science scott foresman a

Organisms in the Biosphere Scientists have discovered and named nearly two million different organisms in Earth’s biosphere.. Variety Among Living Things If your class wrote the names o

8dbeVgZVcY8dcigVhi

@cdl^c\]dli]^c\hdgZkZcihVgZVầZVcYY^[[ZgZciXVc]Zaendj jcYZghiVcYi]ZhX^ZcXZndjgZVY#L]ZcndjXdbeVgZild^iZbh!ndj

iZaa]dli]ZnVgZVầZ#L]ZcndjXdcigVhii]Zb!ndjiZaa]dli]ZnVgZ

)TSEDGESSURFACE WAS

6eean>i

BV`ZV\gVe]^Xdg\Vc^oZg ầZi]^hdcZ#8dbeVgZVcY XdcigVhii]ZaZVkZh^ci]Z

_djgcVaZcign#Lg^iZlVnh i]Vii]ZaZVkZhVgZVầZ^c

i]ZXZciZg#I]Zc^ci]ZAZV[6 Wdm!iZaal]VibV`ZhAZV[6 Y^[[ZgZci[gdbAZV[7#>ci]Z

A useful strategy for understanding anything you read is to create

a graphic organizer

A graphic organizer can help you think about the information and relate parts of

it to each other

Each reading skill has a certain graphic organizer

A page like this one is toward the beginning of each chapter

It shows you how to use a reading skill that will help you

understand what you read

Before Reading

Before you read the chapter, read the Build Background page

and think about how to answer the question Recall what you

already know as you answer the question Work with a partner

to make a list of what you already know Then read the How

to Read Science pagẹ

XVgWdcY^dm^YZ a^\]iZcZg\n

X]adgde]naa

\ajXdhZdmn\Zc XVgWdcY^dm^YZlViZgZcZg\n

4HE PRODUCED FOR PHOTOSYNTHESIS OXYGEN

4HE

$AY OXYGEN BOTH ENERGY THE THE THAT

&# L]ViYdeaVcihcZZYidXVggndce]didhnci]Zh^h4

'# L]nYdbdhiaZVkZh]VkZbdgZhidbViVdci]ZadlZgZe^YZgb^h

i]Vcdci]ZjeeZgZe^YZgb^h4 (# 8dbeVgZVcY8dcigVhi=dlYdZhi]ZgdaZd[ZcZg\nY^[[Zg

^ce]didhnci]Zh^hVcYXZaajaVggZhe^gVi^dc4



HeZX^Zh6 HeZX^Zh7 HeZX^Zh8

HiZb g^\^YVcYhigdc\

\gZZc!

ZVhnid

WZcY g^\^YVcY higdc\

xxi

After Reading

After you have read the chapter, think about what you found out Exchange ideas with your partner Compare the list you made before you read the chapter with what you learned

by reading it Answer the questions

in the Chapter Review One question uses the reading target skill.

During Reading

As you read the lesson, use the Checkpoint to check your understanding Some Checkpoints ask you to use the reading

target skill.

These are the target reading skills with their graphic organizers.

Predict

and Details

Graphic Organizers

28962_xxii-xxvii_FSD i 11/13/06 5:58:34 PM

xxiii

28962_xxii-xxvii_FSD iii 11/13/06 5:58:42 PM

xxv

What material is best for keeping heat in water?

Ask a question.

You might have a question

about something you observe

State your hypothesis.

A hypothesis is a possible

answer to your question

If I wrap the jar in fake fur, then the water will stay warmer longer

Identify and

control variables.

Variables are things

that can change For

a fair test, you choose

just one variable to

change Keep all other

variables the same Test other materials Put the same

amount of warm water in other jars that are the same size and shape

Scientists use scientific methods as they work Scientific methods are

organized ways to answer questions and solve problems Scientific methods

include the steps shown here Scientists might not use all the steps They

might not use the steps in this order You will use scientific methods when

you do the Full Inquiry activity at the end of each unit You also will

use scientific methods when you do Science Fair Projects.

