Evolution: Definition and Early Views

Evolution Concept

• Evolution is the concept that describes the gradual change of species over time through natural selection, genetic drift, mutation, and gene flow.

Essentialism vs. Population Thinking

• Essentialism is the view that the biological world contains discrete types with little variation within them.
• Population thinking, in contrast, emphasizes the importance of variation within populations to understand the process of evolution.

Darwin's Finches

• Darwin's study of finches in the Galápagos Islands contributed to supporting the idea of evolution by showing that different finch species had distinct beak shapes and sizes adapted to their specific environments.

Natural Selection

• The tall stem length of sunflowers is an example of natural selection for survival and reproduction, as it allows them to compete more effectively for sunlight and resources.

Peppered Moths

• When factories caused pollution and darkened the trees, the peppered moths evolved from a light-colored to a dark-colored morph, providing an example of adaptation to a changing environment.

Catastrophism

• Georges Cuvier, a French scientist, is associated with the concept of Catastrophism, which suggests that sudden, catastrophic events have shaped the Earth's history.
• Cuvier studied fossils to support his concept of Catastrophism.

Carolus Linnaeus

• Carolus Linnaeus believed that species are fixed and unchanging, and that each species has a distinct, essential characteristics.

Gradualism

• Charles Lyell, a British scientist, proposed the idea of Gradualism, which suggests that slow and continuous processes, such as geological changes, have led to significant changes over time.