Summary:

In this video, Life Noggin, gives a brief explanation on the five mass extinctions that have happened on earth thus far. These five mass extinctions have occurred because of natural processes rather than human activity. It is believed that we are currently on the road to the sixth extinction where human life may be at risk.

Why Watch this Video:

• Have you ever wondered the causes of mass extinctions?
• Would you like to know if mass extinctions can be prevented by human beings
• Have you ever been confused by the selectiveness of mass extinctions? Why some species die off while others remain unscathed?

Key Terms:

Extinction: the disappearance of a group, species or larger group due to some cause.

Species: living organisms sharing similar characteristics and are capable of interbreeding/reproducing.

Selectiveness: characterized by selection, the ability to select some while rejecting others of a similar group.

Loose Ends:

#1: The five mass extinctions that have occurred were caused by natural effects rather than human activity. High CO2 levels, massive influxes of methane/carbon dioxide, volcanic eruptions, lack of oxygen in the oceans and ice ages are a few of the examples of the natural effects that caused mass extinctions.

#2: This video could explain why some species survived mass extinctions while other similar species did not. Although it is not entirely known why some species survived while others, like themselves, did not there is speculation surrounding this. For example, the lack of oxygen in the oceans that caused 75% of species to be wiped out during the Late Devonian Extinction took much of the marine life but did not affect sharks – this could be because of oxygen existing where the sharks resided and being non-existent in other parts of the ocean.

#3: This video could have expanded on the theme of selectiveness. Why some species were targeted and affected while other remained untouched. Amphibians and marine creatures died during the Triassic-Jurassic Extinction but plants survived. This was due to a massive influx of carbon dioxide caused by a volcanic activity that acidified oceans and raised air temperatures.

Self-Test Questions:

Q1: What can human beings do to help prevent another mass extinction from happening?

a] water plants

b] use plastic straws

c] go vegan

d] ride their bikes

Correct Answer: A. Watering plants is vital as plants provide food, medicine and they absorb massive amounts of CO2 which helps keep global warming at bay. If plants go extinct humans could be next so keep watering those plants!

Q2: What was the name of the extinction in which the dinosaurs were wiped out?

a] Late Devonian Extinction

b] Triassic-Jurassic Extinction

c] Permian Mass Extinction

d] K-T Extinction

Correct Answer: D. The K-T Extinction occurred 65 million years ago. It is believed to have been caused by either an asteroid in Mexico or volcanic eruptions in India – dust and debris blocked out sunlight causing the animals to die off.

Q3: What percentage of species were wiped out in the Permian mass extinction?

a] 75%

b] 40%

c] 95%

d] 80%

Correct Answer: C. The Permian Extinction is also known as “The Great Dying”. It is one of the worst extinctions in history wiping out 95% of species including insects!

Q4: Which extinction lost a majority of marine life except for sharks?

a] Late Stegosaurus Extinction

b] Late Devonian Extinction

c] Late Ordovician Extinction

d] K-T Extinction

Correct Answer: B. 75% of marine life was wiped out during the Late Devonian Extinction except for sharks. This mass extinctions occurred 360 million years ago and lasted 20 million years. The extinction was due to a lack of oxygen in the oceans which may have been caused by either a change in sea levels or new plants altering soil environments.

Q5: When did the Late Ordovician extinction occur?

a] 450 million years ago

b] 2010

c] 20 billion years ago

d] 200 million years ago

Correct Answer: A. The Late Ordovician extinction occurred 450 million years ago. It was the first extinction to occur on earth. An ice age caused sea levels to drop, ocean currents to reroute and oxygen levels in the water to drop. 85% of species were wiped out during this extinction.