1 The reference to “North American” is conceptual rather than geographic, as Mexico’s wildlife conservation movement has developed under different circumstances and does not parallel the approach taken by the U.S. and Canada. – : B&C Position Statement – The North American Model of Wildlife Conservation
Contents
What is the most essential aspect of wildlife management?
The goal of wildlife conservation is to ensure the wise use and management of renewable resources without wasting them. Preservation saves natural resources with no consumptive use of them. Both are necessary to sustain resources for future generations. 
Wildlife management is the science and practice of maintaining wildlife populations and their habitats. Wildlife managers know that nature overproduces its game resources and that good management yields a surplus that can be harvested by hunters. 
The most essential aspect of wildlife management is managing habitat for game species. This provides a species with the essential elements needed to meet its needs: food, water, cover, space, and an arrangement of these elements that lets animals meet their needs. 
Carrying capacity is the number of animals a given habitat can support all year long without damaging the animals or the habitat. 
Factors that can limit the potential production of wildlife include disease/parasites, starvation, predators, pollution, accidents, old age, and hunting.
What five essential elements must be present?
The most critical aspect of wildlife conservation is habitat management. Habitat loss presents the greatest threat to wildlife. Five essential elements must be present to provide a viable habitat: food, water, cover, space, and arrangement, The need for food and water is obvious.
Cover is needed not only to provide shelter from the elements and predators but also to protect animals while they are feeding, breeding, roosting, nesting, and traveling. Cover can range from thick weeds and brush to a few rocks piled together. Space is necessary to avoid over-competition for food. Some animals also need a certain amount of territorial space for mating and nesting.
When crowded, some species may develop stress-related diseases. Arrangement refers to the placement of food, water, cover, and space in a habitat. The ideal arrangement allows animals to meet all of their needs in a small area so that they minimize the energy they use traveling from food to cover to water.
River bottoms are ideal, offering many animals all their habitat needs along one corridor. Edge effects can be in the form of topographical or vegetation edges, such as the saddle of a mountain range. For example, quail and ptarmigan will spend much of their time where shrub and grassland or rock/gravel ridges converge.
Water and food are essential elements of a viable habitat. 
Cover provides shelter from the elements. 
Space is necessary to avoid over-competition for food.
Which of these does not provide funding for the Missouri Department of Conservation?
The Missouri Department of Conservation Funding – The department receives its funding from a variety of sources as shown in this pie chart. The department receives no monies from any fines on game law violations. All fines collected go into the county school district where the violation occurred. 
What 4 management principles are in nature?
Key Takeaway – The principles of management can be distilled down to four critical functions. These functions are planning, organizing, leading, and controlling. This P-O-L-C framework provides useful guidance into what the ideal job of a manager should look like.
What are management principles in nature?
6. Based on Cause and Effect: – The principles of management are intended to establish cause and effect relationship so that the findings can be applied to such given situations frequently. The principles of management tell the likely effect if a certain principle is applied.
What are the four 4 essential elements?
What elements are present in the human body? – Scientists believe that about 25 of the known elements are essential to life. Just four of these – carbon (C), oxygen (O), hydrogen (H) and nitrogen (N) – make up about 96% of the human body. These four elements are found in the basic structure of all biochemical molecules.
What are the 4 key essential elements?
Technology blog – 
Carbon, hydrogen, oxygen, and nitrogen are four elements essential to life. They form the building blocks that make life possible and account for 96% of all atoms in living things. Just as there are core elements in nature, there are foundational elements that power the startup world.
DATA: The company has reliable access to enough relevant data to train ML models. RELEVANCE: The company is capable of creating a bridge between data science and customer value to drive revenue growth. SCIENCE: The company has effective algorithms to extract relevant insights from its data. PIPELINE: The company has the infrastructure in place to deploy machine learning models at scale.
These elements may seem like natural building blocks, and yet many AI startups today only have one or two in place. A recent report from MMC ventures concluded that among 3,000 startups, only 60% had evidence of AI material to a company’s value proposition, leaving a staggering 40% without.40% of AI startups do not have evidence of the four essential elements.
What are the 5 basic needs of animals?
The five basic needs of animals are food, water, shelter, space, and air.
What is a conservation scheme?
Category:Conservation projects Wikimedia Commons has media related to, Conservation projects are programmes undertaken by and organizations to protect,, wild places or, This category has the following 6 subcategories, out of 6 total.