28962_xxii-xxvii_FSD v 11/13/06 5:58:51 PM

cientists know they must work safely when doing experiments You need to be

careful when doing science activities too

Follow these safety rules.

• Read the activity carefully before you start.

• Listen to the teacher’s instructions

Ask questions about things you do not understand.

• Wear safety goggles when needed.

• Keep your work area neat and clean

Clean up spills right away.

• Never taste or smell substances unless directed

to do so by your teacher.

• Handle sharp items and other equipment

carefully.

• Use chemicals carefully.

• Help keep plants and animals that you

use safe.

• Tell your teacher if there is an accident

or you see something that looks unsafe.

• Put materials away when you finish.

• Dispose of chemicals properly.

• Wash your hands well when you

are finished.

xxxii

A microscope uses a series

of lenses that make objects appear larger When you change the combination and position of lenses, you magnify objects by different amounts

A hand lens makes objects appear larger A hand lens,

or magnifying glass, doesn’t enlarge things as much as a microscope does, but you can easily carry a hand lens

Graduated cylinders

and beakers can be used

to measure volume, or the amount of space an object takes up

A meterstick or metric ruler is used to measure length

A meterstick is one meter long

The stick is divided into smaller units—usually centimeters and millimeters

A stopwatch is a watch with a hand that can be stopped or started It can be used for timing experiments

cientists use many different kinds of tools

Tools can make objects appear larger They can

help you measure volume, temperature, length,

distance, and mass Tools can help you figure out

amounts and analyze your data Tools can also

help you find the latest scientific information.

A thermometer is used to measure the temperature of

an object The liquid in the thermometer expands when

it gets warmer and contracts when it cools This causes the liquid to move up and down the temperature scale In the Celsius scale, 0° represents the freezing point of water, and 100° represents the boiling point of water

Cameras can be used

to take pictures of objects

Pictures help you record and compare objects and observe changes

Scientists use computers in many ways, such as for collecting, recording, and analyzing data

A balance is used to measure mass To find the

mass of an object, add standard masses to the pan

opposite the pan holding the object When the two

pans are at the same level, the sum of the standard

masses equals the mass of the object

Computer-aided design is a way of using a computer to make plans such as drawings for a new machine or building

A spring scale is used to

measure force Because the weight of an object is a measure of the force of gravity on the object, you can use a spring scale to measure weight in grams

Calculators make

analyzing data

easier and faster

Tape recorders are used by scientists

to record and learn about sounds made

by organisms or objects

Scientists use

barometers to measure the air pressure, which can

be a good indicator

of weather patterns

Field guides are books that you might take into the field to learn the details of objects that you are observing, such as plants, animals, or stars

Binoculars have two eyepieces that contain lenses that magnify objects Binoculars allow you to see the details of objects that you wouldn’t

be able to see because they are too far away, such as birds in a tree

An anemometer

measures wind speed

Some anemometers also measure the direction of the wind

A probe is an instrument used for investigating hard-to-reach objects or parts of objects A temperature probe is

a sticklike tool inserted into an object to measure temperature A space probe explores planets and other objects in space that people cannot reach

Scientists use

voltmeters to measure the difference

in electrical charge between two points within a circuit

where living things on Earth live.

how Earth’s living things are classifi ed.

1

28962_001-003_FSD 1 10/3/06 10:52:01 AM

biosphere

adaptation

nonvascular plant

The part of Earth that

can support living things

2

species classifi cation

bacteria

fungi vascular plant

Explore How are mushrooms different?

