What makes a population grow or shrink

Grade 7 Science Worksheet - Building Confidence

Circle the best answer.

1. 1.

   Bo reads a graph of duckweed floating on a pond. What percent of the pond surface did the duckweed cover in year 4?

   • 25 percent
   • 4 percent
   • 50 percent
   • 80 percent
2. 2.

   Esme reads a graph from a park where nest boxes were added in year 3. How many bluebird pairs nested in year 4?

   • 4 pairs
   • 6 pairs
   • 12 pairs
   • 10 pairs
3. 3.

   Jun's class grows beans in one small box with plenty of sun and water. The line levels off at 30 plants and the leaves touch. Which resource ran short?

   • The number of weeks
   • Shelter from rain
   • Nesting spots
   • Space to grow
4. 4.

   The park has 8 nest boxes, plenty of water and plenty of food. Kira sees the line level off at 8 pairs. Which resource ran short?

   • Nesting spots
   • The calendar year
   • Food for the pairs
   • Drinking water
5. 5.

   Luz sees the sunflower line fall in year 4, a dry year. The field is big and sunny. Which resource ran short?

   • Water
   • The number of years
   • Sunlight
   • Space
6. 6.

   Milo looks at the line for duckweed on a pond. Which sentence describes the shape of the line?

   • It keeps speeding up with no end
   • It starts flat, then falls steadily
   • It speeds up, then slows and levels off
   • It rises at one steady speed
7. 7.

   Pia compares two sunflower fields. Which field's line shows that resources are starting to run short?

   • Field B: its line levels off
   • Field A: its line reaches the top
   • Both: the lines start the same
   • Field A: its line keeps rising
8. 8.

   Ren reads that duckweed covers 90 percent of the pond in years 5, 6 and 7. What does the flat part of the line show?

   • No new plants are being made
   • The pond is growing faster now
   • The count was skipped those years
   • Plants added are about equal to plants lost
9. 9.

   The line for bluebird pairs is flat in years 4, 5 and 6. Tala says nothing happens in those years. What is right?

   • The nest boxes were taken away
   • The pairs moved to a new park
   • No young are raised in those years
   • Young are still raised, but the count stays steady
10. 10.

    Zee sees the sunflower line flat at 120 plants in years 3 to 6. What is true about the number of plants in those years?

    • It is 3 plants, then 4, 5 and 6
    • No new plants sprout in those years
    • It keeps rising a little each year
    • It stays about the same from year to year