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Species on the Move

Science · Ecosystems & Habitats · ages 12-13

Name ______________________ Date ____________

Which description defines an invasive species?
- Any species introduced outside its native range, including those unable to spread or cause harm there
- A species introduced outside its native range that causes or can cause harm there
- A native species travelling between its usual breeding and wintering areas
Which example shows habitat loss changing where wild animals live?
- A family sorts empty bottles while nearby woodland stays unchanged
- A forest is cleared, so animals lose shelter and leave the area
- A zoo changes feeding times while nearby wild habitats stay unchanged
The comma butterfly's range in Britain has expanded northwards as the climate has warmed.
Circle one: True False
Cargo carries an ant outside its native range to a northern city. Cold winters once prevented survival there. Winters become milder, and the ant survives and displaces native ants. What does this show?
- Transport explains both arrival and winter survival, so the temperature change played no part
- Native ants would have disappeared after milder winters even if the introduced ants had never arrived
- Milder winters can help an introduced species establish and harm native species
A specialist eats only one plant. A generalist eats that plant and several others. If the shared plant disappears but the other foods remain, which has fewer food options?
- The specialist, because its only food plant has disappeared
- The generalist, because several foods give it fewer options
- Neither species, because losing that plant leaves both with the same food options
In an invented survey, a northern range boundary changes from 30 km to 90 km north of the same reference point. How many kilometres north has the boundary shifted?
Answer: ______________
A road separates a beetle population from suitable woodland. The beetles cannot cross the road. Food and shelter remain suitable in both woods. Which action directly addresses the stated barrier?
- Add more food to the far woodland
- Count beetles more often without changing access between the woods
- Provide a crossing the beetles can use to reach the other woodland
Tom says, 'If a species loses one habitat, it must become globally extinct.' Which explanation challenges his claim?
- Other populations may survive or individuals may reach suitable habitat elsewhere
- Losing one habitat proves that every population and every suitable habitat on Earth has disappeared
- Every individual can immediately change all its food and temperature needs after its habitat is lost

Answer key

For grown-ups. Fold this page away before handing over the rest.

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A species introduced outside its native range that causes or can cause harm there · An invasive species is introduced outside its native range and causes, or can cause, harm there. Introduction without possible harm and travel within usual seasonal habitats do not meet both conditions.
A forest is cleared, so animals lose shelter and leave the area · Forest clearance removes shelter. When animals leave that area, their distribution changes. The other examples do not describe loss of wild habitat.
True · Warmer northern conditions have helped comma butterflies survive and breed there, allowing their range to expand.
Milder winters can help an introduced species establish and harm native species · Cargo explains arrival outside the native range. Milder winters explain the changed survival conditions. Displacing native ants shows harm.
The specialist, because its only food plant has disappeared · The specialist loses its only stated food. The generalist still has other foods available, so the specialist has fewer options in this example.
60 · Subtract positions measured from the same reference point: 90 minus 30 equals 60 km. The boundary shifted north by 60 km.
Provide a crossing the beetles can use to reach the other woodland · The stated problem is access, not missing food or shelter. A usable crossing directly reconnects the population with suitable habitat.
Other populations may survive or individuals may reach suitable habitat elsewhere · Global extinction means no individuals remain anywhere. A local loss does not prove the species is gone everywhere: other populations may survive or individuals may reach suitable habitat elsewhere.