MASS EXTINCTION

EXTINCTION• EXTINCTION IS THE TOTAL DISAPPEARANCE OF ALL THE MEMBERS OF A

CERTAIN SPECIES.SOME REASONS ARE CLIMATE CHANGE,CHANGES IN SEA LEVELS,NATURAL PHENOMENONS AND WHAT IS HAPPENING NOW HUMAN ACTIVITIES.ALL OF THESE MAY LEAD TO EXTINCTION OF EVERY LIVING ORGANISM IN THE PLANET INCLUDING HUMANS.• THERE ARE 5 MASS EXTINCTIONS IN HISTORY NAMELY THE ORDOVICIAN-

SULIRIAN,DEVONIAN,PERMIAN,TRIASDIC-JURASSIC AND THE CRETACOUS TERTIARY.• THIS 21ST CENTURY THEY FOUND A NEW MASS EXTINCTION WHICH IS CALLED

THE 6TH MASS EXTICTON/HOLOCENE EXTINCTION.

HOLOCENE EXTINCTION• THE HOLOCENE EXTINCTION, SOMETIMES CALLED THE SIXTH

EXTINCTION, IS A NAME PROPOSED TO DESCRIBE THE EXTINCTION EVENT OF SPECIES THAT HAS OCCURRED DURING THE PRESENT HOLOCENE EPOCH (SINCE AROUND 10,000 BCE) MAINLY DUE TO HUMAN ACTIVITY.

5 MASS EXTICTIONS IN HISTORY

1ST MASS EXTINCTION

ORDOVICIAN-SILURIAN PERIODTHIRD LARGEST EXTINCTION IN EARTHS HISTORY.85% OF SEA LKFE WAS WIPED

OUT.CAUSE:

A HUG ICE SHEET CAUSED THE CLIMATE TO CHANGE,WHICHALTED THE CHEMISTRY OF TH OCEANS.