What makes a population grow or shrink

Grade 7 Science Worksheet - Challenge Me

Circle the best answer.

1. 1.

   Ari reads the wood duck graph and the creek's resource table. Which resource limited the pairs after year 3, and why?

   • Open water, since it stayed at 6 hectares in the creek
   • Nest boxes, since pairs rose with boxes and stopped at 12
   • Neither, since the line will keep rising after year 6
   • Neither, since a flat line means no new pairs formed
2. 2.

   Two meadow plots get the same care. Bo reads the graph and the table. Which column best explains why Plot B levels off higher?

   • Water, since Plot B gets more liters
   • No column, since the plots differ by chance
   • Size, since Plot B has twice the room
   • Sunlight, since Plot B gets more hours
3. 3.

   Esme doubled the fish food in week 5, and the count stayed at 12. What do the graph and the table show about food?

   • More food should have raised the count
   • Food was not what limited the count
   • The fish stopped having young in week 3
   • The count will rise a week or two later
4. 4.

   Jun sees that Box B was sown with twice the seeds of Box A, yet both lines level off at 24. The boxes are the same size. Why?

   • Box B will pass Box A later
   • Box B's extra seeds made no new plants
   • More seeds mean more plants, so Box B is wrong
   • Each box's room sets the limit at 24
5. 5.

   Kira sees pairs fall in the dry year 4 and return to 12 once a new pond was dug in year 5. Water stayed plentiful in year 6, yet pairs stayed at 12. Why?

   • Plentiful water stopped pairs from forming
   • The pairs will pass 12 once water rises more
   • The 12 boxes still set the limit
   • The line is flat, so no young were raised
6. 6.

   Luz sees that both meadow plots have the same room and sunlight. Plot A is watered and Plot B is not. Why does Plot B level off lower?

   • Plot B will pass Plot A later
   • Plot B has less room than Plot A has
   • Plot B stopped making seeds in year 4
   • Plot B's water supply caps its count
7. 7.

   Milo says the flat line at 16 fish means no young fish are born. The class moves extra young fish to a second tank each week. What is the flaw?

   • Moving fish makes the line rise faster each week
   • A flat line shows the tank has endless room for more
   • Young are still born; moving fish holds the count
   • The fish count should be read on the bottom axis
8. 8.

   Noah says the line shows the box will hold 100 radish plants by week 8. The box has room for about 30 plants. What is the flaw?

   • Growth slows as room fills and levels off near 30
   • The weeks should be read on the side axis
   • There is no flaw, since the line keeps rising each week
   • Growth stops at 28 because births stop there
9. 9.

   Pia says the line rose after the nest boxes were added in year 2, so water must have caused the rise. What is the flaw?

   • The marked change was boxes, so boxes explain the rise
   • Neither one matters, since counts rise by pure luck
   • Water is a resource, so it matters more than boxes
   • The line will keep rising, so the boxes do not matter
10. 10.

    A radish box on a dim shelf has room and water, but the line levels off at 18 plants. Ren wants more plants. Which change is best?

    • Leave it, since a flat line means it is finished
    • Add water to the box each day, so water is plentiful
    • Move the box by a window, so plants get more light
    • Sow more seeds in the box, so the count rises