Invasive Species
Understand that invasive species are animals (or plants) that have been introduced to a place where they don't naturally belong — like grey squirrels outcompeting red squirrels in the UK, cane toads poisoning native predators in Australia, or rabbits devastating ecosystems in Australia — and that they can cause serious harm to native wildlife by competing for food, spreading disease, or having no natural predators
What a learner can do afterwards
- Defines invasive species as non-native animals introduced to a new environment
- Names at least 2 examples of invasive species and their impacts
- Explains at least 2 reasons invasive species are harmful (no predators, outcompete natives, spread disease)
- Understands the difference between a species naturally expanding its range and being introduced by humans
The lesson
Most animals live where they have lived for a long time, in balance with their neighbors. An invasive species is an animal or plant that people move to a new place where it never lived before. Without its usual predators or competitors, it can spread fast and hurt the animals already living there.
Grey squirrels came from North America to the UK in the 1870s. They eat the same nuts and seeds as native red squirrels, so red squirrels often go hungry. Grey squirrels also carry a disease called squirrelpox. It barely affects them, but it kills red squirrels.
In 1935, people brought cane toads to Australia to eat beetles that were damaging sugar cane crops. The toads barely touched the beetles. Instead, they spread across the country, and their poisonous skin killed native predators like quolls and snakes that tried to eat them.
Not every new animal is invasive. Some animals naturally spread into new areas on their own, like birds migrating further as the climate changes. An animal becomes invasive only when people move it somewhere it could never have reached by itself, and it then harms the wildlife already there.
Invasive species are animals moved by people to new places, where they outcompete, out-eat, or outlast native wildlife with no natural predators to stop them.
Watch it
Where it sits
Where this leads
Jobs that lean on this skill. Follow one to see everything it is built on.
8 questions wait behind this lesson, each with its answer explained. Every answer feeds the sky: stars light as they are learned, and dim when it is time to come back.