Final answer:
The concept of a giraffe developing a long neck passed on to its offspring is an example of evolution by natural selection, where giraffes with longer necks had higher reproductive success and thus this trait became more common over generations, contrasting with Lamarck's incorrect theory of inherited acquired characteristics.
Step-by-step explanation:
The idea that a giraffe develops a long neck and it is passed on to its offspring is an example of evolution by natural selection, a concept put forth by Charles Darwin. Giraffes with longer necks could reach higher leaves, giving them a survival advantage in an environment where food might be scarce, leading to greater reproductive success and the passing of the long-neck trait to their offspring. Over time, this results in a population of giraffes with long necks. This is different from Lamarck's theory of inheritance of acquired characteristics, which incorrectly suggested that traits developed during an organism's lifetime could be passed on to their offspring. To contrast, Darwin's observations, such as those of giant tortoises with longer necks on the Galápagos Islands, supported the idea of natural selection where only traits present in the genes can be passed down.