mass extinction
TRANSCRIPT
![Page 1: Mass extinction](https://reader035.vdocuments.us/reader035/viewer/2022062904/588acb731a28ab89058b4f77/html5/thumbnails/1.jpg)
MASS EXTINCTION
![Page 2: Mass extinction](https://reader035.vdocuments.us/reader035/viewer/2022062904/588acb731a28ab89058b4f77/html5/thumbnails/2.jpg)
Mass Extinction - Definition
A MASS EXTICTION IS A GLOBAL DECREASE IN THE AMOUNT OF LIFE.
IT IS THE EXTINCTION OF A NUMBER OF SPECIES IN A RELATIVELY SHORT TIME
![Page 3: Mass extinction](https://reader035.vdocuments.us/reader035/viewer/2022062904/588acb731a28ab89058b4f77/html5/thumbnails/3.jpg)
The 5 Major Mass Extinctions
![Page 4: Mass extinction](https://reader035.vdocuments.us/reader035/viewer/2022062904/588acb731a28ab89058b4f77/html5/thumbnails/4.jpg)
Extinction
Ordovician-Silurian
![Page 5: Mass extinction](https://reader035.vdocuments.us/reader035/viewer/2022062904/588acb731a28ab89058b4f77/html5/thumbnails/5.jpg)
End of Ordovician Mass Extinction – 443 Ma70% of marine species became extinct
Main groups affected are Trilobites, Graptolites, Echinoids, Brachiopods
![Page 6: Mass extinction](https://reader035.vdocuments.us/reader035/viewer/2022062904/588acb731a28ab89058b4f77/html5/thumbnails/6.jpg)
Glaciations-Possible Causes
Supercontinent positioned in high latitudes/close to the poles
![Page 7: Mass extinction](https://reader035.vdocuments.us/reader035/viewer/2022062904/588acb731a28ab89058b4f77/html5/thumbnails/7.jpg)
Glaciations-Effects on Ecosystems
Loss of habitat as ice masses growCould eventually lead to ‘Snowball Earth’ scenario
Global cooling.
![Page 8: Mass extinction](https://reader035.vdocuments.us/reader035/viewer/2022062904/588acb731a28ab89058b4f77/html5/thumbnails/8.jpg)
G A M M A R A Y B L A S TA small minority of scientist have suggested
that the initial extinction could have been caused by a gamma ray blast originating from a hyper nova within 6000 Lys from earth.
A Gamma ray blast are a flashes of gamma rays associated with extremely energetic high speed particles and radiation moving in space.
A mere ten seconds of blast could have destroyed earth’s ozone layer.
![Page 9: Mass extinction](https://reader035.vdocuments.us/reader035/viewer/2022062904/588acb731a28ab89058b4f77/html5/thumbnails/9.jpg)
ExtinctionLate Devonian
![Page 10: Mass extinction](https://reader035.vdocuments.us/reader035/viewer/2022062904/588acb731a28ab89058b4f77/html5/thumbnails/10.jpg)
Late Devonian Mass Extinction – 375 Ma A series of events that lasted around 10 Ma
Cephalopods, Fish and Corals most affected
Late Devonian Mass Extinction – 375 Ma
![Page 11: Mass extinction](https://reader035.vdocuments.us/reader035/viewer/2022062904/588acb731a28ab89058b4f77/html5/thumbnails/11.jpg)
TERRESTRIAL PLANT
New root system Decreased
CO2Boosted soil formation
Releasing nutrients into seas & ocean
Algae boom
Anoxia
Chiller climate
Glaciation
TERRESTRIAL PLANT
New root system Decreased
CO2Boosted soil formation
Releasing nutrients into seas & ocean
Eutrophication
Anoxia
![Page 12: Mass extinction](https://reader035.vdocuments.us/reader035/viewer/2022062904/588acb731a28ab89058b4f77/html5/thumbnails/12.jpg)
PERMIAN-TRIASSIC
EXTINCTION
![Page 13: Mass extinction](https://reader035.vdocuments.us/reader035/viewer/2022062904/588acb731a28ab89058b4f77/html5/thumbnails/13.jpg)
The largest mass extinction event removing 95% of marine species and 50% of marine families
Trilobites, Cephalopods, Bryozoans, Corals, Crinoids badly affected
Major faunal and floral overturn on land Marks the boundary between dominance
by the Palaeozoic and Modern Fauna
![Page 14: Mass extinction](https://reader035.vdocuments.us/reader035/viewer/2022062904/588acb731a28ab89058b4f77/html5/thumbnails/14.jpg)
