Final answer:
Evolution by natural selection is Darwinian evolution, which is a process that explains how living things change over time due to differences in reproductive success among individuals.
Step-by-step explanation:
Evolution by natural selection is B. Darwinian evolution. The theory of evolution by natural selection is a scientific concept that explains how changes occur in the characteristics of living things over time. This process occurs as certain individuals with favorable traits are more likely to survive and reproduce, thereby passing on those advantageous traits to future generations. Over many generations, these changes can lead to significant differences and eventually give rise to new species.
Charles Darwin and Alfred Russel Wallace are credited with proposing this theory in the 19th century. They recognized that natural variations exist within populations and that the environment can 'select' the traits that are most advantageous for survival.
Phylogenetic trees and cladograms are used in biology to represent the evolutionary relationships between species and illustrate these changes over time. However, they are not the answer to this specific question; rather, they are tools used to understand and represent the outcomes of evolutionary processes, including natural selection.