Theory of evolution

Definition

The theory of evolution is a scientific explanation for the diversity of life on Earth, proposing that species change over time through processes such as natural selection, genetic drift, and mutation. This concept connects various biological phenomena and illustrates how life forms adapt to their environments across generations, leading to the hierarchical organization of life where species are categorized based on shared characteristics and common ancestry.

5 Must Know Facts For Your Next Test

1. The theory of evolution was most famously formulated by Charles Darwin in the 19th century, particularly through his work 'On the Origin of Species'.
2. Evolution operates on the principle of descent with modification, where species share a common ancestor but evolve different traits over time due to environmental pressures.
3. Fossil evidence plays a critical role in supporting the theory of evolution by providing snapshots of different life forms throughout Earth's history, showing transitional forms between species.
4. Genetic evidence, including DNA sequencing, has reinforced the theory by demonstrating genetic similarities among species that suggest a shared evolutionary past.
5. The hierarchical organization of life can be seen in taxonomic classification, where organisms are grouped based on evolutionary relationships, from domain down to species.

Review Questions

• How does the theory of evolution explain the hierarchical organization of life?
  • The theory of evolution explains the hierarchical organization of life through the concept of common descent, which suggests that all living organisms share a common ancestor. As species evolve over time due to mechanisms like natural selection and genetic drift, they diverge into different lineages. This leads to a classification system where organisms are grouped based on shared characteristics and evolutionary history, reflecting their relationships and how they have adapted to various environments.
• Discuss the role of natural selection in shaping the diversity of life as described by the theory of evolution.
  • Natural selection is a fundamental mechanism in the theory of evolution that drives adaptation and speciation. It acts on individuals within a population that exhibit variations in traits, favoring those better suited for survival and reproduction in a given environment. Over generations, these advantageous traits become more common within the population, leading to increased diversity as different populations adapt to different ecological niches and environments.
• Evaluate how fossil records and genetic evidence support the theory of evolution and contribute to our understanding of life's diversity.
  • Fossil records provide crucial evidence for the theory of evolution by documenting changes in species over time and showing transitional forms that illustrate how one species can evolve into another. Genetic evidence further supports this theory by revealing DNA similarities among different species, indicating their shared ancestry. Together, these types of evidence not only validate the mechanisms proposed by evolution but also enhance our understanding of life's complexity and interconnectedness through time.

Related terms

Natural Selection: A process by which organisms better adapted to their environment tend to survive and produce more offspring, leading to evolutionary changes in a population over time.

Speciation: The process through which new distinct species arise from existing species, often as a result of evolutionary mechanisms like geographic isolation or genetic divergence.

Phylogenetics: A branch of biology that deals with the evolutionary history and relationships among various biological species, often represented as a tree-like diagram illustrating common ancestry.