In pond 1, the scientists found a high density of tadpoles, little food available and that most of the tadpoles counted were either detritus feeders or carnivores, with only a few intermediates. Describe and suggest explanations for the type of natural selection that appears to be acting in pond 1.
In pond 2, the scientists found a low density of tadpoles, enough food for all tadpoles and that most of the tadpoles counted were intermediates, with fewer detritus feeders or carnivores. Describe and suggest explanations for the type of natural selection that appears to be acting in pond 2.
The intestine length of S. multiplicata tadpoles shows continuous variation. Sketch a curve on Fig. 7.2 to show how intestine length varies across the tadpole population in pond 2.
A student proposed that the variation in S. multiplicata tadpoles might result in sympatric speciation in some populations. Outline the features of sympatric speciation.
The intestine length of $S.\,multiplicata$ tadpoles shows continuous variation. Sketch a curve on Fig. 7.2 to show how intestine length varies in the pond 2 tadpole population.
A student suggested that the variation seen in S.\,multiplicata tadpoles could give rise to sympatric speciation in some populations. Outline the features of sympatric speciation.
Fig. 7.3 shows the evolutionary relationships between three species of American spadefoot toad. Explain how DNA analysis allowed the extra evolutionary relationships shown in Fig. 7.3 to be determined.