Darwin

Belief: Suggested humans and apes have a common ancestor and that Earth is older than 6000 years.

Contribution: Developed paleontology; observed fossils in rock layers (strata) showing extinction and introduced “catastrophism” – natural disasters causing species disappearance.

Survival of the Fittest: Species with advantageous traits survive and reproduce, leading to gradual changes in populations over generations.

Theory: Believed in Uniformitarianism – Earth’s changes happen gradually, not from sudden events, supporting the idea that Earth is older than 6000 years.

Theory: Proposed that species evolve by inheritance of acquired characteristics, where traits used more frequently become stronger over time.

Voyage of the Beagle: Observed species variation in South America, especially the Galapagos finches adapting to different niches, leading to his theory of natural selection.

• Finches on each island adapted to specific food sources. • Physical separation prevented interbreeding, leading to distinct species. • Adapted traits passed on, creating a new gene pool over time.

• Overproduction: Species produce more offspring than needed; few survive. • Competition: Limited resources force organisms to compete. • Genetic Variation: Differences within a species make each organism unique. • Adaptation: Traits that increase survival in an environment. • Natural Selection: Environment favors traits that aid survival. • Speciation: Accumulation of adaptations over time creates new species.

Definition: The gradual change in the genetic composition of a population over generations, leading to diversity in life forms.

Definition: The specific role or habitat of an organism in its environment (e.g., arctic fish adapted to cold waters).

Steps: Geographic isolation → Accumulation of unique traits → Reproductive isolation → Formation of a new species.

Definition: Producing more offspring than can survive, ensuring only the fittest continue.

Concept: Offspring compete for resources like food and space, with only a few surviving.

Definition: Differences within individuals of a species; essential for evolution and adaptation.

Definition: An inherited trait that improves survival chances in a specific environment.

Concept: Nature “selects” organisms with beneficial traits to survive and reproduce, leading to a more adapted population.

Definition: Formation of a new species over many generations as traits accumulate and change.

Catastrophism: Earth changes due to sudden events (Cuvier). Uniformitarianism: Slow, gradual changes shape Earth (Lyell).

Metaphor: Life’s diversity grows like branches on a tree from a common root (common ancestor).