What do organisms do

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Connect with us. Safeopedia Explains Organism. What Does Organism Mean? Safeopedia Explains Organism A defining parameter of all organisms is their life span.

Energy from light is needed for plants because the chemical reaction that produces plant matter from air and water requires an energy input to occur. Animals acquire matter from food, that is, from plants or other animals. The chemical elements that make up the molecules of organisms pass through food webs and the environment and are combined and recombined in different ways.

At each level in a food web, some matter provides energy for life functions, some is stored in newly made structures, and much is discarded to the surrounding environment. Only a small fraction of the matter consumed at one level is captured by the next level up. As matter cycles and energy flows through living systems and between living systems and the physical environment, matter and energy are conserved in each change.

The carbon cycle provides an example of matter cycling and energy flow in ecosystems. Photosynthesis, digestion of plant matter, respiration, and decomposition are important components of the carbon cycle, in which carbon is exchanged between the biosphere, atmosphere, oceans, and geosphere through chemical, physical, geological, and biological processes. Organisms obtain the materials they need to grow and survive from the environment. Many of these materials come from organisms and are used again by other organisms.

Matter cycles between the air and soil and among plants, animals, and microbes as these organisms live and die. Organisms obtain gases, water, and minerals from the environment and release waste matter gas, liquid, or solid back into the environment. Food webs are models that demonstrate how matter and energy is transferred between producers generally plants and other organisms that engage in photosynthesis , consumers, and decomposers as the three groups interact—primarily for food—within an ecosystem.

Transfers of matter into and out of the physical environment occur at every level—for example, when molecules from food react with oxygen captured from the environment, the carbon dioxide and water thus produced are transferred back to the environment, and ultimately so are waste products, such as fecal material. Decomposers recycle nutrients from dead plant or animal matter back to the soil in terrestrial environments or to the water in aquatic environments.

The atoms that make up the. Ecosystems are sustained by the continuous flow of energy, originating primarily from the sun, and the recycling of matter and nutrients within the system. Photosynthesis and cellular respiration including anaerobic processes provide most of the energy for life processes.

Plants or algae form the lowest level of the food web. At each link upward in a food web, only a small fraction of the matter consumed at the lower level is transferred upward, to produce growth and release energy in cellular respiration at the higher level. Given this inefficiency, there are generally fewer organisms at higher levels of a food web, and there is a limit to the number of organisms that an ecosystem can sustain.

The chemical elements that make up the molecules of organisms pass through food webs and into and out of the atmosphere and soil and are combined and recombined in different ways. At each link in an ecosystem, matter and energy are conserved; some matter reacts to release energy for life functions, some matter is stored in newly made structures, and much is discarded.

Competition among species is ultimately competition for the matter and energy needed for life. Photosynthesis and cellular respiration are important components of the carbon cycle, in which carbon is exchanged between the biosphere, atmosphere, oceans, and geosphere through chemical, physical, geological, and biological processes.

Ecosystems are dynamic in nature; their characteristics fluctuate over time, depending on changes in the environment and in the populations of various species. Changes may derive from the fall of canopy trees in a forest, for example, or from cataclysmic events, such as volcanic eruptions. But many changes are induced by human activity, such as resource extraction, adverse land use patterns, pollution, introduction of nonnative species, and global climate change.

Extinction of species or evolution of new species may occur in response to significant ecosystem disruptions. Species in an environment develop behavioral and physiological patterns that facilitate their survival under the prevailing conditions, but these patterns may be maladapted when conditions change or new species are introduced. Ecosystems with a wide variety of species—that is, greater biodiversity—tend to be more resilient to change than those with few species.

The places where plants and animals live often change, sometimes slowly and sometimes rapidly. When animals and plants get too hot or too cold, they may die. If they cannot find enough food, water, or air, they may die.

Ecosystems are dynamic in nature; their characteristics can vary over time. Disruptions to any physical or biological component of an ecosystem can lead to shifts in all of its populations. A complex set of interactions within an ecosystem can keep its numbers and types of organisms relatively constant over long periods of time under stable conditions. If a modest biological or physical disturbance to an ecosystem occurs, it may return to its more or less original status i. Extreme fluctuations in conditions or the size of any population, however, can challenge the functioning of ecosystems in terms of resources and habitat availability.

Group behaviors are found in organisms ranging from unicellular slime molds to ants to primates, including humans. Many species, with a strong drive for social affiliation, live in groups formed on the basis of genetic relatedness, physical proximity, or other recognition mechanisms which may be species specific.

