Biodiversity and why it keeps ecosystems steady
Grade 9 Science Worksheet
Circle the best answer.
Read this first
Plants counted in one meadow (model data)
species plants clover 120 yarrow 40 plantain 20 dandelion 20 total plants 200 Kira reads the table. What share of the plants in the meadow belongs to the most common species?
- 75%: 120 out of 160, the two largest counts
- 60%: 120 out of 200 plants
- 20%: 40 out of 200 plants, the second species
- 25%: 4 species share the plants evenly
Growth in two plots (model data)
plot species before the dry year during the dry year D 16 480 360 L 1 320 160 Jun reads the table. By what percent did the growth of plot D change in the dry year?
- It fell 33%: 120 ÷ 360
- It fell 75%: 360 ÷ 480, the share left
- It fell 0%: a plot with many species does not change
- It fell 25%: 120 ÷ 480
Noah reads the table. By what percent did the growth of plot F change in the dry year?
- It fell 92%: 120 ÷ 130
- It fell 52%: 130 ÷ 250, the share left
- It fell 25%: 160 ÷ 640, the change of plot E
- It fell 48%: 120 ÷ 250
Zee reads the table. Which plot’s growth changed by the larger percent in the dry year?
- Plot G: it lost more growth, 200 grams against 150 grams
- Plot H: it fell 50%, against 25% for plot G
- Neither: the two plots changed by the same percent
- Plot G: it had more growth left, 600 against 150
Growth in one plot (model data)
time growth (grams per square meter) before the dry year 400 during the dry year 300 a year later 390 Resistance is how little a plot changes during an event. Pia reads the table. Which comparison shows the plot’s resistance?
- A year later against before: 390 against 400
- A year later against the dry year: 390 against 300
- Growth before the dry year, by itself: 400
- The dry year against before: 300 against 400
Growth in two plots (model data)
plot before the dry year during the dry year a year later many-species plot 400 300 380 one-species plot 400 200 380 Ari reads the table. Which statement does the table support?
- The many-species plot recovered faster because it fell less in the dry year
- The many-species plot did not change during the dry year, so it had nothing to recover
- The one-species plot recovered more because it rose 180 grams, against 80
- Both plots reached 380 a year later, so recovery here did not depend on diversity
Growth in four plots (model data)
plot species normal dry year a year later P1 1 300 150 300 P2 2 500 260 500 P3 16 1000 750 1000 P4 32 800 624 800 Luz reads the table. Which statement fits the table?
- Plots with more species recovered faster, since they lost less in the dry year
- The four plots were equally resistant because all ended at their normal growth
- Plot P1 was the most resistant because it lost the fewest grams, 150
- Plot P4 was the most resistant, losing 22%, and all four plots were back to normal a year later
Gene versions in two wildflower populations (model data)
version of the gene population P plants population Q plants version 1 40 100 version 2 30 0 version 3 20 0 version 4 10 0 Esme reads the table for two populations of one wildflower species. Which has more genetic diversity?
- Neither: genes inside one species do not count as diversity
- Population P: its plants carry 4 versions of the gene, against 1 in Q
- Population Q: it has the most plants with one version, 100
- The same: both populations are one species, so their species diversity is equal
Dry-year growth by gene version (model data)
gene version growth per plant (grams) population P plants population Q plants version A 20 90 100 version D 50 10 0 Kira reads the model data. Which population grew more in total in the dry year?
- Population Q: 2,000 grams, against 1,800 for P
- The same, 2,000 grams: each population has 100 plants
- Population P: 2,300 grams, against 2,000 for Q
- Population P: 3,500 grams, counting 35 grams for each plant
Gene versions in one clover population (model data)
version of the gene plants version 1 60 version 2 40 Tala reads the table for a clover population. Which change would raise its genetic diversity?
- Adding plants of a different species to the meadow
- Adding a pond beside the meadow
- Adding plants that carry a new version of the gene
- Adding more plants of the two versions already there
