Program: Computer Engineering (NBA Accredited)

Problem Based Learning

Program: Computer Engineering

Course: Environmental Studies. Course Code: 22447

Class: CO5IC Name of Subject Teacher: Prf. Suyog Satawalekar

Name of Student: Vaishnavi Mahesh Roll ID:19203C1002

Nagaonkar

Problem Statement: Extinction of animals.

Abstract:
An endangered species is a population of organisms which is at risk of becoming extinct because
it is either few in numbers, or threatened by changing environmental or predation parameters. ...
'Habitat loss is the most widespread cause of species endangerment in the U.S., affecting 85% of
imperiled species'.
Objectives:

Wildlife Institute of India, Forget Me Not Animal Rescue are some agencies or institutions that
are working for conserving Endangered Species all over the world. To prevent the habitat loss of
such species, improve their counts in the environment, etc. are some activities conducted by such
organizations.

Introduction:

Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species.
The moment of extinction is generally considered to be the death of the last individual of the
species, although the capacity to breed and recover may have been lost before this point. Because a
species' potential range may be very large, determining this moment is difficult, and is usually done
retrospectively. This difficulty leads to phenomena such as Lazarus taxa, where a species presumed
extinct abruptly "reappears" (typically in the fossil record) after a period of apparent absence.
More than 99 percent of all species, amounting to over five billion species, that ever lived on Earth
are estimated to have died out. Notable extinct animal species include non-avian dinosaurs, saber-
toothed cats, dodos, mammoths, ground sloths, thylacines, trilobites and golden toads. It is
estimated that there are currently around 8.7 million species of eukaryote globally, and possibly
many times more if microorganisms, like bacteria, are included.
Through evolution, species arise through the process of speciation—where new varieties of
organisms arise and thrive when they are able to find and exploit an ecological niche—and species
become extinct when they are no longer able to survive in changing conditions or against
superior competition. The relationship between animals and their ecological niches has been firmly
established. A typical species becomes extinct within 10 million years of its first
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Problem Based Learning

appearance,[5] although some species, called living fossils, survive with little to
no morphological change for hundreds of millions of years.
Mass extinctions are relatively rare events; however, isolated extinctions are quite common. Only
recently have extinctions been recorded and scientists have become alarmed at the current high rate
of extinctions. Most species that become extinct are never scientifically documented. Some
scientists estimate that up to half of presently existing plant and animal species may become extinct
by 2100. A 2018 report indicated that the phylogenetic diversity of 300 mammalian species erased
during the human era since the Late Pleistocene would require 5 to 7 million years to recover.
According to the 2019 Global Assessment Report on Biodiversity and Ecosystem
Services by IPBES, the biomass of wild mammals has fallen by 82%, natural ecosystems have lost
about half their area and a million species are at risk of extinction—all largely as a result of human
actions. Twenty-five percent of plant and animal species are threatened with extinction.
In June 2019, one million species of plants and animals were at risk of extinction. At least 571
species are lost since 1750 but likely many more. The main cause of the extinctions is the
destruction of natural habitats by human activities, such as cutting down forests and converting land
into fields for farming.

Skeletons of various extinct animals.

