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

Biology is the scientific research that researches life. What exactly is life? This may sound choose a silly question with an noticeable answer, yet it is not easy to define life. For example, a branch that biology dubbed virology research studies viruses, i beg your pardon exhibit few of the characteristics of living entities but lack others. It transforms out the although viruses can strike living organisms, reason diseases, and also even reproduce, they perform not accomplish the criteria the biologists use to define life.

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From its earliest beginnings, biology has wrestled with 4 questions: What space the common properties that make miscellaneous “alive”? how do those miscellaneous living points function? When confronted with the exceptional diversity that life, just how do us organize the different kinds of biology so that we can better understand them? And, finally—what biologists ultimately seek come understand—how walk this diversity arise and also how is that continuing? As new organisms are uncovered every day, biologists continue to seek answers come these and also other questions.

Properties that Life

All teams of living organisms re-publishing multiple crucial characteristics or functions: order, sensitivity or solution to stimuli, reproduction, adaptation, growth and development, regulation, homeostasis, and energy processing. Once viewed together, these eight qualities serve to specify life.


Organisms are highly organized frameworks that covers one or more cells. Even very simple, single-celled organisms room remarkably complex. Within each cell, atoms make up molecules. These in turn comprise cell components or organelles. Multicell organisms, which may consist of millions of individual cells, have an benefit over single-celled organisms in the their cells can be specialized to perform particular functions, and also even sacrificed in specific situations for the good of the organism as a whole. Just how these dedicated cells come with each other to kind organs such as the heart, lung, or skin in organisms prefer the toad shown in number 1. 2 will be discussed later.

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

Sensitivity or an answer to Stimuli

Organisms respond to varied stimuli. Because that example, plants have the right to bend towards a resource of irradiate or respond to touch. Also tiny bacteria can move towards or away from chemicals (a process called chemotaxis) or irradiate (phototaxis). Movement toward a stimulus is taken into consideration a confident response, while movement away indigenous a economic stimulation is taken into consideration a negative response.

Figure 1.3 The leaves of this sensitive plant (Mimosa pudica) will instantly droop and fold when touched. After ~ a couple of minutes, the tree returns to its common state.

Concept in Action


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


Single-celled biology reproduce by an initial duplicating their DNA, which is the genetic material, and also then splitting it equally as the cell prepares to divide to kind two new cells. Countless multicellular biology (those consisted of of more than one cell) produce committed reproductive cells the will kind new individuals. Once reproduction occurs, DNA containing gene is passed follow me to an organism’s offspring. These genes room the factor that the offspring will belong come the same varieties and will have characteristics comparable to the parent, such as fur color and also blood type.


All life organisms exhibition a “fit” to your environment. Biologists describe this fit as adaptation and also it is a repercussion of advancement by herbal selection, which operates in every lineage of reproducing organisms. Examples of adaptations are diverse and also unique, indigenous heat-resistant Archaea the live in boiling hot springs to the tongue length of a nectar-feeding moth that matches the dimension of the flower native which that feeds. Every adaptations enhance the reproductive potential the the separation, personal, instance exhibiting them, including their capability to make it through to reproduce. Adaptations are not constant. Together an environment changes, natural selection causes the features of the individuals in a population to monitor those changes.

Growth and Development

Organisms grow and develop follow to details instructions coded because that by their genes. These genes provide instructions the will direct cellular growth and development, ensuring that a species’ young will thrive up to exhibit plenty of of the same attributes as the parents.

Figure 1.4 back no 2 look alike, these kittens have actually inherited gene from both parents and share numerous of the exact same characteristics.


Even the the smallest organisms are complex and need multiple regulation mechanisms come coordinate inner functions, such together the transfer of nutrients, response to stimuli, and coping with environmental stresses. For example, organ systems such together the cradle or circulatory systems perform certain functions like carrying oxygen transparent the body, removed wastes, carrying nutrients to every cell, and cooling the body.


