An example of an alternative conception:
It is sometimes suggested that individual specimens of a species can adapt to their environment, and that such adaptations are passed on to their offspring. So, for example, this perspective might suggest the explanation of giraffes having such long necks in terms of how giraffes that originally had much shorter necks stretched their necks to reach the foliage on tall trees, and as a result had children with longer necks. This is supposed to have continued over many generations.
Natural selection suggests instead that different specimens are likely to have different levels of success in leaving offspring, determined in part by differences between them (as well as a good deal of luck) and that those characteristics which tend to lead to fecundity will be passed on to offspring.* So, if those giraffes that were naturally born with longer necks were more often the ones that live to adulthood and produce healthy offspring the genes associated with long necks would come to be better represented in each generation.
Learners sometimes entertain this alternative conception (even after being introduced to natural selection) – and it was at one time a perfectly respectable scientific theory (known as Lamarckism after the French naturalist Jean-Baptiste de Monet, chevalier de Lamarck). That is, it can be considered as an historical scientific conception.
Read 'Many generations later it's just naturally always having fur'
Read about Historical scientific conceptions
* Although the canonical biological account now rejects the conception that acquired characteristics can be passed on to offspring, as it is now understood that an individual's genome is fixed at birth; in recent years epigenetics has begun to explore how the expression of genes in an individual may sometimes be influenced by the life experiences of the parents or earlier generations.
