Planet Earth - Sepulveda Middle School

sepulvedams.org

Planet Earth - Sepulveda Middle School

A STUDYGUIDE bY Andrew Fildes

7

www.metromagazine.com.au www.theeducationshop.com.au


Overview

Planet Earth is a BBC production with five episodes in the first series (episodes one through

five) and six episodes in the second series (episodes six through eleven). Each episode

examines a specific environment, focussing on key species or relationships in each habitat;

the challenges they face; the behaviours they exhibit and the adaptations that enable them to

survive. Recent advances in photography are used to achieve some spectacular ‘first sights’

– in particular, stabilised aerial photography gives us remarkable views of migrating animals

and the techniques used by their predators to hunt them.

As the series examines pristine environments where possible, they are often extreme.

These are the parts of the world where few humans have chosen to live as the climate and

landscape is too challenging, too difficult and dangerous. The plants and animals that do

survive here have made some spectacular adaptations in forms and behaviour to live in these

far reaches of the planet.

The series is suitable for middle secondary students studying Science and SOSE, and for

senior secondary students of Biology, Environmental Science and Geography.

SCREEN EDUCATION


1

Episode Seven: Great Plains

Grass is the engine that powers all

life on land and the great swathes of

grass that blanket the plains of the

earth are the focus of this second episode.

Nothing living on earth can exist

without the grass, or at least some

similar green species.

Grassland plains cover between one

fifth and one quarter of the earth,

usually in central continental areas

where rainfall is low or highly seasonal.

Every continent has its grasslands – the

chilled steppes of Asia that extend

one third of the way around the planet;

the Pampas of South America and the

prairies of North America, the tropical

central savannah and drier southern

veldt of Africa; the spinifex scrub of arid

Central Australia. Any area of the world

that has some soil but insufficient rains

to support forest beyond occasional

clumps of small trees supports extensive

grassland. Even remote areas of

central Europe still have some rare pristine

grasslands. All are homes to herds

of grazing herbivores and the predators

that stalk them, huge flocks of birds

that feed on their seeds and burrowing

rodents that live nervous lives, fearful of

sudden eagles in a treeless landscape.

These are threatened habitats – many

have been destroyed or modified

beyond recognition as they have been

replaced with wheatlands in particular

and introduced grasses for grazing

huge herds of cattle and sheep. Of

course, a wheatfield is technically a

grassland as wheat and other cereals

are modified grasses, reminders of the

times when humans collected grass

seeds to make basic breads. Ninetyeight

per cent of the North American

long and short grass prairies have

been lost and the mallee of southern

Australia and remote Asian steppes

are threatened in the same way as

they are converted to food and textile

production. However, many of the

central Australian ‘deserts’ returned to

arid grassland condition once the rabbits

had been removed by introduced

diseases in recent years.

Web Resources

Teacher Links

http://www.southern.cma.nsw.gov.

au/pdf/SRBI-Grasslands.pdf

Episode 7:

Great Plains

(Timings Are ApproximATe)

Time Log

Intro 00:00 - 01:50

Mongolian Gazelles

and Eagles

Grassland fire and

Recovery

Savannah – Quelea

Flocks

01:50 - 03:45

03:45 - 06:00

06:00 - 07:30

Wildebeest Herds 07:30 - 08:25

Arctic Grasses 08:25 - 09.50

Snow Geese 09:50 - 12:47

Arctic Fox and Geese 12:47 - 14:35

Arctic Wolf and

Caribou

14:35 - 18:05

Arctic Fox and Geese 18:05 - 20:52

Prairies and Bison 20:52 - 23.21

Grasses Flowering 23:21 - 25:30

Tibetan Plateau and

Yak

25:25 - 27:09

Wild Tibetan Asses 27:09 - 29:08

Pika (rodents) and

Foxes

Tropical Indian Long

Grasslands

African Savannah

and Elephants

29:00 - 31:35

31:35 - 34:50

34:50 - 36:50

Elephants and Lions 36:50 - 38:10

Lion night Hunt 38:10 - 43:20

Savannah Floods and

Baboons

43:20 - end

(Australian Grasslands systems)

http://www.science.org.au/events/

grasslands/pech.htm

(Tibetan Pikas assessed as pests as

they compete with cattle for feed)

http://www.arazpa.org.au/Education_

Onsite_Grassland.htm

Werribee Zoo (Melbourne) excursion

- Senior Biology/Environmental

Sci. workshop

Student Links

http://www.bellmuseum.org/

distancelearning/prairie/build

(interactive - junior)

http://www.ucmp.berkeley.edu/

exhibits/biomes/grasslands.php

(Senior – precise definitions of

terms like Steppe and Savannah

– and other ecosystems)

Species List






















Mongolian Gazelle – Procapra gutturosa

Red-billed Quelea – Quelea quelea

Wildebeest – Connochaetes spp.

