{"id":147,"date":"2016-09-20T17:41:47","date_gmt":"2016-09-20T17:41:47","guid":{"rendered":"https:\/\/pressbooks.hcfl.edu\/bio1\/chapter\/properties-of-life\/"},"modified":"2025-12-03T16:30:04","modified_gmt":"2025-12-03T16:30:04","slug":"properties-of-life","status":"publish","type":"chapter","link":"https:\/\/pressbooks.hcfl.edu\/bio1\/chapter\/properties-of-life\/","title":{"raw":"Properties of Life","rendered":"Properties of Life"},"content":{"raw":"All groups of living organisms share several key characteristics or functions:\r\n<ul>\r\n \t<li>Cells \/ Order<\/li>\r\n \t<li>Sensitivity or response to stimuli<\/li>\r\n \t<li>Reproduction<\/li>\r\n \t<li>Evolution and Adaptation<\/li>\r\n \t<li>Growth and development<\/li>\r\n \t<li>Regulation<\/li>\r\n \t<li>Homeostasis<\/li>\r\n \t<li>Metabolism<\/li>\r\n<\/ul>\r\nWhen viewed together, these eight characteristics serve to define life. Let\u2019s examine what each of these characteristics means to in a scientific sense.\r\n<h2><strong>Cells \/ Order <\/strong><\/h2>\r\nOrganisms, in the most basic form, consist of highly organized structures that are made up of one or more cells. Even very simple, single-celled organisms are remarkably complex. Inside each cell, atoms make up molecules. These in turn make up cell components or organelles. Multicellular organisms, which may consist of millions of individual cells, have an advantage over single-celled organisms in that their cells can be specialized to perform specific functions.\r\n\r\n[caption id=\"attachment_114\" align=\"alignnone\" width=\"150\"]<img class=\"wp-image-110 size-thumbnail\" src=\"http:\/\/pressbooks.hcfl.edu\/bio1\/wp-content\/uploads\/sites\/106\/2016\/09\/1.2.toad_-150x150.jpg\" alt=\"1-2-toad\" width=\"150\" height=\"150\" \/> Figure 2 A toad represents a highly organized structure consisting of cells, tissues, organs, and organ systems. (credit: \"Ivengo(RUS)\"\/Wikimedia Commons)[\/caption]\r\n<h2><strong>Sensitivity or Response to Stimuli<\/strong><\/h2>\r\nOrganisms respond to diverse signals from the environment (stimuli). For example, plants can bend toward a source of light or respond to touch (Figure 1.3). Even tiny bacteria can move toward or away from chemicals (a process called chemotaxis) or light (phototaxis). Movement toward a stimulus is considered a positive response, while movement away from a stimulus is considered a negative response.\r\n\r\n[caption id=\"attachment_114\" align=\"alignnone\" width=\"150\"]<img class=\"wp-image-111 size-thumbnail\" src=\"http:\/\/pressbooks.hcfl.edu\/bio1\/wp-content\/uploads\/sites\/106\/2025\/08\/1.3.mimosa-150x150.jpg\" alt=\"1-3-mimosa\" width=\"150\" height=\"150\" \/> Figure 3: The leaves of this sensitive plant (<em>Mimosa pudica<\/em>) will instantly droop and fold when touched. After a few minutes, the plant returns to its normal state. (credit: Alex Lomas)[\/caption]\r\n<h2><strong>Reproduction<\/strong><\/h2>\r\nSingle-celled organisms reproduce by duplicating their DNA (deoxyribonucleic acid, the genetic material; see Figure 7) and then dividing it equally as the cell prepares to divide to form two new cells.\r\n\r\nMany multicellular organisms produce specialized reproductive cells that will form new individuals. When reproduction occurs, DNA is passed along to an organism\u2019s offspring. Genes, made up of DNA, are the basic units by which traits are passed from parent to offspring.\u00a0 DNA, and the information that it encodes in genes, is the reason that offspring will belong to the same species as parents and will have similar characteristics.