season and how. Explainthat the artificially controlledconditions of a greenhouse permitthe cultivation of a large variety ofplants all year round.


Could

For example, you could only buycucumbers in summer.

Society/Investigate

ConceptCultivation of plants.

VocabularyFertilizer, greenhouse, humidity, nectar,pollen.

Answer Key: 2 1. The bat drinks the nectar of the cactus flower. 2. The pollen fromthe stamen sticks to the bat’s face. 3. The bat flies away from the flower with a lot ofpollen on its face. 4. The pollen on the bat’s face comes into contact with the stigma of another cactus flower.

Wash Fruit before You Eat ItAsk students where the fruit they eat at home comes from. Ask if theygrow fruits or vegetables at home. Invite students to talk about theirfavorite fruits and vegetables.

In pairs, have students read the text and answer the questions.Answer Key: • To remove dirt and other substances, which may make us sick. • Sampleanswer: Apples, pears, peaches, plums, grapes. I normally eat fruit with the skin on.

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Class Cookbook

Materials: Paper, yarn.

Divide the class into pairs. Askstudents to write recipes for dishescontaining fruits or vegetables.Explain that a recipe should beginwith a list of ingredients, includingthe quantity of each, followed byinstructions, along with the utensilsneeded, for preparing the dish.

Bind the finished recipes togetherwith yarn to make a class cookbook.Invite individual students to givetheir classmates cooking classes.


Social Studies: Plant Foodsaround the World

Materials: Reference books on history,computer with Internet access.

Explain that although some plantsare now cultivated virtually all overthe world, this was not always thecase. In groups, ask students to lookfor information about fruits andvegetables (e.g., sugarcane, corn,tomatoes, potatoes, pineapples)brought from one part of the worldto be cultivated in another, such asfrom Europe to the Americas. Haveeach group prepare a presentation ona fruit or vegetable, including maps,illustrations, fruits and vegetables.


Plants through the Seasons


Answer Key: 1. 1. Spring. 2. Flowersattract insects and other animals. 3. Fruit develops from the ovary andseeds from the fertilized ovules. 2. 1—It has flowers; Spring. 2—It has fruit and leaves; Summer. 4—It does not have any leaves; Winter. 3—Its leaves are falling; Autumn.

Worksheet 16

Put the sentences in the correct order. Writethem in the table.

The pollen from the stamen sticks to thebat’s face.The bat drinks the nectar of the cactus flower.The pollen on the bat’s face comes into contact with the stigma of anothercactus flower.The bat flies away from the flower with a lot of pollen on its face.

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Pollination of a Cactus Flower

1.

2.

3.

4.

Animal Pollination

INVESTIGATE

HEALTH EDUCATIONWash Fruit before

You Eat ItYou can eat some fruit, like apples, withthe skin still on. The skin containsnutrients too and is good for your teeth. Before you eat fruit, wash it well toremove dirt and other substances. Thesesubstances can get on the skin of thefruit while the plant is growing. It canalso get on the skin when the fruit istransported or sold.

• Why should we wash fruit before eating it?• Make a list of fruits that we can eat with the skin still on. How do you normally eat fruit?

Grapevine

1 2 34

Look at the pictures. 1

Have students do the activities in pairs or groups. Encourage them to lookback in the unit for information they do not remember.Answer Key: 1 asexual; involves stem, leaves; for example: bulbs, tubers, stolons.sexual; involves flowers; these produce sex cells; female, male. 2 Answers given clockwisefrom top left: a) 1. petal; pollen grains; style. 2. female sex cells; pollen grain; male sexcell; ovary. 3. female sex cell; ovary; fertilized cell. b) 1. The pollen grains in thestamen fall on the stigma of the pistil. 2. The pollen grains open. The male sex cellsappear and move to the inside of the pistil. 3. The female sex cells and the male sexcells unite inside the pistil. c) Pollination. The result of pollination is the productionof fertilized cells that will turn into seeds. 3 1. Appearance of the flowers. 2. Pollination. 3. Fertilization. 4. Formation of the fruit and seeds. 5. Germination. 6. Development of the plant.

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Test Your Knowledge

Copy and complete the diagram.

Complete and answer.

a) Copy the pictures. Label the parts.b) Write these sentences in the correct boxes:

• The pollen grains in the stamen fall on the stigma of the pistil.• The female sex cells and the male sex cells unite inside the pistil.• The pollen grains open. The male sex cells appear and move to the inside

of the pistil.c) What is this process called? What is the result?

Put these stages in the correct order. Complete the diagram.

• Formation of the fruit and seeds. • Development of the plant.• Fertilization. • Appearance of the flowers.

3

2

1

involves

leaves

for example

involves

these produce

sex cells

Plant Reproduction

2. Pollination.1. 3.

4. 6. 5. Germination.

bulbsfemale

1 2 3

Reinforcement Activities

Sexual Reproduction in Animalsand Plants

In groups, ask students to explainthe similarities and differencesbetween fertilization in animals andplants. Encourage them to useillustrations to aid their explanations.

Sexual and Asexual Reproduction

Ask students to find out how theseplants reproduce: potato, apple tree,rose bush, onion, pepper, strawberry.

Fruits and Seeds

Show photos of different fruits andask these questions: What plant doesit come from? How many seeds doeseach fruit have? What type of seed coatdoes it have?

Seeds

Ask students to write an explanation,including diagrams, in answer to thequestion How do plants make seeds?

Garden Centers

Take students to a garden center andhave them find out how differentplant species are propagated.

Test Your Knowledge

Assessment 8

Flowering Plants


Answer Key: 1. 1. Petals protect otherparts of the flower and attract animals.2. The stigma is where the pollen fromanother flower is deposited. 3. Theovary produces the female sex cells(ovules). 4. The anthers produce themale sex cells (pollen). 5. The sepalsprotect the flower before it opens. 2. 1. When pollen falls on the stigma ofthe same plant. 2. When pollen falls onthe stigma of another plant. 3. Whenwind carries pollen from the stamen ofone plant to the stigma of another. 4. When animals carry pollen from thestamen of one plant to the stigma ofanother. 5. When a male sex cell and afemale sex cell unite in the ovary.

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Assessment 8

PHOTOCOPIABLE Science 5 © 2003 Santillana Educación, S. L./Richmond Publishing

Name: Date:

Flowering Plants

1. Label the parts of the flower with the words in the box and describe their functions. (5 points)

1.2.3.4.5.

2. Define the terms. (5 points)

1. Self-pollination:

2. Cross-pollination:

3. Wind pollination:

4. Pollination by animals:

5. Fertilization:

1.

3.

2.

4.

5.

petals stigma sepals anthers ovary

plant reproduction scientific basis - worldarcstudio …richmond-elt/files/science5tchsample.pdfunit...

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