Scientists can tell one type of mushroom from another by studying

spore prints, the patterns and colors made by mushroom spores

What to Do

Cut off the stem so the mushroom lies flat Place the mushroom on the paper

Materials

Cover the mushroom with a cup and leave it for 2 days

Repeat steps 1 and 2 with 2 other kinds of mushrooms

After 2 days, remove the cups Carefully remove the mushrooms Observe

the spore prints on the paper

Explain Your Results

1 How are the spore prints alike and different? Are the prints a useful way to tell mushrooms apart? Explain

2 How can you use a spore print to classify mushrooms?

3 kinds of mushrooms

plastic knife

white and black paper

3 cups

Spore prints can

help you classify

Compare and Contrast

When you look at how things are alike and different, you are

comparing and contrasting. When comparing two items, tell how they are alike When contrasting, tell how items are different

• Clue words and phrases such as similar, like, all, both, in the same way, and as well as signal comparisons.

• Clue words such as different, unlike, in a different way, and in contrast

signal contrasts

Clue words are marked in the article below

Science ArticleFungiMolds and mushrooms are two kinds of fungi Molds, such as the black, fuzzy mold that grows on bread, are threadlike fungi In contrast, mushrooms are club fungi, fungi that are somewhat umbrella shaped Both molds and mushrooms grow rootlike structures that often are hidden underneath the ground All fungi get their food from other organisms

Molds Alike Mushrooms

You are trudging along in the hot desert,

and a flash of bright yellow catches your

attention A closer look reveals bright cactus

flowers Suddenly you hear a rustling noise

What is this shocking beauty among the

blossoms? A snake! What kind of snake is

this? How can you find out? Perhaps no one

has ever seen this type of snake before—you

may have discovered a new organism!

6

is large But if you could shrink Earth to the size of an apple, the area in which things can live would be less than the thickness of the apple’s skin.

The part of Earth that can support living things is called

the biosphere Living things and their environments make

up the biosphere The biosphere has many environments, such as deserts, oceans, fields, beaches, backyards, and the sidewalks of the busiest streets

Organisms in the Biosphere

Scientists have discovered and named nearly two million different organisms in Earth’s biosphere Even so, scientists think that millions more organisms have not been discovered

Why are so many living things still unknown? Some parts

of Earth have not been well studied Earth’s deep oceans, polar areas, dense rain forests, and vast deserts are just some

of the areas about which we still have a lot to learn Also, many of Earth’s organisms are very tiny and hard to find

Each organism in the biosphere interacts with other organisms and the environment to produce a web of interactions Humans, too, play an important part in this changing web Because all parts of the web are connected,

a small change in one part can produce a large change in another part

that describes an environment in your area Name the types of organisms that live there

These colorful fungi are well suited to grow on the damp forest floor

Determined dandelions poke through this sidewalk Your neighborhood is also part of the biosphere

This blackside hawkfish spends much of its time motionless among the coral Coral are living organisms What you usually see are coral shells The soft, living body of the coral grows inside holes in the shell

Variety Among Living Things

If your class wrote the names of all the different organisms each student knows, imagine how long the list would be! But your list would be very small compared to all the known organisms on our planet

Earth has an amazing variety of living things

These organisms have many different body plans and structures These differences make it possible for organisms to live in almost every place on Earth

Look at the plants and animals pictured on these pages

They all are alike in some ways For example, they are made of cells, they require a source of energy, and they reproduce But these organisms are also very different

The differences enable each kind of organism to survive

in its particular environment

A characteristic that enables an organism to survive and reproduce in its environment is called an

adaptation For example, the spines of the cactus are

actually modified leaves Their shape helps stop water loss from the plant They also protect the cactus from being eaten The thick, fleshy stems of a cactus can store a lot of water—an important adaptation for

a plant that grows in such a dry environment

As you look at the other pictures on these pages, think about how each organism’s adaptations help it survive in its

environment

Groups of Organisms

Although there is great variety among organisms, some groups of organisms share many of the same characteristics These organisms may

be members of the same species

A species is a group of very similar

organisms whose members can mate with one another and produce offspring that are able to produce offspring For example, the horses in the photo are members of the same species Each species has a two-part scientific name The scientific name

for the horse is Equus caballus

Each type of fish has a

mouth designed for its

own style of feeding This

parrotfish scrapes algae off

the surrounding coral Can

you see how it gets its name?