Snow Goose – Chen caerulescens

Arctic Fox – Alopex lagopus

Arctic Wolf – Canis lupus arctos

Caribou – Rangifer tarandus

Bison (Buffalo) – Bison bison

Yak – Bos grunniens

Wild Ass (Khulan) – Equus hemionus

hemionus

Plateau Pika – Ochotona curzoniae

Golden Eagle – Aquila chrysaetos

Tibetan Snow Finch – Montifringilla

henrici

Tibetan Fox – Vulpes ferrilata

Asian Elephant – Elephas maximus

Lesser Florican – Sypheotides

indica

Pygmy Hog – Sus salvanius

African Bush Elephant – Loxodonta

africana

Lion – Panthera leo

African Buffalo – Syncerus caffer

Chacma Baboon – Papio ursinus

SCREEN EDUCATION


Blackline Master | Planet Earth | Episode 7: Great Plains

Viewing Questions

1

SCREEN EDUCATION


1a

11 What proportion of the earth’s surface is grassland?

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2 What climatic conditions are required to create a grassland?

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3 What animal grazes the Mongolian steppe?

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4 How does grass recover from fire?

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5 Which species of bird is the most numerous? Where

does it live?

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6 Which animal migrates in huge numbers across the

African Savannah?

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7 Where do the snow geese spend the winter?

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8 How many snow geese migrate each year?

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9 What animal is the goose’s main predator in the Arctic?

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10 What do the Arctic wolves hunt?

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SCREEN EDUCATION


11b

11 What was the original large grazing animal of the

American prairie?

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12 What is the highest great plain in the world?

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13 Why is this plain such a dry place?

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14 Name the main large grazer of this system.

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15 What small animal is the most common inhabitant of

the plateau?

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16 What is its main predator?

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17 What is the advantage of long grassland for the animals?

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18 What techniques do lions use to attack and kill an

elephant?

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SCREEN EDUCATION


Case Study | Planet Earth | Episode 7: Great Plains

The Dust Bowl

2

SCREEN EDUCATION

7


2a

Ever since humans began to cultivate

the land rather than hunt and gather,

the grasslands have been threatened.

They were the obvious environment to

graze animals for meat and wool or to

plant dry country crops such as wheat,

oats and barley that require rain in

their early stages but need a dry, hot

summer to dry the seeds on the stem.

Of course, many of these cereal crops

are just grasses that humans had collected

for thousands of years, modified

by selective breeding for larger

seed heads and heavier yields.

The vast grasslands of the Great

Plains and the Great Basin in the

United States were once inhabited

by many different Indian tribes and

abundant wildlife who had lived

in balance with the ecosystem for

thousands of years, taking no more

than they needed. Twenty million bison

thundered across the plains, which the

Indians depended upon for food and

clothing. Then as Europeans began

to move west in search of farmland to

develop, encouraged by the Homestead

Act of 1862, 6 million settlers

came to the prairies and created one

of the worst environmental disasters in

world history.

As the settlers moved out over the

plains, forcing out the Indian tribes,

they brought cattle and sheep to graze

in the grasslands. They slaughtered

millions of bison, almost to the brink

of extinction. They were not a ‘useful’

species as they were migratory and

hard to control. Many were killed to

feed the workers building the railroads

that would bring even more settlers.

By 1889 only 541 bison were known

to be alive in the U.S. The Indians had

been deprived of their main source of

food.

The settlers farmed the land once

covered with native bluestem, buffalo

and grama grasses. The topsoil was

ploughed up and with it, the extensive

root systems of the native grasses.

The farmers planted fleshy, introduced

feed grasses for their animals and

grain crops such as barley, oats and

mostly wheat.

Early in the 1930s, an eight year

drought began, and a series of major

SCREEN EDUCATION


2b

wind storms swept over the Great

Plains and the southwest creating

huge smothering dust storms. The

soil in the grasslands had become dry

and loose from European style farm

techniques such as ploughing and the

damage caused by livestock grazing.

The roots of the grain crops and introduced

grasses could not hold the dry

topsoil under such severe winds. Tons

of loose fertile topsoil was picked up

and carried for hundreds of kilometres.

Fences were buried by huge drifts and

dirt had to be shovelled out of houses.

The dust was so thick that people

could not see, lungs were damaged,

and some people even became lost in

the storms and died.

The southern Great Plains soon

became known as the Dust Bowl

as the drought continued and the

land stripped of its topsoil could not

recover. Grass could not grow even

when there was rain and the clay subsoils

continued to create new dust

storms every summer. Farms were

now worthless.