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The following 77 pages are in this category, out of 77 total., Retrieved from “” : Category:Conservation projects
What are the 5 types of principles of management?
At the most fundamental level, management is a discipline that consists of a set of five general functions: planning, organizing, staffing, leading and controlling.
Who proposed 4 principles of management?
The four principles of Taylor’s scientific management are: Science, not rule of thumb. Harmony, not discord. Cooperation, not individualism.
What are the 4 importance of principles of management?
The five points of importance of management are achieving organization goals, achieving individual goals, creating a dynamic environment, developing society, and improving efficiency. Management refers to the process of performing tasks efficiently and effectively while achieving personal and organizational goals.
- Achieving organisation goals – Management plays a vital role in achieving organisational goals by aligning resources and providing guidance on all matters. Managers play an important role in developing strategies that help organisations achieve their goals.
- Achieving individual goals – Management is also responsible for helping individuals achieve their personal goals. They ensure that every individual in the organization is satisfied with their growth and development. There is a directly proportional relationship between achieving individual and organizational goals.
- Creating a dynamic environment – Management plays a vital role in ensuring that the organisation does not stagnate and stays up to date with the latest trends in the industry. They ensure that the organisation changes with the changing times.
- Developing Society – As management is responsible for the development of an organization, they also help in the development of society. Every organisation has a social responsibility that they can fulfill in a better way even if they achieve their own goals.
- Improving Efficiency – Management involves an array of functions like planning, controlling, directing, and organising, which helps improve the efficiency of the organisation.
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What are any 7 principles of management?
1. Customer Focus – The ultimate focus of quality management is to meet and exceed customer expectations. This means treating every customer interaction as an opportunity to deliver more value, increasing repeat business, revenue and your brand’s reputation in the process.
Connect organizational objectives to current and future customer expectations Actively manage customer relationships for long-term success Monitor customer satisfaction and proactively address issues Enable direct feedback from customers to reduce the time to respond to issues
7 key quality management principles—customer focus, leadership, engagement of people, process approach, improvement, evidence-based decision making and relationship management.
How many principles of management are important?
Q1. What is Fayol theory of management? – Henri Fayol was known as the father of modern management. He gave us the famous 14 principles of management. According to him, the 5 main functions of management are Planning, Organizing, Commanding, Coordinating and Controlling.
What are the objectives of the principles of management?
Vital Objectives of Management: –
- Organisational Objectives : Management is accountable for establishing and attaining objectives for the company. It has to deliver a variety of objectives in all operations contemplating the interest of all shareholders including, stakeholders, consumers, the government and employees. The principal objective of any company must be to use material and human resources to the maximum potential benefit, i.e., to meet the financial objectives of a firm. And, they are survival, profit and growth.
- Survival : The essential objectives of any industry is survival. Management must attempt to assure the continuation of the business. In order to survive, an industry must gain enough funds to meet the costs that would be incurred.
- Profit : Poor survival is not sufficient for the industry. Management has to make sure that the company earns the profit. Profit contributes to a necessary catalyst for the sustained successful performance of the firm. Profit is crucial for meeting the costs and uncertainties of the business concern.
- Growth : A firm requires to add to its chances, in the long run, for this it is necessary for the concern to develop. To prevail in the business, management must utilise adequately the growth potential of the firm.
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- Social objectives : It includes the establishment of benefit for the community. As a part of the community, every business whether it is a trade or non-trading concern has a social responsibility to meet. This applies to consistently generating financial value for many components of society. This includes using environmentally beneficial technologies of production, providing job opportunities to the disadvantaged sections of the community and furnishing the primary facilities like crèches and schools to employees.
- Personal Objectives : Establishments are made up of resources who possess different backgrounds, experiences, objectives and personalities. They all become part of the establishment to meet their several demands. These differ from economic necessities such as ambitious perks and salaries, social obligations such as equal attention and higher level demands such as individual growth and progress.
