Identify and also describe the nature of lifeDescribe the levels of organization amongst living thingsList instances of different sub disciplines in biology

Biology is the science that research studies life. What exactly is life? This may sound favor a silly inquiry with an obvious answer, yet it is not simple to specify life. For example, a branch the biology called virology research studies viruses, i m sorry exhibit few of the attributes of living entities but lack others. It turns out that although viruses can attack living organisms, reason diseases, and even reproduce, they perform not accomplish the criteria that biologists usage to define life.

You are watching: Which of the following properties or processes do we associate with living things?

From its earliest beginnings, biology has actually wrestled with 4 questions: What room the shared properties that make miscellaneous “alive”? exactly how do those assorted living things function? When faced with the impressive diversity the life, exactly how do we organize the various kinds of organisms so that us can much better understand them? And, finally—what biologists at some point seek to understand—how go this diversity arise and also how is the continuing? As new organisms are found every day, biologists proceed to seek answers come these and also other questions.

Properties the Life

All groups of living organisms share multiple vital characteristics or functions: order, sensitivity or response to stimuli, reproduction, adaptation, growth and also development, regulation, homeostasis, and also energy processing. Once viewed together, these eight qualities serve to define life.


Organisms are very organized structures that consist of one or much more cells. Even an extremely simple, single-celled organisms space remarkably complex. Inside each cell, atoms make up molecules. These in turn make up cell contents or organelles. Multicell organisms, which may consist of countless individual cells, have an advantage over single-celled organisms in that their cells can be committed to perform certain functions, and also even sacrificed in specific situations for the great of the organism together a whole. How these committed cells come together to type organs such as the heart, lung, or skin in organisms like the toad displayed in figure 1. 2 will be questioned later.

Figure 1.2 A toad represents a highly organized structure consisting the cells, tissues, organs, and also organ systems.

Sensitivity or response to Stimuli

Organisms answer to diverse stimuli. Because that example, plants have the right to bend towards a resource of irradiate or respond come touch. Even tiny bacteria have the right to move towards or far from chemistry (a procedure called chemotaxis) or irradiate (phototaxis). Motion toward a economic stimulation is thought about a hopeful response, while movement away from a economic stimulation is thought about a an adverse response.

Figure 1.3 The leaves of this perceptible plant (Mimosa pudica) will certainly instantly droop and also fold once touched. After a few minutes, the tree returns come its common state.

Concept in Action


Watch this video to see how the sensitive plant responds come a touch stimulus.


Single-celled biology reproduce by an initial duplicating their DNA, which is the genetic material, and then splitting it equally together the cabinet prepares to divide to kind two new cells. Numerous multicellular organisms (those consisted of of an ext than one cell) produce dedicated reproductive cells that will form new individuals. As soon as reproduction occurs, DNA containing gene is passed follow me to an organism’s offspring. This genes room the factor that the offspring will certainly belong come the same types and will have actually characteristics comparable to the parent, together as hair color and also blood type.


All life organisms exhibition a “fit” to your environment. Biologists describe this fit together adaptation and it is a repercussion of advancement by natural selection, i beg your pardon operates in every lineage of reproducing organisms. Instances of adaptations are diverse and also unique, indigenous heat-resistant Archaea the live in boiling hot springs come the tongue length of a nectar-feeding moth that matches the size of the flower from which that feeds. Every adaptations boost the reproductive potential the the separation, personal, instance exhibiting them, including their capacity to survive to reproduce. Adaptations room not constant. Together an atmosphere changes, natural choice causes the attributes of the individuals in a populace to monitor those changes.

Growth and also Development

Organisms grow and develop according to details instructions coded because that by their genes. These genes administer instructions that will direct cellular growth and also development, ensuring the a species’ young will thrive up to exhibit many of the same qualities as its parents.

Figure 1.4 return no 2 look alike, this kittens have actually inherited gene from both parents and also share plenty of of the same characteristics.


Even the the smallest organisms are facility and require multiple regulatory mechanisms to coordinate interior functions, such as the carry of nutrients, solution to stimuli, and also coping with environmental stresses. For example, organ systems such as the digestive or circulatory systems perform specific functions like carrying oxygen transparent the body, removing wastes, moving nutrients come every cell, and also cooling the body.


