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
   • Open water, since it stayed at 6 hectares in the creek
   • Neither, since a flat line means no new pairs formed
   • Neither, since the line will keep rising after year 6
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?

   • No column, since the plots differ by chance
   • Water, since Plot B gets more liters
   • 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?

   • The fish stopped having young in week 3
   • The count will rise a week or two later
   • More food should have raised the count
   • Food was not what limited the count
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
   • More seeds mean more plants, so Box B is wrong
   • Each box's room sets the limit at 24
   • Box B's extra seeds made no new plants
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?

   • The line is flat, so no young were raised
   • The 12 boxes still set the limit
   • The pairs will pass 12 once water rises more
   • Plentiful water stopped pairs from forming
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 stopped making seeds in year 4
   • Plot B has less room than Plot A has
   • 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?

   • Young are still born; moving fish holds the count
   • The fish count should be read on the bottom axis
   • A flat line shows the tank has endless room for more
   • Moving fish makes the line rise faster each week
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
   • Growth stops at 28 because births stop there
   • There is no flaw, since the line keeps rising each week
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?

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

    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
    • Water the plot twice a day, so water is plentiful
    • Build a fence around the plot, so the line rises
    • Add a second plot, so seedlings get more room