Darwin & Evidence of Evolution

Main Principals of Evolution

All living things are related, natural processes drive natural selection

Evidence of Evolution

Comparative Anatomy, embryology, fossil records, biochemical comparisons, biogeography, and observational evidence

Fossil Evidence

Fossils show how species have changed over time and include transitional forms linking ancient and modern species

Comparative Anatomy

Studying similarities and differences in body structures of different species to indicate past ancestry

Comparative Embryology

Early development stages of different species often resemble each other, suggesting shared ancestry

Molecular Evidence

DNA and protein comparisons show that species with similar sequences share a recent common ancestor

Biogeography

The study of where species live; closely related species are often found near each other, and isolated populations evolve unique traits.

Observational Evidence

Directly seeing evolution occur in nature or in experiments with fast reproducing organisms

What’s the difference between homologous and vestigial structures?

Homologous structures indicate shared ancestry; vestigial structures are remnants of once-useful organs

Why do embryos of different species look similar in early development?

Because they share a common ancestor, and early development patterns are conserved

How can DNA differences estimate how long ago species diverged?

More DNA differences usually indicate a longer time since two species shared a common ancestor

Why do islands often have unique species?

Geographic isolation allows populations to evolve independently, creating new species

Example of evolution observed in real time.

Bacteria evolving resistance to antibiotics

Transitional Species

A species that shows traits of both an ancestral group and its descendants, providing evidence for evolution

Archaeopteryx

A fossil species with both dinosaur and bird characteristics, showing the evolution of birds from dinosaurs

Why are transitional species important for evolution?

They provide direct evidence of how major groups of organisms evolved from common ancestors.