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Health in the Wild

Many animals seem able to treat their illnesses themselves. Humans may

have a thing or two to learn from them.

For the past decade Dr Engel, a lecture in environmental sciences at

Britain’s

Open

University,

has

been

collating

examples

of

self-medicating behavior in wild animals. She recently published a book

on the subject.

In a talk at

the

Edinburgh science

Festival earlier this

month,

she

explained that

the

idea

that

animals

can

treat

themselves

has

been regarded with some skepticism by her colleagues in the past. But a

growing number of animal behaviourists now think that wild animals can

and do deal with their own medical needs.

One example of self- medication was discovered in 1987. Michael Huffman

and Mohamedi Seifu, working in the Mahale Mountains National Park in

Tanzania,

noticed

that

local

chimpanzees

suffering

from

intestinal

worms

would dose themselves with pith of a plant called Veronia. This plant

produces

poisonous

chemicals

called

terpenes.

Its

pith

contains

a

strong

enough concentration to kill

gut parasites, but

not so strong as

to kill

chimps(nor people, for that matter; locals use the pith for the same

purpose).Given

that

the

plant

is

known

locally

as

“goat

-

killer”,

however,

it

seems

that

not

all

animals

are

as

smart

as

chimps

and

humans.

Some consume it indiscriminately, and succumb.

Since

the

Veronia-eating

chimps

were

discovered,

more

evidence

has

emerged

suggesting

that

animals

often

eat

things

for

medical

rather

than

nutritional

reasons.

Many

species,

for

example,

consume

dirt-

a

behavior

known

as

geophagy.

Historically,

the

preferred

explanation

was

that

soil

supplies minerals such as salt. But geophagy occurs in areas where the

earth

is

not

a

useful

source

of

minerals,

and

also

in

places

where

minerals

can

be

more

easily

obtained

from

certain

plants

that

are

known

to

be

rich

in

them.

Clearly,

the

animals

must

be

getting

something

else

out

of

eating

earth.

The

current

belief

is

that

soil-and

particularly

the

clay

in

it-helps

to

detoxify

the

defensive

posions

that

some

plants

produce

in

an attempt

to

prevent

themselves

from

being

eaten.

Evidence

for

the

detoxifying

nature

of clay came in 1999, from an experiment carried out on macaws by James

Gilardi

and

his

colleagues

at

the

University

of

California,

Davis,

Macaws

eat

seeds

containing

alkaloids,

a

group

of

chemicals

that

has

some

notoriously

toxic

members

such

as

strychnine.

In

the

wild,

the

birds

are

frequently seen perched on eroding riverbanks eating clay. Dr Gillardi

fed one group of macaws a mixture of a harmless alkaloid and clay, and

a second group just the alkaloid. Several hours later, the macaws that

had

eaten

the

clay

had

60%

less

alkaloid

in

their

blood

streams

than

those

that had not, suggesting that the hypothesis is correct.

Other observations

also support the idea that clays is detoxifying.

Towards the tropics the amount toxic compounds in plants increases-and

so

does

the

amount

of

earth

eaten

by

herbivores.

Elephants

lick

clay

from

mud holes all year

around, except

in

September when they

are bingeing on

fruit which, because it has evolved to be eaten, is not toxic. And the

addition of

clay

to the

diets of domestic cattle increases

the amount of

nutrients that they can absorb from their food by 10-20%.

A third instance of animal self-medications is the use of mechanical

scours

to

get

rid

of

gut

parasites.

In

1972

Richard

Wrangham,

a

researcher

at the Gombe Stream Reserve in Tanzania, noticed that chimpanzees were

eating the leaves of a tree called Aspilla. The chimps chose the leaves

carefully by testing them in their

mouths. Having chosen a leaf,

a chimp

would fold it into a fan and swallow it. Some of the chimps were noticed

wrinkling their noses as they swallowed these leaves, suggesting the

experience was unpleasant. Later, undigested leaves were found on the

forest floor.

Dr

Wrangham

rightly

guessed

that

the

leaves

had

a

medicinal

purpose-this

was, indeed, one of the earliest interpretations of a behavior pattern

as self-medication. However, he guessed wrong about what the mechanism

was. His(and everybody else’s) assumption was that Aspilla contained a

drug,

and

his

sparked

more

than

two

decades

of

phytochemical

research

to

try to find out what chemical the chimps were after. But by the 1990s,

chimps

across

Africa had

been

seen

swallowing

the

leaves

of

19 different

species that seemed to have few suitable chemicals in common. The drug

hypothesis was looking more and more dubious.

It

was

Dr

Huffman

who

got

to

the

bottom

of

the

problem.

He

did

so

by

watching

what came out of

the chimps,

rather than concentrating on what went in.

He

found

that

the

egested

leaves

were

full

of

intestinal

worms.

The

factor

common

to

all

19

species

of

leaves

swallowed

by

the

chimps

was

that

they

were

covered

with

microscopic

hooks.

