PRACTICUM
Topic: A study on the extinct species in our world
INTRODUCTION
A species is extinct when the last existing member dies.
Extinction therefore becomes a certainly when there are no surviving
individuals that can reproduce and create a new generation. A species may
become functionally extinct when only a handful of individual survive ,which
cannot reproduce due to poor health ,age ,sparse distribution over a large
range , a lack of individuals of both sexes, or other reasons.
Currently an important aspect of extinction
is human attempts to preserve critically endangered species. These are
reflected by the creation of the conservation status “extinction in the wild “.
Species listed under this status by the international union for conservation of
nature are not known to have any living specimens in the wild, and are
maintained only in zoos or other artificial environment. Some of these species
are functionally extinct, as they are no longer part of their natural habitat
and it is unlikely the species will ever be restored to the wild. When
possible, modern zoological institutions try to maintain a viable population
for species preservation and possible future reintroduction to the wild,
through use of carefully planned breeding programs.
NEED AND SIGNIFICANCE
There are several types of species in
our world, but some of them are extinct. To study about various distinct
species. Those are endangered. They are to be preserved for next generation.
There by the world can see and understand those species is if the use of man
hand, the change in the habitat, pollution, deforestation. So we should
conserve those species.
STATEMENT OF THE PROBLEM
The
present study aims to find out the extinct species in our world. It was
entitled as “The study on the extinct species in our world”.
OBJECTIVES OF THE STUDY
1. To find out variety of extinct
species.
2. To find out the reason for the
species that extinct.
3. To find out the ecological balance.
METHODOLOGY ADOPTED
The present study ,it eas
decided to adopt documentary method.
PROCEDURE ADOPTED
For collecting data necessary for the study on the topic “The
study on the extinct species in our world
“. For this data to adopt documentary analysis, i.e. analysis of the
books, internet etc.
DATA COLLECTION
JAVAN TIGER
The Javan tiger was very small compared to
other subspecies of the Asian mainland,
but larger in size than the Bali tiger. It usually had long and thin stripes, which were
slightly more numerous than those of the Sumatran tiger. Its nose was long and narrow, plane remarkably narrow and carnassials relatively
long. Based on these cranial differences,
the Javan tiger was proposed to be assigne. At the end of the 19th
century, Javan tigers inhabited most of Java. Around 1850, the people living in
the rural areas still considered them a plague. In 1890, Dutch author Jan Gerhard
ten Bokkel noted how the fear of tigers brought the people to superstitious use
of language: "A Javan will never speak about a tiger without calling him
"Mister", it's always: Mr. Tiger. The beast might hear him once, and
take revenge at him for merely saying tiger in a familiar way.
By 1940, tigers had retreated to remote
mountainous and forested areas. Around 1970, the only known tigers lived in the
region of Mount Betiri, with an altitude of 1,192 m (3,911 ft) the
highest mountain in Java's southeast, which had not been settled due to the
rugged and sloping terrain. In 1972, the 500 km2 (190 sq mi)
area was gazetted as wildlife reserve. The last tigers were sighted there in
1976.
They preyed on rusa deer, banteng and wild boar,
less often on water fowl and reptiles.
Nothing is known about their gestation period, or life span in the wild and in
captivity. Up to World War II, Javan tigers were kept in some
Indonesian zoos, but these were closed down during the war.
PINTA ISLAND TORTOISE
The Pinta Island tortoise (Chelonoidis nigra abingdonii), also
known as the Pinta giant tortoise,Abingdon Island tortoise, or Abingdon Island giant tortoise, is a subspecies of Galapagos tortoise native to Ecuador's Pinta Island that is probably extinct.
The subspecies was described by Albert
Günther in 1877 after
specimens arrived in London.
By the end of the 19th century, most of the Pinta Island tortoises had been
wiped out due to hunting. By the mid-20th century, the subspecies
was assumed to be extinct until a single male was discovered on the
island in 1971. Efforts were made to mate the male, named Lonesome
George, with other subspecies, but no viable eggs were produced.
Lonesome George died on 24 June 2012 and the subspecies was believed to have
become extinct with his death. However, 17 first-generation hybrids
have been found at Wolf Volcano on Isabela Islandduring a recent trip by Yale
University researchers.
As these specimens are juveniles, their parents may still be alive.
he origin and
systematic relationships are still unresolved today, it even captivated Charles
Darwin himself. Scientists used DNA sequencing and decided to collect a few
tortoises from the Pinta Island in 1906. With DNA sequencing as their method,
their results show that the three best candidates for the closest living
relative of the Galapagos tortoises are all located in South America. It is the
yellow-footed tortoise (Geochelone denticulata), the red-footed tortoise
(Geochelone carbonara), and the Chaco tortoise (Geochelone chilensis).
These 3 species are known as extant species.
BAIJI RIVER DOLPHIN
The baiji is a
functionally extinct species of freshwater
dolphin formerly found
only in the Yangtze River in China. Nicknamed
"Goddess of the Yangtze". In China, the dolphin is also called Chinese river dolphin, Yangtze River dolphin, white fin dolphin and Yangtze dolphin. It was regarded as the goddess of protection by
local fishermen and boatmen in China (Zhou, 1991). It is not to be
confused with the Chinese white dolphin or the finless porpoise.