To duty properly, cells require appropriate conditions such as appropriate temperature, pH, and concentrations of varied chemicals. These conditions may, however, readjust from one minute to the next. Organisms are able to maintain internal conditions within a narrow variety almost constantly, regardless of environmental changes, v a process called homeostasis or “steady state”—the capacity of an organism to maintain constant internal conditions. Because that example, plenty of organisms control their body temperature in a procedure known together thermoregulation. Organisms the live in cold climates, such as the polar bear, have body frameworks that help them stand up to low temperatures and also conserve body heat. In hot climates, organisms have methods (such together perspiration in human beings or panting in dogs) that help them to burned excess human body heat.

Figure 1.5 Polar bears and also other mammals living in ice-covered regions preserve their body temperature by generating heat and also reducing warm loss through thick fur and also a dense layer of fat under your skin.

Energy Processing

All biology (such together the California condor presented in figure 1.6) usage a resource of energy for their metabolic activities. Part organisms catch energy indigenous the sun and also convert it into chemical energy in food; others use chemical power from molecules they take in.

Figure 1.6 A lot of power is forced for a California condor to fly. Chemistry energy derived from food is used to strength flight. California condors are an endangered species; scientists have strived to place a wing tag on every bird to aid them identify and also locate every individual bird.Levels of company of life Things

Living things are extremely organized and also structured, complying with a power structure on a scale from small to large. The atom is the smallest and most basic unit that matter. It is composed of a nucleus surrounded by electrons. Atoms kind molecules. A molecule is a chemical framework consisting that at the very least two atoms hosted together through a chemical bond. Numerous molecules that room biologically important are macromolecules, huge molecules that are frequently formed by combining smaller sized units dubbed monomers. An example of a macromolecule is deoxyribonucleic mountain (DNA), which includes the instructions for the work of the organism that consists of it.

Figure 1.7 A molecule, like this big DNA molecule, is written of atoms.

Concept in Action


To view an animation of this DNA molecule, click here.

Some cells contain aggregates that macromolecules surrounding by membranes; these are dubbed organelles. Organelles are small structures the exist in ~ cells and also perform committed functions. All living things room made the cells; the cell itself is the smallest an essential unit of framework and function in living organisms. (This necessity is why viruses room not taken into consideration living: they room not do of cells. To make brand-new viruses, they need to invade and also hijack a life cell; only then have the right to they attain the products they must reproduce.) some organisms consists a single cell and others room multicellular. Cells space classified as prokaryotes or eukaryotic. Prokaryotes room single-celled organisms that absence organelles surrounding by a membrane and also do not have nuclei surrounding by nuclear membranes; in contrast, the cells of eukaryotes do have membrane-bound organelles and also nuclei.

In most multicellular organisms, cells incorporate to make tissues, which are teams of similar cells delivering out the same function. Organs are collections of tissues grouped together based upon a usual function. Offal are current not only in pets but additionally in plants. One organ device is a greater level of company that is composed of functionally connected organs. For instance vertebrate pets have numerous organ systems, such together the circulatory system that transports blood throughout the body and to and from the lungs; it consists of organs such together the heart and also blood vessels. Organisms are individual life entities. For example, each tree in a woodland is one organism. Single-celled prokaryotes and also single-celled standard scale are likewise considered organisms and are frequently referred to as microorganisms.

Figure 1.8 from an atom to the whole Earth, biology examines all facets of life.

Which the the adhering to statements is false?

Tissues exist within organs i m sorry exist within organ systems.Communities exist within populations which exist in ~ ecosystems.Organelles exist within cells which exist within tissues.Communities exist in ~ ecosystems i m sorry exist in the biosphere.

All the people of a species living within a certain area are jointly called a population. Because that example, a woodland may include countless white pine trees. Every one of these jaw trees represent the populace of white pine tree in this forest. Various populations might live in the same certain area. For example, the woodland with the pine tree trees consists of populations the flowering plants and additionally insects and microbial populations. A community is the collection of populations inhabiting a certain area. Because that instance, all of the trees, flowers, insects, and also other populations in a forest type the forest’s community. The forest itself is one ecosystem. An ecosystem consists of every the living things in a details area along with the abiotic, or non-living, parts of that environment such together nitrogen in the soil or rainwater. At the highest level the organization, the biosphere is the arsenal of all ecosystems, and it represents the area of life ~ above Earth. It includes land, water, and portions of the atmosphere.