![Page 15: Mass extinction](https://reader035.vdocuments.us/reader035/viewer/2022062904/588acb731a28ab89058b4f77/html5/thumbnails/15.jpg)
![Page 16: Mass extinction](https://reader035.vdocuments.us/reader035/viewer/2022062904/588acb731a28ab89058b4f77/html5/thumbnails/16.jpg)
Methane Hydrates in Ocean Floor Sediments
Global warming may result in deep ocean
temperatures rising and the release of large volumes of
methane from ocean sediments
The rapid release of large amounts of methane into the atmosphere will result
in highly accelerated global warming
![Page 17: Mass extinction](https://reader035.vdocuments.us/reader035/viewer/2022062904/588acb731a28ab89058b4f77/html5/thumbnails/17.jpg)
Triassic - Jurrasic Extinction
![Page 18: Mass extinction](https://reader035.vdocuments.us/reader035/viewer/2022062904/588acb731a28ab89058b4f77/html5/thumbnails/18.jpg)
End Triassic Mass Extinction – 200 Ma Multiple event mostly affected the land
where over 95% floral species eliminated
Around 30% marine species became extinct – mainly reef dwellers, Ceratites, Brachiopods and Bivalves
![Page 19: Mass extinction](https://reader035.vdocuments.us/reader035/viewer/2022062904/588acb731a28ab89058b4f77/html5/thumbnails/19.jpg)
Flood Basalt Eruptions
Pangea broke up and eventually splitting America from Europe and Africa and forming
the Atlantic ocean.The Central American Magmatic Province
had begun to erupt huge amount of basalt lava
![Page 20: Mass extinction](https://reader035.vdocuments.us/reader035/viewer/2022062904/588acb731a28ab89058b4f77/html5/thumbnails/20.jpg)
Flood Basalt Eruptions
Billions of tonnes of carbon dioxide and
sulphur dioxide released into the atmosphere
during eruptions
Both are powerful greenhouse gases and will contribute to very rapid global warming
![Page 21: Mass extinction](https://reader035.vdocuments.us/reader035/viewer/2022062904/588acb731a28ab89058b4f77/html5/thumbnails/21.jpg)
Flood Basalt Eruptions
When it rains the sulphur dioxide will come back down to Earth dissolved in rainwater and
the acid rain will kill vegetation on a large scale
CO2 will cause global warming.Rise in sea levelGlobal anoxia.
![Page 22: Mass extinction](https://reader035.vdocuments.us/reader035/viewer/2022062904/588acb731a28ab89058b4f77/html5/thumbnails/22.jpg)
![Page 23: Mass extinction](https://reader035.vdocuments.us/reader035/viewer/2022062904/588acb731a28ab89058b4f77/html5/thumbnails/23.jpg)
CRETACEOUS –PALEOGENE
EXTINCTION
![Page 24: Mass extinction](https://reader035.vdocuments.us/reader035/viewer/2022062904/588acb731a28ab89058b4f77/html5/thumbnails/24.jpg)
K-T Mass Extinction
Around 70% of all species wiped outDinosaurs, Reptiles, Ammonites, Belemnites,
Brachiopods, Bivalves, Foraminifera
![Page 25: Mass extinction](https://reader035.vdocuments.us/reader035/viewer/2022062904/588acb731a28ab89058b4f77/html5/thumbnails/25.jpg)
A large asteroid or meteorite (10km in diameter) collided with the Earth 65 million years ago
![Page 26: Mass extinction](https://reader035.vdocuments.us/reader035/viewer/2022062904/588acb731a28ab89058b4f77/html5/thumbnails/26.jpg)
Evidence - Asteroid Impact Location
Location of possible impact site discovered on the Yucatan Peninsula in Mexico at Chixulub
The impact structure is a circular depression about 180 km in diameter
![Page 27: Mass extinction](https://reader035.vdocuments.us/reader035/viewer/2022062904/588acb731a28ab89058b4f77/html5/thumbnails/27.jpg)
Evidence – The K-T Boundary LayerThe presence of a thin 2cm
layer of iridium-rich clay found all over the world
within sedimentary rocks
The K-T Boundary Layer dates the same everywhere
at 65.5 Ma +/- 0.3 Ma
Iridium is a transition element, rare on Earth but
found in meteorites.