\r\n<h2><strong>Evolution and Adaptation<\/strong><\/h2>\r\nAll living organisms exhibit a \u201cfit\u201d to their environment. Biologists refer to this fit as adaptation and it is a consequence of evolution by natural selection, which operates in every lineage of reproducing organisms. Examples of adaptations are diverse and unique, from heat-resistant Archaea that live in boiling hot springs to the tongue length of a nectar-feeding moth that matches the size of the flower from which it feeds. All adaptations enhance the reproductive potential of the individual exhibiting them, including their ability to survive to reproduce. Adaptations are not constant. As an environment changes, natural selection causes the characteristics of the individuals in a population to track those changes.\r\n\r\nNOTE: \"Adaptation\" in a biological concept is used differently from how you might use it in normal conversation. Adaptations are changes that occur in the characteristics of an organism due to evolution. These changes take place over many generations and are (mainly) due to changes in the DNA of the organism. An example of an adaptation that your dog has would be that it sheds its winter coat as the weather starts to get warmer, because this is a characteristic that has been developed over many generations. An example of something that is NOT an adaptation would be that your dog has \"adapted\" to living in your house by learning to live with your cat.\r\n<h2><strong>Growth and Development<\/strong><\/h2>\r\nOrganisms grow (get larger) and develop (change over their lifespan) according to specific instructions coded for by their genes. These genes provide instructions that will direct cellular growth and development, ensuring that a species\u2019 young (Figure 4) will grow up to exhibit many of the same characteristics as its parents.\r\n\r\n[caption id=\"attachment_114\" align=\"alignnone\" width=\"150\"]<img class=\"wp-image-112 size-thumbnail\" src=\"http:\/\/pressbooks.hcfl.edu\/bio1\/wp-content\/uploads\/sites\/106\/2025\/08\/1.4.kittens-150x150.jpg\" alt=\"1-4-kittens\" width=\"150\" height=\"150\" \/> Figure 4 Although no two look alike, these kittens have inherited genes from both parents and share many of the same characteristics. (credit: Pieter &amp; Ren\u00e9e Lanser)[\/caption]\r\n<h2><strong>Regulation<\/strong><\/h2>\r\nEven the smallest organisms are complex and require multiple regulatory mechanisms to coordinate internal functions, such as the transport of nutrients, response to stimuli, and coping with environmental stresses. For example, organ systems such as the digestive or circulatory systems perform specific functions like carrying oxygen throughout the body, removing wastes, delivering nutrients to every cell, and cooling the body.\r\n<h2><strong>Homeostasis<\/strong><\/h2>\r\nTo function properly, cells require appropriate conditions such as proper temperature, pH, and concentrations 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 a process called homeostasis or \u201csteady state\u201d\u2014the ability of an organism to maintain constant internal conditions. For example, many organisms regulate their body temperature in a process known as thermoregulation. Organisms that live in cold climates, such as the polar bear (Figure 5), have body structures that help them withstand low temperatures and conserve body heat. In hot climates, organisms have methods (such as perspiration in humans or panting in dogs) that help them to shed excess body heat.\r\n\r\n[caption id=\"attachment_114\" align=\"alignnone\" width=\"150\"]<img class=\"wp-image-113 size-thumbnail\" src=\"http:\/\/pressbooks.hcfl.edu\/bio1\/wp-content\/uploads\/sites\/106\/2025\/08\/1.5.polarbear-150x150.jpg\" alt=\"1-5-polarbear\" width=\"150\" height=\"150\" \/> Figure 5 Polar bears 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. (credit: \"longhorndave\"\/Flickr)[\/caption]\r\n<h2><strong>Metabolism<\/strong><\/h2>\r\nMetabolism means taking in and using energy. All organisms (such as the California condor shown in Figure 6) use a source of energy for their metabolic activities. Some organisms capture energy from the Sun and convert it into chemical energy in food; others use chemical energy from molecules they take in.