<h2 class="section-header"><strong class="title">Important Principles and Relationships in Biology</strong></h2>
<h3 class="para"><b class="emphasis">Surface area and volume</b></h3>
<p class="para">Depending on the system it is advantageous to either have a large surface to volume ratio or a small surface to volume ratio.</p>
<p class="para">This is highlighted in the following examples:</p>
<div class="list">
<ul class="bullet">
<li class="item">Flatworms and leeches have more surface area to volume to increase the area for <a data-lesson="diffusion-2" data-subject="biology" data-tutorial="cell-biology" href="https://app.ulearngo.com/biology/cell-biology/diffusion-2">diffusion</a> for nutrients and respiratory gases across their whole bodies.</li>
<li class="item">In animals the shapes of organs are defined by surface area to volume requirements. For example, in the <a data-lesson="types-of-breathing" data-subject="biology" data-tutorial="respiratory-system" href="https://app.ulearngo.com/biology/respiratory-system/types-of-breathing">lungs</a> there are many branches to increase the surface area through which gases can be exchanged.</li>
<li class="item">Cells with a greater volume compared to surface area are able to metabolise more and ingest and excrete more through the membrane.</li>
</ul>
</div>
<h3 class="para">Structure and function</h3>
<p class="para">In living organisms, the structure of a particular biological feature is related to what function it performs. Thus for all the structures you will study in biology, the important questions to ask are the following:</p>
<div class="list">
<ol class="arabic">
<li class="item">What makes this structure suited to its function?</li>
<li class="item">How has the structure adapted to its function?</li>
<li class="item">Why is this structure so efficient for its function?</li>
</ol>
</div>

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Some Important Principles in Biology

Biology studies life and living organisms. Biology can be divided into different sections that cover the morphology, physiology, anatomy, behavior, and so on of living organisms.

Biology

Learn the fundamentals of biology, including the characteristics of living things, scientific method, important principles and tools such as drawing graphs, tables, and biological drawings, and safety procedures in a lab environment.


Some Important Principles in Biology

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