Group behavior evolved because group membership can increase the chances of survival for individuals and their relatives. While some groups are stable over long periods of time, others are fluid, with members moving in and out. Groups often dissolve if their size or operation becomes counterproductive, if dominant members lose their place, or if other key members are removed from the group.

Group inter-dependence is so strong that animals that usually live in groups suffer, behaviorally as well as physiologically, when reared in isolation, even if all of their physical needs are met. Being part of a group helps animals obtain food, defend themselves, and cope with changes.

Groups may serve different functions and vary dramatically in size. Groups can be collections of equal individuals, hierarchies with dominant members, small families, groups of single or mixed gender, or groups composed of individuals similar in age. Some groups are stable over long periods of time; others are fluid, with members moving in and out.

Some groups assign specialized tasks to each member; in others, all members perform the same or a similar range of functions. Groups may form because of genetic relatedness, physical proximity, or other recognition mechanisms which may be species specific. Animals, including humans, having a strong drive for social affiliation with members of their own species and will suffer, behaviorally as well as physiologically, if reared in isolation, even if all of their physical needs are met.

Some forms of affiliation arise from the bonds between offspring and parents. Other groups form among peers. Group behavior has evolved because membership can increase the chances of survival for individuals and their genetic relatives.

How can individuals of the same species and even siblings have different characteristics? Heredity explains why offspring resemble, but are not identical to, their parents and is a unifying biological principle.

Heredity refers to specific mechanisms by which characteristics or traits are passed from one generation to the next via genes. Genes encode the information for making specific proteins, which are responsible for the specific traits of an individual.

Each gene can have several variants, called alleles, which code for different variants of the trait in question. Every cell of any individual organism contains the identical set of chromosomes. When organisms reproduce, genetic information is transferred to their offspring. In species that reproduce sexually, each cell contains two variants of each chromosome, one inherited from each parent. Thus sexual reproduction gives rise to a new combination of chromosome pairs with variations between parent and offspring.

Environmental as well as genetic variation and the relative dominance of each of the genes in a pair play an important role in how traits develop within an individual. Complex relationships between genes and interactions of genes with the environment determine how an organism will develop and function. How are the characteristics of one generation related to the previous generation? Each chromosome consists of a single very long DNA molecule, and each gene on the chromosome is a particular segment of that DNA.

DNA molecules contain four different kinds of building blocks, called nucleotides, linked together in a sequential chain. The sequence of nucleotides spells out the information in a gene. Before a cell divides, the DNA sequence of its chromosomes is replicated and each daughter cell receives a copy.

When organisms reproduce, genetic information is transferred to their offspring, with half coming from each parent in sexual reproduction. Inheritance is the key factor causing the similarity among individuals in a species population. Organisms have characteristics that can be similar or different. Young animals are very much, but not exactly, like their parents and also resemble other animals of the same kind. Plants also are very much, but not exactly, like their parents and resemble other plants of the same kind.

Many characteristics of organisms are inherited from their parents. Many characteristics involve both inheritance and environment. Genes are located in the chromosomes of cells, with each chromosome pair containing two variants of each of many distinct genes.

Changes mutations to genes can result in changes to proteins, which can affect the structures and functions of the organism and thereby change traits. Sexual reproduction provides for transmission of genetic information to offspring through egg and sperm cells. Variations of inherited traits between parent and offspring arise from genetic differences that result from the subset of chromosomes and therefore genes inherited or more rarely from mutations.

Boundary: The stress here is on the impact of gene transmission in reproduction, not the mechanism. All cells in an organism have the same genetic content, but the genes used expressed by the cell may be regulated in different ways. Not all DNA codes for a protein; some segments of DNA are involved in regulatory or structural functions, and some have no as-yet known function.

Why do individuals of the same species vary in how they look, function, and behave? Variation among individuals of the same species can be explained by both genetic and environmental factors.

Individuals within a species have similar but not identical genes. In sexual reproduction, variations in traits between parent and offspring arise from the particular set of chromosomes and their respective multiple genes inherited, with each parent contributing half of each chromosome pair. More rarely, such variations result from mutations, which are changes in the information that genes carry.

The set of variations of genes present, together with the interactions of genes with their environment, determines the distribution of variation of traits in a population. Individuals of the same kind of plant or animal are recognizable as similar but can also vary in many ways. Offspring acquire a mix of traits from their biological parents. Different organisms vary in how they look and function because they have different inherited information.

In each kind of organism there is variation in the traits themselves, and different kinds of organisms may have different versions of the trait. The environment also affects the traits that an organism develops—differences in where they grow or in the food they consume may cause organisms that are related to end up looking or behaving differently.

