When an Ecosystem Changes
Aligned to MS-LS2-4 — Next Generation Science Standards.
What this lesson teaches
Ecosystems can be disturbed by physical changes, like fire or drought, or biological changes, like a new species arriving or a disease. Because organisms are connected through food webs, a change to one part shifts the sizes of many populations.
Worked example
When wolves were removed from a park, deer populations exploded and ate so many young trees that beavers and songbirds lost habitat — evidence that removing one species changed populations throughout the ecosystem.
Practice questions
- List every organism that would be affected if a pond in your area dried up.
- Diagram a food web, then cross out one organism and mark which others would rise or fall.
- Construct an argument, supported by evidence, that a single change to an ecosystem can affect populations far from where it started.
Watch the lesson
Every lesson comes with a video taught in English and Spanish — the same video the QR code in the printed workbook opens.
▶ Watch this lessonEn español
Cuando un ecosistema cambia
Los ecosistemas pueden verse alterados por cambios físicos, como un incendio o una sequía, o por cambios biológicos, como la llegada de una nueva especie o una enfermedad. Como los organismos están conectados a través de las redes alimentarias, un cambio en una parte modifica el tamaño de muchas poblaciones.
Ejemplo: Cuando se eliminó a los lobos de un parque, las poblaciones de venados se dispararon y comieron tantos árboles jóvenes que los castores y las aves cantoras perdieron su hábitat — evidencia de que quitar una especie cambió poblaciones por todo el ecosistema.
More Ecosystems: Interactions, Energy & Dynamics lessons
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