First proposed by Luis Alvarez in 1980
![Page 28: Mass extinction](https://reader035.vdocuments.us/reader035/viewer/2022062904/588acb731a28ab89058b4f77/html5/thumbnails/28.jpg)
Evidence – Wildfires & Fossil
The K-T Layer has high concentrations of carbon in many locations,suggesting that the asteroid impact may have generated wildfires.
![Page 29: Mass extinction](https://reader035.vdocuments.us/reader035/viewer/2022062904/588acb731a28ab89058b4f77/html5/thumbnails/29.jpg)
Evidence – Tsunami DepositsIt is thought that the asteroid
impact occurred in the sea and initially produced a crater 100
km wide and 30 km deep
This would have displaced vast volumes of seawater and
generated a series of very large tsunamis possibly over
100 metres in height
The tsunamis would have travelled great distances inland, and in Texas at Waco there are
large-scale sedimentary deposits thought to be of tsunami origin.
![Page 30: Mass extinction](https://reader035.vdocuments.us/reader035/viewer/2022062904/588acb731a28ab89058b4f77/html5/thumbnails/30.jpg)
Evidence – Tsunami Deposits
The tsunami deposits in Waco, Texas are thought to be from the waves generated by the K-T asteroid impact.
The sediments are estimated to have been deposited at least 300km inland by the tsunamis!
![Page 31: Mass extinction](https://reader035.vdocuments.us/reader035/viewer/2022062904/588acb731a28ab89058b4f77/html5/thumbnails/31.jpg)
Flood Basalt Eruptions 66 Ma – The Deccan Traps
Lasted over a period of 2 My . Over 2000 metres thick and cover 500,000 km²
May have originally covered 1,500,000 km²Released dust and sulphuric aerosols and blocking sunlight
thus reduced photosynthesis.Also emitted CO2 .
![Page 32: Mass extinction](https://reader035.vdocuments.us/reader035/viewer/2022062904/588acb731a28ab89058b4f77/html5/thumbnails/32.jpg)
HOLOCENE EXTINCTION
![Page 33: Mass extinction](https://reader035.vdocuments.us/reader035/viewer/2022062904/588acb731a28ab89058b4f77/html5/thumbnails/33.jpg)
Holocene Extinction The Earth is currently losing about 30,000
species of plants, animals and insects a year.
That is about 3 species every hour! Lost forever. It will take millions of years to repair what we
destroy in just a few decades.
![Page 34: Mass extinction](https://reader035.vdocuments.us/reader035/viewer/2022062904/588acb731a28ab89058b4f77/html5/thumbnails/34.jpg)
CAUSES
Rising CO2 levelsHabitat destructionInvasive speciesPollutionOver harvesting
![Page 35: Mass extinction](https://reader035.vdocuments.us/reader035/viewer/2022062904/588acb731a28ab89058b4f77/html5/thumbnails/35.jpg)
How You Can Help
Turn lights and appliances off when not using them.
Use energy efficient light bulbs.
Make space for wildlife. Build a birdhouse , plant a tree, compost your wastes and don’t use harmful chemicals in your home or garden.
Recycle, Reduce and Reuse.
![Page 36: Mass extinction](https://reader035.vdocuments.us/reader035/viewer/2022062904/588acb731a28ab89058b4f77/html5/thumbnails/36.jpg)
That’s All Folks!
THANK YOU..!!!