How do the adaptations of

this cactus help it survive?

The hard shells of these snails

help protect their soft bodies,

much the same as your skull

protects your brain

keyword: adaptation code: g6p8

that you are familiar with Describe its environment and some of its adaptations Tell how the organism’s adaptations help it survive in its environment

Like the horses below, individuals in the same species often don’t look exactly alike In fact, they can be different in many ways, including size, color, and shape

But they do share similar body plans and structures

As you can see from the chart, the number of species for different kinds of organisms is very large The chart, however, only includes the species that have been identified and live today Some scientists think that

99 percent of all species that have ever lived on Earth

no longer exist Most of them have left no fossil evidence that they lived

Group

Number

of Living Species

Mammals 4,000 Birds 9,000 Reptiles 6,000 Amphibians 4,000 Fish 19,000

Invertebrates 980,000

What characteristics do these horses share?

9

Scientists sort organisms into groups with similar characteristics

Grouping organisms makes studying them easier Many scientists today divide all Earth’s organisms into six main groups called kingdoms

How Organisms Are Grouped

With so many kinds of organisms, how can scientists study them?

Think about how a music store organizes the CDs it sells Most music stores group together musicians that share certain characteristics

Animals

The organisms shown here

are all members of the

animal kingdom Animals

are multicellular organisms

that must obtain their food

by eating other organisms

Insects

The insect class contains only arthropods with bodies that are divided into three sections and that usually have three pairs of legs at the middle section

Arthropods

Animals that belong to the arthropod phylum share these characteristics: jointed legs, a body divided into segments, and a hard outer skeleton

Species Genus

11

A music store may sort the musicians by the type of music they play In a similar way, scientists group Earth’s many organisms by the similarities of their characteristics These similarities may or may not

be easily seen The grouping of things according to their similarities is

1 Why do scientists classify organisms?

2 Scientists have discovered about 800,000 species of insects But scientists think that there may be as many

as 10,000,000 insect species What percentage of the total number

of insect species have been discovered?

Coleoptera

This order contains only insects with two pairs of wings that meet in a straight line along the back The longer back wings are under the front wings

Coccinellidae

This family contains only ladybug beetles All members are dome-shaped, usually brightly colored and spotted, have short legs, and are less than one centimeter long

Coccinella novemnotata

Members of different species

in the same genus are very similar but cannot mate with one another The red spotted ladybug beetle belongs to

the genus Coccinella and the species novemnotata.

Order

Family

Organisms in The Six Kingdoms

Linnaeus did not have the scientific tools that scientists have today, such as powerful microscopes to study an organism’s cells As scientists developed new tools for studying organisms, they recognized living things that didn’t fit into Linnaeus’s two kingdoms —plants and animals For example, scientists discovered

bacteria, single-celled organisms that do not have a nucleus

Both plant and animal cells contain a nucleus This important difference caused many scientists to think that bacteria should be grouped separately from plants or animals Today most scientists classify organisms according to their cell structure and how they get food and reproduce

Many scientists put organisms into six kingdoms Kingdom Archaebacteria includes bacteria that live where most other organisms cannot—in water that has a lot of salt or is very hot

The kingdom Eubacteria includes all other bacteria They live in almost every environment, including your body In fact, there are more bacteria in your mouth than there are people on Earth!

Protists and Fungi

The more than 200,000 known species of protists are mostly one-celled organisms Some scientists think that this kingdom should be broken into smaller kingdoms The cells of all protists contain a nucleus

Some protists are like animals They get energy by eating other organisms The ameba is an example Plantlike protists contain chlorophyll that they use to make their own food during photosynthesis Algae are plantlike protists Some protists are like fungi They grow in damp, nutrient-rich environments, where they absorb food through their cell membranes

