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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

Greetings, eco-warrior! Our mission today? Understanding the vibrant world of species richness, species diversity, and how to measure them with the Simpson Diversity Index. So, let&#39;s dive in!

Imagine you&#39;re at a party. Species richness is the number of different people present. Species diversity, however, considers not just the number of different people, but also how evenly distributed they are at the party. In a highly diverse party, all the different people would mingle evenly, not just a few dominating the dance floor.

Ready to add some math to the mix? The Simpson Diversity Index (D) is our tool to measure this biodiversity. Don&#39;t worry, the formula isn&#39;t as scary as it seems: 
&nbsp;

Where:

<ul>
	<li>D = diversity index</li>
	<li>N = total number of organisms of all species found</li>
	<li>n = number of individuals of a particular species</li>
	<li>&sum; = just means to add all of the n(n - 1) components together.</li>
</ul>

You don&#39;t have to memorize the formula, but knowing what the symbols mean is crucial.

&nbsp;

High D values suggest an ancient, stable site with even species distribution. Low D values could point to pollution, recent colonization, or agricultural management, where one species might dominate.

This is where the fun really begins! Let&#39;s consider two streams (A and B) teeming with different aquatic invertebrates. Based on the numbers given, we&#39;ll calculate the Simpson diversity index, identify differences between the streams, and suggest reasons for those differences.

&nbsp;

Keep in mind the concept of species richness and diversity when comparing the streams.

<ul>
	<li>
	Stream A: More diverse types of invertebrates, but one species (freshwater shrimp) clearly dominates.
	</li>
	<li>
	Stream B: Fewer types of invertebrates, but bloodworms and sludgeworms are the main players.
	</li>
</ul>

Why might there be differences in the diversity index? Maybe different water quality, food resources, or human activities have influenced each stream&#39;s species composition.

&nbsp;

Remember, conservation isn&#39;t just about saving the &quot;popular&quot; species. Every organism, from the tiniest bloodworm to the most vibrant butterfly, plays a part in the ecosystem&#39;s symphony. Happy studying, and keep exploring our planet&#39;s incredible diversity!

Dive into Biodiversity with the Simpson Index

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Standard Level

Environmental Systems & Societies SL

Unit 2 - Ecosystems & Ecology

Dive into Biodiversity with the Simpson Index

Table of content

Species richness vs. species diversity

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Unit 2 - Ecosystems & Ecology

Dive into Biodiversity with the Simpson Index

Table of content

Species richness vs. species diversity

Unlock the Full Content!