The land became so damaged there

was very little to harvest, so thousands

of farmers and ranchers walked away

to seek their fortunes elsewhere. Many

continued west into California, often

looking like the lines of refugees seen

in wartimes. It is estimated that some

20 million hectares of land were badly

damaged and 20 million more threatened.

The worst damage occurred in

Oklahoma, Kansas, Colorado, Texas

and New Mexico.

Because of the poor judgement of

humans in converting the natural

grassland ecosystems into grain crops

(monocultures), allowing the remaining

grasslands to be overgrazed, and

not using proper farming methods, the

land was unable to cope with such

a long drought and unusually severe

wind storms. The government set up

programs to help restore the land, and

they taught the remaining farmers how

to protect the soil and reduce erosion.

The settlers began to restore and protect

the land, and they planted trees

as windbreaks. The land, the Indians,

the settlers, and the bison species

had all suffered greatly, and harsh

lessons had been learned. But around

the world in many countries, the same

mistakes are being made and climate

changes such as global warming are

accelerating the process.

Great Plains – Discussion

Questions

The grassland plains cover huge areas

of the earth and vary considerably

depending on climate, some are short

grasslands (steppes), some long grass

(savannah) and some seasonal as in

the Arctic. Each provides a habitat for

a complex ecosystem, including soil

fauna, grazers and predators. They

range from the wet, long grasslands

of northern India, which can conceal

an elephant, to the arid grasslands of

central Australia which were reduced

to desert by rabbit infestation.

1. The flowering of the grasses (did

you even know that grasses flowered

so beautifully?) was done with

‘time-lapse’ photography. How is

that process achieved?

2. The snow goose eggs all hatch

within one to two days of each

other – a million goslings at once.

What survival advantage would

there be in this close timing?

3. The Tibetan fox must hunt the

pika out in the open with very little

cover and get close enough to

catch it. What physical adaptations

and behaviours help it to achieve

this.

4. What similarities and what differences

are visible in the various

grasslands in the documentary.

How do you explain these similarities

and differences?

Extension Tasks



Draw up a table or a visual presentation

(poster) that compares two

different grassland habitats and

the numerous differences between

the two.

Discuss the principle threats to

grasslands from human activities

such as farming and grazing.

Prepare a visual presentation such

as a poster or PowerPoint presentation

that shows the extent of

damage and the possible restoration

measures.

SCREEN EDUCATION


ANSWER SHEET

Viewing Questions

1. One quarter of the earth’s surface

is grassland

2. Insufficient rain for forest but too

much for desert

3. The Mongolian gazelle

4. It re-grows quickly from the protected

base of the stem

5. The red-billed quelea of the African

Savannah

6. Wildebeest – two million herd

7. In the Gulf of Mexico (very sensibly)

8. Five million

9. Arctic fox

10. Caribou

11. The bison (or buffalo) was the

original prairie grazer

12. The highest plain is the Tibetan

plateau

13. The Himalayas act as a barrier,

blocking clouds from the south

(rain shadow effect)

14. The wild Asian ass

15. The pika, a relative of the rabbit

16. The Tibetan fox hunts the pika

17. Even large animals like elephants

can conceal themselves and feed

themselves

18. They attack by night, select an

isolated animal of the right size

and attack in large numbers

Great Plains – Discussion

Questions

1. A film camera is locked into

position on a tripod. It is set to

take one shot every few seconds

instead of twenty-four shots every

second. The film is then shown at

normal speed that has the effect

of speeding up the motion by up

to several hundred times. It makes

plants come to life. The same

process is used for animating clay

models like Wallace and Grommit

and is easy to do – but very slow.

2. There are huge numbers of

goslings and only a few foxes to

predate them so the chances of

survival are much better for each

individual gosling. It is one in a million

possible targets for a fox!

3. Its colour and the strange stalking

movements help it to get close

enough to dig out the pika before it

can get too deep. Even the strange

square face may make it harder to

see when it keeps still.

4. None of them has trees in any

numbers. All have grazing animals

that rely exclusively on grass as

a food source. All have predators

which have the ability to hunt

out in the open by various means

– sneaky animals like foxes, birds

like eagles, pack hunters like lions.

However, some have sparse seasonal

grasses so grazers like snow

geese migrate for the growing season,

others have permanent short

grasses that support migrating

herds and others have lush, long

grasses that support large animals

all year around.

BBC and Planet Earth are trade marks

of the British Broadcasting Corporation

and are used under licence.

Planet Earth logo © BBC 2006. BBC

logo © BBC 1996.

This study guide was produced by ATOM

editor@atom.org.au

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SCREEN EDUCATION

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