Syllabus Edition

First teaching 2015

Last exams 2025

|

Extinct, Critically Endangered & Improving Species (DP IB Environmental Systems & Societies (ESS))

Revision Note

Alistair Marjot

Written by: Alistair Marjot

Reviewed by: Bridgette Barrett

Extinct, Critically Endangered & Improving Species

Extinct Species

512px-passenger-pigeon-6

James St. John, CC BY 2.5, via Wikimedia Commons 

The passenger pigeon is now only seen in museums

  • Passenger Pigeon (Ectopistes migratorius):

    • The Passenger pigeon was once one of the most abundant bird species in North America, with flocks numbering in the billions

    • However, due to overhunting and habitat destruction, the passenger pigeon went extinct in the early 20th century

    • The hunting of these birds for meat, as well as the destruction of their forest habitats, led to a sharp decline in their numbers

    • By the late 1800s, the species was in serious decline, and despite some attempts at conservation, it went extinct in 1914

  • Tasmanian Tiger (Thylacinus cynocephalus):

    • The Tasmanian tiger, also known as the thylacine, was a carnivorous marsupial that once inhabited the Australian island of Tasmania

    • Human activity such as hunting, habitat loss, and disease transmission by introduced species caused their population to decline, and the last known Tasmanian tiger died in captivity in 1936, marking the extinction of the species

Critically Endangered Species

 

1024px-orangutan-with-infant

The sumatran orangutan is critically endangered

  • Sumatran Orangutan (Pongo abelii):

    • The Sumatran orangutan is one of three species of orangutan and is found only on the Indonesian island of Sumatra

    • Habitat destruction and fragmentation due to logging, conversion of forests to agriculture, and infrastructure development have been the primary causes of its decline

    • In addition, illegal hunting and capture of orangutans for the pet trade have also contributed to their decline

    • The Sumatran orangutan is now critically endangered, with only around 14,000 individuals remaining in the wild

  • Black rhinoceros (Diceros bicornis):

    • The black rhinoceros is a large mammal native to Africa and is critically endangered due to poaching for their horns, habitat loss, and civil unrest in the countries of their range

    • Their population has declined by over 90% since the 1960s, and there are currently only around 5,500 individuals remaining in the wild

    • Conservation efforts such as anti-poaching patrols, habitat restoration, and captive breeding programs are underway to try to save this species from extinction

An Improving Species

 

1024px-southern-white-rhino-2916896941

Becker1999 from Grove City, OH, CC BY 2.0 by/2.0 via Wikimedia Commons

The southern white rhino is a success story in conversation having been brought back from the brink of extinction

  • Southern white rhinoceros (Ceratotherium simum):

    • The Southern white rhinoceros was once on the brink of extinction due to poaching for their horns, with only a handful of individuals surviving in the wild in South Africa in the early 20th century

    • However, conservation efforts including increased law enforcement, habitat protection, and captive breeding programs have helped their population recover to over 18,000 individuals today

    • While they are still threatened by poaching and habitat loss, the Southern white rhinoceros' conservation status has greatly improved thanks to human intervention

  • Bald eagle (Haliaeetus leucocephalus):

    • The bald eagle is a bird of prey native to North America and was once on the brink of extinction due to habitat destruction, hunting, and pesticide use, which caused eggshell thinning and reproductive failure

    • Conservation efforts such as habitat protection, captive breeding programs, and the banning of harmful pesticides like DDT have helped their population recover from less than 500 pairs in the 1960s to over 10,000 pairs today

    • The bald eagle's conservation status has greatly improved thanks to human intervention

Last updated:

You've read 0 of your 5 free revision notes this week

Sign up now. It’s free!

Join the 100,000+ Students that ❤️ Save My Exams

the (exam) results speak for themselves:

Did this page help you?

Alistair Marjot

Author: Alistair Marjot

Expertise: Biology & Environmental Systems and Societies

Alistair graduated from Oxford University with a degree in Biological Sciences. He has taught GCSE/IGCSE Biology, as well as Biology and Environmental Systems & Societies for the International Baccalaureate Diploma Programme. While teaching in Oxford, Alistair completed his MA Education as Head of Department for Environmental Systems & Societies. Alistair has continued to pursue his interests in ecology and environmental science, recently gaining an MSc in Wildlife Biology & Conservation with Edinburgh Napier University.

Bridgette Barrett

Author: Bridgette Barrett

Expertise: Geography Lead

After graduating with a degree in Geography, Bridgette completed a PGCE over 25 years ago. She later gained an MA Learning, Technology and Education from the University of Nottingham focussing on online learning. At a time when the study of geography has never been more important, Bridgette is passionate about creating content which supports students in achieving their potential in geography and builds their confidence.