How relationships between species keep an ecosystem stable
Grade 9 Science Worksheet - Building Confidence
Circle the best answer.
Read this first
Effects on a bird and the tree that holds its nest (data: OpenStax Biology)
partner effect bird gains tree unchanged Bo reads the table about a bird that builds a nest in a tree. Which relationship does it show?
- Commensalism: the bird gains and the tree is unchanged
- Mutualism: the bird gains and the tree gains too
- Parasitism: the bird gains and the tree is harmed
- Competition: the bird and the tree use one resource
Effects on a model parasite and its host plant (model data)
partner effect parasite gains host plant harmed Esme reads the table about a model parasite that lives on a host plant. Which relationship does it show?
- Parasitism: the parasite gains and the host is harmed
- Competition: the parasite and the host both lose
- Commensalism: the parasite gains and the host is unchanged
- Mutualism: the parasite gains and the host gains too
Jun reads the graph of hare and lynx counts. Which sentence fits the graph?
- The lynx count peaks first, and the hare count follows it
- The hare count peaks, but the lynx count stays flat
- Both counts peak in the same year, then fall together
- The hare count peaks first, and the lynx count follows it
Kira reads the graph. How many years after the hare peak does the lynx peak come?
- 1 year after: hares peak at year 3, lynx at year 4
- 3 years after: the gap is the year of the hare peak
- 0 years: both counts peak at year 4 together
- 1 year before: lynx peak at year 3, hares at year 4
Luz reads the graph. How many years pass from one hare peak to the next hare peak?
- 5 years: halfway between two hare peaks
- 10 years: from year 4 to year 14
- 2 years: the gap from the hare peak to the lynx peak
- 14 years: the whole time shown on the graph
Two cases of living things sharing a place (model data)
case what happens A two plant species in one plot use the same limited supply of water, and both grow less B a bird builds a nest in a tree, and the tree stays the same Noah reads the two cases. Which case shows competition?
- Neither case: competition needs animals that touch
- Case B: the bird uses the tree for a nest
- Case A: both species use the same limited water
- Both cases: living things share a place in each
Effects on a model parasite and a model host (model data)
partner effect model parasite Q gains model host R harmed Pia reads the table about a model parasite and its model host. Which partner is the host?
- Q: the host is the partner that gains
- Both: each partner is a host to the other
- R: the host is the partner that is harmed
- Neither: a host is a third kind of species
Phosphorus in two model streams (model data)
stream banded tetra phosphorus level (model units) P present 40 Q absent 10 Ren reads the model data. What does the table show about phosphorus?
- Phosphorus is lower in stream Q, where the banded tetra is absent
- Phosphorus is lower in stream P, where the banded tetra is present
- Phosphorus is the same in both, so one species does not matter
- Phosphorus is higher in stream Q, where the banded tetra is absent
Removing one species from a model community of 12 species (model data)
species removed individuals of that species species left A 500 11 B 40 5 Tala reads the model data. Which removal changed the community more?
- Species A: it had the most individuals, 500
- Species B: 7 species were lost, though it had fewer individuals
- Neither: both removals changed the community the same way
- Species A: 11 species were left, the larger number
Species in a model stream community by year (model data)
year species 1 12 2 12 3 9 4 8 Zee reads the model data. The banded tetra is absent from the start of year 3. How many fewer species are in year 4 than in year 2?
- 0 fewer: losing one species leaves the community as it was
- 3 fewer: 12 species in year 2 and 9 in year 3
- 1 fewer: 9 species in year 3 and 8 in year 4
- 4 fewer: 12 species in year 2 and 8 in year 4