\r\n\r\n[caption id=\"attachment_114\" align=\"alignnone\" width=\"150\"]<img class=\"wp-image-114 size-thumbnail\" src=\"http:\/\/pressbooks.hcfl.edu\/bio1\/wp-content\/uploads\/sites\/106\/2025\/08\/1.6.condor-150x150.jpg\" alt=\"1-6-condor\" width=\"150\" height=\"150\" \/> Figure 6 A lot of energy is required for a California condor to fly. Chemical energy derived from food is used to power flight. California condors are an endangered species; scientists have strived to place a wing tag on each bird to help them identify and locate each individual bird. (credit: Pacific Southwest Region U.S. Fish and Wildlife)[\/caption]\r\n\r\n&nbsp;","rendered":"<p>All groups of living organisms share several key characteristics or functions:<\/p>\n<ul>\n<li>Cells \/ Order<\/li>\n<li>Sensitivity or response to stimuli<\/li>\n<li>Reproduction<\/li>\n<li>Evolution and Adaptation<\/li>\n<li>Growth and development<\/li>\n<li>Regulation<\/li>\n<li>Homeostasis<\/li>\n<li>Metabolism<\/li>\n<\/ul>\n<p>When viewed together, these eight characteristics serve to define life. Let\u2019s examine what each of these characteristics means to in a scientific sense.<\/p>\n<h2><strong>Cells \/ Order <\/strong><\/h2>\n<p>Organisms, in the most basic form, consist of highly organized structures that are made up of one or more cells. Even very simple, single-celled organisms are remarkably complex. Inside each cell, atoms make up molecules. These in turn make up cell components or organelles. Multicellular organisms, which may consist of millions of individual cells, have an advantage over single-celled organisms in that their cells can be specialized to perform specific functions.<\/p>\n<figure id=\"attachment_114\" aria-describedby=\"caption-attachment-114\" style=\"width: 150px\" class=\"wp-caption alignnone\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-110 size-thumbnail\" src=\"http:\/\/pressbooks.hcfl.edu\/bio1\/wp-content\/uploads\/sites\/106\/2016\/09\/1.2.toad_-150x150.jpg\" alt=\"1-2-toad\" width=\"150\" height=\"150\" \/><figcaption id=\"caption-attachment-114\" class=\"wp-caption-text\">Figure 2 A toad represents a highly organized structure consisting of cells, tissues, organs, and organ systems. (credit: &#8220;Ivengo(RUS)&#8221;\/Wikimedia Commons)<\/figcaption><\/figure>\n<h2><strong>Sensitivity or Response to Stimuli<\/strong><\/h2>\n<p>Organisms respond to diverse signals from the environment (stimuli). For example, plants can bend toward a source of light or respond to touch (Figure 1.3). Even tiny bacteria can move toward or away from chemicals (a process called chemotaxis) or light (phototaxis). Movement toward a stimulus is considered a positive response, while movement away from a stimulus is considered a negative response.<\/p>\n<figure id=\"attachment_114\" aria-describedby=\"caption-attachment-114\" style=\"width: 150px\" class=\"wp-caption alignnone\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-111 size-thumbnail\" src=\"http:\/\/pressbooks.hcfl.edu\/bio1\/wp-content\/uploads\/sites\/106\/2025\/08\/1.3.mimosa-150x150.jpg\" alt=\"1-3-mimosa\" width=\"150\" height=\"150\" \/><figcaption id=\"caption-attachment-114\" class=\"wp-caption-text\">Figure 3: The leaves of this sensitive plant (<em>Mimosa pudica<\/em>) will instantly droop and fold when touched. After a few minutes, the plant returns to its normal state. (credit: Alex Lomas)<\/figcaption><\/figure>\n<h2><strong>Reproduction<\/strong><\/h2>\n<p>Single-celled organisms reproduce by duplicating their DNA (deoxyribonucleic acid, the genetic material; see Figure 7) and then dividing it equally as the cell prepares to divide to form two new cells.