To function properly, cell require ideal conditions such as proper temperature, pH, and concentrations of varied chemicals. These conditions may, however, adjust from one moment to the next. Organisms are able to keep internal conditions within a narrow range almost constantly, regardless of environmental changes, through a procedure called homeostasis or “steady state”—the ability of an biology to maintain continuous internal conditions. For example, countless organisms regulate their body temperature in a process known together thermoregulation. Organisms that live in cold climates, such together the polar bear, have body structures that assist them withstand low temperatures and conserve human body heat. In warm climates, organisms have actually methods (such together perspiration in human beings or panting in dogs) that assist them to melted excess human body heat.

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

Energy Processing

All organisms (such together the California condor presented in number 1.6) usage a resource of power for their metabolic activities. Some organisms catch energy native the sun and convert it into chemical energy in food; others usage chemical power from molecule they take in.

Figure 1.6 A lot of of energy is forced for a California condor to fly. Chemical energy obtained from food is used to strength flight. California condors room an endangered species; scientists have strived to location a wing tag on every bird to help them identify and locate every individual bird.Levels of company of life Things

Living things are extremely organized and also structured, following a pecking order on a range from little to large. The atom is the smallest and also most basic unit of matter. It is composed of a nucleus surrounded by electrons. Atoms kind molecules. A molecule is a chemical structure consisting of at least two atoms held together through a chemical bond. Plenty of molecules that space biologically necessary are macromolecules, big molecules the are commonly formed through combining smaller sized units called monomers. An example of a macromolecule is deoxyribonucleic acid (DNA), which includes the instructions for the functioning of the organism that includes it.

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

Concept in Action


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

Some cell contain aggregates of macromolecules surrounding by membranes; this are called organelles. Oribel are small structures that exist in ~ cells and perform committed functions. Every living things are made that cells; the cabinet itself is the smallest an essential unit of framework and duty in life organisms. (This necessity is why viruses space not taken into consideration living: they room not make of cells. Come make brand-new viruses, they need to invade and hijack a life cell; just then can they acquire the materials they have to reproduce.) some organisms consists a single cell and also others are multicellular. Cells room classified as prokaryotic or eukaryotic. Prokaryotes room single-celled biology that absence organelles surrounding by a membrane and also do not have nuclei surrounded by nuclear membranes; in contrast, the cell of eukaryotes do have membrane-bound organelles and nuclei.

In many multicellular organisms, cells incorporate to make tissues, i m sorry are teams of comparable cells moving out the same function. Organs space collections of organization grouped together based upon a usual function. Guts are existing not only in pets but also in plants. An organ mechanism is a higher level of organization that consists of functionally related organs. For example vertebrate pets have many organ systems, such together the circulatory system that transports blood transparent the body and also to and also from the lungs; it contains organs such as the heart and also blood vessels. Organisms room individual living entities. For example, each tree in a forest is an organism. Single-celled prokaryotes and single-celled standard scale are additionally considered organisms and are generally referred to together microorganisms.

Figure 1.8 native an atom come the entire Earth, biology examines all aspects of life.

Which of the complying with statements is false?

Tissues exist in ~ organs i beg your pardon exist within organ systems.Communities exist within populaces which exist in ~ ecosystems.Organelles exist within cell which exist within tissues.Communities exist within ecosystems i m sorry exist in the biosphere.

All the people of a types living within a certain area are collectively called a population. For example, a woodland may include countless white pine trees. All of these jaw trees represent the population of white pine tree in this forest. Various populations may live in the same particular area. Because that example, the forest with the pine trees includes populations the flowering tree and also insects and also microbial populations. A ar is the set of populations inhabiting a particular area. Because that instance, every one of the trees, flowers, insects, and other populations in a forest type the forest’s community. The forest itself is one ecosystem. An ecosystem is composed of every the living points in a certain area in addition to the abiotic, or non-living, components of that environment such as nitrogen in the soil or rainwater. In ~ the greatest level the organization, the biosphere is the repertoire of every ecosystems, and it represents the area of life ~ above Earth. It contains land, water, and portions that the atmosphere.

