Details of Mass extinction events occurred in the history of earth

1. MASS EXTINCTION EVENTS IN HISTORIC ERA
P. Karthikeyan, 13-520-001
M.Sc. (Ag.) Molecular Plant Breeding

2. Mother earth was dominated by
different kind of organisms at
different period of time
Natural Creations

3. Natural Disasters
Mother earth was demolished by
different kind of disasters at
different times

4. Natural Creations
Natural Disasters
Mass extinction
followed by slow
recovery

5. Time periods in the history of life on Earth during which exceptionally
large numbers of species go extinct are called mass extinctions.
Many species vanished in five cataclysmic mass extinctions and today,
99.9 percent of all species that have existed on Earth are extinct.

6. Earth's Big Five Mass Extinction Events
There have been a few large-scale extinction events in the history
of our planet, but these 5 were the big ones, determined by the
sheer scale of death across both land and ocean

7. End of the Ordovician
445 Million Years Ago
The oldest, and the 3rd largest, this Event lost 57% of all
genera
Because its so long ago, it's very difficult to resolve what
happened here
Climate change is the most likely culprit - and speculation
about the location of Pangea
South Pole would have created the largest glacial landmass in
the history of the planet
All that ice locked on land would have lowered sea levels
dramatically
This would have made living very difficult for all the shallow
marine life --- which was pretty much all of it at this time

8. The Late Devonian
370 Million Years Ago
This is a difficult event to pin down
Two or more events over the period of 25 million years
70% of all marine species died off.
Theories about anoxia (oxygen depletion) are high
as less oxygen in the water would explain the death rate
of marine life

9. End of the Permian
250 Million Years Ago
This is the big one...
The one that is easily the closest life has ever come to
being eradicated from Earth
83% of all genera on land and sea went extinct during
this period.
It was likely a combination of many, many bad things
happening all around the same time.
The supercontinent of Pangea was just forming, for one,
but the immense Siberian Traps also erupted at this
time.
There's some speculation that there was also a meteor
impact... but this has yet to be confirmed

10. End of the Triassic
200 Million Years Ago
According to the fossil record, 1/5th of all families of
marine life were killed.
The most likely cause of all the death is the eruption of
the Central Atlantic magmatic province.
2 million cubic km of lava spilled out over a few hundred
years...
but worse, 2 quadrillion kg of sulfur was released along
with twice as much C02.

11. Most famous and Recent

12. End of the Cretaceous
65 Million Years Ago
Up first, the most famous (and recent) of all the Extinction
Events...
The one that killed all but a small few of the dinosaurs (the ones
that ended up being today's birds).
This die-off killed more than just big land reptiles, however, it also
obliterated 17% of all living things on Earth.
Asteroid impact off today's Yucatan Penninsula is the most well
known theory as to the cause
Two other terrible things were happening at that time
the breakup of a super-continent and
the monstrous multi-millennial eruption of the
Deccan Traps in India.
Not a good time to visit when we finally invent that time machine.

13. The Sixth Mass Extinction has begun!
The sixth mass extinction is in progress, now, with animals going extinct 100 to 1,000 times
(possibly even 1,000 to 10,000 times)
faster than at the normal background extinction rate, which is about 10 to 25 species per year
Many researchers claim that we are in
the middle of a mass extinction event
faster than the Cretaceous-Tertiary
extinction which wiped out the
dinosaurs.

14. Rather than a meteorite or large volcanic eruption, the alarming decline of biodiversity
(diversity of species on earth) leading to the current mass extinction is the results of five
major human activities
• Habitat destruction including human-induced climate change
• Invasive species. Invasive/aliens species displace native species
through predation, competition, and disease organisms
• Pollution
• Human overpopulation
• Over-harvesting (hunting, fishing, and gathering

15. Time to correct ourselves
Thank you