Fungi are mostly many-celled organisms that often grow in

moist, dark places Many give off chemicals that break down the organisms on which they grow In the process, fungi get the nutrients they need In two types of fungi, mushrooms and molds, cells form threadlike strands called hyphae The hyphae take in the nutrients for the organism Hyphae can form thick, large mats One single mushroom in Oregon has a web of underground hyphae that spreads 2,200 acres That’s the size of 1,665 football fields! Yeast cells, another kind of fungus that you can see in the picture, are not connected by hyphae

Many fungi look like plants and have cells similar to plants

But plant cells contain chlorophyll, which plants use as they make food Fungi do not have chlorophyll Instead they take in nutrients from other organisms

Yeasts are important fungi

used in the process of

making bread

Like most fungi, this mold

absorbs nutrients from

other organisms—in this

case a strawberry

1 What are the six kingdoms of organisms? Give an example of each

2 Compare and Contrast How do fungi differ from plants?

3 Descriptive Collect leaves from local trees and

write descriptions of them Use your descriptions and a field guide for trees from your local library or other sources to identify the trees the leaves came from

Archaebacteria

Archaebacteria have been on Earth for billions of years Some can live in hot springs where water temperatures can reach 110°C Archaebacteria can grow in water that is ten times saltier than seawater

Eubacteria

Eubacteria can cause disease, but many are helpful They make soil fertile and are necessary for making foods such as yogurts and cheeses Some eubacteria make vitamins in the human body

Protists

Protists formed much of the gas and oil we use today Although some protists are harmful, most are helpful Many are food for other organisms, including Earth’s largest organisms—whales

Animals

Animals get energy by eating other organisms or their remains Topi, such as this one, live in Africa Like all organisms, a topi has special adaptations that make it able to find and eat the type of food it needs

The Six Kingdoms

14

Lesson 3

How are plants and

animals classifi ed?

Plants can make their own food Animals get energy from other living things Organisms in the plant and animal

kingdoms can be classified into smaller groups.

Plant Classification

Look around How many different kinds of plants do you see? Plants come in many colors, sizes, and shapes Some

are as tall as the coast redwoods in California, which can

rise 112 meters Others, like the duckweed that covers

many ponds, are tiny—as little as 0.6 millimeters tall

But whether big or small, plants are important to all other

living organisms on Earth Most living things gain energy

directly or indirectly from plants Besides being a source

of food, plants also help make Earth’s climate stable

Notice in the diagram on the next page that all plants can be divided into two groups—vascular plants and

nonvascular plants Vascular plants have cells that

form tubes for carrying water and nutrients throughout

the plants These tubes can carry materials long distances,

such as up the trunk of a 112-meter redwood

Vascular plants can be divided into two groups—plants that make seeds and plants that do not You probably

are most familiar with plants that produce seeds Some

examples of seed plants are tulips, grasses, maple trees,

and tomato plants Some seed plants are gymnosperms,

seed plants that do not produce flowers They include

plants that you might call “evergreens,” such as pine

or fir Angiosperms are seed plants that produce flowers

Horsetails and ferns are two kinds of seedless plants

Other plants, called nonvascular plants, do not have

tubes to carry materials Instead materials must pass

slowly from one cell to another For this reason, most

nonvascular plants, such as mosses, are small There

are at least 232,000 species of vascular plants and about

16,000 species of nonvascular plants

Materials cannot travel quickly through nonvascular plants,

so nonvascular plants such as this moss live

in damp places, where water is plentiful

Vascular

Seed

Gymnosperms Plants

15

1 Name the two groups of vascular plants and give examples of each

to classify living things was Aristotle, a Greek scholar Research Aristotle’s classification system Summarize Aristotle’s system in a graphic organizer

Horsetails were very common hundreds of millions of years ago

Then they grew as tall

as trees Today only about 35 species can

be found, and they are much smaller

This sequoia and other gymnosperms do not produce flowers They make seeds in cones Roses are flowering

plants that produce seeds Flowering seed plants are the most abundant type

of plant today

Angiosperms

Animal Classification

You probably recognize some of the organisms pictured

on these two pages as animals But you might think that some, such as the peacock worms or sea fans, are plants

