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What does this mean?

When all the members of a species die out the species has become extinct. A species is deduced to be extinct if it stops appearing in apparently later (more recent) rock. There seem to have been times in the earth’s history when many species have become extinct at about the same time. Such an event is called a mass extinction.

Five major mass extinctions

Evolutionists think that there were five large mass extinctions, with the two largest being:

  • The first major mass extinction is said to have occurred at the end of the Permian period. This is thought to have been about 225 million years ago. At that time 90% of marine life seems to have become extinct.
  • The second is thought to have occurred about 65 million years ago, at the end of the Cretaceous Period. This led to the disappearance of the dinosaurs.

Each time a mass extinction seems to have happened, many new kinds of fossils appear in later (more recent) rocks. These are considered new because their fossils were absent from older-dated rocks. Transitional evolutionary ancestors of these new organisms are also not found in older rock. This sudden appearance of new species is explained as follows. After a mass extinction a large part of the environment is cleared of the life forms which had previously dominated (controlled) the earth. This makes way for new forms to evolve and fill the many new vacant ecological niches (open spaces in the ecosystem).

Possible causes of mass extinctions

Mass extinctions can be caused by various factors. These may be extra-terrestrial, due to climate change, caused by humans, genetic, or due to continental drift:

  • Extra-terrestrial events are caused by something outside of the earth, e.g. by a meteorite. At least two mass extinctions are thought to have been caused by huge meteorites striking the earth. A meteorite is s chunk of rock from outer space, which enters the earth’s atmosphere. These meteorites are thought to have been about 10 km in diameter. Some scientists believe that such impacts happened many millions of years ago. Other data suggests that a meteor of diameter 200km hit the earth only a few thousand years ago. This does not fit in with the geological time scale and is usually ignored. (This is based on observations of the changing tilt of the earth’s axis, made over a period covering most of recorded history.
  • Climate change can cause extinction.
  • Link to simulation - glaciers (External Link)
  • Human activity can cause extinction. Humans are destroying the habitat of many types of plants and animals. This is done by chopping down forests and draining swamps to grow crops and to build houses.
  • Continental drift might have caused extinction. According to the theory of continental drift, all land used to be joined in a supercontinent called Pangaea. This later split into Laurasia in the north and Gondwanaland in the south. There is much evidence for this. As the continents moved apart, some populations were split and moved apart. This could have caused extinction as habitats and climates changed as a result of the continental drift.

See (External Link)

What killed the dinosaurs: (External Link)

Biodiversity: the 6th great wave: (External Link)

Vertebrate extinction crisis (videos): (External Link)&id=db50e9fd5d&e=&utm_source=ARKive&utm_campaign=db50e9fd5d-IUCN_Press_Release10_27_2010&utm_medium=email

Activity: mass extinctions

1. How do extinction events seem to help the process of evolution?
2. Name any four possible causes of mass extinctions.
3. Complete this table:

Geological time period when extinction is thought to have occurred. Years before present when evolutionists think this happened Main feature of extinction event
End of the Permian period.
Dinosaurs became extinct.

Activity: Answers

1. How do extinction events seem to help the process of evolution? They possibly cleared the earth of previously dominant species, allowing new species to evolve into the ecological niches this opened up.
2. Name any four possible causes of mass extinctions. Meteorites, volcanoes, climactic changes (e.g. ice age / global warming), man-caused (e.g. over-hunting), due to genetic deterioration
3. Complete this table:

Geological time period when extinction is thought to have occurred. Years before present when evolutionists think this happened Main feature of extinction event
End of the Permian period. 225 million years ago 90% of marine life became extinct
End of Cretaceous era 65 million years ago Dinosaurs became extinct.

Questions & Answers

are nano particles real
Missy Reply
Hello, if I study Physics teacher in bachelor, can I study Nanotechnology in master?
Lale Reply
no can't
where we get a research paper on Nano chemistry....?
Maira Reply
nanopartical of organic/inorganic / physical chemistry , pdf / thesis / review
what are the products of Nano chemistry?
Maira Reply
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Preparation and Applications of Nanomaterial for Drug Delivery
Hafiz Reply
Application of nanotechnology in medicine
has a lot of application modern world
what is variations in raman spectra for nanomaterials
Jyoti Reply
ya I also want to know the raman spectra
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
yes that's correct
I think
Nasa has use it in the 60's, copper as water purification in the moon travel.
nanocopper obvius
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
How we are making nano material?
what is a peer
What is meant by 'nano scale'?
What is STMs full form?
scanning tunneling microscope
how nano science is used for hydrophobicity
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
what is differents between GO and RGO?
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
analytical skills graphene is prepared to kill any type viruses .
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
The nanotechnology is as new science, to scale nanometric
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
why and for what was five kingdom of classification of organisms introduced
give the ans as fast as possible
Comment on the ozone depletion over the period of 1982 to 1996
Mpho Reply

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Source:  OpenStax, Siyavula: life sciences grade 10. OpenStax CNX. Apr 11, 2012 Download for free at http://cnx.org/content/col11410/1.3
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