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?

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

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

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

   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
   • More seeds mean more plants, so Box B is wrong
   • Box B's extra seeds made no new plants
   • Each box's room sets the limit at 24
4. 4.

   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?

   • The 12 boxes still set the limit
   • The line is flat, so no young were raised
   • Plentiful water stopped pairs from forming
   • The pairs will pass 12 once water rises more
5. 5.

   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 stopped making seeds in year 4
   • Plot B's water supply caps its count
   • Plot B has less room than Plot A has
6. 6.

   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?

   • A flat line shows the tank has endless room for more
   • Moving fish makes the line rise faster each week
   • The fish count should be read on the bottom axis
   • Young are still born; moving fish holds the count
7. 7.

   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?

   • The weeks should be read on the side axis
   • Growth stops at 28 because births stop there
   • There is no flaw, since the line keeps rising each week
   • Growth slows as room fills and levels off near 30
8. 8.

   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
   • The line will keep rising, so the boxes do not matter
   • Water is a resource, so it matters more than boxes
   • Neither one matters, since counts rise by pure luck
9. 9.

   A meadow plot has plenty of sunlight and water, but the wildflowers are crowded at 60 plants. Tala wants more plants. Which change is best?

   • Sow more seeds in the plot, so more plants can grow
   • Add a second plot, so seedlings get more room
   • Build a fence around the plot, so the line rises
   • Water the plot twice a day, so water is plentiful
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?

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