These

caught

the

worms

and

dragged

them form their lodgings.

Following that observation, Dr Engel is now particularly excited about

how

knowledge

of

the

way

that

animals

look

after

themselves

could

be

used

t

to

improve

the

health

of

live-stock.

People

might

also

be

able

to

learn

a thing or two-and may, indeed, already have done so. Geophagy. For

example, is a common behavior in many parts of the world. The medical

stalls

in

African

markets

frequently

sell

tablets

made

of

different

sorts

of clays, appropriate to different medical conditions.

Africans

brought

to

the

Americas

as

slaves

continued

this

tradition,

which

gave their owners one more excuse to affect to despise them. Yet, as Dr

Engel points out, Rwandan mountain gorillas eat a type of clay rather

similar to kaolinite-the main ingredient of many patent medicines sold

over

the

counter

in

the

west

for

digestive

complaints.

Dirt

can

sometimes

be good for you, and to be “as sick as a parrot” may, after all, be

a state to be desired.

Questions 1-4

Do the following statements agree with the information given in Reading

Passage 1

In boxes 1-4 on your answer sheet, write

TRUE

if the statement agrees with the information

FALSE

if the statement contradicts the information

NOT GIVEN

if there is no information on this

1.

Dr. Engel has been working on animal self-medication research for 10

years.

2.

Animals

often

walk

a

considerable

distance

to

find

plants

medication.

3.

Birds, like

Macaw,

often eat

clay

because it is part

of their natural

diet.

4.

According

to

Dr.

Engel,

research

into

animal

self-medication

can

help

to invent new painkillers.

Questions 5-9

Complete the notes below using NO MORE THAN ONE WORD OR NUMBER from

passage.

Write your answers in boxes 5-9 on your answer sheet.

Date

Name

Animal

Food

Mechanism

1987

Michael

Chimpanzee

5______of

Contained

Huffman

and

Veronia

chemicals,6_

Mohanmedi

__, that can

Seifu

kill

parasites

1999

James

Macaw

Seeds(contai

Clay

Gilardi

and

n

can8____the

his

7_____)and

poisonous

colleagues

clay

contents

in

food

1972

Richard

Chimpanzee

Leaves

with

Such

leaves

Wrang-ham

tiny

can

catch

and

9_____on

expel

worms

surface

from

intestines

Questions 10-13

Complete the summary below using words from the box.

Write your answers, A-H, in boxes 10-13 on your answer sheet.

Though often doubted, the self-medicating behavior of animals has been

supported by an increasing amount of evidence. One piece of evidence

particularly deals with10___, a soil-consuming behavior commonly found

across animals species, because earth, often clay, can neutralize the

11____content

of

their

diet.

Such

behavior

can

also

be

found

among

humans

in

Africa,

where

people

purchase

12__at

market

stalls

as

a

kind

of

medication

to

their

illnesses.

Another

example

if

this

is

found

in

chimps

eating leaves of often 13____taste but with no apparent medicinal value

until its unique structure came into light.

A.

Mineral B plants C unpleasant D toxic E clay tablets F nutritional G

geophagy H harmless

READING PASSAGE

4

You should spend about 20 minutes on Questions 27-40 which are based on

Reading Passage 3 below.

文章背景

：

本文主要讲述了某种人造制雨器。

The Rainmaker

Sometimes

ideas

just

pop

up

out

of

t

he

blue.

Or

in

Charlie

Paton’s

case,

out of the rain. “ I was in a bus in Morocco travelling through the

desert,”

he

remembers.

“It

had

been

raining

and

the

bus

was

full

of

hot,

wet

people.

The

windows

steamed

up

and

I

went

to

sleep

with

a

towel

against

the

glass.

When

I

woke,

the

thing

was

soaking

wet.

I

had

to

wring

it

out.

And it set me thinking. Why was it so wet”

The

answer,

of

course,

was

condensation.

Back

home

in

London,

a

physicist

friend, Philip Davies, explained that the glass, chilled by the rain

outside,

had

cooled

the

hot

humid

air

inside

the

bus

below

its

dew

point,

causing

droplets

of

water

to

form

on

the

inside

of

the

window.

Intrigued,

Paton-a

lighting

engineer

by

profession-started

rigging

up

his

own

equipment.

“I

made

my

own

solar

stills

.

It

occurred

to

me

that

you

might

be

able

to

produce

water

in

this

way

in

the

desert,

simply

by

cooling

the

air.

I

wondered

whether

you

could

make

enough

to

irrigate

fields

and

grow

crops.”

Today, a decade on, his dream has taken shape as giant greenhouse on a

desert

island

off

Abu

Dhabi

in

the

Persian

Gulf

---the

first

commercially

viable

Version

of

his

“seawater

greenhouse”.

