First proposed by naturalist Charles Darwin in his 1859 book On the Origin of Species,

the theory of evolution explains how all plants and animals-including humans slowly change over time to improve their chances of survival. All life-forms are subject to the forces of "natural selection," in which nature favors changes (tougher beaks, sharper teeth, keener eyesight, etc.) that help a species survive and reproduce. These helpful "adap- tations" are then passed on to the next generation. Even- tually, all these adaptations add up until one species evolves into a new one. If you go back far enough in Earth's history, all life-forms-from great white sharks to cherry trees- evolved from a common ancestor.

If humans evolved from apes, then why do chimpanzees and other apes still exist?

This question is often posed by people who disagree with the theory of evolution, but it ignores one important fact: Humans didn't evolve from modern chimpanzees. We all share a common ancestor, which lived about six million years ago and served as a branching point in the evolu- tionary tree. The branch that gave rise to humans went in one direction, while the one that led to today's chimpanzees went in another. Also, just because a particular group of animals evolves into a new species doesn't mean the original species has to go extinct. The process of evolution follows a branching path rather than a series of dead ends and new beginnings. New species branch off from the original group all the time.

What ARE THE OLDEST LIVING THINGS ON EARTH?

While many animals outlive humans (giant tortoises live more than 200 years, lobsters and bowhead whales celebrate a hundred birthdays, and the tiny freshwater hydra can live as long as 1,400 years), life spans really start to stretch when you look at other forms of life...

FIELDS OF MOSS in Antarctica have been around for 2,000 years.

Scientists estimate that a PALMER'S OAK TREE in California, U.S.A., is MORE THAN 13,000 YEARS OLD, meaning it was already old by the time the ancient Egyptians built the pyramids.

Acres of QUAKING ASPEN TREES in Utah, U.S.A., share a root sys-

tem that has survived for 80,000 YEARS.

But the leader in longevity is a BATCH OF BACTERIA discovered in the frozen ground of Siberia. Scientists estimate it has been growing for HALF A MILLION YEARS, making these microbes Earth's senior citizens.

Evaluation is the process of examining the performance of an organization, program, project, policy, or any other intervention to determine its relevance, adequacy, effectiveness, efficiency, and progress for the purpose of identifying areas for improvement. Essentially, it refers to the combination of evidence and values to determine whether an intervention has merit, worth, or significance.

Evaluation is a complex and dynamic process that requires the use of a variety of data collection and analysis techniques to assess the performance of an organization, program, policy, or project. Evaluation can be used to inform decisions about how to improve the effectiveness of programs, projects, policies, and organizations.