| 5-6 MARKS QUESTIONS | |
| Q1. AN ORGANISATION SETS DIFFERENT OBJECTIVES FOR ITSELF AND OTHER STAKEHOLDERS. EXPLAIN SUCH OBJECTIVES BRIEFLY. | |
| ANSWER: AN ORGANISATION SETS AND ACHIEVES THE FOLLOWING OBJECTIVES: | |
| (a)ORGANISATIONAL OR ECONOMIC OBJECTIVES |
These objectives are classified as: (1)SURVIVAL:
Example: If Ram is running a shop and incurring a cost of Rs.50,000 per month then he has to collect minimum revenue of Rs.50,000 to cover all his costs otherwise his business won’t survive. (2)PROFIT:
Example: If the revenue of the shop is more than Rs.50,000, than Ram is earning a profit. The more the gap between the cost of production and revenue collected, the better the profit. It will help him in reducing business risk. (3)GROWTH: Regular earning of profits makes it possible for an organisation to expand and stay in the industry and face competition. Growth of an organisation can be measured by:
Example: Patanjali is growing as it is dealing in a variety of products and opening megastores in multiple cities. |
| (b) SOCIAL OBJECTIVES |
Some of the social objectives are:
|
| (c) PERSONAL OR INDIVIDUAL OBJECTIVES |
These objectives are related to the growth of the employees working in an organisation. Some of these objectives are:
|
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- (A) RECOGNISE AND EXPLAIN THE AIMS OF MANAGEMENT DISCUSSED ABOVE.
- (B) STATE ANY 2 VALUES WHICH THE COMPANY WANTED TO COMMUNICATE TO THE SOCIETY.
- (OUTSIDE DELHI 2014)
Organisational Objectives: These objectives are set on the basis of goals of the organisation and management is responsible to set and achieve such objectives.
These objectives are Survival, Profit and Growth of an organisation.
Social Objectives: Survival of any organisation whether it is private or government, depends upon its commitment towards society.
- The organisations which care for society enjoy long term growth.
- Example:
- Using environment-friendly methods of production, generating employment opportunities etc.,
- Generation of employment opportunity.
- Balanced regional development.
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- Using environment-friendly methods of production.
- Community services like opening of schools and crèches.
The above mentioned is the concept, that is elucidated in detail about the Objectives of Management for the class 12 Commerce students. To know The above mentioned is the concept, that is elucidated in detail about the Objectives of Management for the class 12 Commerce students. To know more, stay tuned to BYJU’S. : Management Objectives: Top 3 Objectives of Management
What are the 5 essential parts of a habitat?
Ask students what they think are the most basic requirements for animal survival. Guide them to an understanding that the five basic components of habitat are food, water, air, shelter, and space.
Which elements are most essential for life?
Biological roles of the elements – Wikipedia
| This article’s factual accuracy is, Relevant discussion may be found on the, Please help to ensure that disputed statements are, ( January 2023 ) ( ) |
A large fraction of the that occur naturally on the earth’s surface are essential to the structure and metabolism of living things. Four of these elements (hydrogen, carbon, nitrogen, and oxygen) are essential to every living thing and collectively make up 99% of the mass of,
Phosphorus and sulfur are also common essential elements, essential to the structure of and, respectively. Chlorine, potassium, magnesium, calcium and phosphorus have important roles due to their ready and utility in regulating and, The remaining elements found in living things are primarily that play a role in determining protein structure.
Examples include iron, essential to ; and magnesium, essential to, Some elements are essential only to certain of organisms, particularly the, For instance, the series rare earths are essential for, As shown in the following table, there is strong evidence that 19 of the elements are essential to all living things, and another 17 are essential to some taxonomic groups.
- Apart from the known essential elements, most elements have only received direct biological study in connection with their significance to human health; this has incidentally included study of some such as chickens and rats, and plants of agricultural importance. There is evidence that certain elements are essential to groups other than humans, but there has been little effort to systematically study any group other than humans or laboratory animals to determine the effects of of uncommon elements, and for these groups knowledge is largely limited to information that has been gathered incidentally to study of other aspects of each organism.
- The helium, neon, argon, krypton, xenon are nonreactive and have no known direct biological role — albeit xenon nevertheless very surprisingly exhibits both and side-effects despite usually being considered “chemically inert,” and can at least one human, (Radon is radioactive, discussed below.)
- Some elements are very rare on the earth’s surface and any lifeform to which these were essential would have limited habitat and possibly a limited term of existence as geological change altered the availability of these elements. Examples are rhodium and tantalum.
- Some elements readily substitute for other, more common elements in molecular structures; e.g. bromine often substitutes for chlorine, or tungsten for molybdenum. Sometimes this substitution has no biological effect; sometimes it has an adverse effect.
