Answer:

On a trip to a dense forest, a biologist NOTICED that MILLIPEDES (small invertebrates) were plentiful under

logs but were rarely seen in any other location.

(a) Propose THREE environmental variables (two abiotic and one biotic) that could explain why

millipedes are FOUND more frequently under logs. (1 point each; 3 points maximum)

The following list is not exhaustive.

Abiotic factors

2 points maximum

Biotic factors

1 point maximum

Light Reproduction

Temperature Predation

Water Food supply

Soil

Texture

Nutrients

pH

Competition

Wind

Periodic disturbances —

fire/storms/volcanoes

Note: Nutrient can be abiotic or biotic depending on how it is used. Climate/weather/shelter are too

general!

(b) For ONE of the abiotic environmental variables you chose above, design a controlled experiment to

test a hypothesis that this factor affects the distribution of millipedes on the forest floor. Describe data

that would support your hypothesis. (1 point each; 6 points maximum)

Must relate to one of the two abiotic factors accepted in part (a) AND measure/relate to millipede

distribution.

• Hypothesis — proposes a relationship between one abiotic factor and the distribution of

millipedes.

• Prediction/expected results — states what should be observed if the hypothesis is supported.

Can be in an “if … then” format.

• Design — describes an experiment that manipulates one abiotic independent variable/factor.

• Constants — explicitly holds all other factors constant.

• Control — indicates a valid control group that serves as a comparison

• Data collection — describes what observations will be collected or how they will be collected, or

both.

for experimental groups.

• SAMPLE size — indicates test of multiple millipedes or replicates.

• Statistical analysis — suggests a mathematical and/or statistical comparison of control and

experimental groups or of observed and expected. A specific statistical test need not be

mentioned.

• Feasibility — experiment could be performed and would yield data that would answer the

question posed.

On a trip to a dense forest, a biologist noticed that millipedes (small invertebrates) were plentiful under

logs but were rarely seen in any other location.

(a) Propose THREE environmental variables (two abiotic and one biotic) that could explain why

millipedes are found more frequently under logs. (1 point each; 3 points maximum)

The following list is not exhaustive.

Abiotic factors

2 points maximum

Biotic factors

1 point maximum

Light Reproduction

Temperature Predation

Water Food supply

Soil

Texture

Nutrients

pH

Competition

Wind

Periodic disturbances —

fire/storms/volcanoes

Note: Nutrient can be abiotic or biotic depending on how it is used. Climate/weather/shelter are too

general!

(b) For ONE of the abiotic environmental variables you chose above, design a controlled experiment to

test a hypothesis that this factor affects the distribution of millipedes on the forest floor. Describe data

that would support your hypothesis. (1 point each; 6 points maximum)

Must relate to one of the two abiotic factors accepted in part (a) AND measure/relate to millipede

distribution.

• Hypothesis — proposes a relationship between one abiotic factor and the distribution of

millipedes.

• Prediction/expected results — states what should be observed if the hypothesis is supported.

Can be in an “if … then” format.

• Design — describes an experiment that manipulates one abiotic independent variable/factor.

• Constants — explicitly holds all other factors constant.

• Control — indicates a valid control group that serves as a comparison

• Data collection — describes what observations will be collected or how they will be collected, or

both.

for experimental groups.

• Sample size — indicates test of multiple millipedes or replicates.

• Statistical analysis — suggests a mathematical and/or statistical comparison of control and

experimental groups or of observed and expected. A specific statistical test need not be

mentioned.

• Feasibility — experiment could be performed and would yield data that would answer the

question posed.