Charles Darwin and the Galapagos Islands

Charles Darwin's Voyage and Theories

• Charles Darwin set out as a naturalist on the ship HMS Beagle.
• He created two important biology-related theories: the theory of natural selection and the theory of biological evolution.

Adaptation and Environment

• The term "adaptation" describes the characteristics of organisms that make them suited to their environment.

Galapagos Islands and Finches

• Darwin visited the Galapagos Islands and found a variety of species similar to those in South America, yet uniquely suited to the environment of the isolated islands.
• He focused on finches during his visit to the Galapagos Islands.
• Darwin proposed that the finches on the islands had evolved from a common ancestor.
• Geographic isolation led to the formation of different species of finches on different islands.
• The characteristics of island birds differed from those of their mainland ancestor due to adaptation to their environment.
• Over time, the characteristics of the island birds shifted away from those of their mainland ancestor.
• This led to the formation of unique species.

Natural Selection and Artificial Selection

• The theory of natural selection is based on the idea that all species produce more offspring than can survive, leading to a struggle for existence.
• Natural selection differs from artificial selection in that it occurs naturally, whereas artificial selection is selective breeding by humans.
• "Survival of the fittest" refers to the process of natural selection, where individuals with advantageous traits are more likely to survive and reproduce.
• Artificial selection involves deliberate breeding for desired traits.
• Traits are naturally selected in natural selection when they provide a survival or reproductive advantage.

Biological Evolution and Speciation

• Darwin used the term "descent with modification" to describe the process of living things changing over time.
• In his 1854 work, "On the Origin of Species," Darwin introduced the concept of biological evolution.
• Speciation occurs when species become so different from related organisms that they can no longer successfully mate with related populations.
• In Darwin's theory of biological evolution, species that don't adapt to changing environmental conditions are more likely to become extinct.
• The formation of new species is initiated by geographic isolation and adaptation to new environments.