Mosasaur fossils have been recovered from Late Cretaceous rocks all over the world. Most are just a fossilized tooth or perhaps a loose rib or vertebra. Occasionally, several bones are discovered still together. Conventional wisdom holds that creatures from this period died millions of year ago. If that's true, why do some still have soft tissue?

Sponges have long been considered one of the "simplest" forms of life. Now an international team of scientists has analyzed sponge DNA and concluded that it shares representative genes associated with the core processes of all animal cells--including human cells. What does this say about where sponges and people came from?

Humans are in rare company when it comes to singing duets. Humpback whales perform original couples' songs, as do a handful of birds. It was thought that bird duets were just for mating purposes, but a study on zebra finches has opened a new window on bird behavior.

Marsupials are mammals that nurture their young in a special pouch. Their fossils are rare. Few have been discovered in Australia, for example, which is home to several unique marsupials, including kangaroos. So, determining their origins has been a longstanding challenge for evolutionists.