The Sixth Extinction

2023 Science Without Borders Challenge the Sixth Extinction

The theme of the 2023 Science Without Borders® Challenge is “The Sixth Extinction.” To apply for this year’s contest, students should submit a piece of artwork that highlights the beauty and importance of an endangered marine species.

Throughout the history of our planet, there have been five mass extinctions. The last one took place during the Cretaceous Period when an asteroid hit Earth, drastically changing the climate and causing the dinosaurs to go extinct.

We are now in what is termed “the sixth mass extinction.” Humans have been altering the Earth’s environment as far back as the hunters and gatherers. As time progressed, humans invented more sophisticated technologies that simplified their way of living, but many of these advances resulted in great environmental losses. For example, during the agricultural revolution, humans cleared forests and other habitats to plant crops and raise domesticated animals. These actions negatively impacted the environment leading to a loss of habitat, decrease in biodiversity, and increase in infectious diseases.

With the onset of the Industrial Revolution, humans created the greatest number of technological advances. These developments drastically increased the rate of animal extinction. Pre-human estimates show that the extinction rate was 0.1 extinctions per million species per year. Scientists estimate that the current extinction rate is 1,000 times greater, which means that the extinction rate is 100 extinctions per million species per year. They also believe that this is an underestimate, as there are many species that have yet to be discovered.

The reason for the sixth extinction isn’t due to an asteroid crashing into Earth or volcanoes changing the climate. The sixth extinction is due to humans. We are altering the planet in many ways, including over-exploiting natural resources, destroying habitats, changing the climate, polluting, introducing invasive species, and causing diseases.

Human threats can lead to species becoming endangered, which means that organisms are threatened by extinction. This is a sign that the ecosystem is not functioning well. Each species, however small, plays an important role in its ecosystem. When one species is endangered or has gone extinct, the entire ecosystem suffers. The organisms that rely on the threatened species also suffer and can become endangered as well. Important ecosystem functions also may cease to exist.

Let’s look at the example of black rhinos (Diceros bicornis), which are now considered critically endangered. These species are a key part of African ecosystems. Rhinos are “mega-herbivores,” meaning that they are very large herbivores that consume large quantities of plant material each day. They help to reshape the entire ecosystem by eating woody plants. Removing these woody plants clears the land for grasses to grow which benefits many different animals. Black rhinos also help reshape the land when they bathe in mud puddles. This helps create natural watering holes that other animals depend on for drinking water. Rhinos contribute to many parts of the food web. Because they consume so much vegetation, they also produce a lot of dung. This helps to fertilize the soil and provide food for many other organisms such as dung beetles. The black rhino plays other roles in its ecosystem, but from these examples, we can see how important one organism can be to the entire ecosystem.


How can you find which species are on the verge of extinction?

The International Union for Conservation of Nature’s (IUCN) established the Red List of threatened and endangered species in 1964. The IUCN Red List is the most comprehensive source of information on the status of species around the world. Their website provides a variety of information for each species, such as where these species live (range), their population size, habitat, and threats. It also lists the species status or risk of extinction. There are nine different categories that characterize how close a species is to becoming extinct. See the chart below.

IUCN Red List of Endangered Species Image Citation: Sciencia58, CC0, 16 October 2020 via Wikimedia Commons

The categories that scientists are more concerned about are the “threatened categories”: Critically Endangered (CE), Endangered (EN), and Vulnerable (VU). When species are listed in one of these three threatened categories, they are at high risk of extinction in the wild.

For this contest, we are going to focus on the two endangered categories because these organisms are at the greatest risk of extinction. When creating artwork make sure that the organism is an endangered or a critically endangered marine species. Remember that it’s not just marine animals that could go extinct, marine plants are also at risk.

To begin searching for endangered marine species, go to: On this webpage, you can search by selecting different filters on the left side of the page. See the screenshot below. Filter by the two endangered categories.

IUCN Red List Screenshot


Select additional filters to find marine species by selecting marine regions, habitats, or systems. You may choose a marine species that spends all its time in the ocean or part of its time in the ocean and part of it on land and/or in freshwater. For example, female bull sharks (Carcharhinus leucas) spend most of their time in the ocean, but the females give birth in freshwater rivers and estuaries. One marine species that lives partially on land and in the ocean is the snares penguin (Eudyptes robustus). This vulnerable species lives on land but finds food in the ocean.


There is hope!

It’s not too late. Endangered species can recover. One of the greatest ocean conservation success stories is bringing humpback whales back from the verge of extinction. Most humpback whale populations had shrunk by more than 95% between the late 1700’s to the 1980’s. In 1985, global conservation measures were put in place by the International Whaling Commission (IWC) to protect humpback whales. The commission declared a moratorium to stop the commercial harvest of humpback whales. It has taken decades for these whale populations to recover. Their status went from being listed as endangered in 1986 to least concern in 2008. With the right actions, endangered species can recover.  

Be a part of the solution! Your artwork can help bring awareness to endangered marine species. Choose one or more endangered marine species and create a piece of artwork that illustrates the beauty and importance of this threatened organism.


The Sixth Extinction: An Unnatural History

The Sixth ExtinctionThe term ‘The Sixth Extinction’ was popularized by science writer Elizabeth Kolbert in her Pulitzer Prize winning book, The Sixth Extinction: An Unnatural History. In this book, Kolbert makes a compelling case for why we are in the middle of a new mass extinction event, one that rivals those in scale of the one that killed off the dinosaurs. She explains how human beings have altered life on this planet in a way no species has before and provides a moving account of the species being lost before our eyes. The Sixth Extinction is a must-read for anyone concerned about the future of the world, and our place in it.



Related Educational Resources

Endangered Species Coalition

World Wildlife Fund:

  • Educators ToolkitsToolkits include information about endangered species (e.g., polar bears, river dolphin, sea turtles) and the ecosystem that they live in. Toolkits are mostly geared towards grades 3-5. There is a “Teaching Tools about Biodiversity” toolkit for grades 6-8. 
  • Extinction! A Biodiversity Crisis MinecraftStudents learn about extinction, climate change, and ecosystems and how these concepts are related to biodiversity all while playing Minecraft.
PBS Learning Media

There are many resources about endangered species and biodiversity on this website for all grade levels. The link above includes a search for the term “endangered species.”

U.S. National Park Service
Explore endangered species throughout several of the United States national parks.
National Geographic
There is a resource library collection titled “Extinction” that contains multiple lesson plans, videos, and articles for various grade levels.

National Wildlife Federation
Educator’s resources can be found under the “Endangered and At-risk Species” section on this webpage.

Note: These lesson plans focus on a wide variety of endangered species. Teachers can use these lessons to introduce the concept of endangered species, but artwork submitted for the competition should be of endangered marine species. 




Image Citation: Sciencia58, CC0, 16 October 2020 via Wikimedia Commons