＜p＞Extinct is a classification category on the International Union for the Conservation of Nature’s (IUCN) Threatened Species List.＜br /＞ Extinction occurs when a species ー also called “taxon” for the list ー no longer exists anywhere on earth. When scientists have done extensive research and agree that there is no longer a single individual specimen of the species they declare it extinct. Essentially, extinction represents the termination of a taxon.＜br /＞ There are six main reasons why species become extinct:＜/p＞ ＜ul＞ ＜li＞Habitat loss＜/li＞ ＜li＞Introduction of a foreign species＜/li＞ ＜li＞Hunting＜/li＞ ＜li＞Pollution＜/li＞ ＜li＞Disease＜/li＞ ＜li＞Loss of genetic variation＜/li＞ ＜/ul＞ ＜p＞Human actions play a huge role in species extinction, but they’re not the only culprit. Incredibly, 99 percent of species that have ever lived on the planet have gone extinct. Typically, species have a lifespan of about 10 million years, but there are some that stick around for hundreds of millions. Take jellyfish; they have shimmied around the world’s oceans for about 550 million years! However, just because most animals eventually go extinct doesn’t mean we should not be concerned with their conservation status. When species are unnaturally dying out, to maintain the planet’s ecological balance, we must make an effort to ensure their survival.＜/p＞画面が切り替わりますので、しばらくお待ち下さい。 ※ご購入は、楽天kobo商品ページからお願いします。※切り替わらない場合は、こちら をクリックして下さい。 ※このページからは注文できません。