How people affect biodiversity
Grade 9 Science Worksheet - Challenge Me
Circle the best answer.
Read this first
Fish stock counts at the end of 2023 (real data, NOAA Fisheries, 2023)
group of stocks number of stocks managed 506 with a known overfishing status 364 subject to overfishing, of the known ones 21 Ari assumes the stocks with unknown status match the known ones. About how many of all 506 stocks would be subject to overfishing?
- About 21, because the known stocks count and the rest do not
- About 29: 21 of 364 is 5.8%, and 5.8% of 506 is about 29
- About 42, the 21 doubled for the unknown stocks
- About 142, the number of stocks with an unknown status
Evidence in lake Y (model data)
driver evidence zebra mussels 90 per square meter shoreline cleared 30 percent pesticide 4 parts per billion native mussels before 20 per square meter native mussels after 8 per square meter Bo reads the lake Y table. By what percent did native mussels fall, and what do the rows support?
- 60%, and the zebra mussels are the one cause, at 90 per square meter
- 60%, and three drivers have evidence, so the fall may have several causes
- 150%, and zebra mussels alone explain the fall as the largest number
- 40%, the share that fell, and the cause is mixed
Record of one model site after a ban (model data)
years after the ban water looks pesticide level (parts per billion) 0 clear 16 2 clear 8 4 clear 4 6 clear 2 Esme reads the record. The safe level is 1 part per billion. When does the level reach it?
- Year 8: the level halves every 2 years, 16 → 8 → 4 → 2 → 1
- Year 4: the water already looks clear, so it is safe
- Year 15: it falls 1 each year from 16 until it reaches 1
- Year 2: the ban stopped the pollutant, so it is already gone
Use this
States with a first zebra mussel record (each point counts the states whose first record was in that year or earlier) (real data, USGS Nonindigenous Aquatic Species). Year (calendar year) across, 1988 to 2028, a mark every 8. States (number of states) up, 0 to 40, a mark every 10. The line "States with a record" joins (1988, 3), (1996, 19), (2004, 22), (2012, 30), (2020, 31) with straight pieces.
Jun reads the graph. Which statement about the spread of the mussels does it support?
- The spread stayed steady at about 2 states a year
- The first 8 years added 16 states, 2 a year; 2004 to 2020 added 9, about 0.6 a year
- The mussels are native to each new state, so the records show where they already lived
- Records fell after 1996, so the mussels left some states
A model fish stock under a rebuilding plan (model data)
year catch (thousand tonnes) stock size (thousand tonnes) 1 30 40 6 10 28 11 10 45 16 12 70 Kira reads the table. Between years 6 and 11, about how much did the stock grow each year before the catch was taken?
- About 3 thousand tonnes: the net gain each year
- About 13 thousand tonnes: a net gain of 3.4 a year plus the 10 caught
- About 27 thousand tonnes a year: the 17 gained in total plus the 10 caught
- About 7 thousand tonnes: 17 minus the 10 caught
One plant species on a mountain (model data)
year air temperature (°C) lowest elevation of the plant (meters) grazing on the lower slope 1980 8.0 800 light 2000 8.6 870 heavy 2020 9.2 940 heavy Luz sees the plant's lowest elevation rise as the air warms. Which new evidence would best separate warming from grazing as the cause?
- The plant's count at the grazed sites, measured again
- The plant's lowest elevation on ungrazed slopes over the same years
- Warming explains the move, so no other driver could be acting on the mountain
- The air temperature at the top of the mountain
Notebook
Notes on two model meadows (classmate's notebook), 4 lines. Columns: line, entry. Line 1: Meadow A had 20 plant species and now has 14. Line 2: Meadow B had 50 plant species and now has 40. Line 3: A lost 6 and B lost 10, so B was hit harder. Line 4: A share compares the loss with the starting number.
Milo reads a classmate's notebook about two meadows. Which line has the mistake?
- Line 3: A lost 6 ÷ 20 = 30% and B lost 10 ÷ 50 = 20%, so A was hit harder
- Line 4: a share should divide by the number now, not the starting number
- Line 2: B lost 10, so the line should say B has 60 species
- Line 1: A lost 14 species, since 14 is the number it has now
Notebook
Notes on one model stream (classmate's notebook), 4 lines. Columns: line, entry. Line 1: One test at one site in autumn found 2 parts per billion of a pesticide. Line 2: The limit is 5 parts per billion. Line 3: The farm sprays only in spring. Line 4: So the stream never goes over the limit.
Pia reads a classmate's notebook about a stream test. Which line has the mistake?
- Line 4: one autumn sample from one site cannot show the spring level
- Line 3: clear autumn water shows the spring level was the same
- Line 2: a limit cannot protect the stream, so line 4 does not matter
- Line 1: the pesticide would be visible in the water, so the 2 must be wrong
Record of one model site after a ban (model data)
years after the ban water looks pesticide level (parts per billion) 0 clear 16 2 clear 8 4 clear 4 Ren's friend says the ban fixed the stream by year 4. Which reply fits the record? The safe level is 1 part per billion.
- Yes: the level fell 75%, from 16 to 4, so the stream is safe and the problem is solved
- Yes: the level fell by 12, which is a big drop
- Yes: the water looks clear, so the stream is clean
- Not yet: at year 4 the level is 4, still four times the safe level of 1
Direct drivers of change in nature, ranked by global impact so far (real data, IPBES 2019)
rank driver 1 changes in land and sea use 2 direct exploitation of organisms 3 climate change 4 pollution 5 invasive alien species Zee's friend says pollution does not matter, since it ranks fourth. Which reply fits the IPBES ranking?
- Disagree: the ranking is global, so a driver ranked fourth can be the main one in one place
- Agree: the top driver explains the loss, so the lower four can be ignored
- Disagree: the ranking is wrong, because invasive species have spread faster than pollution has
- Agree: a fourth-place driver has not harmed any species anywhere