Read data on a helpful trait spreading through a population
Grade 9 Science Worksheet
Circle the best answer.
Read this first
Two plate samples (model data)
sample resistant all bacteria sample A 400 8,000 sample B 600 20,000 Bo compares two plate samples. Which sample has the larger percent of resistant bacteria?
- Sample A: 5%, compared with 3% for sample B
- Sample B: it has 20,000 bacteria in total, more than sample A
- Sample B: it has 600 resistant bacteria, more than the 400 in sample A
- Neither sample: the totals differ, so the percents cannot be compared
Purple plants in three generations (model data)
plants generation 1 generation 2 generation 3 purple 20 40 9 all plants 40 100 30 Esme reads the table. In which generation are purple plants the largest share of all plants?
- Generation 2: it has the most plants in total, 100
- Generation 2: it has the most purple plants, 40
- Generation 1: 20 of 40 is 50%, above 40% and 30%
- Generation 3: 9 purple of 30 plants is 90%
Dark moths per 100 moths (model data)
generation dark moths per 100 generation 1 40 generation 2 60 Kira reads the table. Which sentence describes the change from generation 1 to generation 2 correctly?
- It rose 50 percent points, which is a 20% increase on 40
- It rose 20 percent points, which is a 50% increase on 40
- It rose 20 percent points, which is a 33% increase on 60
- It rose 20 percent points, which is a 20% increase on 40
Light moths per 100 moths (model data)
generation light moths per 100 generation 1 50 generation 2 20 Luz reads the table. By what percent did the light share fall from generation 1 to generation 2?
- 150%: the fall of 30 points is 150% of the new 20
- 40%: the share left, 20 of the 50 you started with
- 60%: the fall of 30 points is 60% of the 50 you started with
- 30%: the fall in percent points, called a percent
Moths before breeding: each survivor leaves 2 young like itself (model data)
moth color generation 1 survive to breed (percent) dark 50 60 light 50 20 Milo predicts generation 2 from the rule in the title. What percent of generation 2 will be dark?
- 30%: the count of dark survivors, written as a percent
- 75%: 30 dark survivors out of 40 survivors
- 60%: the survival percent of the dark moths
- 50%: both colors started with 50 moths
Bacteria in a flask before an antibiotic, per 10,000 bacteria (model data)
bacteria before survive the antibiotic (percent) resistant 1,000 90 not resistant 9,000 10 Noah predicts the survivors. After the antibiotic, what percent of the surviving bacteria are resistant?
- 10%: the starting share, since survival does not change a share
- 50%: 900 resistant survivors and 900 other survivors
- 90%: the survival percent of the resistant bacteria
- 100%: the antibiotic made the other survivors resistant too
Moths on cleaned trunks: each survivor leaves 3 young like itself (model data)
moth color generation 5 survive to breed (percent) dark 50 20 light 50 60 The trunks were cleaned, so light moths now survive better. Pia predicts generation 6. What percent will be dark?
- 20%: the survival percent of the dark moths
- 75%: the light moths' share of the survivors
- 0%: dark moths turn light on cleaned trunks
- 25%: 10 dark survivors out of 40 survivors
Dark moths in a small woodland of 20 moths (model data)
generation dark moths dark percent generation 1 10 50 generation 2 11 55 generation 3 9 45 generation 4 10 50 Ren reads the dark share across four generations of one small woodland. Which explanation fits the data?
- Selection: the share rose from 50% to 55%, so dark moths are favored
- Chance: the share goes up and down and ends where it began
- Neither: the share cannot change while the total stays at 20 moths
- Selection: the share fell from 55% to 45%, so light moths are favored
Tala reads the bars for a garden of 10 plants. Which explanation fits the data best?
- Selection: tall plants rose from 4 to 6 out of 10 in generations 3 to 5
- Selection: tall plants went up and down, so each generation favors a new height
- Chance: in 10 plants, a change of one plant moves the share by 10 points
- Each plant grew taller or shorter between generations, which moved the bars
Resistant bacteria per 10,000 bacteria after repeated antibiotic rounds (model data)
round resistant per 10,000 round 0 6 round 1 150 round 2 2,700 round 3 8,800 Zee reads the table of rounds. Which explanation fits the data best?
- Chance: the share jumps around between rounds with no steady direction
- Selection: resistant bacteria were already there and left more offspring each round
- Each bacterium became a little more resistant in each round of the antibiotic
- The antibiotic caused resistance, raising it from 6 to 8,800 per 10,000
