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Herb

Unit 2 - Ecosystems & Ecology

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Globe Showing Europe Africa

Unit 1 - Foundations Of Environmental Systems & Societies

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Flexed Biceps

Unit 3 - Biodiversity & Conservation

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Writing Hand

Unit 4 -Water & Aquatic Food Production Systems & Societies

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Deciduous Tree

Unit 5 - Soil Systems & Terrestrial Food Production Systems & Societies

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Cloud

Unit 6 - Atmospheric Systems & Societies

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Thermometer

Unit 7 - Climate Change & Energy Production

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Briefcase

Unit 8 - Human Systems & Resource Use

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Bar-Chart

Internal Assessment

Let&#39;s embark on an exciting journey to the past, unveiling the mysteries of mass extinctions and their causes!

Since life began, extinction (bye-bye species) and speciation (hello new species) have been balancing each other. It&#39;s like nature&#39;s scale, if you will. But at times, this scale tipped significantly in favor of extinction. How? Glad you asked!

Picture this - an unusually high number of species vanishing in a geological blink of an eye (which could range from a few hundred thousand to a few million years). This is a mass extinction event. It&#39;s as if nature decided to clean house! These events have created 5 distinct periods in the fossil record.

Many culprits have been blamed for these events. Most of them are dramatic changes in global natural cycles or catastrophic events.

<ul>
	<li>One example is volcanic activity due to plate tectonics (imagine super explosive, earth-shaking eruptions, kind of like Mother Nature having a really bad day!).</li>
	<li>Another suspect is an asteroid impact. The most infamous one struck the Gulf of Mexico about 65 million years ago, possibly bidding an abrupt farewell to our dinosaur friends. This is like a scene straight out of a sci-fi movie, isn&#39;t it?</li>
</ul>

The mass extinction events not only knocked out species through their initial effect, but also through the chain reaction that followed. Think of it as the domino effect but in the natural world! Changes in the atmosphere leading to climate change or planetary cooling are among these secondary repercussions.

The old-time mass extinctions had one silver lining - they took place over geological time, giving life a chance to bounce back and evolve new species (nature&#39;s version of a phoenix rising from the ashes).

<ul>
	<li>Now consider the present scenario. Changes are happening faster than ever before, mostly within human lifetimes. We&#39;re essentially speeding up the clock, leaving no room for species to adapt or evolve. It&#39;s as if we&#39;ve put nature on a fast-forward mode without a pause button. This may escalate the rate of extinctions, pushing us towards another mass extinction event. Not so cool, huh?</li>
</ul>

So, there you have it! A snapshot of the chilling yet fascinating story of mass extinctions, their causes, and the contrast between past and present rates of extinction. Don&#39;t forget to ponder on our role and responsibility in preserving the natural balance as you close your books tonight!

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Remember, we&#39;re part of the story, and the plot can still change for the better. Now, that&#39;s what I call a cliffhanger!

Extinction Events: Past to Present

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Standard Level

Environmental Systems & Societies SL

Unit 2 - Ecosystems & Ecology

Extinction Events: Past to Present

Table of content

Constancy of extinction & speciation

Mass extinction events

Unlock the Full Content!

Unit 2 - Ecosystems & Ecology

Extinction Events: Past to Present

Table of content

Constancy of extinction & speciation

Mass extinction events

Unlock the Full Content!