The Diversity of Life

The scientific research of biological is an extremely broad in scope because there is a tremendous diversity the life on Earth. The resource of this diversity is evolution, the procedure of gradual change during which brand-new species arise indigenous older species. Evolution biologists examine the evolution of living points in everything from the microscopic human being to ecosystems.

In the 18th century, a scientist called Carl Linnaeus very first proposed arranging the known species of organisms into a hierarchical taxonomy. In this system, types that room most similar to each various other are placed together in ~ a grouping recognized as a genus. Furthermore, comparable genera (the many of genus) are placed together within a family. This grouping proceeds until every organisms are built up together into groups at the greatest level. The present taxonomic device now has actually eight levels in that hierarchy, from shortest to highest, castle are: species, genus, family, order, class, phylum, kingdom, and also domain. Thus types are grouped within genera, genera are grouped in ~ families, households are grouped within orders, and so on.

Figure 1.9 This diagram reflects the level of taxonomic power structure for a dog, native the broadest category—domain—to the most specific—species.

The highest level, domain, is a relatively brand-new addition to the system because the 1990s. Scientists now recognize three domain names of life, the Eukarya, the Archaea, and also the Bacteria. The domain Eukarya contains organisms that have cells with nuclei. It includes the kingdoms that fungi, plants, animals, and also several kingdoms the protists. The Archaea, are single-celled organisms there is no nuclei and include many extremophiles the live in harsh environments like warm springs. The Bacteria are another quite different group of single-celled organisms there is no nuclei. Both the Archaea and the Bacteria are prokaryotes, an informal name for cells without nuclei. The acknowledgment in the 1990s that details “bacteria,” now known as the Archaea, to be as various genetically and also biochemically from other bacterial cells together they to be from eukaryotes, encouraged the recommendation to division life right into three domains. This dramatic readjust in our expertise of the tree the life demonstrates the classifications are not permanent and will readjust when brand-new information becomes available.

In addition to the ordered taxonomic system, Linnaeus was the an initial to name organisms utilizing two distinct names, now referred to as the binomial specify name system. Before Linnaeus, the use of typical names to refer to organisms resulted in confusion since there were regional differences in these typical names. Binomial name consist of the genus name (which is capitalized) and the species name (all lower-case). Both surname are collection in italics as soon as they are printed. Every varieties is provided a distinct binomial which is recognized the human being over, so that a scientist in any kind of location can know which biology is gift referred to. For example, the north American blue jay is known uniquely as Cyanocitta cristata. Our own varieties is Homo sapiens.

Figure 1.10 These photos represent various domains. The scanning electron micrograph mirrors (a) bacterial cells belong come the domain Bacteria, if the (b) extremophiles, seen all together as colored carpet in this hot spring, belong to domain Archaea. Both the (c) sunflower and also (d) lion are part of domain Eukarya.

Evolution in Action

Carl Woese and also the Phylogenetic Tree

The evolutionary relationship of miscellaneous life creates on planet can be summarized in a phylogenetic tree. A phylogenetic tree is a diagram showing the evolution relationships among biological varieties based ~ above similarities and differences in hereditary or physical traits or both. A phylogenetic tree is composed of branch points, or nodes, and also branches. The internal nodes stand for ancestors and also are points in development when, based on scientific evidence, an ancestor is thought to have diverged to kind two new species. The size of each branch have the right to be thought about as estimates of relative time.

In the past, biologist grouped living organisms into five kingdoms: animals, plants, fungi, protists, and also bacteria. The pioneering job-related of American microbiologist Carl Woese in the early on 1970s has shown, however, the life on earth has evolved along three lineages, now called domains—Bacteria, Archaea, and also Eukarya. Woese propose the domain together a new taxonomic level and Archaea as a new domain, to reflect the new phylogenetic tree. Many organisms belonging to the Archaea domain live under extreme conditions and are called extremophiles. To construct his tree, Woese used hereditary relationships fairly than similarities based on morphology (shape). Assorted genes were used in phylogenetic studies. Woese’s tree was constructed from to compare sequencing of the gene that are universally distributed, uncovered in some slightly altered form in every organism, conserved (meaning the these genes have actually remained only slightly changed throughout evolution), and also of an proper length.

