1. When a population decreases significantly, the species can become extinct, endangered or threatened.

2.  99.9% of all species that ever lived on Earth are now extinct.  Extinction appears to be a natural cycle and part of our changing Earth, but the cause of early extinctions are a cause for concern.

3.  Dinosaurs were believed to be extinct due to a meteorite crashing into Earth.  Are humans causing the next mass extinction- the sixth in the history of life on Earth?

4.  An extinct species is one that has died out and left no living relatives.  Species become extinct due to due to climate change, disease, destruction of habitat, natural disasters and development into a new species.

5.  The dodo bird was found on the Island of Mauritius in 1505.  The last dodo bird was killed in 1681.

6.  Quaggas were hunted to the brink of extinction in the mid 1900s.  The last Quagga died in the Amsterdam zoo in 1883.

7.  Mastodons roamed the Earth 15 million years ago.  They became extinct about 16,000 years ago.

8.  Endangered species are species that numbers are so small, they are in danger of becoming extinct.

9.  The Miami butterfly lives mainly in Florida  Their numbers are believed to be only around 50 to 60 adults.

10.  The gray wolf numbers are declining rapidly.  They are being killed by farmers and hunters.

11.  Leatherback turtles weigh 1,000 pounds and have roamed the oceans for hundreds of years.  It is now on the endangered list.

12.  Threatened Species are species that are vulnerable to become endangered in the future.

13.  Polar Bears are threatened due to global warming and the changing of their habitat.

14.  Orca whales are residents of the Pacific Northwest.  Due to population decline, many realize they are a species threatened to become extinct.

15.  Although marine turtles have been around for millions of years, they are now threatened.  Reasons for their decline are poachers and predators pillaging their nests as well as habitat degradation by human impact.