The animal kingdom is divided into about 35 different phyla

You can read about six of these phyla on the next page

Although animals can be very different, they all share certain characteristics Animals are multicellular organisms, and they cannot make their own food They get food by eating other organisms The cells of animals contain

a nucleus but do not have a cell wall

About 95 percent of all animal species on Earth are invertebrates

Invertebrates are animals that do not have a backbone They range

in size from microscopic mites that cover your body to the giant squid, which can be 20 meters long

Only the phylum Chordates contains animals that are vertebrates, or animals with backbones Fishes, amphibians, reptiles, birds, and mammals are vertebrates

1 Use the information on page 17 to identify one characteristic of each phylum

2 Give at least three details to support this statement:

The plant kingdom includes species with a variety of characteristics

3 Compare and Contrast Use a compare and

contrast graphic organizer to show how plants and animals are alike and different

How is this squid

similar to other

mollusks?

The segmented body,

jointed legs, and hard

outer skeleton make this

centipede a member of

what phylum?

Mollusks

It’s hard to believe, but this graceful animal is related

to a clam This nautilus belongs to the invertebrate phylum Mollusks, which includes clams, squid, octopuses, snails, and slugs All mollusks have soft bodies, and most have hard shells

Segmented Worms

These feathers are actually the tentacles of peacock worms that live on the ocean floor The worm uses its tentacles to catch food Other animals in this phylum are the common earthworm and leeches

Arthropods

This tarantula spider is not an insect, but it belongs to the same phylum as insects—Arthropods Other spiders, crabs, millipedes, and centipedes are also arthropods All arthropods have segmented bodies, jointed appendages, and hard skeletons on the outside of their bodies Arthropods include almost 85 percent of Earth’s animal species

Echinoderms

Sea stars are echinoderms, animals that live in the ocean and have tough, spiny skins This phylum also includes brittle stars, sea lilies, sea urchins, and sea cucumbers Echinoderm bodies have a unique five-part balanced arrangement of parts that makes these animals easy to recognize They have skeletons made of hard calcium plates inside their bodies

Cnidarians

These beauties on the coral reef are animals, not exotic plants The fan-shaped creatures are corals called sea fans The phylum Cnidarians also includes jellyfish and anemones Cnidarians have a single body opening that

is usually surrounded by a ring of stinging cells

Investigate How can you identify

and classify organisms?

An identification key is a tool that helps a user to

identify an organism based on its characteristics

Materials What to Do

Study the steps in the first part of How to Read and Construct Keys Then follow the steps to learn how to use a key to identify the insects below

Following the steps

banana

flight wings: protected shape: round

June Beetle flight wings: protected shape: oblong

flight wings: unprotected wings: point to back end of body

How to Read and

1 a If the flight wings are protected by a hard covering, go to step 2

b If the flight wings are not protected by a hard covering, go to step 3

2 a If the body has a round shape, it is a ladybug

b If the body has an oblong shape, it is a June beetle

3 a If the wings stick out from the side of the body,

it is a dragonfly

b If the wings point to the back end of the body,

it is a housefly

First, think of ways to classify the fruits based on their characteristics Then, study the second part of How to Read and Construct Keys Use what you learn to help you complete the Fruit Identification Key

Fruit Identification Key

1 a If the skin is bumpy, go to step 2.

b If the skin is smooth, go to step 3.

2 a If the fruit is round, it is an .

b If the fruit is oval, it is a .

3 a If the color is solid, go to step 4.

b If the color is striped, it is a

4 a If the shape is long and narrow, it is a .

b If the shape is round, it is a .

Explain Your Results

1 The key lists one special characteristic for each fruit

How does this help you identify a fruit?