- Many elements are benign, meaning that they generally neither help nor harm organisms, but may be, However, since the literature on these “benign” elements is almost entirely focused on their role in humans and laboratory animals, some of them may eventually be found to have an essential role in other organisms. In the following table are 56 benign elements.
- A few elements have been found to have a function in humans (and possibly in other living things as well; the phenomenon has not been widely studied). In these, a normally nonessential element can treat a disease (often a micronutrient deficiency). An example is fluorine, which reduces the effects of in rats.
- Some of the benign elements are, As such they alter life due to their potential to cause, This effect could be interpreted as either adverse or beneficial, but since mutation would proceed even in the absence of ionizing radiation, these mutagenic elements are not essential to living things.
- All elements with atomic number 95 or higher are and radioactive with a very short half-life. These elements have never existed on the surface of the earth except in minute quantities for very brief time periods. None have any biological significance.
Aluminum warrants special mention because it is the most abundant metal and the third most abundant element in the Earth’s crust; despite this, it is not essential for life. With this sole exception, the eight most, making up over 90% of the crustal mass, are also essential for life.
- The following list identifies in rank order the possible biological roles of the chemical elements, ranging from a score of 5 for elements essential to all living things, to a score of 1 for elements that have no known effects on living things.
- There are also letter scores for special functions of the elements.
These rank scores are used to characterize each element in the following table.
| Rank | Biological Importance |
|---|---|
| 5 | Essential for all (or most) living things. |
| 4 | Essential for some living things. |
| 3 | Not essential, but has a pharmacologic role; helps to treat disease in some organisms. |
| 2 | Benign: present in some organisms, sometimes bioaccumulating, but generally having no apparent effects (except possible harmful effects, notes “a” or “b”). |
| 1 | Extremely rare on the earth’s surface (less than 1×10 −7 %, i.e. less than 1/10 as common as the least common essential element, selenium), thus has low potential for any kind of biological role. |
| a | Toxic in some molecular forms. |
| b | Radioactive. |
| c | Has uses in medicine as a drug or implant. |
The following table identifies the 94 chemical elements that occur naturally on the earth’s surface, their atomic numbers, their biological rank as defined above, and their general beneficial and harmful roles in living things.
| Element | Rank | Beneficial role | Harmful role | |
|---|---|---|---|---|
| 89 | 1b | Has no known biological role. | Radioactive. | |
| 13 | 2a | Has no known biological role. | The metal, or various compounds, can be toxic to humans. In plants, aluminum can be the primary limitation on growth in acidic soils. | |
| 51 | 2c | Has no known biological role, but has a variety of uses in medicine, e.g. antibacterial. | Some compounds are highly toxic to humans. | |
| 18 | 2 | None known. | None known. | |
| 33 | 4a | Essential to some species, including humans, for whom it is necessary for the functioning of the nervous system. Some marine algae and shrimp contain arsenic compounds. | Toxic to humans in some forms. | |
| 85 | 1b | None known. | Radioactive. | |
| 56 | 2ac | Has no known biological role, but a variety of plants concentrate it from the soil, and it has a variety of uses in medicine. | Some compounds are toxic. In humans, barium ion affects the, | |
| 4 | 2c | Has no known biological role, but has medical use in certain dental alloys | Toxic to humans, esp. via inhalation. Can substitute for magnesium in certain key enzymes, causing malfunction. | |
| 83 | 2ac | Has no known biological role, but has a variety of uses in medicine, e.g. in antiulcer, antibacterial, anti‐HIV and radiotherapeutic uses. | Slightly toxic, perhaps the least toxic heavy metal, though poisonings have been reported. | |
| 5 | 4 | In plants, it has important roles in nucleic acid metabolism, carbohydrate and protein metabolism, cell wall synthesis, cell wall structure, membrane integrity and function, and phenol metabolism. Probably essential to animals, for reasons not well understood. | Toxic to both animals and plants. | |
| 35 | 5 | Essential to membrane architecture and tissue development in animals. May have antibiotic effects in some compounds when it substitutes for chlorine. Bromine compounds are very common in and presumably essential to a variety of marine organisms, including bacteria, fungi, seaweeds, and diatoms. Most marine organobromine compounds are made by the action of a unique algal enzyme, | Toxic in excessive concentrations, causing the human disease, | |
