Narrator: This is Science Today. Paleontologist Kevin Padian (PAY-DIAN) of the University of California, Berkeley says dinosaurs may have already been petering out before a giant meteor hit the Earth.
Padian: Some groups were still growing strong, some groups were already dying out because things were changing. We donít know exactly all the environmental influences that contributed to the demise of every single species, but we know that lots of things were changing.
Narrator: Some of these changes included the shifting of continents and volcanic activity. But Padian (PAY-DIAN) says a wane of dinosaur reproduction may have also led to their demise.
Padian: Because the existing species are constantly becoming extinct and if you donít keep producing new species to keep up with your extinction rate, your gonna be out of business real fast.
Narrator: But Padian does not discredit the whole asteroid theory..
Padian: When asteroid proponents end their sentences of explaining their research with "and killed the dinosaurs", the paleontologists have a problem with that, but not with the rest of it.
Narrator: For Science Today, Iím Larissa Branin.