Methodology:
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Causes

The passenger pigeon, one of hundreds of species of extinct birds, was hunted to extinction over the
course of a few decades
As long as species have been evolving, species have been going extinct. It is estimated that over
99.9% of all species that ever lived are extinct. The average lifespan of a species is 1–10 million
years, although this varies widely between taxa. There are a variety of causes that can contribute
directly or indirectly to the extinction of a species or group of species. "Just as each species is
unique", write Beverly and Stephen C. Stearns, "so is each extinction ... the causes for each are
varied—some subtle and complex, others obvious and simple". Most simply, any species that
cannot survive and reproduce in its environment and cannot move to a new environment where it
can do so, dies out and becomes extinct. Extinction of a species may come suddenly when an
otherwise healthy species is wiped out completely, as when toxic pollution renders its
entire habitat unlivable; or may occur gradually over thousands or millions of years, such as when a
species gradually loses out in competition for food to better adapted competitors. Extinction may
occur a long time after the events that set it in motion, a phenomenon known as extinction debt.
Assessing the relative importance of genetic factors compared to environmental ones as the causes
of extinction has been compared to the debate on nature and nurture. The question of whether more
extinctions in the fossil record have been caused by evolution or by catastrophe is a subject of
discussion; Mark Newman, the author of Modeling Extinction, argues for a mathematical model that
falls between the two positions. By contrast, conservation biology uses the extinction vortex model
to classify extinctions by cause. When concerns about human extinction have been raised, for
example in Sir Martin Rees' 2003 book Our Final Hour, those concerns lie with the effects
of climate change or technological disaster.
Currently, environmental groups and some governments are concerned with the extinction of
species caused by humanity, and they try to prevent further extinctions through a variety
of conservation programs.[9] Humans can cause extinction of a species
through overharvesting, pollution, habitat destruction, introduction of invasive species (such as
new predators and food competitors), overhunting, and other influences. Explosive, unsustainable
human population growth and increasing per capita consumption are essential drivers of the
extinction crisis.[32][33][34][35] According to the International Union for Conservation of
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Problem Based Learning

Nature (IUCN), 784 extinctions have been recorded since the year 1500, the arbitrary date selected
to define "recent" extinctions, up to the year 2004; with many more likely to have gone unnoticed.
Several species have also been listed as extinct since 2004.

Genetic pollution

Extinction can threaten species evolved to specific ecologies through the process of genetic
pollution—i.e., uncontrolled hybridization, introgression genetic swamping which leads to
homogenization or out-competition from the introduced (or hybrid) species. Endemic populations
can face such extinctions when new populations are imported or selectively bred by people, or when
habitat modification brings previously isolated species into contact. Extinction is likeliest for rare
species coming into contact with more abundant ones; interbreeding can swamp the rarer gene pool
and create hybrids, depleting the purebred gene pool (for example, the endangered wild water
buffalo is most threatened with extinction by genetic pollution from the abundant domestic water
buffalo). Such extinctions are not always apparent from morphological (non-genetic) observations.
Some degree of gene flow is a normal evolutionarily process, nevertheless, hybridization (with or
without introgression) threatens rare species' existence.
The gene pool of a species or a population is the variety of genetic information in its living
members. A large gene pool (extensive genetic diversity) is associated with robust populations that
can survive bouts of intense selection. Meanwhile, low genetic diversity
(see inbreeding and population bottlenecks) reduces the range of adaptions possible. Replacing
native with alien genes narrows genetic diversity within the original population, thereby increasing
the chance of extinction.

Scorched land resulting from slash-and-burn agriculture

Habitat degradation
Habitat degradation is currently the main anthropogenic cause of species extinctions. The main
cause of habitat degradation worldwide is agriculture, with urban sprawl, logging, mining and some
fishing practices close behind. The degradation of a species' habitat may alter the fitness
landscape to such an extent that the species is no longer able to survive and becomes extinct. This
may occur by direct effects, such as the environment becoming toxic, or indirectly, by limiting a
species' ability to compete effectively for diminished resources or against new competitor species.
Habitat degradation through toxicity can kill off a species very rapidly, by killing all living
members through contamination or sterilizing them. It can also occur over longer periods at lower
toxicity levels by affecting life span, reproductive capacity, or competitiveness.
Habitat degradation can also take the form of a physical destruction of niche habitats. The
widespread destruction of tropical rainforests and replacement with open pastureland is widely cited
as an example of this; elimination of the dense forest eliminated the infrastructure needed by many
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Problem Based Learning

species to survive. For example, a fern that depends on dense shade for protection from direct
sunlight can no longer survive without forest to shelter it. Another example is the destruction of
ocean floors by bottom trawling.
Diminished resources or introduction of new competitor species also often accompany habitat
degradation. Global warming has allowed some species to expand their range, bringing
unwelcome competition to other species that previously occupied that area. Sometimes these new
competitors are predators and directly affect prey species, while at other times they may merely
outcompete vulnerable species for limited resources. Vital resources including water and food can
also be limited during habitat degradation, leading to extinction.

