The figure below shows an example of a tool that can be used to help ecologists identify the organisms present within an ecosystem.
State the name of this tool.
Use the tool in part (a) to identify the organism shown in the figure below.
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Distinguish between species richness and species diversity.
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1 markSome ecologists captured a random sample of 100 deer and marked them with ear tags.
They then release the marked deer back into the population and allowed them to mix with the unmarked deer.
After a set period of time, the ecologists recaptured a random sample of 50 deer and found that 10 of them were marked.
Using the Lincoln Index, estimate the population size of the deer.
Outline one limitation of using the capture-mark-recapture method.
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List three abiotic factors that can be measured in an aquatic ecosystem.
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Explain how a variety of ecological data collection methods could be used to show how an ecosystem changes as a result of human activity.
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Evaluate methods for estimating biomass and energy at different trophic levels in ecosystems.
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The figure below shows the data for a wolf population and the amount of suitable habitat that is available to the wolves.
Suggest one possible method for estimating the wolf population size.
Outline two reasons why collecting this type of data on wolves might be challenging.
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Lichens are organisms that grow well on stone walls in unpolluted air. Lichens grow less well in polluted air.
Car exhaust fumes contain sulfur dioxide that pollutes air.
A scientist investigates the effect of pollution by cars in a city.
This is their method:
The table shows their results.
| DIstance from city centre in km | Percentage area covered by lichen (%) |
| 0 | 0 |
| 2 | 6 |
| 4 | 20 |
| 6 | 30 |
| 8 | 50 |
| 10 | 64 |
| 12 | 70 |
Explain the results shown in the table.
Describe a method to measure the percentage of a stone wall covered by lichen.
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Use the dichotomous key provided to identify the organisms below.
| KEY | ||
| 1 (a) | Body is completely or partly covered in a shell | Go to 2 |
| (b) | Body is not completely or partly covered in a shell | Limax flavus |
| 2 (a) | Shell is attached to rocks by thin threads | Mytilus edulis |
| (b) | Shell is not attached to rocks by thin threads | Go to 3 |
| 3 (a) | Shell is a spire that comes to a point | Buccinum undatum |
| (b) | Shell is not a spire that comes to a point | Go to 4 |
| 4 (a) | Animal has tentacles | Nautilus pompilius |
| (b) | Animal has 2 tentacles | Planorbis planorbis |
Identify three limitations of using dichotomous keys for identifying organisms.
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A group of students compares the distribution of plant species in two fields using the following method:
The tables below show the students’ results.
| Species | Field A | ||||||
| Number of plants in each quadrat | Number of plants per m2 | ||||||
| First | Second | Third | Forth | Fifth | Mean | ||
| Dandelion | 7 | 0 | 6 | 3 | 4 | 4 | 16 |
| Buttercup | 2 | 1 | 0 | 3 | 2 | 2 | 6 |
| Violet | 1 | 0 | 2 | 1 | 2 | 1 | 5 |
| Heather | 2 | 3 | 1 | 2 | 1 | 2 | 7 |
| Species | Field B | ||||||
| Number of plants in each quadrat | Number of plants per m2 | ||||||
| First | Second | Third | Forth | Fifth | Mean | ||
| Dandelion | 7 | 3 | 2 | 1 | 2 | ||
| Buttercup | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Violet | 0 | 0 | 0 | 1 | 0 | 0 | 0 |
| Heather | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
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Describe the differences in species distribution in field A and field B.
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