In sexually reproducing organisms, each parent contributes half of the genes acquired at random by the offspring. Individuals have two of each chromosome and hence two alleles of each gene, one acquired from each parent. These versions may be identical or may differ from each other. In addition to variations that arise from sexual reproduction, genetic information can be altered because of mutations. Though rare, mutations may result in changes to the structure and function of proteins.

Some changes are beneficial, others harmful, and some neutral to the organism. The information passed from parents to offspring is coded in the DNA molecules that form the chromosomes.

In sexual reproduction, chromosomes can sometimes swap sections during the process of meiosis cell division , thereby creating new genetic combinations and thus more genetic variation. Although DNA replication is tightly regulated and remarkably accurate, errors do occur and result in mutations, which are also a source of genetic variation. Environmental factors can also cause mutations in genes, and viable mutations are inherited.

The most common form of energy utilized by a living thing is ATP , i. In plants and other photosynthetic organisms, light energy is converted into chemical energy via the process of photosynthesis. Another way of producing energy is by cellular respiration. Cellular respiration is a cellular process wherein carbohydrates are processed to produce chemical energy.

Organisms metabolize. This means that they carry out processes that keep them alive. Metabolic processes include growth, response to stimuli, reproduction, waste elimination, and biosynthesis.

Two forms of metabolism are anabolism and catabolism. Anabolism includes the energy-requiring reactions that lead to the building up of biomolecules. Conversely, catabolism includes processes of breaking down particles into simpler molecules.

Living things carry out these metabolic processes in an orchestrated, systematized manner. They have diverse regulatory mechanisms to ensure that homeostatic conditions are kept and sustained.

Organisms are capable of detecting and responding to stimuli. They can detect changes in their environment. Humans and other animals have senses to detect stimuli. The five fundamental senses are sight, smell, touch, taste, and hearing. The response is crucial to survival. For instance, an individual organism might move away from the source of the stimuli. Others might move towards it.

Organisms can reproduce. They can give rise to another of the same kind species. There are essentially two ways to do this: 1 by sexual reproduction , i. In asexual reproduction, the offspring is a clone of the parent. In sexual reproduction, the offspring is a new individual formed by the union of the sex cells.

Organisms go through life stages. The offspring will grow to adulthood, meaning the phase at which it is also capable of reproducing. At the cellular level, growth entails an increase in size or an increase in number. An increase in cell size is one in which the cell increases in girth as it synthesizes and stores biomolecules. An increase in the number entails an increase in the cell number through cellular division.

A great activity for learning about the four major groups of biomolecules: fats, carbohydrates, nucleic acids, and proteins. The nucleus is an organelle that has a membrane called the nuclear envelope perforated with holes called nuclear pores. Inside the nucleus are genetic material and nuclear bodies suspended in the nucleoplasm.

Nucleoplasm is the protoplast material inside the nucleus. These nuclear structures are absent in a prokaryotic cell. The nucleus of a eukaryotic cell is where DNA replication the process in which a DNA segment is duplicated and transcription a process where mRNA transcript is produced occurs. Conversely, these processes occur in the cytoplasm of a prokaryotic cell.

The presence of a nucleus compartmentalizes the genetic material and these processes. The nuclear envelope prevents the easy entry of molecules and thereby regulates the passage of molecules into and out of the nucleus. There is an instance though when the nucleus apparently disappears. During cellular division, the nuclear envelope disintegrates to allow the chromosomes to separate and move to opposite poles, and then reforms to compartmentalize the genetic material in each of the two new cells.

Apart from the nucleus, other membrane-bound organelles found in a eukaryotic cell that are not present in a prokaryotic cell are mitochondria , plastids , endoplasmic reticulum , Golgi apparatus , lysosomes , and endosomes. Because of the presence of larger cytoplasmic structures, a eukaryotic cell is notably larger than a prokaryotic cell. What is common between a prokaryotic cell and a eukaryotic cell is the presence of genes that store genetic information.

Ribosomes cytoplasmic structures that serve as the site of protein synthesis are also present in both cell types.

Nevertheless, the prokaryotic ribosomes are 70S made up of 50S and 30S whereas the eukaryotic ribosomes are 80S made up of 60S and 40S. And while the ribosomes of the prokaryotes are made in the cytoplasm the process of ribosome synthesis involves both the cytoplasm and the nucleolus of the nucleus in eukaryotes.