<\/p>\n<p>Many multicellular organisms produce specialized reproductive cells that will form new individuals. When reproduction occurs, DNA is passed along to an organism\u2019s offspring. Genes, made up of DNA, are the basic units by which traits are passed from parent to offspring.\u00a0 DNA, and the information that it encodes in genes, is the reason that offspring will belong to the same species as parents and will have similar characteristics.<\/p>\n<h2><strong>Evolution and Adaptation<\/strong><\/h2>\n<p>All living organisms exhibit a \u201cfit\u201d to their environment. Biologists refer to this fit as adaptation and it is a consequence of evolution by natural selection, which operates in every lineage of reproducing organisms. Examples of adaptations are diverse and unique, from heat-resistant Archaea that live in boiling hot springs to the tongue length of a nectar-feeding moth that matches the size of the flower from which it feeds. All adaptations enhance the reproductive potential of the individual exhibiting them, including their ability to survive to reproduce. Adaptations are not constant. As an environment changes, natural selection causes the characteristics of the individuals in a population to track those changes.<\/p>\n<p>NOTE: &#8220;Adaptation&#8221; in a biological concept is used differently from how you might use it in normal conversation. Adaptations are changes that occur in the characteristics of an organism due to evolution. These changes take place over many generations and are (mainly) due to changes in the DNA of the organism. An example of an adaptation that your dog has would be that it sheds its winter coat as the weather starts to get warmer, because this is a characteristic that has been developed over many generations. An example of something that is NOT an adaptation would be that your dog has &#8220;adapted&#8221; to living in your house by learning to live with your cat.<\/p>\n<h2><strong>Growth and Development<\/strong><\/h2>\n<p>Organisms grow (get larger) and develop (change over their lifespan) according to specific instructions coded for by their genes. These genes provide instructions that will direct cellular growth and development, ensuring that a species\u2019 young (Figure 4) will grow up to exhibit many of the same characteristics as its parents.<\/p>\n<figure id=\"attachment_114\" aria-describedby=\"caption-attachment-114\" style=\"width: 150px\" class=\"wp-caption alignnone\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-112 size-thumbnail\" src=\"http:\/\/pressbooks.hcfl.edu\/bio1\/wp-content\/uploads\/sites\/106\/2025\/08\/1.4.kittens-150x150.jpg\" alt=\"1-4-kittens\" width=\"150\" height=\"150\" \/><figcaption id=\"caption-attachment-114\" class=\"wp-caption-text\">Figure 4 Although no two look alike, these kittens have inherited genes from both parents and share many of the same characteristics. (credit: Pieter &amp; Ren\u00e9e Lanser)<\/figcaption><\/figure>\n<h2><strong>Regulation<\/strong><\/h2>\n<p>Even the smallest organisms are complex and require multiple regulatory mechanisms to coordinate internal functions, such as the transport of nutrients, response to stimuli, and coping with environmental stresses. For example, organ systems such as the digestive or circulatory systems perform specific functions like carrying oxygen throughout the body, removing wastes, delivering nutrients to every cell, and cooling the body.<\/p>\n<h2><strong>Homeostasis<\/strong><\/h2>\n<p>To function properly, cells require appropriate conditions such as proper temperature, pH, and concentrations 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 a process called homeostasis or \u201csteady state\u201d\u2014the ability of an organism to maintain constant internal conditions. For example, many organisms regulate their body temperature in a process known as thermoregulation. Organisms that live in cold climates, such as the polar bear (Figure 5), have body structures that help them withstand low temperatures and conserve body heat. In hot climates, organisms have methods (such as perspiration in humans or panting in dogs) that help them to shed excess body heat.