WHAT IS EXTINCTION: All the organisms that people know about are classified by biologists into separate species (as well as bigger groups of classifications, such as a genus or family.) When no more individuals of a given species can be found anywhere on earth, the species is considered extinct. Many animals have been placed on the endangered species list because their populations are close to becoming extinct. If one animal relies on another for its food or protection, it can become part of the extinction chain. Possibly the most famous extinction happened at the end of the Cretaceous period, about 65 million years ago, when most of the species on Earth were wiped out by a large asteroid's impact with the Earth. That was when all the non-bird-like dinosaurs went extinct.
WHAT IS GLOBAL WARMING DOING TO THE OCEANS? It's raising the oceans' temperatures ever so slowly, but also, it's making it easier for them to absorb Carbon Dioxide (CO2). Large amounts of CO2 are absorbed by the ocean, up to a million tons an hour worldwide. This changes the chemistry of the ocean, making it slightly more acidic. This can harm the environment as far as many marine animals and plants are concerned, causing devastation in ecosystems like coral reefs. Also, because more acidic seawater absorbs less low- and mid-frequency sound (the frequencies at which many animals communicate), water becomes better able to transmit certain frequencies, meaning that equally loud noises can be heard farther away in water with lower pH levels.