amazing earth 1

8/14/2019 Amazing Earth 1

1/8


2/8

t g mn

mIGrAtIon fActs

most migrations are triggered by

environmental changes: ood shortage,

changes in temperature, changes in length

o daylight

only the tropics dont experience these

changes

environmental changes work with a

genetically inherited sense o impending

change to impel animals to migrate

billions o animals migrate, rom the smallest

insect to the Humpback whale

a migration journey may be just a ewhundred eet or thousands o miles over

land, or through air and sea

most animals navigate during their migration

using the sun as their guide

elephants use the sun in combination with

land cues

Humpback whales are thought to use

magnetite in their brains to detect changes in

the Earths magnetic eld

many experienced migratory birds use

landmarks to pilot their way

the caribou trail: the loNgest

oVerlaNd migratioN

cArIBoU fActs

caribou are ound across Northern Europe

and Asia rom Scandinavia to Siberia as wellas in Alaska, Canada and Greenland

they eat grass and plants in summer and

lichen in winter

a emale caribou gives birth to one or two

calves ater about an eight-month gestation

male and emale caribou both have antlers

reindeer are caribou

The caribou undertake the worlds longest

land migration: some 2,000 miles. As spring

arrives in the northern hemisphere and the sun

returns to the Arctic, the thaw moves north

across the tundra and more than three million

caribou ollow. The caribous migration is

matched to the pattern and speed o the melt.

They travel in vast herds searching or resh

pasture and a place to calve, taking advantage

o the new plant growth and the nutrition thiswill oer their newborns.

Educators Guide


3/8

t g mn

ArctIc tUnDrA fActs

the tundra is the most northerly o Earths

major terrestrial biomes, circling the globe tothe south o the North Pole

it has very cold winters; short, cool summers

and little rainall

winter temperatures can all to -60F (-51C)

summer temperatures can rise to between

37F (2.7C) and 50F (12.2C)

the soil o the tundra is requently rozen

a meter below the surace is permanent ice:permarost

no trees grow in the tundralonG rAnGe trAVelers

Caribou are built or their epic journey. Their

hooves are large and concave. These act

like snowshoes, holding the caribou up both

on winter snow and on the soggy summer

tundra. In water, they operate as enormous

paddles, propelling the animal orward.

Caribou can swim across ast-fowing rivers

and large lakes with ease. They even have

the added benet o a kind o fotation jacket.The hollow hairs o their coat trap air and help

to keep them afoat. Nevertheless, they take

care when crossing rivers, either scouting or

a sae crossing point or waiting or avorable

conditions in which to cross.

DAnGeroUs encoUnters

Throughout their journey the caribou herds

have to keep constantly on the move. Calves

born on the migration must be on their eetand running the day they emerge. This is a

perilous time or the caribou. Their constant

companions are wolves. They shadow the

herds as they migrate. The wolves hunting

strategy is to run at the caribou, creating

panic and chaos in which they can separate

young calves rom their mothers. Once a wol

is chasing it, the cal has a ty-ty chance o

survival. I it can stay on its eet, it is capable

o outrunning a wol. A caribou can run at 50

miles (80 kilometers) per hour. I it makes one

mistake, the wol will be on the cal.

GreY Wolf fActs

grey wolves travel greater distances than any

other land mammal except the caribou

the wolves may hunt alone, but usually theyhunt in packs o 3 to 30 members

the size o a packs territory in Alaska andCanada is about 600 square miles (1,500 sqkm) but it can be as large as 1,000 square

miles (2,500 sq km)

grey wolves are good swimmers and willpursue their prey into water

At the other end o the scale, another danger

or the caribou are mosquitoes. These are

widespread in the caribous summer range

and a major irritant to them. I a caribou

spends too much time and energy running

away rom mosquitoes, it will not eat enough

and put on sucient weight in the summer tosee it through the ollowing winter.

sUmmer rAnGe AnD WInter rAnGe

In their summer range the caribou have

access to a rich supply o ood, which means

that both adults and calves can gain weight

and build their strength in order to survive the

ollowing winter. This is crucially important

or the survival o the herd. They head south

again to their winter range oten ater the rst

severe autumn storm. Here the weather is less

harsh and the snow cover less impenetrable,

which means they will still be able to nd ood.

They oten migrate to a dierent area o their

winter range in successive years so they avoid

stripping an area o available ood.