| 48 | 4 | A using cadmium has been found in some marine that inhabit environments with very low zinc availability; the cadmium evidently provides a similar function. Many plants bioaccumulate cadmium, which deters herbivory. Cadmium deprivation in goats and rats leads to depressed growth, but has not been shown to be essential. | is widely recognized in humans, but has not been described in other organisms. In general, cadmium acts by substituting for calcium, zinc, or iron, and can disrupt biochemical pathways dependent upon those metals. | |
| 20 | 5a | Ubiquitous, essential | Appears in various toxic organochemicals; contributes to diseases e.g., | |
| 6 | 5c | Ubiquitous, essential. | Its oxide is a pollutant. | |
| 58 | 4a | The methanol dehydrogenase of the methanotrophic bacterium SolV requires a cofactor, lanthanum, cerium, praseodymium, or neodymium (or possibly other lanthanides) but it appears that any of these lanthanides can perform this function, so cerium is only essential if no other suitable lanthanides are available. Has medical uses, e.g. in burn treatment. | Can substitute for calcium with possible adverse effects, and in metallic form, is mildly toxic. | |
| 55 | 2a | Has no known biological role. | Can substitute for potassium (a biologically essential element) with possible adverse effects, particularly if the substitution is of radioactive cesium, which was the primary biologically active isotope released in the 1986 nuclear disaster. | |
| 17 | 4a | Chlorine salts are critical for many species, including humans. Its ion is used as an electrolyte, as well as making the hydrochloric acid the stomach uses for digestion. | Elemental Cl 2 is toxic. | |
| 24 | 4 | Appears to be essential in humans. Affects metabolism. Also influences metabolism, replication and transcription of, and decreases the content of in plasma. | Toxic in some forms. | |
| 27 | 5 | Essential to the metabolism of all animals, as a key constituent of cobalamin, also known as, | Toxic in some forms, probably carcinogenic. | |
| 29 | 5a | Essential in many ways; an important component of many enzymes, especially, which is present in nearly all living things. | Some compounds are toxic; the metal is highly toxic to viruses. | |
| 66 | 2 | Has no known biological role. | Some salts have low toxicity. | |
| 68 | 2a | Has no known function in humans, and is not taken up by plants. | Soluble salts are mildly toxic. | |
| 63 | 2a | Has no known function in humans, and is not taken up by plants. | Possible low toxicity in some forms. | |
| 9 | 3a | Affects bone density in humans; creates fluoroapatite, which makes tooth enamel hard and relatively impervious to chemical action, compared to bone. Improves growth in rats; has pharmacologic effects – helps to treat other deficiencies, e.g. of iron. Absence of fluorine has no clear adverse consequences in animals. | Excess fluorine in humans results in, and can substitute for iodine, causing, | |
| 87 | 1b | Due to its very short half-life, there is almost no potential for a living thing to be exposed to it. Even synthesis cannot produce more than minute quantities before it decays, so there is no medical use. | Radioactive. | |
| 64 | 2ac | Has no known function in humans, and is not taken up by plants. There has been limited use in experimental medicine. | Soluble salts are mildly toxic. See medical discussion in, | |
| 31 | 2ac | Although nonessential, plays a complex role in humans, including concentrating in bone, binding to plasma proteins, and concentrating in malignancies. It is selectively taken up by plants, so there are a variety of possible roles in plant metabolism. There is limited medical use. | Inhibits iron uptake and metabolism in a variety of plants and bacteria. | |
| 32 | 2a | Some plants will take it up, but it has no known metabolic role. | Some salts are deadly to some bacteria. | |
| 79 | 2a | Although some plants bioaccumulate gold, no living organism is known to require it. There are, including treatment of rheumatoid arthritis and fabrication of dental implants. | Some used in medicine have adverse side effects. | |
| 72 | 2 | Has no known biological role. | Salts have low toxicity. | |
| 2 | 2 | As with other, has no known biological role. | Has no known harmful role. | |
| 67 | 2a | This has no known biological roles, and is not taken up by plants. There are medical uses; for example, holmium-containing nanoparticles are biocompatible and facilitate NMR imaging. | Some salts are known to be toxic to humans. | |
| 1 | 5 | Ubiquitous, essential. | None known. | |
