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Evolution

What is Evolution?

• Evolution is the process by which the characteristics of a species change over time.

• New traits that develop over time allow certain members of a species to gather more resources.

• Individuals with advantageous traits are more likely to survive and pass these traits to their offspring.

Darwin and Evolution

• Charles Darwin first observed evolution in the late 19th century.

• Studied a group of finches in the Galapagos Islands and noted varying traits among them despite being the same species.

• In 1859, he published "On The Origin of Species," which laid the groundwork for the Theory of Evolution.

The Theory of Evolution

• All species have evolved from simpler life forms.

• Evolution occurs through a process known as natural selection.

Natural Selection

• Key components include:

  • Individuals within a species exhibit a wide variety of traits.

  • Variation in traits is due to genetic differences.

  • Traits that give individuals an advantage in their environment lead to greater chances of survival and reproduction ("survival of the fittest").

  • The successful genes are passed onto offspring.

• Note: Some variations in traits may arise from environmental factors.

Cladograms

• A cladogram is a diagram that illustrates the evolutionary relationships between different groups.

• Based on phylogeny, the study of evolutionary relationships through the comparison of specific features.

Evolutionary Evidence

• Fossils provide crucial historical records of species.

• Comparative Anatomy: Identifies homologous structures (similar structures with different functions across species).

• Biochemical Evidence: Involves comparing DNA or amino acid sequences to show relationships.

The Geological Time Scale

• The geological time scale records the Earth's history from its formation, approximately 4.5 billion years ago, to the present.