Examples of prokaryotes are bacteria and archaea whereas eukaryotes include protists, fungi, plants, and animals. Organisms may be described as single-celled unicellular or multicellular. Unicellular organisms are those that are made up of only one cell. Conversely, multicellular organisms are comprised of many cells that act as a unit performing a particular function. Examples of unicellular prokaryotes are bacteria and archaea and unicellular eukaryotes are protists and certain fungi.

Multicellular organisms include plants and animals. In multicellular organisms, a group of cells makes up a tissue. The cells in a tissue have a similar structure and function.

Examples of animal tissues are nervous tissue , muscle tissue , vascular tissue , and connective tissue. As for plants, the examples of tissues are the meristematic tissues, the permanent tissues, and the reproductive tissues. A group of tissues that are organized into an anatomical unit is called a biological organ. Examples of animal organs are as follows: heart, lungs, brain, stomach, skin, pancreas, liver, intestines, kidneys, and sex organs.

In plants, the organs are roots, stems, leaves, flowers, fruits, and seeds. In animals, the organs may further organize into an organ system. In humans and other vertebrates, the systems are as follows: integumentary system, lymphatic system, muscular system, nervous system, reproductive system, respiratory system, skeletal system, endocrine system, immune system, and urinary system.

Each of these systems carries out a particular function. For instance, the digestive system is responsible for the digestion of food. For example, while sea lions rely on thick layers of fat for insulation, sea otters Enhydra lutris swimming in the same cold waters depend on unusually thick fur to retain heat. As a result, sea otters spend more time grooming Figure 3b , and their thick fur attracted hunters who drove them nearly to extinction Riedman On land, research shows that plants and cold-blooded animals develop dark coloration and position themselves to maximize solar energy gain in cool weather.

In hotter regions, studies reveal that animals may avoid intense sun, while plants protect themselves by transpiring large amounts of water, maximizing air flow through their foliage, or going dormant until cooler temperatures returns. Some temperature adaptations can be surprising. For example, scientists recently found that grasses growing near geothermal vents gain heat tolerance from a virus within a fungus inside their roots Marquez Figure 3b: Sea otter Enhydra lutris displaying its insulating fur.

The environment is dynamic because physical processes drive change in Earth's attributes over time. However, research demonstrates that life itself drives equally important environmental changes. In some cases, the loss of a native species, or introduction of a non-native one, can threaten the survival of other organisms. For this reason, the conservation of endangered organisms and control of invasive species are of broad concern. Figure 5: Satellite image false color infrared showing abundance and distribution of grassy termite mounds in Kenya Red color indicates areas of high plant productivity that are associated with increased animal diversity.

Small red circles are termite mounds distributed in a matrix of lower productivity grasslands. Large red circles are abandoned cattle corrals. White box indicates 0. Courtesy of Pringle et al. In antagonistic relationships, organisms compete for resources, spread disease to their neighbors, or consume each other. In more mutualistic associations, one organism shelters another, two organisms exchange resources, or tighter dependencies evolve, such as coevolved relationships between specialized pollinators and flowers.

In some cases, species even cultivate others. For example, ecologists recently found that coral reef damselfish tend underwater algal gardens, where they remove less desirable algae species and chase away predators Hata et al. In other cases, species with large structures become habitat for smaller organisms.

For example, the human digestive tract harbors so many bacteria that they outnumber the cells in the human body by tenfold Dethlefsenet et al. Investigating how digestive tract microbes influence their hosts is now a promising area of microbial ecology and medicine. At a bigger scale, the evolutionary rise of flowering plants angiosperms and the development of extensive rainforest canopies produced novel environments in which animals tested new ecological strategies.

Scientists suggest that evolution of the open branch structure of rainforest trees helped drive the evolution of forelimb structure in apes, permitting tree-to-tree swinging, and bequeathing manual dexterity to humans Figure 4; Burger Research demonstrates that organisms have additional power to change the environment by altering stocks and flows of water, energy, and elements at both small and large scales Beerling ; Morton The ozone layer then reduced UV radiation on terrestrial surfaces, and helped to protect organisms emerging onto land from potentially lethal does of UV.

Today plant life controls a large fraction of energy and water fluxes between land and the atmosphere. Animals also play critical roles in influencing the physical properties of ecosystems. For example, recent work shows how underground termites in Kenya increase grassland productivity and biodiversity over large areas by raising soil fertility in evenly spaced circles Figure 5; Pringle et al.

Future research will grapple with conflicts between human needs for food, fuel, and fiber, and preservation of natural biodiversity and ecological function World Health Organization Beerling, D. Biro, P. Small within-day increases in temperature affects boldness and alters personality in coral reef fish. Chapin, F. Principles of Terrestrial Ecosystem Ecology.

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