| 49 | 2a | Has no known biological role. | Highly toxic to humans in fairly small doses; mildly toxic to plants, comparable to aluminum; may inhibit growth of some bacteria. | |
| 53 | 5ac | Iodine has a role in biochemical pathways of organisms from all biological kingdoms, indicating it is uniformly essential to life Widely used in medicine, mainly for treatment of and for its antibacterial properties. | Highly toxic to humans in its elemental form. | |
| 77 | 1a | Due to its extreme rarity, iridium has no biological role. | The chloride is moderately toxic to humans. | |
| 26 | 5 | Essential to almost all living things, usually as a in a protein; it is most familiar as an essential element in the protein, | Toxic in some forms. | |
| 36 | 1 | As with other, has no known biological role. It is also the rarest non-radioactive element in the earth’s crust. | None known. | |
| 57 | 4ac | The methanol dehydrogenase of the methanotrophic bacterium SolV requires a cofactor, lanthanum, cerium, praseodymium, or neodymium (or possibly other lanthanides) but it appears that any of these lanthanides can perform this function, so lanthanum is only essential if no other suitable lanthanides are available. Among plants, Carya accumulates lanthanum and other, perhaps as an adaptation to certain site-limiting environmental stresses. | The chloride is mildly toxic to humans. | |
| 82 | 3a | Pb deprivation leads to suboptimal growth of rats, along with anemia, and reduced function of a variety of enzymes; but results have been inconclusive, and the effects may be pharmacologic. | Toxic in some forms, teratogenic, and carcinogenic; historically, lead poisoning has frequently been widespread in human societies. It seems to have been rarely documented in other organisms. | |
| 3 | 4a | There is some evidence that lithium deprivation adversely affects multiple functions, especially fertility and adrenal gland function, in rats and goats, and some plants accumulate lithium. However, it is not known to be essential for any organism. There are medical uses, especially in treatment of manic-depressive symptoms. | Toxic in some forms. | |
| 71 | 2a | This has no known biological roles, and is not taken up by plants. | Mildly toxic to humans in some forms. | |
| 12 | 5a | Essential for almost all living things; needed for, and is a co-factor for many other enzymes; has multiple medical uses. | Large doses can have toxic effects. | |
| 25 | 5a | Essential for almost all living things, although in very small amounts; it is a cofactor for many classes of enzymes. At least one of these, mitochondrial superoxide dismutase (MnSOD), is present in all aerobic Bacteria and in the mitochondria of all eukaryotes. | Large doses can have toxic effects. | |
| 80 | 2ac | Although nearly ubiquitous in the environment, mercury has no known biological role. Traditionally used in medicine and dental fillings, it is now avoided due to toxic side effects. | Can inactivate certain enzymes, as a result, both the metal and some compounds (especially ) are harmful to most life forms; there is a long and complex history of in humans. | |
| 42 | 5 | Found in many enzymes; essential to all, and to some bacteria. Molybdenum in proteins is bound by or to other chemical moieties to give one of the, | Metallic molybdenum is toxic if ingested. | |
| 60 | 4 | The methanol dehydrogenase of the methanotrophic bacterium SolV requires a cofactor, lanthanum, cerium, praseodymium, or neodymium (or possibly other lanthanides) but it appears that any of these lanthanides can perform this function, so neodymium is only essential if no other suitable lanthanides are available. | Toxic in some forms. Anticoagulant. | |
| 10 | 2 | As with other, has no known biological role. | None known. | |
| 93 | 1b | Has no known biological role. | Radioactive. | |
| 28 | 4 | As a component of, and many other enzymes as well, nickel is needed by most living things in all domains. Nickel hyperaccumulator plants use it to deter herbivory. | Toxic in some forms. | |
| 41 | 2 | Has no known biological role, although it does in human bone. Is and, both alone and in a niobium-titanium alloy, is used in some medical implants including prosthetics, orthopedic implants, and dental implants. | Toxic in some forms. | |
| 7 | 5 | Ubiquitous, essential for all forms of life; all proteins and nucleic acids contain substantial amounts of nitrogen. | Toxic in some forms. | |
| 76 | 1a | None known. Osmium is very rare, substantially more so than any element essential to life. | The oxide is toxic to humans. | |
| 8 | 5 | Ubiquitous, essential for all forms of life; essentially all biological molecules (not to mention water) contain substantial amounts of oxygen. | In high concentrations, can occur. | |