<\/p>\n<figure id=\"attachment_114\" aria-describedby=\"caption-attachment-114\" style=\"width: 150px\" class=\"wp-caption alignnone\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-113 size-thumbnail\" src=\"http:\/\/pressbooks.hcfl.edu\/bio1\/wp-content\/uploads\/sites\/106\/2025\/08\/1.5.polarbear-150x150.jpg\" alt=\"1-5-polarbear\" width=\"150\" height=\"150\" \/><figcaption id=\"caption-attachment-114\" class=\"wp-caption-text\">Figure 5 Polar bears 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. (credit: &#8220;longhorndave&#8221;\/Flickr)<\/figcaption><\/figure>\n<h2><strong>Metabolism<\/strong><\/h2>\n<p>Metabolism means taking in and using energy. All organisms (such as the California condor shown in Figure 6) use a source of energy for their metabolic activities. Some organisms capture energy from the Sun and convert it into chemical energy in food; others use chemical energy from molecules they take in.<\/p>\n<figure id=\"attachment_114\" aria-describedby=\"caption-attachment-114\" style=\"width: 150px\" class=\"wp-caption alignnone\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-114 size-thumbnail\" src=\"http:\/\/pressbooks.hcfl.edu\/bio1\/wp-content\/uploads\/sites\/106\/2025\/08\/1.6.condor-150x150.jpg\" alt=\"1-6-condor\" width=\"150\" height=\"150\" \/><figcaption id=\"caption-attachment-114\" class=\"wp-caption-text\">Figure 6 A lot of energy is required for a California condor to fly. Chemical energy derived from food is used to power flight. California condors are an endangered species; scientists have strived to place a wing tag on each bird to help them identify and locate each individual bird. (credit: Pacific Southwest Region U.S. Fish and Wildlife)<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n","protected":false},"author":130,"menu_order":1,"template":"","meta":{"pb_show_title":"on","pb_short_title":"","pb_subtitle":"","pb_authors":["lisa-bartee","christine-anderson"],"pb_section_license":"cc-by"},"chapter-type":[],"contributor":[65,64],"license":[53],"class_list":["post-147","chapter","type-chapter","status-publish","hentry","contributor-christine-anderson","contributor-lisa-bartee","license-cc-by"],"part":108,"_links":{"self":[{"href":"https:\/\/pressbooks.hcfl.edu\/bio1\/wp-json\/pressbooks\/v2\/chapters\/147","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/pressbooks.hcfl.edu\/bio1\/wp-json\/pressbooks\/v2\/chapters"}],"about":[{"href":"https:\/\/pressbooks.hcfl.edu\/bio1\/wp-json\/wp\/v2\/types\/chapter"}],"author":[{"embeddable":true,"href":"https:\/\/pressbooks.hcfl.edu\/bio1\/wp-json\/wp\/v2\/users\/130"}],"version-history":[{"count":7,"href":"https:\/\/pressbooks.hcfl.edu\/bio1\/wp-json\/pressbooks\/v2\/chapters\/147\/revisions"}],"predecessor-version":[{"id":1335,"href":"https:\/\/pressbooks.hcfl.edu\/bio1\/wp-json\/pressbooks\/v2\/chapters\/147\/revisions\/1335"}],"part":[{"href":"https:\/\/pressbooks.hcfl.edu\/bio1\/wp-json\/pressbooks\/v2\/parts\/108"}],"metadata":[{"href":"https:\/\/pressbooks.hcfl.edu\/bio1\/wp-json\/pressbooks\/v2\/chapters\/147\/metadata\/"}],"wp:attachment":[{"href":"https:\/\/pressbooks.hcfl.edu\/bio1\/wp-json\/wp\/v2\/media?parent=147"}],"wp:term":[{"taxonomy":"chapter-type","embeddable":true,"href":"https:\/\/pressbooks.hcfl.edu\/bio1\/wp-json\/pressbooks\/v2\/chapter-type?post=147"},{"taxonomy":"contributor","embeddable":true,"href":"https:\/\/pressbooks.hcfl.edu\/bio1\/wp-json\/wp\/v2\/contributor?post=147"},{"taxonomy":"license","embeddable":true,"href":"https:\/\/pressbooks.hcfl.edu\/bio1\/wp-json\/wp\/v2\/license?post=147"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}