<h2>Other Characteristics of Life</h2>
<p>In the <a href="https://app.ulearngo.com/lesson/properties-of-life">previous lesson</a>, we looked at some of the <a href="https://app.ulearngo.com/tutorials/introducing-study-of-life/properties-of-life">properties of life</a> such as order, sensitivity, reproduction, <a data-lesson="population-growth-patterns" data-subject="biology" data-tutorial="ecology-overview" href="https://app.ulearngo.com/biology/ecology-overview/population-growth-patterns">growth</a> and development. In this lesson, we'll continue from where we stopped and look at other characteristics of life.</p>
<h3 data-type="title">Regulation</h3>
<p>Even the smallest organisms are complex and require multiple <a data-lesson="regulatory-mechanisms" data-subject="biology" data-tutorial="cellular-respiration" href="https://app.ulearngo.com/biology/cellular-respiration/regulatory-mechanisms">regulatory mechanisms</a> to coordinate internal functions, respond to stimuli, and cope with environmental stresses. Two examples of internal functions regulated in an organism are nutrient transport and <a data-lesson="blood-2" data-subject="biology" data-tutorial="human-biology" href="https://app.ulearngo.com/biology/human-biology/blood-2">blood</a> flow. Organs (groups of tissues working together) perform specific functions, such as carrying <a data-lesson="transport-of-oxygen-in-the-blood" data-subject="biology" data-tutorial="respiratory-system" href="https://app.ulearngo.com/biology/respiratory-system/transport-of-oxygen-in-the-blood">oxygen</a> throughout the body, removing wastes, delivering nutrients to every cell, and cooling the body.</p>
<h3 data-type="title">Homeostasis</h3>
<p>In order to function properly, <a data-lesson="prokaryotic-and-eukaryotic-cells" data-subject="biology" data-tutorial="cell-biology" href="https://app.ulearngo.com/biology/cell-biology/prokaryotic-and-eukaryotic-cells">cells</a> need to have appropriate conditions such as proper temperature, pH, and appropriate <a data-lesson="basic-principles-of-gas-exchange" data-subject="biology" data-tutorial="respiratory-system" href="https://app.ulearngo.com/biology/respiratory-system/basic-principles-of-gas-exchange">concentration</a> of diverse chemicals. These conditions may, however, change from one moment to the next. Organisms are able to maintain internal conditions within a narrow range almost constantly, despite environmental changes, through <strong>homeostasis</strong> (literally, "steady state")—the ability of an organism to maintain constant internal conditions.</p>
<div class="wp-caption alignnone" id="attachment_68760" style="width: 530px"><a href="https://data.ulearngo.com/assets/7a5c2f49-35f6-41da-bc65-7ad4d7785472"><img alt="polar-bear" class="size-full wp-image-68760" height="378" src="https://data.ulearngo.com/assets/7a5c2f49-35f6-41da-bc65-7ad4d7785472" width="530"/></a><p class="wp-caption-text">Polar bears (<em>Ursus maritimus</em>) and other mammals living in ice-covered regions maintain their body temperature by generating heat and reducing heat loss through thick fur and a dense layer of fat under their skin. Image Attribution: longhorndave/Flickr.</p></div>
<p>For example, an organism needs to regulate body temperature through a process known as <strong>thermoregulation</strong>. Organisms that live in cold climates, such as the polar bear (<a href="#attachment_68760">see image above</a>), have body structures that help them withstand low temperatures and conserve body heat. Structures that aid in this type of insulation include fur, feathers, blubber, and fat. In hot climates, organisms have methods (such as perspiration in humans or panting in dogs) that help them to shed excess body heat.</p>
<h3 data-type="title">Energy Processing</h3>
<div class="wp-caption alignnone" id="attachment_68761" style="width: 530px"><a href="https://data.ulearngo.com/assets/83ef18d2-859d-4ee3-b91d-2a16fe02cb10"><img alt="california-condor" class="size-full wp-image-68761" height="662" src="https://data.ulearngo.com/assets/83ef18d2-859d-4ee3-b91d-2a16fe02cb10" width="530"/></a><p class="wp-caption-text">The California condor (<em>Gymnogyps californianus</em>) uses chemical energy derived from food to power flight. California condors are an endangered species; this bird has a wing tag that helps biologists identify the individual. Image Attribution: Pacific Southwest Region U.S. Fish and Wildlife Service.</p></div>
<p>All organisms use a source of energy for their metabolic activities. Some organisms capture energy from the sun and convert it into chemical energy in food. On the other hand, others use chemical energy in <a data-lesson="first-organic-molecules" data-subject="biology" data-tutorial="evolution-overview" href="https://app.ulearngo.com/biology/evolution-overview/first-organic-molecules">molecules</a> they take in as food (<a href="#attachment_68761">see image above</a>).</p>
<h2>How do organisms respond to change?</h2>
<p>Organisms use energy to grow, develop, respond to stimuli, and maintain homeostasis. <strong>Energy</strong> is the <em>ability to cause change</em>. In general, organisms get their energy from food.</p>
<div class="wp-caption alignnone" id="attachment_47384" style="width: 700px"><a href="https://data.ulearngo.com/assets/97d3d80d-7a4e-4ba1-b350-5dfab787d76d"><img alt="desert-plants" class="size-full wp-image-47384" height="467" src="https://data.ulearngo.com/assets/97d3d80d-7a4e-4ba1-b350-5dfab787d76d" width="700"/></a><p class="wp-caption-text">Image Attribution: Desert plants, by DesertUSA</p></div>
<p>Any behavior, structure, or internal process that allows an organism to make changes in response to environmental factors and live long enough to reproduce is called an <strong>adaptation</strong>. For example, the <a data-lesson="leaf-arrangement-and-leaf-form" data-subject="biology" data-tutorial="plant-form-and-physiology" href="https://app.ulearngo.com/biology/plant-form-and-physiology/leaf-arrangement-and-leaf-form">leaves</a> of many desert plants as in the <a href="#attachment_47384">image above</a> have a thick, waxy coating. This is an adaptation that helps these plants conserve water. Similarly, having large eyes is an adaptation that lets owls see well at night. The gradual change in a species over time due to adaptations is called <strong>evolution</strong>.</p>

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Properties of Life Continued

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

Explore the foundations of biology as a science, including scientific reasoning, the scientific method, controlled experiments, and reporting scientific work to gain an understanding of the properties of life, levels of organization, and diversity of living things.


Properties of Life Continued

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