| 46 | 2a | Has no known biological role. Medically, it is used in some to decrease corrosion and increase the of the final restoration. | Toxic in some forms. | |
| 15 | 5 | Ubiquitous, essential for all forms of life; all contain substantial amounts of phosphorus; it is also essential to (ATP), the basis for all cellular energy transfer; and it performs many other essential roles in different organisms. | Toxic in some forms; pure phosphorus is poisonous to humans. | |
| 78 | 2c | Has no known biological role, but it is a component of the drug, which is highly effective in treating some forms of cancer. | Toxic in some forms. Contact can promote an allergic reaction () in humans. | |
| 94 | 1bc | Has no known biological role, and is extremely rare in the earth’s crust. The isotope plutonium-238 is used as an energy source in some heart pacemakers. | Both, | |
| 84 | 1b | Has no known biological role, and due to its short half-life, is nearly nonexistent outside of research facilities. | Both highly, | |
| 19 | 5a | Essential for almost all living things, except perhaps some prokaryotes; performs, most of which are related to the transport of potassium ions. | Potassium ion in excess causes paralysis and depresses central nervous system activity in humans. | |
| 59 | 4 | The methanol dehydrogenase of the methanotrophic bacterium SolV requires a cofactor, lanthanum, cerium, praseodymium, or neodymium (or possibly other lanthanides) but it appears that any of these lanthanides can perform this function, so praseodymium is only essential if no other suitable lanthanides are available. | Some forms are mildly toxic to humans. | |
| 61 | 1b | Has no known biological role; as it is radioactive with a short half-life, it is very rare and is seldom present for long. | Radioactive. | |
| 91 | 1b | Has no known biological role; as it is radioactive with a short half-life, it is very rare and is seldom present for long. | Both, | |
| 88 | 1bc | Has no known biological role; as it is radioactive it is very rare. There have been, | Radioactive; historically, there have been many cases of, most notably in the case of the, | |
| 86 | 1bc | Has no known biological role. Historically, there have been various, | Radioactive, with a variety of documented harmful effects on, | |
| 75 | 1 | Has no known biological role, and is extremely rare in the earth’s crust. | None known. | |
| 45 | 1 | Has no known biological role, and is extremely rare in the earth’s crust. | Toxic in some forms. | |
| 37 | 2c | Has no known biological role, although it seems to substitute for potassium, and bioaccumulates in plants. It has seen limited medical use. | None known. | |
| 44 | 1a | Has no known biological role; it bioaccumulates, but does not appear to have any function. It is extremely rare. | There is a highly toxic oxide, RuO 4, but it is not naturally occurring. | |
| 62 | 2ac | Has no known biological role, although it can bioaccumulate in some plants. One radioisotope is approved for medical use. | Toxic in some forms. | |
| 21 | 2a | Has no known biological role, but can bioaccumulate in some plants, perhaps because it can substitute for aluminum in some compounds. | Some compounds may be carcinogenic; some forms are mildly toxic to humans. | |
| 34 | 4 | Selenium, which is an essential element for animals and prokaryotes and is a beneficial element for many plants, is the least-common of all the elements essential to life. Selenium acts as the catalytic center of several antioxidant enzymes, such as, and plays a wide variety of other, | Toxic in some forms. | |
| 14 | 4c | Essential for connective tissue and bone in birds and mammals. appears in many organisms; e.g. as (shells) of, of, and of plants. Also has medical uses, e.g. cosmetic implants. | is a lung disease caused by inhalation of silica dust. | |
| 47 | 2c | Has no known biological role, apart from medical use (antibiotic, mainly; also dental fillings). | Can produce a variety of in humans and other animals; also toxic to various microorganisms. | |
| 11 | 5 | Essential to animals and plants in many ways, such as osmoregulation and transmission of nerve impulses. Essential to energy metabolism of some bacteria, particularly extremophiles. | Toxic in some forms, and since it is essential to living things, either a lack or an excess can have harmful results. | |
| 38 | 4c | Essential to radiolarians, which have skeletons of, Also essential to some, Limited medical use in drugs such as, | Non-toxic; in humans, it often substitutes for calcium. | |
| 16 | 5 | Sulfur is essential and ubiquitous, partly because it is part of the and, Many metals that appear as enzyme are, and methionine is essential for protein, | Toxic in some forms. | |
| 73 | 1c | Has no known biological role, but is biocompatible, used in, e.g. skull plates. | Has not been found to be toxic, though some patients with tantalum implants have shown a mildly allergic reaction. | |