Educators Guide


4/8

from the tropics to the polar

seas: the 4,000 mile JourNey of

the humpback Whale

hUmpBAcK fActs

Humpbacks are among the largestmammals on Earth. They can grow up to

around 48 t (15 meters ) long and can weigh

more than 33 tons

they eed on krill and small sh, each whale

eating up to 1.11.65 tons o ood a day

they are ound in all the oceans o the world,

apart rom the Mediterranean and the

extreme Arctic

they mature between 6 and 8 years o age

and a emale may give birth once every 2 to

3 years the gestation period lasts about

12 months

a Humpback whale cal is between 10-15

eet (45 meters) long when its born and

weighs up to 1.1 ton

they can live up to 70 years o age, the

average being about 50

all Humpbacks sing

the whale song varies geographically and is

more oten heard when they are in tropical

waters

t g mn

In tropIcAl WAters

ollows the migration o the Southern

hemisphere population o Humpbacks.

They spend their winter, rom May through

late November, in the warm waters o the

tropics: waters that are suitable or breedingand calving. During these winter months, a

Humpback cal develops rapidly by suckling

requently on its mother and consuming her

high-energy milk: it has a 45-60% at content.

The cal will need all its strength to endure

the epic 4,000-mile journey it will make with

its mother to the waters o the Antarctic

peninsula.

The cals mother doesnt eed at all in these

months; she survives on her blubber. Tropical

waters are comparatively poor in nutrients.

They support a diversity o lie, but not

the large populations o krill and small sh

that a whale needs to eed on. By the time

November comes the whales must migrate

in order to eed on the vast quantities o ood

they will nd in the Antarctic.

Educators Guide 3


5/8

the JoUrneY soUth

Mothers and calves tend to be the last whales

to begin their migration, delaying until the cal

is as strong as possible. The journey south

is long, arduous and potentially perilous or

a young whale and a weak mother whale that

hasnt eaten or our months. On their journey

they will cross hal the globe, rom the tropics

all the way to the edge o Antarctica. The

Humpbacks migration is the longest migration

undertaken by any mammal on the planet.

When theyre migrating, Humpbacks travel at

an average speed o about 5 mph (8 km/hr).

As they leave the calm o the tropical seas

behind them the waters become colder and

rougher. Its essential that the mother and cal

stay close to each other; young Humpback

calves making their rst migratory journey

to Antarctica are particularly vulnerable to

attacks by sharks and Killer whales. To avoid

getting separated and losing track o each

other, mother and cal keep in contact by

slapping their ns on the surace o the water.

They can hear these sound signals above the

roar o the ocean.

The journey or the cal is massively energy

consuming. It conserves energy by swimming

in its mothers slipstream. It positions itsel

just behind the mothers widest diameter,

just underneath and to the side o her dorsal

n. By doing this, it can keep pace with its

mother using only 75% o the eort it would

use otherwise. Nevertheless, even employing

this energy-saving strategy, many calves die oexhaustion during the journey.

the AntArctIc sUmmer

The Humpbacks reach their destination in time

or the brie, three-month Antarctic summer. At

last, ater their 4,000-mile journey, the whales

can eed.

AntArctIc sUmmer fActs

Antarctic waters are rich in nutrients

the continuous 24 hours o daylight insummer produce an annual bloom o

phytoplankton in the Antarctic Ocean

phytoplankton are the basis or the AntarcticOcean ood chain

krill, small shrimp-like creatures, eed on thephytoplankton and multiply in vast numbers

swarms o krill become concentrated in ice-

ree bays and attract whales

The arrival o the whales in the Antarctic

coincides with the melting o the sea ice and

the explosion in numbers o swarming krill.

Humpbacks sometimes eed on the krill co-

operatively using a method called bubble

netting. A group o whales dive perhaps

160 eet (50 meters) below a shoal o krill

then slowly return to the surace in a spiral

ormation, blowing bubbles. These underwater

bubbles create a sort o curtain that herds

the krill together and orces them towards the

surace at the center o the circle. Eventuallythe whales surace, their mouths wide open

as they take in mouthuls o the mass o krill

trapped in the middle o the circle o bubbles.

As the season changes and the sun starts to

sink below the horizon again, the whales will

make their return journey to the warm water o

the tropics.

t g mn

Educators Guide 4


6/8

aboVe the roof of the

World: the migratioN of

the demoiselle craNes

DemoIselle crAne fActs

Demoiselles are the smallest o the cranes,just 3 t (90 cm) tall and weighing 47 lbs(23 kg)

they have a wing span o 1 t 6 in (50 cm)

they live mainly in grassland areas nearwater but can be ound in deserts wherewater is available

Demoiselles mate or lie and continue theircourtship dance throughout their lives to

maintain their bond

they usually lay their eggs directly on theground and their chicks fedge astest o allcranes at around 55 days

Demoiselle cranes were given their name byQueen Marie Antoinette, because o theirdelicate, maiden-like appearance

Demoiselle cranes undertake one o the mostchallenging migrations in nature. Each year,

thousands o them bid to escape the harshwinters o the Tibetan steppe by fying south.