The golden toad was last seen on May 15, 1989. Decline in amphibian populations is ongoing
worldwide
Predation, competition, and disease

In the natural course of events, species become extinct for a number of reasons, including but not
limited to: extinction of a necessary host, prey or pollinator, inter-species competition, inability to
deal with evolving diseases and changing environmental conditions (particularly sudden changes)
which can act to introduce novel predators, or to remove prey. Recently in geological time, humans
have become an additional cause of extinction (some people would say premature extinction) of
some species, either as a new mega-predator or by transporting animals and plants from one part of
the world to another. Such introductions have been occurring for thousands of years, sometimes
intentionally (e.g. livestock released by sailors on islands as a future source of food) and sometimes
accidentally (e.g. rats escaping from boats). In most cases, the introductions are unsuccessful, but
when an invasive alien species does become established, the consequences can be catastrophic.
Invasive alien species can affect native species directly by eating them, competing with them, and
introducing pathogens or parasites that sicken or kill them; or indirectly by destroying or degrading
their habitat. Human populations may themselves act as invasive predators. According to the
"overkill hypothesis", the swift extinction of the megafauna in areas such as Australia (40,000 years
before present), North and South America (12,000 years before present), Madagascar, Hawaii (AD
300–1000), and New Zealand (AD 1300–1500), resulted from the sudden introduction of human
beings to environments full of animals that had never seen them before, and were therefore
completely unadapted to their predation techniques.
Coextinction
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The large Haast's eagle and moa from New Zealand

Coextinction refers to the loss of a species due to the extinction of another; for example, the
extinction of parasitic insects following the loss of their hosts. Coextinction can also occur when a
species loses its pollinator, or to predators in a food chain who lose their prey. "Species coextinction
is a manifestation of one of the interconnectedness of organisms in complex ecosystems ... While
coextinction may not be the most important cause of species extinctions, it is certainly an insidious
one". Coextinction is especially common when a keystone species goes extinct. Models suggest that
coextinction is the most common form of biodiversity loss. There may be a cascade of coextinction
across the trophic levels. Such effects are most severe in mutualistic and parasitic relationships. An
example of coextinction is the Haast's eagle and the moa: the Haast's eagle was a predator that
became extinct because its food source became extinct. The moa were several species of flightless
birds that were a food source for the Haast's eagle.
Climate change
Extinction as a result of climate change has been confirmed by fossil studies. Particularly, the
extinction of amphibians during the Carboniferous Rainforest Collapse, 305 million years ago. A
2003 review across 14 biodiversity research centers predicted that, because of climate change, 15–
37% of land species would be "committed to extinction" by 2050. The ecologically rich areas that
would potentially suffer the heaviest losses include the Cape Floristic Region, and the Caribbean
Basin. These areas might see a doubling of present carbon dioxide levels and rising temperatures
that could eliminate 56,000 plant and 3,700 animal species. Climate change has also been found to
be a factor in habitat loss and desertification.

Conclusion:

It is important remember to take care of the animals we have today, and their environment. We
humans are the main cause of extinction. Because of us, they lose their home just because we need
to make paper, or they die because we need food. Poachers also kill endangered animals or sell
them to people who have money and are willing to spend it on a rare or endangered animal.
There are a lot of ways to help endangered animals today such as volunteering or donating to help
build animal homes. If you want to learn more about extinct and endangered animals,
check out some of these organizations: Defenders of Wildlife, Wildlife Conservation Society,
Wildlife Alliance, African Wildlife Foundation, and the Animal Welfare Institute. They help
endangered animals by finding them a new home, taking care of them temporarily if they are hurt.
Some are dedicated to animals from a specific country.
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References:

1. http://extictanimals.weebly.com/conclusion.html
2. https://en.wikipedia.org/wiki/Extinction
3. https://www.google.com/search?q=abstract+of+animal+extinction&rlz=1C1GCEA_enIN886IN8
86&oq=abstract+of+animal+extinction&aqs=chrome..69i57j33i22i29i30l4.7742j0j7&sourceid=c
hrome&ie=UTF-8
4. https://brainly.in/question/15835655