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?
____________________________________________________
____________________________________________________
____________________________________________________
____________________________________________________
____________________________________________________
2 What climatic conditions are required to create a grassland?
____________________________________________________
____________________________________________________
____________________________________________________
____________________________________________________
____________________________________________________
3 What animal grazes the Mongolian steppe?
____________________________________________________
____________________________________________________
____________________________________________________
4 How does grass recover from fire?
____________________________________________________
____________________________________________________
____________________________________________________
____________________________________________________
____________________________________________________
5 Which species of bird is the most numerous? Where
does it live?
____________________________________________________
____________________________________________________
____________________________________________________
6 Which animal migrates in huge numbers across the
African Savannah?
____________________________________________________
____________________________________________________
____________________________________________________
7 Where do the snow geese spend the winter?
____________________________________________________
____________________________________________________
____________________________________________________
____________________________________________________
____________________________________________________
8 How many snow geese migrate each year?
____________________________________________________
____________________________________________________
9 What animal is the goose’s main predator in the Arctic?
____________________________________________________
____________________________________________________
____________________________________________________
____________________________________________________
____________________________________________________
10 What do the Arctic wolves hunt?
____________________________________________________
____________________________________________________
____________________________________________________
SCREEN EDUCATION

11b
11 What was the original large grazing animal of the
American prairie?
____________________________________________________
____________________________________________________
____________________________________________________
____________________________________________________
____________________________________________________
12 What is the highest great plain in the world?
____________________________________________________
____________________________________________________
____________________________________________________
____________________________________________________
____________________________________________________
13 Why is this plain such a dry place?
____________________________________________________
____________________________________________________
____________________________________________________
____________________________________________________
14 Name the main large grazer of this system.
____________________________________________________
____________________________________________________
____________________________________________________
____________________________________________________
____________________________________________________
15 What small animal is the most common inhabitant of
the plateau?
____________________________________________________
____________________________________________________
____________________________________________________
____________________________________________________
____________________________________________________
____________________________________________________
____________________________________________________
16 What is its main predator?
____________________________________________________
____________________________________________________
____________________________________________________
____________________________________________________
____________________________________________________
17 What is the advantage of long grassland for the animals?
____________________________________________________
____________________________________________________
____________________________________________________
____________________________________________________
____________________________________________________
18 What techniques do lions use to attack and kill an
elephant?
____________________________________________________
____________________________________________________
____________________________________________________
____________________________________________________
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
For more information on Screen education magazine
or to download other free study guides visit
www.metromagazine.com.au
For hundreds of articles on Film as Text, Screen Literacy,
Multiliteracy and Media Studies, visit
www.theeducationshop.com.au
Notice: An educational institution may make copies of all or part of this Study Guide,
provided that it only makes and uses copies as reasonably required for its own
educational, non-commercial, classroom purposes and does not sell or lend such copies.
SCREEN EDUCATION
10