They fy in a V-ormation at very high altitudes,

up to 25,000 eet (7,620 meters), and keep incontact by constantly calling to each other. Theirdestination is the warmer climates o India, but to

get there they have to cross the highest mountainrange on Earth: the Himalayas.

hImAlAYA fActs

the planets 14 highest peaks are in the

Himalayas

the highest is Mount Everest at 29,028 eet(8,848 meters)

the Himalayan range o mountains stretchesacross one-tenth o the planet

the Himalayas prevent the cold, dry winds

o the Arctic rom reaching the Indiansubcontinent and keep South Asia warm

they orce the monsoon winds blowing north

rom the tropics to drop their rain as they riseover the mountains

As the sun heats the slopes o the mountains,

warm air rises rom the valleys. The cranes usethe uplit o the thermals to gain height as theyfy towards the summit o the mountains. I the

weather changes, these small, elegant birdscan be bueted so violently by the wind that

they would be orced to give up and delay theirattempt to surmount the peaks to anotherday. They would try again when the sun rises.

As they attempt their crossing, they have tojudge whether or not they have the strength tobattle against the reezing winds around the

peaks. I they turn back they will ace the bitterextremes o winter on the Tibetan steppes.

They must go on i they are to reach theirwinter sanctuary.

t g mn

Educators Guide 5


7/8

t g mn av

the great migratioNs: actiVities

GrADes K-2: seAsons DIArY

Learning objective:

to understand that the Earth experiences

seasonal change

For children o this age to begin to understandthe concept o migration they need rstto understand that the Earth experiencesseasonal change.

Tasks

1.Several sequences in the lm showseasonal change. The deciduous orest

sequence shows it particularly well,although very young children may havediculty in understanding that a lming trickis used to show change at an acceleratedspeed. How many changes can childrenremember seeing (e.g., lea growth,blossom, spring fowers, animals and theirnew ospring, etc.)?

2.Have the children seen changes like thesein their own environment? Talk about them

and create seasons pictures. Collectthese together into a gallery o picturesor a particular season.

3. Talk about how seasonal change aectshumans. How does it aect the children? Dothey wear dierent clothes? Does what theyeat change? Do their daily activities change(e.g., travelling to school, playing, etc.)?

GrADes 3-6: seAson WAtchInG

Learning objectives:

to develop skills o scientic observation

to understand how environmental change

impacts on animals

Tasks

1.Become a Season Watcher. This canbe done by a class as a group or by anindividual. Start a notebook in which tokeep observations o the natural world.What do children notice about temperature,trees, plants, local wildlie, weather, hourso daylight? Take photographs and make

drawings.

2. Think about how the local environmentchanges seasonally and the eect thismight have on wildlie. Talk about howthese changes trigger migration.

3. Think about the conditions in theenvironments the eatured animals in migrate between. How are theydierent? How are they the same? Record

this inormation in a chart. What impels theanimal to migrate? What does the animalnd in its new location (e.g., ood, water,security rom predators during breeding,more avorable weather conditions)?

4.Plot on a map or globe (real or virtual) theroutes o the migrating animals eatured

in .

Educators Guide 6


8/8

GrADes 7-12: JoUrneYs of lIfe

Learning objective:

to understand the importance o migration

to a species survival

The stories in demonstrate vividly

the epic and perilous nature o the migration

journeys many animals take. Yet, despite the

risks, these annual treks continue, indicating

this behavior must be immensely benecial to

the species as a whole.

Tasks

1.Use the stories o migration in as

the starting point or a discussion o the

part played by migration in the continuingsurvival o a species. How does migration

benet each o the species eatured?

Does it benet them in the same or in

dierent ways?

2.Study migration in the local area. Birds are

a particularly good ocus or a migration

project because some stay in a locality

all year, some visit during a season and

some pass through on their way to another

destination. Monitor the bird population in

an area and make a record o it.

3. Focus on one os migrating animals

and research their journey in urther detail.

How could changes in environmental actors

aect these animals? The caribou are a good

case in point. As land migrating animals, they

have to cope with any obstacle in their way.

Roads and pipelines are known to cause

problems or caribou, defecting them rom

their migratory route. What might be theconsequences or the caribou o obstacles

placed in their path? What would happen i the

caribou were diverted rom the rich vegetation

o their calving areas? How might the impact

o obstacles be limited?

4.Research the navigational devices animals

use to pilot their way on their migrations.

t g mn av

Educators Guide 7

amazing earth 1

Documents