Similarities and differences: Understanding homology and analogy

• Biological evolution accounts for diversity over long periods of time.
• Through billions of years of evolution, life forms have continued to diversify in a branching pattern, from single-celled ancestors to the diversity of life on Earth today.
• There is a fit between organisms and their environments, though not always a perfect fit.
• Not every feature of an organism is an adaptation, but features often reflect their evolutionary history.
• Features sometimes evolve to function in new ways.
• All organisms, including humans, retain evidence of their evolutionary history.
• 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.
• The process by which advantageous traits are maintained and disadvantageous traits are weeded out of a population is known as natural selection.
• Complex structures may be produced incrementally by the accumulation of smaller useful mutations.

• Evidence for Evolution
• Adaptation
• Natural Selection