- Jean-Baptiste Lamarck proposed the idea that evolution occurs. However, Darwin
differed with Lamarck on several other points. Lamarck proposed that traits acquired
during one’s lifetime could be passed to the next generation. - Darwin’s grandfather, Erasmus Darwin, wrote a book calledZoonomia. Charles Dar-
win was influenced by many of his grandfather’s ideas including his descriptions of how
species change (evolve) through artificial selection. During artificial selection, people
choose specific traits to pass to the next generation, such as with horse or dog breeding
(See below). - Charles Lyell, a well-known geologist and one of Darwin’s instructors. Darwin learned
about geology, paleontology and the changing Earth from Lyell. These findings sug-
gested the Earth must be much older than 6,000 years. - Thomas Malthus: Darwin’s ideas of natural selection were inspired by reading an essay
by Thomas Malthus, an economist who suggested that humans could overpopulate
and potentially exhaust food supplies. Darwin thought this must be especially true
for animals, as they have a tendency to have more offspring than people have. There
would therefore be a competition for survival. - Charles Darwin came upon some of his ideas about natural selection and adaptations
from reading about artificial selection and breeding dogs. All dogs, from Chihuahuas
to St. Bernards are part of the same species as wolves (Canis lupus). Humans created
the different breeds of dogs by selecting dogs with specific traits to breed together. For
example, greyhounds were created by selecting the fastest runners and breeding them
together (Figure7.11). - After the Voyage of the Beagle: Alfred Russel Wallace, another naturalist, also devel-
oped a theory of evolution by natural selection. Alfred Wallace toured South American
and came up with a very similar theory of evolution by natural selection at the same
time that Darwin did. Darwin and Wallace presented their theories and evidence in
public together. Because of the vastness of Darwin’s data, and his book, he is mostly
credited and associated with this theory.
Natural Selection and Adaptation
The Theory of Evolution by Natural Selection means that the inherited traits of a population
change over time through natural selection. Inherited traits are features that are passed from
one generation to the next. For example, your eye color is an inherited trait (you inherited
from your parents). Acquired traits are features such strong muscles from working out.
Natural selection happens when some organisms have traits that make them better suited
(they have better accommodation) to live in a certain environment than others. They are
more likely to survive, reproduce and pass their traits on to future generations than those
without the special traits. The process of natural selection helps us understand how organ-
isms appear to be so well suited or adapted to their environments. Every plant and animal
depends on its traits to survive. Survival may include getting food, building homes, and