| 43 | 1b | Nonexistent (radioactive). | Nonexistent (radioactive). | |
| 52 | 1a | Is not known to be essential to any organism, but is metabolized by humans, typically through, | Toxic in some forms; the is fatal to humans in small doses, and the oxide causes severe bad breath. | |
| 65 | 2a | Has no known biological role, but is probably similar to other such as and, i.e., not known to be essential. Terbium is also one of the rarer lanthanides. | Toxic in some forms. | |
| 81 | 2a | Has no known biological role. Medically, it was used for many years to induce hair loss, but this has ended due to its numerous other toxic effects on human health. Its role, if any, in living things other than humans has been very little explored. | It is very toxic and there is evidence that the vapor is both teratogenic and carcinogenic. It can displace potassium in humans affecting the central nervous system. has a long history in humans, especially as it has sometimes been a preferred poison. | |
| 90 | 1b | Has no known biological role. | Radioactive. | |
| 69 | 2a | No known function in humans, and is not taken up by plants. | Toxic in some forms. | |
| 50 | 4a | In mammals, deprivation causes impaired reproduction and other abnormal growth, suggesting that it is an essential element. Tin may have a role in tertiary structure of proteins. Some plants are tin, possibly to deter herbivory. | Toxic in some forms, especially the compounds, which include many potent, | |
| 22 | 2c | Present in most animals, possibly beneficial to plant growth, but not known to be essential; some plants are, Common in medical implants. | The common compounds are nontoxic. | |
| 74 | 4a | Is a (presumably essential) component of a few bacterial enzymes, and is the heaviest biologically essential element. Appears to be essential in metabolism of some, Can substitute for in some proteins. Some plants it, though its function is unknown. | Toxic, at least to animals, in some forms. | |
| 92 | 4b | Some bacteria reduce uranium and use it as a terminal electron acceptor for respiration with acetate as electron donor. Some bacteria hyperaccumulate uranium. | Radioactive, and most compounds are also chemically toxic to humans. | |
| 23 | 4a | Can mimic and potentiate the effect of various growth factors such as insulin and epidermal growth factor. Can also affect processes regulated by, Also used by some bacteria. Dinitrogenases, essential for nitrogen metabolism, normally use molybdenum but in its absence vanadium (or iron) will substitute. Vanadium is also an essential for a variety of peroxidases found in many taxonomic groups, including bromoperoxidases, haloperoxidases, and chloroperoxidases. | Some compounds are toxic, and are implicated in several human diseases of including diabetes, cancer, chlorosis, anemia, and tuberculosis. | |
| 54 | 1 | Has no known biological role. | None known. | |
| 70 | 2a | No known function in humans, where it concentrates in bones. Not taken up by plants. | Toxic in some forms. | |
| 39 | 2a | Not well understood. It occurs in most organisms and at widely varying concentrations, suggesting it does have a role, but not known whether essential. | Toxic in some forms, and it may be carcinogenic. | |
| 30 | 5a | Essential, involved in numerous aspects of cellular metabolism (more than 200 different proteins). Some plants are, There are also medical uses, e.g. in dentistry. | Some compounds are toxic. | |
| 40 | 2a | Some plants have high uptake, but it doesn’t appear to be essential or even to have a role; benign. | Compounds generally have low toxicity. |
What are the most common essential elements of life?
Images – 
The six most common elements of life on Earth (including more than 97% of the mass of a human body) are carbon, hydrogen, nitrogen, oxygen, sulphur and phosphorus. The colors in the spectra show dips, the size of which reveal the amount of these elements in the atmosphere of a star.
The human body on the left uses the same color coding to evoke the important role these elements play in different parts of our bodies, from oxygen in our lungs to phosphorous in our bones (although in reality all elements are found all across the body). In the background is an artist’s impression of the Galaxy, with cyan dots to show the APOGEE measurements of the oxygen abundance in different stars; brighter dots indicate higher oxygen abundance.
Click on the image for a link to download a larger version. Image Credit: Dana Berry/SkyWorks Digital Inc.; SDSS collaboration
What essential elements mean?
Any chemical element required by an organism for healthy growth. It may be required in large amounts (macronutrient) or in very small amounts (trace element)