The Diversity the Life

The science of biologic is very broad in scope due to the fact that there is a significant diversity that life on Earth. The resource of this diversity is evolution, the process of gradual adjust during which new species arise indigenous older species. Evolution biologists examine the evolution of living things in everything from the microscopic world to ecosystems.

In the 18th century, a scientist named Carl Linnaeus first proposed organizing the known types of organisms into a hierarchical taxonomy. In this system, types that space most similar to each other are placed together within a grouping well-known as a genus. Furthermore, similar genera (the plural of genus) are placed together within a family. This grouping continues until every organisms are collected together into groups at the highest possible level. The present taxonomic mechanism now has eight level in that is hierarchy, from lowest to highest, castle are: species, genus, family, order, class, phylum, kingdom, and also domain. Thus species are grouped in ~ genera, genera space grouped within families, families are grouped in ~ orders, and so on.

Figure 1.9 This diagram reflects the level of taxonomic pecking order for a dog, indigenous the broadest category—domain—to the most specific—species.

The highest possible level, domain, is a relatively new addition to the system because the 1990s. Scientists now recognize three domain names of life, the Eukarya, the Archaea, and the Bacteria. The domain Eukarya includes organisms that have actually cells with nuclei. It contains the kingdoms that fungi, plants, animals, and several kingdoms that protists. The Archaea, room single-celled organisms there is no nuclei and also include numerous extremophiles that live in harsh settings like hot springs. The Bacteria are another quite different group of single-celled organisms there is no nuclei. Both the Archaea and the Bacteria are prokaryotes, casual name for cells there is no nuclei. The recognition in the 1990s that particular “bacteria,” now recognized as the Archaea, to be as different genetically and biochemically from other bacterial cells as they to be from eukaryotes, urged the reference to divide life right into three domains. This dramatic adjust in our expertise of the tree of life demonstrates the classifications space not permanent and also will adjust when brand-new information i do not care available.

In addition to the ordered taxonomic system, Linnaeus was the first to surname organisms making use of two distinctive names, now called the binomial naming system. Prior to Linnaeus, the usage of usual names to describe organisms resulted in confusion because there were regional differences in these common names. Binomial surname consist of the genus surname (which is capitalized) and the varieties name (all lower-case). Both surname are set in italics when they are printed. Every types is provided a distinctive binomial which is recognized the people over, so that a scientist in any location can know which biology is gift referred to. Because that example, the north American blue jay is recognized uniquely as Cyanocitta cristata. Our own types is Homo sapiens.

Figure 1.10 These images represent various domains. The scanning electron micrograph reflects (a) bacterial cell belong come the domain Bacteria, when the (b) extremophiles, seen all together as colored mats in this hot spring, belong come domain Archaea. Both the (c) sunflower and (d) lion are part of domain Eukarya.

Evolution in Action

Carl Woese and the Phylogenetic Tree

The evolutionary relationship of miscellaneous life forms on planet can be summarized in a phylogenetic tree. A phylogenetic tree is a diagram reflecting the evolutionary relationships amongst biological species based ~ above similarities and also differences in genetic or physical traits or both. A phylogenetic tree is created of branch points, or nodes, and also branches. The inner nodes represent ancestors and also are points in advancement when, based upon scientific evidence, one ancestor is believed to have actually diverged to form two new species. The length of each branch have the right to be taken into consideration as approximates of relative time.

In the past, biologist grouped living organisms into five kingdoms: animals, plants, fungi, protists, and bacteria. The pioneering work of American microbiologist Carl Woese in the beforehand 1970s has shown, however, that life on planet has advanced along three lineages, now referred to as domains—Bacteria, Archaea, and also Eukarya. Woese suggest the domain as a new taxonomic level and Archaea together a brand-new domain, to reflect the new phylogenetic tree. Many organisms belonging come the Archaea domain live under extreme conditions and are referred to as extremophiles. To construct his tree, Woese used hereditary relationships rather than similarities based on morphology (shape). Assorted genes were supplied in phylogenetic studies. Woese’s tree was created from compare sequencing of the genes that space universally distributed, found in part slightly altered type in every organism, conserved (meaning the these genes have remained only slightly readjusted throughout evolution), and also of an appropriate 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 also Eukarya. Bacteria and also Archaea space organisms without a cell core or other organelles surrounded by a membrane and, therefore, room prokaryotes.