Figure 1.11 This phylogenetic tree was built by microbiologist Carl Woese using hereditary relationships. The tree reflects the separation of living organisms right into three domains: Bacteria, Archaea, and Eukarya. Bacteria and Archaea space organisms without a cell core or other organelles surrounding by a membrane and, therefore, room prokaryotes.

The scope of biology is wide and because of this contains countless branches and also sub disciplines. Biologists might pursue among those below disciplines and also work in a much more focused field. Because that instance, molecular biology studies biological processes in ~ the molecular level, consisting of interactions amongst molecules such together DNA, RNA, and also proteins, as well as the means they room regulated. Microbiology is the study of the structure and function of microorganisms. That is rather a large branch itself, and depending ~ above the topic of study, over there are additionally microbial physiologists, ecologists, and geneticists, amongst others.

Another ar of biological study, neurobiology, researches the biological of the worried system, and also although it is taken into consideration a branch of biology, the is also recognized as an interdisciplinary field of study recognized as neuroscience. Due to the fact that of that is interdisciplinary nature, this sub technique studies various functions that the nervous mechanism using molecular, cellular, developmental, medical, and computational approaches.

Figure 1.12 Researchers occupational on excavating dinosaur fossils in ~ a website in Castellón, Spain.

Paleontology, one more branch the biology, offers fossils to study life’s history. Zoology and botany space the research of animals and also plants, respectively. Biologist can additionally specialize as biotechnologists, ecologists, or physiologists, come name simply a few areas. Biotechnologists use the expertise of biology come create beneficial products. Ecologists examine the interaction of biology in your environments. Physiologists study the operations of cells, tissues and also organs. This is simply a little sample of the many fields the biologists have the right to pursue. Native our own bodies come the people we live in, discoveries in biologic can influence us in an extremely direct and important ways. We count on these discoveries for ours health, our food sources, and the benefits noted by our ecosystem. Due to the fact that of this, knowledge of biological can advantage us in making decisions in ours day-to-day lives.

The development of modern technology in the twenty century that proceeds today, an especially the technology to describe and manipulate the hereditary material, DNA, has actually transformed biology. This revolution will allow biologists to continue to recognize the history of life in higher detail, exactly how the person body works, our human being origins, and also how humans have the right to survive as a types on this planet despite the stresses led to by our enhancing numbers. Biologists continue to decipher large mysteries about life suggesting that we have actually only begun to recognize life on the planet, its history, and also our partnership to it. For this and also other reasons, the understanding of biology acquired through this textbook and also other printed and also electronic media need to be a benefit in whichever ar you enter.

Forensic Scientist

Forensic science is the application of scientific research to answer inquiries related to the law. Biologists and chemists and biochemists have the right to be forensic scientists. Forensic scientists carry out scientific proof for use in courts, and also their job involves analyzing trace material connected with crimes. Attention in forensic science has increased in the last few years, possibly since of famous television reflects that function forensic researchers on the job. Also, the advance of molecular techniques and the establishment of DNA databases have updated the types of work-related that forensic scientists can do. Your job activities are primarily related come crimes against people such together murder, rape, and assault. Their work involves examining samples such together hair, blood, and also other body fluids and additionally processing DNA uncovered in plenty of different environments and materials. Forensic scientists additionally analyze other organic evidence left at crime scenes, such together insect parts or pollen grains. Students who want to go after careers in forensic science will most most likely be compelled to take it chemistry and biology courses and some extensive math courses.

Figure 1.13 This forensic scientist functions in a DNA exploit room at the U.S. Army Criminal investigation Laboratory.

See more: How Long Does It Take For A Giraffe To Throw Up ? How Long Does It Take For A Giraffe To Throw Up

Section Summary

Biology is the science of life. All living biology share several vital properties such as order, sensitivity or response to stimuli, reproduction, adaptation, growth and development, regulation, homeostasis, and energy processing. Living things are highly organized adhering to a pecking order that has atoms, molecules, organelles, cells, tissues, organs, and also organ systems. Organisms, in turn, are grouped as populations, communities, ecosystems, and the biosphere. Evolution is the resource of the tremendous organic diversity on earth today. A diagram dubbed a phylogenetic tree have the right to be provided to display evolutionary relationships amongst organisms. Biological is really broad and includes plenty of branches and also sub disciplines. Examples include molecular biology, microbiology, neurobiology, zoology, and botany, among others.