SHSK Thinks

Academic enrichment

July 2024

Extinction of animals

Kimika (8L)

In the Trinity term 2024 edition of our student-led magazine, Compass, contributor Kimika (8L) discusses the causes of extinction for different species of animals and how society can prevent it through ‘de-extinction’ methods.

What does extinction mean?

Extinction is when a species, family or another group of animals goes extinct. In the past, many different species have gone extinct. Of the 44,838 species assessed worldwide using the IUCN Red List criteria, 905 are extinct and 16,928 are threatened to be, yet millions of species still need to be assessed in order to know their status. Species are classified into one of nine ‘red list’ categories: Extinct, Extinct in the Wild, Critically Endangered, Endangered, Vulnerable, Near Threatened, Least Concern, Data Deficient and Not Evaluated. Vulnerable, Endangered and Critically Endangered species are considered to be threatened with extinction.

Dodos are an extinct, flightless bird of Mauritius, an island of the Indian Ocean, and is one of the three species that constituted the family Raphidae. The other two species, also found on the islands of the Indian Ocean, were the solitaires. Found by Dutch soldiers in the 1600son an island in the Indian Ocean, the Dodo became extinct less than 80 years later because of deforestation, hunting and destruction of their nests by animals brought to the island by the Dutch. Its last confirmed sighting was in1662, although an escaped slave claimed to have seen the bird as recently as 1674. In fact, it is estimated by using a Weibull distribution method that the dodo may have persisted until1690 – almost 30 years after its presumed extinction date.

Orangutans are listed to be critically endangered on the red list. Both species of orangutans have experienced sharp population declines. A century ago, there were more than 230,000 orangutans in total, but the Bornean orangutan is now estimated to have a population of about 104,700 based on an updated geographic range (Endangered) and about 7,500 of the Sumatran species remain (Critically Endangered). The current economic crisis combined with natural disasters and human abuse of the forest are pushing one of humankind’s closest cousins to extinction. The main threat to the survival of orangutans, is the loss of habitat through deforestation. Land-use estimates indicate a potential loss of 4,000 Sumatran orangutans by 2030, and a population decrease of 81% by the year 2060.

Two centuries ago, the Galapagos Islands were home to more than 200,000 giant tortoises today, four species are extinct and only 10% of the original number remain. The rescue and eventual recovery of the tortoise populations has been slow and steady: twelve living species of giant tortoises remain in the Galapagos and their population is currently estimated at 20,000 individuals. Megalochelys (“great turtle”) is an extinct genus of tortoises that lives from the Miocene to Pleistocene age. They are noted for their giant size, which is among the largest of any known testudines, with a maximum carapace length of over 2m (6.5ft). The giant tortoise is currently ranked critically endangered.

How can it be stopped?

The process of extinction can be stopped by building technology and create processes that can help us secure animal DNA and begin to reverse the damage created by humans. Assisted breeding, cloning, genome editing and synthetic genomics can all aid de-extinction. If we do not try to end extinction, future generations will not be able to see the marvellous animals that we see today.

Kimika (8L)

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