When Resources Run Short
Aligned to MS-LS2-1 — Next Generation Science Standards.
What this lesson teaches
Organisms compete for resources like food, water, sunlight, and space. When a resource becomes scarce, populations that depend on it usually shrink, and when it is plentiful, those populations often grow — the data reveal these patterns.
Worked example
During a drought, a pond shrinks and its plants die back; the data show fish and frog numbers falling as their food and oxygen decline, then rising again after the rains return and resources recover.
Practice questions
- Track how many birds visit a feeder that is full versus nearly empty over several days.
- Graph a set of population numbers against rainfall data and describe the pattern you see.
- Explain, using evidence from your graph, how a change in one resource affected the size of a population.
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 los recursos escasean
Los organismos compiten por recursos como comida, agua, luz solar y espacio. Cuando un recurso se vuelve escaso, las poblaciones que dependen de él suelen reducirse, y cuando es abundante, esas poblaciones a menudo crecen — los datos revelan estos patrones.
Ejemplo: Durante una sequía, un estanque se encoge y sus plantas mueren; los datos muestran que el número de peces y ranas baja al disminuir su alimento y oxígeno, y luego sube de nuevo cuando regresan las lluvias y se recuperan los recursos.
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