انقراض
Extinctions
Ever since human beings appeared on the Earth, we have had a serious impact on other living things. One of the most serious results of the human presence has been the extinction of other species. Since the arrival of humans, many species of animals and plants have died out as a result of human activity.
The extinction of species is a serious problem. When certain species are eliminated, this may disrupt the balance of nature, leading to overpopulation of some species and extinction of others. These changes may have an impact on humans. Also, some of the species that become extinct might have had benefits for human beings. For example, scientists believe that some of the plants growing in rain forest areas might be valuable for treating human diseases. If these plants become extinct as a result of human activity, then these treatments will never be found.
The earliest extinctions caused by humans occurred very long ago. Modern humans emerged in Africa over 100,000 years ago, and some of those people migrated to other parts of the world. When they reached new areas, they found that it was very easy to hunt the large animals, which had not previously been hunted by humans. As these prehistoric people moved into Europe, Australia, and the Americas, they killed large numbers of large animals. Within a few hundred years, many species of animals had become extinct. For example, prehistoric people reached New Zealand less than 1000 years ago, but they soon hunted a huge bird, called the giant moa, to extinction.
With the beginnings of modern technology, several hundred years ago, many other species were driven to extinction. Hunters armed with guns were able to kill vast numbers of animals. In North America, this led to the extinction of bird species such as the passenger pigeon, which had previously been very numerous. Other species were nearly wiped out, such as the large prairie mammals called bison. There were once millions of these animals, but now only a few thousand remain.
Today, many more species of animals and plants are going extinct. Sometimes this happens because of human expansion into areas that are the habitat of certain species. When people clear a forest, some species may be lost.
In the near future, many other extinctions are possible or likely. In some cases, the problem is due to human greed. For example, some people buy ivory that is taken from the bodies of animals such as elephants or rhinoceros. Hunters sometimes kill these animals simply to take their ivory, and the result is a tragic decline in populations. Another example involves bears in North America. Some people buy the sexual organs of these animals for use as aphrodisiacs, or sexual stimulants. The result is that hunters kill bears simply to obtain these organs, and this leads to a reduction in the number of bears.
Fortunately, many countries have laws to prevent the hunting of species that are facing extinction, known as “endangered species.” However, some hunting of these endangered animals continues. Only by refusing to buy the products that are made from endangered species can we prevent this terrible crime.
impact:
to have an important or noticeable effect on someone or something
impact on/upon
The Food Safety Act will progressively impact on the way food businesses operate.
These costs will impact on our profitability.
extinction:
1
when a particular type of animal or plant stops existing
species in danger of extinction on the verge/edge/brink of extinction (=nearly extinct)
The breed was on the verge of extinction.
They were hunted almost to extinction .
Conservationists are trying to save the whale from extinction .
face extinction/be threatened with extinction
Many endangered species now face extinction.
2
when a type of person, custom, skill etc stops existing
Their traditional way of life seems doomed to extinction.
eliminate:
to remove or get rid of completely:
Can we ever eliminate hunger from the world?
Our team was eliminated (from the competition) in the first round.
The police have eliminated all the other suspects (=shown that they are not guilty), so only one now remains.
This new process has eliminated the need for checking the products by hand.
emerge:
to appear or come out from somewhere
The flowers emerge in the spring.
emerge from
The sun emerged from behind the clouds.
extinct: (adj)
an extinct type of animal or plant does not exist any more
Dinosaurs have been extinct for millions of years.
Pandas could become extinct in the wild.
an extinct species
moa:
arm:
to provide weapons for yourself, an army, a country etc in order to prepare for a fight or a war
arm somebody with something
The local farmers have armed themselves with rifles and pistols.
The rebels armed a group of 2000 men to attack the city.
ￚsee also armed, unarmed
prairie:
a wide open area of fairly flat land in North America which is covered in grass or wheat
bison:
an animal like a large cow with hair on its head and shoulders
expansion:
when something increases in size, range, amount etc
ￚsynonym growth
ￚsee also expand
expansion of
The rapid expansion of cities can cause social and economic problems.
expansion in
an expansion in student numbers
habitat:
the natural home of a plant or animal
watching monkeys in their natural habitat
The grassland is an important habitat for many wild flowers.
a habitat for humanity
greed:
a strong desire for more food, money, power, possessions etc than you need
people motivated by jealousy and greed
greed is one of the deadly sins
Another Source:
a strong desire to have a lot of something, esp. food, money, or power, often in a way that is selfish or unfair to other people:
It was pure greed that made me finish all those chocolates!
The speculators’ greed (for profit) has left several small investors penniless.
rhinoceros:
a large heavy African or Asian animal with thick skin and either one or two horns on its nose
ￚsee also hippopotamus
decline:
a decrease in the quality, quantity, or importance of something
decline in
There has been a decline in the size of families.
decline of
the decline of manufacturing
rapid/sharp/steep/dramatic decline
a rapid decline in unemployment
steady/gradual/long-term decline
The island’s population initially numbered 180, but there was a gradual decline until only 40 people were left.
the social and economic decline faced by many cities in decline
There’s a widely held belief that educational standards are in decline (=falling) .
fall/go etc into decline
The port fell into decline (=became less important and less busy) in the 1950s.
aphrodisiac:
a food, drink, or drug that makes you want to have s.e.x
An aphrodisiac is a substance that increases s.e.x.ual desire.
ￚaphrodisiac adjective
stimulan:
a drug or substance that makes you feel more active and full of energy
artificial stimulants
endanger:
to put someone or something in danger of being hurt, damaged, or destroyed
Smoking during pregnancy endangers your baby’s life .
ￚendangered adjective
The lizards are classed as an endangered species (=one that soon may no longer exist) .
‘can we’ is usually used in sentences beginning with ‘only by’
it is used instead of ‘that we can’
Only by exercising , refusing to eat greasy food and controling our weigh can we prevent heart disease
note:
it is seldom used
‘can we’ is usuallyused in sentences beginning with ‘only by’
it is used instead of ‘that we can’
Only by exercising , refusing to eat greasy food and controling our weigh can we prevent heart disease
note:
it is seldom used
فهرست درس های سطح 3
این متن در تاریخ 27 دی 1398 توسط مشاور سلام زبان ویرایش شد.
