An ecologist has been reading the literature on the subject of factors affecting growth and metamorphosis of tadpoles in ponds. Some frog species (e.g. Hyla gratiosa) reproduce in ponds that are ephemeral (i.e. they dry up from time to time), while other frog species (e.g. Hyla cinerea) reproduce in ponds that are permanent. Previous work has suggested that tadpoles of species that reproduce in temporary ponds are able to speed up their growth in response to a drying habitat, so as to metamorphose into frogs before the pond dries up. The ecologist would like to explore these ideas and conduct some experiments.

Considering the above observations and using your knowledge of Underwood's (1990) logical scheme for making progress in science, write down:

a. a possible model (Note: more than one model can flow from these observations - just choose one for this exercise);.

b. a hypothesis derived from your proposed model; and

c. a consequent logical null hypothesis.

d. Propose an appropriate experimental design to test the null hypothesis.