The border of biological is vast and thus contains many branches and sub disciplines. Biologists might pursue among those below disciplines and also work in a much more focused field. For instance, molecule biology studies organic processes in ~ the molecule level, consisting of interactions among molecules such as DNA, RNA, and proteins, and the way they room regulated. Microbiology is the research of the structure and role of microorganisms. The is fairly a broad branch itself, and depending ~ above the subject of study, over there are additionally microbial physiologists, ecologists, and geneticists, among others.

Another field of organic study, neurobiology, studies the biological of the nervous system, and although the is taken into consideration a branch that biology, that is likewise recognized as an interdisciplinary field of study recognized as neuroscience. Since of that interdisciplinary nature, this sub technique studies different functions the the nervous mechanism using molecular, cellular, developmental, medical, and also computational approaches.

Figure 1.12 Researchers job-related on excavating dinosaur fossils at a website in Castellón, Spain.

Paleontology, an additional branch the biology, supplies fossils to examine life’s history. Zoology and also botany room the research of animals and plants, respectively. Biologist can also specialize as biotechnologists, ecologists, or physiologists, to name simply a few areas. Biotechnologists use the understanding of biology to create helpful products. Ecologists research the interactions of organisms in their environments. Physiologists research the workings of cells, tissues and organs. This is simply a little sample of the many fields the biologists have the right to pursue. Native our own bodies come the world we live in, discoveries in biological can affect us in really direct and important ways. We rely on these discoveries for our health, our food sources, and the benefits provided by ours ecosystem. Because of this, expertise of biology can advantage us in making decision in our day-to-day lives.

The advance of modern technology in the twentieth century that proceeds today, particularly the technology to describe and also manipulate the genetic material, DNA, has transformed biology. This change will enable biologists to proceed to know the history of life in higher detail, exactly how the human being body works, our person origins, and also how humans deserve to survive together a species on this planet in spite of the stresses caused by our increasing numbers. Biologists continue to decipher vast mysteries about life arguing that we have actually only begun to recognize life top top the planet, its history, and our partnership to it. For this and other reasons, the knowledge of biology acquired through this textbook and other printed and also electronic media should be a benefit in whichever ar you enter.

Forensic Scientist

Forensic science is the application of science to answer concerns related to the law. Biologists as well as chemists and also biochemists have the right to be forensic scientists. Forensic scientists administer scientific evidence for use in courts, and their task involves examining trace material linked with crimes. Attention in forensic science has actually increased in the last couple of years, possibly since of renowned television shows that feature forensic researchers on the job. Also, the breakthrough of molecule techniques and the establishment of DNA databases have actually updated the species of job-related that forensic scientists deserve to do. Their job activities are generally related to crimes versus people such together murder, rape, and assault. Their job-related involves examining samples such together hair, blood, and also other human body fluids and likewise processing DNA discovered in numerous different environments and also materials. Forensic scientists likewise analyze other biological evidence left in ~ crime scenes, such together insect components or pollen grains. College student who want to seek careers in forensic scientific research will most likely be required to take chemistry and biology courses as well as some intensive math courses.

Figure 1.13 This forensic scientist works in a DNA exploit room in ~ the U.S. Military Criminal investigation Laboratory.

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Section Summary

Biology is the scientific research of life. Every living biology share several crucial properties such as order, sensitivity or an answer to stimuli, reproduction, adaptation, growth and development, regulation, homeostasis, and also energy processing. Living points are very organized adhering to a power structure that contains atoms, molecules, organelles, cells, tissues, organs, and organ systems. Organisms, in turn, space grouped as populations, communities, ecosystems, and the biosphere. Development is the resource of the tremendous organic diversity on planet today. A diagram dubbed a phylogenetic tree deserve to be used to display evolutionary relationships amongst organisms. Biology is very broad and includes numerous branches and sub disciplines. Examples incorporate molecular biology, microbiology, neurobiology, zoology, and botany, among others.