How living in groups helps animals survive

Grade 9 Science Worksheet

Circle the best answer.

1. Read this first

   Group size and visits (model data)

   group size	visits a day
   4	1
   16	2
   64	4

2. 1.

   Luz reads the model table. Each visit takes one animal, picked at random. Which statement about one animal's daily chance of being lost is right?

   • The group of 64 loses 4 animals a day against 1, so its animals are worse off
   • A group 16 times larger meets 4 times the visits, so each animal's chance rises 4 times
   • A group 16 times larger meets 4 times the visits, so each animal's chance falls 4 times
   • Each animal's chance falls 16 times, since the group is 16 times larger

3. Ducks at day 10 (model data)

   group	ducks at start	ducks lost by day 10
   in flocks	30	3
   alone	60	24

4. 2.

   Milo reads the model data. Which statement compares how likely a duck was to be lost by day 10?

   • Ducks in flocks were 4 times as likely to be lost: 10% against 40%
   • Ducks alone were 4 times as likely to be lost: 40% (24 of 60) against 10% (3 of 30)
   • Ducks alone were 8 times as likely to be lost: 24 ducks were lost alone against just 3 in flocks
   • Ducks alone were 30 times as likely to be lost: 40% − 10%

5. Group size, risk and feeding (model data)

   group size	chance of being lost in a day (%)	share of the day spent feeding (%)
   2	8	70
   8	3	62
   32	2	40

6. 3.

   Noah reads the model data on one species. Which group size gives the best balance of risk and feeding?

   • Size 32: it has the lowest chance of being lost, so more safety makes the better balance of the two
   • Size 8: risk falls 5 points for 8 of feeding; size 32 gains 1 point of safety for 22 of feeding
   • Size 8, because the risk and the feeding time are equal there
   • Size 2: it has the most feeding time, so it is the pick

7. Two dances for one patch (the sun moves 15° clockwise each hour) (model data)

   dance	time	sun's compass bearing (°)	angle clockwise from vertical (°)
   dance A	12:00	180	40
   dance B	15:00	225	?

8. 4.

   Pia uses the model rule: bearing to the patch = sun's bearing + angle. Dance B is for the same patch. What angle should dance B show?

   • 40°, the same as dance A, since the patch has not moved
   • 45°, the amount the sun moved
   • 5° counterclockwise from vertical, since 220 − 225 = −5
   • 5° clockwise from vertical, since 225 − 220 = 5

9. Two waggle dances (model data)

   dance	waggle run (s)	angle clockwise from vertical (°)
   dance 1	2.0	40
   dance 2	2.0	130

10. 5.

    Ren reads two dances from one hive at the same time, using 1 s of run = 400 m. Which statement does the card support?

    • Both patches are 800 m away, but in directions 90° apart
    • Patch 2 is farther, since its angle is larger
    • The bees found different resources, since the angles differ
    • The two patches are the same place, since the runs match

11. Five dances for one patch (model data)

    dance	waggle run (s)
    1	2.3
    2	2.4
    3	2.5
    4	2.6
    5	2.7

12. 6.

    Zee reads five dances for one patch, using 1 s of run = 400 m. Which statement about the patch is best supported?

    • Exactly 1,000 m away, since the middle run is 2.5 s
    • Between 2.3 m and 2.7 m away
    • About 920 m away, because dance 1 settles it
    • Likely about 1,000 m away, within about 80 m either side

13. Use the table

    A male's record (shares from Gilbert et al. 2006; the days are model data) (model data and Gilbert et al. 2006)

    measure	value
    days recorded	80
    share of time huddling	38%
    share of huddling time above 20 °C	13%

14. 7.

    Tala applies the published shares to a model record. About how many hours was the temperature above 20 °C?

    • About 730 hours, the time spent huddling
    • About 95 hours: 80 × 24 × 0.38 ≈ 730 huddling hours, then 13% of that
    • About 10 hours, from 13% of 80
    • About 30 hours, from 38% of 80

15. Two birds (model data)

    bird	air around it (°C)	gap from 38 °C (°C)
    alone	−17	?
    in a huddle pocket	20	?

16. 8.

    Ari uses the model rule: heat lost is proportional to the gap from a bird's 38 °C. How does a bird in a 20 °C pocket compare with one alone in −17 °C air?

    • No heat lost, since 20 °C is above 0 °C
    • About 3 times as much heat lost: 55 °C against 18 °C
    • About half as much heat lost: 20 °C against 38 °C
    • About one third as much heat lost: a gap of 18 °C against 55 °C

17. Study card: minnows (model data)

    part of the study	entry
    fish in groups of 10	40 fish in a shaded tank
    fish alone	40 fish in a bright tank
    measured	fish surviving at day 10

18. 9.

    Esme reads the study card. Which flaw most weakens the claim that groups raise survival?

    • Forty fish is always too few, so the study means nothing
    • Light differed between the tanks too, so group living is not the only change
    • Survival at day 10 cannot be used, so the study fails
    • Fish alone act as the control group, which makes the whole result invalid for a comparison

19. Four study plans (model data)

    plan	how birds are placed	trials per flock size
    plan 1	the healthiest birds go in the biggest flocks	1
    plan 2	birds are assigned to flock sizes at random	6
    plan 3	birds choose their own flock size	6
    plan 4	birds are assigned at random	1

20. 10.

    Jun reads four plans. Which plan best tests whether flock size changes survival when birds differ?

    • Plan 1: the healthiest birds make the biggest flocks, so differences between sizes are clearest
    • Plan 2: random assignment evens out bird differences, and six trials show the spread
    • Plan 4: random assignment alone is enough, with a single trial each
    • Plan 3: birds choose, so the result matches real life closely