16.4 Evidence of Evolution
How does the geographic distribution of species today relate to their evolutionary history?- How do fossils help to document the descent of modern species from ancient ancestors?
- What do homologous structures and similarities in embryonic development suggest about the process of evolutionary change?
- How can molecular biology be used to trace the process of evolution?
- What does recent research on the Galápagos finches show about natural selection?
biogeography
homologous structure
analogous structure
vestigial structure
Concept Map Construct a concept map that shows the kinds of evidence that support the theory of evolution.
MYSTERY CLUE
How can biogeography help explain why some species of honeycreepers are found only on the Hawaiian Islands?
THINK ABOUT IT Darwin's theory depended on assumptions that involved many scientific fields. Scientists in some fields, including geology, physics, paleontology, chemistry, and embryology, did not have the technology or understanding to test Darwin's assumptions during his lifetime. And other fields, like genetics and molecular biology, didn't exist yet! In the 150 years since Darwin published On the Origin of Species, discoveries in all these fields have served as independent tests that could have supported or refuted Darwin's work. Astonishingly, every scientific test has supported Darwin's basic ideas about evolution.
Biogeography
How does the geographic distribution of species today relate to their evolutionary history?
Darwin recognized the importance of patterns in the distribution of life—the subject of the field called biogeography. Biogeography is the study of where organisms live now and where they and their ancestors lived in the past. Patterns in the distribution of living and fossil species tell us how modern organisms evolved from their ancestors. Two biogeographical patterns are significant to Darwin's theory. The first is a pattern in which closely related species differentiate in slightly different climates. The second is a pattern in which very distantly related species develop similarities in similar environments.
Closely Related but Different To Darwin, the biogeography of Galápagos species suggested that populations on the island had evolved from mainland species. Over time, natural selection on the islands produced variations among populations that resulted in different, but closely related, island species.
Distantly Related but Similar On the other hand, similar habitats around the world are often home to animals and plants that are only distantly related. Darwin noted that similar ground-dwelling birds inhabit similar grasslands in Europe, Australia, and Africa. Differences in body structures among those animals provide evidence that they evolved from different ancestors. Similarities among those animals, however, provide evidence that similar selection pressures had caused distantly related species to develop similar adaptations.
Table of Contents
- Formulas and Equations
- Applying Formulas and Equations
- Mean, Median, and Mode
- Estimation
- Using Measurements in Calculations
- Effects of Measurement Errors
- Accuracy
- Precision
- Comparing Accuracy and Precision
- Significant Figures
- Calculating With Significant Figures
- Scientific Notation
- Calculating With Scientific Notation
- Dimensional Analysis
- Applying Dimensional Analysis