2 Infer What other characteristics of fruits could be used in an identification key?

shape: oval skin: smooth color: 2-tone, striped

shape: round skin: smooth color: solid, red

shape: round skin: bumpy color: solid, orange

shape: oval skin: bumpy color: solid, yellow

shape: long, narrow skin: smooth

color: solid, yellow

How would you classify another group of things, such as seashells? Design a key that identifies 6 different things in 5 steps

Have you ever seen an ungulate? You have probably seen many of them, even different kinds of ungulates Ungulates are animals with toes that end in hooves

Among ungulates there are two orders—

those that have an even number of toes and those that have an odd number of toes The circle graph below shows the number of species within each family of odd-toed ungulates

20

Use the circle graph to answer the questions.

1 Are there more species of rhinoceroses

or tapirs?

2 Which group has about 25% of the species?

3 If the total number of species is 16, which most likely gives the number of species in each family?

A 8 species of horses and zebras

Choose one of the ungulate families shown

on the circle graph Research to find estimates of how many animals for each species in that family are alive today Write a report or make a bar graph showing what you learned

21

28962_020-021_FSD 2 11/8/06 7:37:58 PM

Use Vocabulary

Write the word from the list above that best

matches each description

_ 1 A group of similar organisms that

can mate and reproduce

_ 2 The grouping of things according to

_ 5 Plant that does not have tubes for

carrying water and nutrients

_ 6 Usually many-celled organisms that

often grow in moist, dark places

_ 7 Single-celled organisms that do not

have a nucleus

_ 8 A characteristic that enables an

organism to survive and reproduce

in its environment

Explain Concepts

9 Why do scientists classify organisms?

10 Explain how mushrooms, molds, and

yeasts are alike and different

11 What percentage of all vertebrate species

are mammals? Use the table below to help you answer the question

(p 14)

species (p 8) vascular plant

(p 14)

Vertebrate Species Group Number of species

is a plant

13 Questions and Hypotheses You want to grow some mushrooms in the classroom, but you aren’t sure what conditions are best for growth Use what you learned about fungi in this chapter to write a testable hypothesis for finding out

14 Classify An organism has the following characteristics: It is made of a single cell with a nucleus, it lives in a pond, and it can make its own food as well as take

in nutrients from other organisms Into what kingdom would you classify this organism? Why?

Compare and Contrast

15 Make a graphic organizer like the one

shown below Fill in the circles to compare and contrast vascular and nonvascular plants

Test Prep

Choose the letter that best completes the statement or answers the question

16 Which feature is probably not the same

for all organisms in the same species?

훽 how they obtain nutrients

훾 their size

훿 how they reproduce

 their body structure

17 Which is an example of a kingdom?

훾 cells without a nucleus

훿 found almost everywhere on Earth

 cells containing chlorophyll

19 Explain why the answer you chose for

Question 18 is the best For each of the answers that you did not choose, give a reason why it is not the best choice

Plants have been used to treat

illnesses for hundreds of years

What treatments and cures are

locked in the thousands of plants

yet to be discovered? That’s one

of the questions Ynes Mexia

wanted to explore.

Mexia’s interest in plants began in 1920 when Mexia was 50 years old She started

taking field trips with the Sierra Club to

explore the variety of flowers growing in the hills around San Francisco

To learn more, she entered the University of California to study botany—

the science of plants

Armed with greater knowledge and endless curiosity, Mexia made her first major expedition in 1925 to western Mexico Over the next 13 years,

she explored many different environments in search of new plant species

She climbed the slopes of Mt McKinley in Alaska She trekked through

the deserts of the American Southwest She even rafted and canoed

thousands of kilometers up the Amazon River to explore the rain forests

of South America

Mexia collected thousands of specimens, including some that were important sources of medicines She also discovered new species Because

of her work, we know more about the amazing variety and uses of plants

Ynes Mexia carefully drew and photographed her specimens for others to study Are you

a keen observer? Take a field trip near your home or in a park Draw, photograph, or describe several kinds of plants Display your work for others to enjoy

24

how scientists learned about cells.

what the function is of some common cell parts.

how cells make new cells.

25

28962_025-027_FSD 25 10/3/06 10:56:21 AM

chromosome DNA

Chapter 2 Vocabulary organelle page 34

endoplasmic reticulum page 34