Interactive investigation: The arthropod story

• Biological evolution accounts for diversity over long periods of time.
• Life forms of the past were in some ways very different from living forms of today, but in other ways very similar.
• Present-day species evolved from earlier species; the relatedness of organisms is the result of common ancestry.
• There is a fit between organisms and their environments, though not always a perfect fit.
• Features sometimes evolve to function in new ways.
• All organisms, including humans, retain evidence of their evolutionary history.
• The fossil record provides evidence for evolution.
• The fossil record documents the biodiversity of the past.
• There are similarities and differences among fossils and living organisms.
• Similarities among existing organisms provide evidence for evolution.
• Anatomical similarities of living things reflect common ancestry.
• Traits that are advantageous often persist in a population.
• Scientists use anatomical evidence to infer the relatedness of taxa.
• Scientists use fossils (including sequences of fossils showing gradual change over time) to learn about past life.
• Classification is based on evolutionary relationships.

• Classification/Phylogenetics
• Evidence for Evolution
• History of Life