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?
- 25% in the dry year and 95% a year later
- 75% in the dry year and 95% a year later
- 75% in the dry year and 127% a year later
- 75% in the dry year and 5% 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 B is more diverse overall, 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 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
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 by 25% and plot L by 50% in each year, so more species meant a smaller change
- 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%
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 R recovered better, because a plot that falls less comes back faster
- Plot S recovered better, because it gained more: 250 grams per square meter, against 125 for plot R
Two model forests (model data)
measure forest F1 forest F2 species 10 10 trees of the commonest species 20 190 trees of the other species together 180 10 trees in all 200 200 Zee reads the table. Which statement about the diversity of the two forests is correct?
- Forest F1 is more diverse, because it has more species than forest F2
- The forests are equally diverse, because both have 10 species
- Forest F1 is more diverse: its trees are evenly spread, 20 in the commonest species against 190 in F2
- Forest F2 is more diverse, because one species has 190 trees, the most of any species in either forest
Notebook
Notes on two wildflower populations (classmate's notebook), 4 lines. Columns: line, entry. Line 1: Population X has 5 versions of one gene among its 100 plants. Line 2: Population Y has 1 version of that gene among its 100 plants. Line 3: Both populations have 100 plants of one species. Line 4: So the two populations have the same diversity.
Jun reads a classmate’s notebook about two wildflower populations. Which line has the mistake?
- Line 3: two populations with 100 plants each must be different species
- Line 4: the populations differ in genetic diversity, 5 versions against 1
- Line 1: 5 versions of a gene cannot occur inside one species of 100 plants
- Line 2: 1 version means Y has no genes to compare
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 2: the falls should be divided by the dry-year growth, 125 ÷ 375 = 33%
- Line 4: both plots were back at 500 a year later, so recovery was alike
- Line 3: a plot cannot return to exactly 500 after a dry year
- Line 1: plot A has 16 species, so it should not fall in the dry year
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 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
- Claim: population P has more species diversity. Reason: its plants carry 5 versions of the gene, and species are counted by kinds
Ren reads the graph. Year 2 was a dry year. Which claim goes with the right reason?
- Claim: diversity did not change recovery here. Reason: both lines were back at 600 in year 3
- 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: the many-species plot recovered faster. Reason: its line fell less, from 600 to 450