The
baiji population declined drastically in decades as China industrialized and
made heavy use of the river for fishing, transportation, and hydroelectricity.
It has been credibly claimed, after surveys in the Yangtze River during the
1980s, that baiji could be the first dolphin species in history that humans
have driven to extinction. A Conservation Action Plan for Cetaceans of the
Yangtze River was approved by the Chinese Government in 2001. Efforts
were made to conserve the species, but a late 2006 expedition failed to find any baiji in the river.
Organizers declared the baiji functionally extinct. The baiji represents
the first documented global extinction of a "megafaunal" vertebrate
for over 50 years since the
demise of the Japanese sea
lion and the Caribbean monk seal in the 1950s. It also signified the
disappearance of an entire mammal family of river dolphins (Lipotidae). The
baiji's extinction would be the first recorded extinction of a well-studied cetacean species (it is unclear if some
previously extinct varieties were species or subspecies) to be directly
attributable to human influence.
Swiss
economist and CEO of the baiji.org Foundation, August Pfluger funded the
expedition, in which an international team, taken in part from the National
Oceanic and Atmospheric Administration and the Fisheries Research Agency in
Japan, searched for six weeks for signs of the dolphin. The search took place
almost a decade after the last exploration in 1997, which turned up only 13 of
the cetaceans.
In
August 2007, a Chinese man reportedly videotaped a large white animal swimming
in the Yangtze. Although it was
tentatively confirmed that the animal on the video is probably a baiji, the
presence of only one or a few animals, particularly of advanced age, is not
enough to save a functionally extinct species from true extinction. The last
known living baiji was Qiqi , who died in 2002. The World Wildlife Fund is calling for the preservation of any
possible baiji habitat, in case the species is located and can be revived.
WESTERN BLACK RHINOCEROS
The western black rhinoceros (Diceros
bicornis longipes) or West African black rhinoceros is a subspecies of
the black rhinoceros, declared extinct by
the IUCN in 2011. The western black rhinoceros was believed to
have been genetically different from other rhino subspecies. It was once
widespread in the savanna of sub-Saharan Africa, but its numbers declined due to poaching. The western black
rhinoceros resided primarily in Cameroon, but surveys since 2006
have failed to locate any individ.
The black rhino, of which the
western black rhinoceros is a subspecies, was most commonly located in several
countries towards the southeast region of the continent of Africa. There were
several subspecies found in the western and southern countries of Tanzania
through Zambia, Zimbabwe and Mozambique, to the northern and north-western and
north-eastern parts of South Africa. The Black Rhino's most abundant population
was found in South Africa and Zimbabwe, with a smaller population found in
southern Tanzania. The Western subspecies of the Black Rhino was last recorded
in Cameroon but is now considered to be extinct.[2] However,
other subspecies were introduced again into Botswana, Malawi, Swaziland and
Zambia.
GASTRIC
BLOODING FROG
The gastric-brooding frogs or platypus frogs (Rheobatrachus) were a genus of
ground-dwelling frogs native to Queensland in
eastern Australia. The genus
consisted of only two species, both of which became extinct in the mid-1980s.
The genus was unique because it contained the only two known frog species that incubated the
prejuvenile stages of their offspring in the stomach of
the mother.
The combined ranges of the
gastric-brooding frogs comprised less than 2,000 square kilometres
(770 sq mi). Both species were associated with creek systems in rainforests at elevations of
between 350 and 1,400 metres (1,150 and 4,590 ft). The causes of the
gastric-brooding frogs' extinction are not clearly understood, but habitat loss
and degradation, pollution, and some diseases may have contributed.
The assignment of the genus to a taxonomic family is
hotly debated. Some biologists class them within Myobatrachidae under
the subfamily Rheobatrachinae, but others place them in their own family,
Rheobatrachidae.
Scientists at the
University of Newcastle and University of New South Wales announced in March
2013 that the frog would be the subject of a cloning attempt, referred to as the ”Lazarus
Project”, to resurrect the species. Embryos
were successfully cloned.[5][6]
The southern gastric
brooding frog has been listed as Extinct by the IUCN because it has not been
recorded in the wild since 1981, and extensive searches over the last 35 years
have failed to locate this species.
CONCLUSION
These are no longer several extinct species in the wild. Now
they are no longer extict in museums. We can only see them in the photograph.
So it is our duty to preserve the wild species and conserve our nature. In our
world, the present species of wildlife is to endangered. So it is our problem
to face a high of extinction in the world or in the near future.
REFERENCE
1. Ecology,Ethology,Evolution,Zoogeogra phy -
K.Vijayakumaran Nair, M.Jayaprakash, Meera George ,Academic
publication,2012.
2. Wikipedia-a free encyclopaedia.
Submitted By,
Divya.R.S
Roll No.:7
Natural Science
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