Biodiversity and why it keeps ecosystems steady
Grade 9 Science Worksheet - Challenge Me
Circle the best answer.
Bo reads the graph. Year 2 was a dry year. Which statement matches the graph?
- The two plots were equally affected: each lost 200 grams per square meter, so diversity made no difference
- The one-species plot was less resistant: it fell 50% against 25%, and both were back to normal in year 3
- The many-species plot recovered faster: it fell less in year 2
- The many-species plot was not affected: its line stays near the top
Read this first
Growth in two plots (model data)
plot species normal dry year a year later M 24 600 450 570 N 1 500 250 475 Esme reads the table. For plot M, what percent of normal growth was reached in the dry year and a year later?
- 75% in the dry year and 127% a year later
- 75% in the dry year and 5% a year later
- 75% in the dry year and 95% a year later
- 25% in the dry year and 95% a year later
Two nature areas (model data)
area different ecosystems different species A 2 14 B 1 20 Kira reads the table. Which statement about the kinds of diversity is correct?
- Area A has more species diversity, since it has more ecosystems, 2 against 1 in area B
- Area B has more ecosystem diversity, since it has more species, 20 against 14 in area A
- Area A has more ecosystem diversity, 2 against 1; area B has more species, 20 against 14
- Area B is more diverse overall, since it has more species, 20 against 14 in area A
Growth in a dry year and a wet year (model data)
plot species normal dry year wet year K 16 600 450 750 L 1 400 200 600 Luz reads the table. Which statement describes the pattern in both the dry year and the wet year?
- Plot K changed less because it recovered faster after each year
- Plot L changed by more, so it was the more resistant plot
- Plot L changed more in the dry year alone; in the wet year both plots changed by the same 25%
- Plot K changed by 25% and plot L by 50% in each year, so more species meant a smaller change
Growth in two plots (model data)
plot normal dry year a year later R 500 375 500 S 500 250 500 Ren says plot R recovered better because it fell less. Which reply uses the table correctly?
- Both plots were back at 500 a year later, so they recovered alike; plot R was more resistant
- Plot S did not recover, because it fell by 50% in the dry year
- Plot S recovered better, because it gained more: 250 grams per square meter, against 125 for plot R
- Plot R recovered better, because a plot that falls less comes back faster
Notebook
Notes on a many-species plot (classmate's notebook), 4 lines. Columns: line, entry. Line 1: Growth was 640 before the dry year and 480 in the dry year. Line 2: The fall is 640 − 480 = 160. Line 3: The percent fall is 160 ÷ 480 = 33%. Line 4: A 33% fall is less than 50%, so the plot resisted well.
Pia reads a classmate’s notebook about a many-species plot. Which line has the mistake?
- Line 2: the fall should be 640 + 480, the two numbers added
- Line 3: divide the fall by the starting growth, 160 ÷ 640 = 25%
- Line 4: a 33% fall is more than 50%, so the plot resisted poorly
- Line 1: the dry-year growth should be larger than the start
Notebook
Notes on two plots in a dry year (classmate's notebook), 4 lines. Columns: line, entry. Line 1: Plot A, with 16 species, fell from 500 to 375, and plot B, with 1 species, fell from 500 to 250. Line 2: So plot A fell 25% and plot B fell 50%. Line 3: A year later both plots were back at 500. Line 4: Plot A fell less, so it also recovered faster.
Noah reads a classmate’s notebook about two plots in a dry year. Which line has the mistake?
- Line 1: plot A has 16 species, so it should not fall in the dry year
- Line 4: both plots were back at 500 a year later, so recovery was alike
- Line 2: the falls should be divided by the dry-year growth, 125 ÷ 375 = 33%
- Line 3: a plot cannot return to exactly 500 after a dry year
Growth in four plots in a dry year (model data)
plot species normal dry year A 1 400 192 B 2 300 159 C 16 900 657 D 32 700 532 Milo reads the table. Which claim goes with the right reason?
- Claim: more species meant more resistance. Reason: C and D lost 27% and 24%, against 52% and 47%
- Claim: more species meant more resistance. Reason: plot C had the most growth in the dry year, 657, more than any other plot
- Claim: species made no difference. Reason: each plot lost some growth in the dry year
- Claim: fewer species meant more resistance. Reason: plot B lost the fewest grams, 141
Gene versions in two wildflower populations (model data)
population versions of the gene plants P 5 250 Q 1 100 Tala reads the table. Which claim about raw material for adaptation goes with the right reason?
- Claim: neither has any to offer. Reason: genes inside one species do not count as diversity
- Claim: population P has more species diversity. Reason: its plants carry 5 versions of the gene, and species are counted by kinds
- Claim: population P has more raw material to adapt. Reason: it has more plants, 250 against 100, and more plants mean more genes
- Claim: population P has more raw material to adapt. Reason: it carries 5 gene versions, against 1
Ren reads the graph. Year 2 was a dry year. Which claim goes with the right reason?
- Claim: the one-species plot recovered faster. Reason: its line rose more, from 300 up to 600 in one year
- Claim: neither plot recovered. Reason: both lines fell in year 2
- Claim: diversity did not change recovery here. Reason: both lines were back at 600 in year 3
- Claim: the many-species plot recovered faster. Reason: its line fell less, from 600 to 450