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?

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

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

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, because the risk and the feeding time are equal there
   • Size 2: it has the most feeding time, so it is the pick
   • Size 8: risk falls 5 points for 8 of feeding; size 32 gains 1 point of safety for 22 of feeding

7. Two waggle dances (model data)

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

8. 4.

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

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

9. 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

10. 5.

    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
    • About 920 m away, because dance 1 settles it
    • Between 2.3 m and 2.7 m away
    • Likely about 1,000 m away, within about 80 m either side

11. 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%

12. 6.

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

    • About 10 hours, from 13% of 80
    • About 95 hours: 80 × 24 × 0.38 ≈ 730 huddling hours, then 13% of that
    • About 730 hours, the time spent huddling
    • About 30 hours, from 38% of 80
13. 7.

    Bo reads the study details. What can the study of 8 birds support?

    • It shows huddling raised the birds' body temperature to 37.5 °C
    • It shows every emperor penguin colony huddles for 1.6 h at a time, since the 8 birds are enough to speak for them
    • It shows nothing, since any study of 8 birds is useless
    • It shows what happened to these 8 birds; it cannot fix a value for every colony

14. 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

15. 8.

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

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

16. 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

17. 9.

    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

18. Pond survey (model data)

    pool	group size	share surviving (%)	shelter plants (%)
    pool A	4	55	5
    pool B	12	75	40
    pool C	30	88	80

19. 10.

    Kira reads a pond survey. Does the table show that bigger groups cause better survival?

    • Yes: survival rises at each step in group size, so bigger groups cause better survival
    • No: a survey cannot be used as evidence
    • No: shelter rises with group size, so shelter may explain the survival
    • Yes: 88% in pool C is the highest, so groups of 30 work well