Potential command term assessment statements Topic 5: Evolution and biodiversity 5.1 Evidence of evolution Essential Idea: There is overwhelming evidence for the evolution of life on Earth. Nature of science: Looking for patterns, trends and discrepancies – there are common features in the bone structure of vertebrate limbs despite their varied use. Define evolution. Evolution is the change in the heritable characteristics of a population. Not only do species evolve but new species arise from preexisting species and this shows the unity of all life by its common origins. Outline the evidence for evolution provided in the: fossil record selective breeding of domesticated animals that shows artificial selection can cause evolution evolution of homologous structure by adaptive radiation to explain similarities in structure when there are differences in function. Outline how populations of species can gradually diverge into separate species by evolution. Outline how continuous variation across the geographical range of related populations matches the concept of gradual divergence. Describe the development of melanistic insects in polluted areas (industrial melanism of the peppered moth, Biston betularia) as example of transient polymorphism. Compare and contrast the pentadactyl limb of mammals, birds, amphibians and reptiles with different methods of locomotion. Theory of Knowledge: Discuss the challenges of evolutionary history as an area of natural science when experiments cannot be performed to establish past events or their causes. Outline the use of scientific methods in establishing beyond reasonable doubt what happened in certain cases of evolutionary history and how these methods compare to those used by historians to reconstruct the past.