Local

scientists,

working

with

Paton

under

a

license

from

his

company

Light

Works,

are

watering

the

desert and growing vegetables in what is basically a giant dew-making

machine that produces

fresh

water and

cool air from sum and seawater. In

awarding Paton first prize in a design competition two years ago, Marco

Goldschmied, president of the Royal Institute of British Architects,

ca

lled it “a truly original idea which has the potential to impact on

the lives of millions of people living in coastal water-starved areas

around the world.”

The

design

has

three main

parts

(see

Graphic).

The

greenhouse

faces

into

the

prevailing

wind

so

that

hot,

dry

desert

air

blows

in

through

the

front

wall of perforated cardboard, kept wet and cool by a constant tickle of

seawater pumped up from the nearby shoreline. The evaporating seawater

cools

and

moistens

the

air.

Last

June,

for

example,

when

the

temperature

outside

the

Abu

Dhabi

greenhouse

was

46°c,

it

was

in

the

low

30s

inside.

While the air outside was dry, the humidity in the greenhouse was 90

percent.

The

cool,

moist

air

allows

the

plants

to

grow

faster,

and

because

much

less

water

evaporates

from

the

leaves

their

demand

for

moisture

drops

dramatically.

Paton’s

crops

thrived

on

a

single

litre

of

water

per

square

metre per day, compared to 8 litres if they were growing outside.

The

second

feature

also

cools

the

air

for

the

plants.

Paton

has

constructed

a

double-layered

roof

with

an

outer

layer

of

clear

polythene

and

an

inner,

coated layer that reflects infrared light. Visible light

can stream

through

to

maximise

photosynthesis,

while

heat

from

the

infrared

radiation

is

trapped

in

the

space

between

the

layer,

away

from

the

plants.

At

the

back

of

the

greenhouse

sits

the

third

element,

the

main

water-production unit. Just before entering this unit, the humid air of

the

greenhouse

mixes

with

hot,

dry

air

from

between

the

two

layers

of

the

roof. This means the air can absorb more moisture as it passes through

a second moist cardboard wall. Finally, the hot saturated air hits a

condenser. This is a metal surface kept cool by still more seawater- the

equivalent

of

the

window

on

Paton’s

Moroccan

bus.

Drop

s

of

pure

distilled

water

from

on

the

condenser

and

flow

into

a

tank

for

irrigating

the

crops.

The

greenhouse

more

or

less

runs

itself.

Sensors

switch

everything

on

when

the sun rises and alter flows of air and seawater through the day in

response to changes in temperature, humidity and sunlight. On windless

days, fans ensure a

constant flow

of

air through the greenhouse.

“ once

it is tuned to the local environment, you don’t need anyone there for

it

to

work,”

says

Paton.

“

we

can

run

the

entire

operation

off

one

13-amp

plug, and in future we could make it entirely independent of the grid,

powered from a few solar panels.”

The

net

effect

is

to

evaporate

seawater

into

hot

desert

air,

then

recondense the moisture

as

fresh water.

At the same time, cool

moist

air

flows through the greenhouse to provide ideal conditions for the crops.

The

key

to

the

seawater

greenhouse’s

potential

is

its

unique

combination

of desalination and air

conditioning. By tapping

the power of

the sun it

can

cool

as

efficiently

as

a

500-kilowatt

air

conditioner

while

using

less

than 3 kilowatts of electricity. In practice, it evaporates 3000 litres

of

seawater

a

day

and

turns

it

into

about

800

litres

of

fresh

water---just

enough to irrigate the plants. The rest is lost as water vapour.

C

ritics

point

out

that

construction

costs

of

?25per

square

metre

mean

the

water is twice as expensive as water from a conventional desalination

plant. But the comparison is misleading, says Paton. The natural air

conditioning

in

the

greenhouse

massively

increases

the

value

of

that

water.

Because the plants need only an eight of the water used by those grown

conventionally, the effective cost is only a quarter that of water from

a standard desalinator. And costs should plummet when mass production

begins, he adds.

Best of all, the greenhouse should be environmentally, friendly. “ I

suppose

there

might

be

aesthetic

objections

to

large

structures

on

coastal

sites,”

says

Harris,

“but

it

is

a

clean

technology

and

doesn’t

produce

pollution or even large quantitie

s of hot water.”

Questions 27-31

Do the following statements agree with the information given in Reading

Passage 3

In boxes 27-31 on your answer sheet, write

TRUE

if the statement agrees with the information

FALSE

if the statement contradicts the information

NOT GIVEN

if there is no information on this

27.

Paton

came

up

with

the

idea

of

making

water

in

desert

by

pure

accident.

28. the bus Paton rode in had poor ventilation because of broken fans.

29. Paton woke up from sleep to discover that his towel was wet.

30.

Paton

started

his

greenhouse

project

immediately

after

meeting

up

with

his friend.

31. Paton later opened his own business in the Persian Gulf.

Questions 32-36(

图形题）

Questions 37-40

Complete the summary below using NO

MORE THAN

TWO WORDS from the passage

Write your answers in boxes 37-40 on your answer sheet.