Levels of Structural Organization in the human body
May 16, · The human body has 6 main levels of structural organization. We will begin this lesson with the simplest level within the structural hierarchy. Chemical level– is the simplest level within the structural hierarchy. The chemical level includes the tiniest building blocks of matter, atoms, which combine to form molecules, like water. Circulatory system, system that transports nutrients, respiratory gases, and metabolic products throughout a living organism. Circulation includes the intake of metabolic materials, the movement of these materials to and from tissues and organs, and the return of harmful by-products to the environment.
Circulatory systemsystem that transports nutrients, respiratory gases, and metabolic products throughout a living organism, permitting integration among the various tissues.
The process of circulation includes the intake of metabolic materials, the conveyance of these materials throughout the organism, and the return of harmful by-products to the environment. Invertebrate animals have a great variety of liquids, cells, and modes of circulation, though many invertebrates have what is called an open system, in which fluid passes more or less freely throughout the tissues or defined areas of tissue.
All vertebrates, however, have a closed system—that is, their circulatory system transmits fluid through an intricate network of vessels. This system contains two fluids, how to make fresh strawberry puree and lymph, and functions by means of two interacting modes of circulation, the cardiovascular system and the lymphatic system; both the fluid components and the vessels through which they flow reach their greatest elaboration and specialization in the mammalian systems and, particularly, in the how to embed a file body.
A full treatment of human blood and its various components can be found in the article human blood. A discussion of how the systems of circulation, respiration, and metabolism work together within an animal organism is found in the article respiration.
All living organisms take in molecules from their environmentsuse them to support the metabolism of their own substance, and release by-products back into the environment. The internal environment differs more or less greatly from the external environment, depending on the species. It is normally maintained at constant conditions by the organism so that it is subject to relatively minor fluctuations. In individual cellseither as independent organisms or as parts of the tissues of multicellular animals, molecules are taken in either by their direct diffusion through the cell wall or by the formation by the surface membrane of vacuoles that carry some of the environmental fluid containing dissolved molecules.
Within the cell, cyclosis streaming of the fluid cytoplasm distributes the metabolic products. Molecules are normally conveyed between cells and throughout the body of multicellular organisms in a circulatory fluid, called bloodthrough special channels, called blood vessels, by some form of pump, which, if restricted in position, is usually called a heart.
In vertebrates blood and lymph the circulating fluids have an essential role in maintaining homeostasis the constancy of the internal environment by distributing substances to parts of the body when required and by removing others from areas in which their accumulation would be harmful. One phylum, Cnidaria Coelenterata —which includes sea anemones, jellyfish, and corals—has a diploblastic level of organization i.
The outer layer, called the ectodermand the inner layer, called the endodermare separated by an amorphousacellular layer called the mesoglea; for these animals, bathing both cellular surfaces with environmental fluid is sufficient to supply their what is melanoma skin cancer definition needs.
All other major eumetazoan phyla i. Nematoda, Rotifera, and a number of other smaller eumetazoan classes and phyla have a fluid-filled cavity, called the pseudocoelomthat arises from an embryonic cavity and contains the internal organs free within it. All other eumetazoans have a body cavity, the coelomwhich originates as a cavity in the embryonic mesoderm.
Mesoderm lines the coelom and forms the peritoneumwhich also surrounds and supports how to tie dye shirts with bleach internal organs. While this increase in complexity allows for increase in animal size, it has certain problems. As the distances from metabolizing cells to the source of metabolites molecules to be metabolized increases, a means of distribution around the body is necessary for all but the smallest coelomates.
Many invertebrate animals are aquatic and the problem of supplying fluid is not critical. For terrestrial organisms, however, the fluid reaching the tissues comes from water that has been drunk, absorbed in the alimentary canaland passed to the bloodstream.
Fluid may leave the blood, usually with food and other organic molecules in solution, and pass to the tissues, from which it returns in the form of lymph. Especially in the vertebrates, lymph passes through special pathways, called lymphatic channels, to provide the lymphatic circulation. In many invertebrates, however, the circulating fluid is not confined to distinct vessels, and it more or less freely bathes the organs directly.
The functions of both circulating and tissue fluid are thus combined in the fluid, often known as hemolymph. The possession of a blood supply and coelom, however, does not exclude the circulation of environmental water through the body. Members of the phylum Echinodermata starfishes and sea urchins, for example have a complex water vascular system used mainly for locomotion.
An internal circulatory system transports essential gases and nutrients around the body of an organism, removes unwanted products of metabolism from the tissues, and carries these products to specialized excretory organs, if present. Although a few invertebrate animals circulate external water through their bodies for respiration, and, in the case of cnidarians, nutrition, most species circulate an internal fluid, called blood.
There may also be external circulation that sets up currents in the environmental fluid to carry it over respiratory surfaces and, especially in the case of sedentary animals, to carry particulate food that is strained out and passed to the alimentary canal. Additionally, the circulatory system may assist the organism in movement; for example, protoplasmic streaming in amoeboid protozoans circulates nutrients and provides pseudopodal locomotion.
The hydrostatic pressure built up in the circulatory systems of many invertebrates is used for a range of whole-body and individual-organ movement. Circulatory system. Article Introduction Main how to size pictures for a locket of circulatory systems General features of circulation Body fluids Fluid compartments Invertebrate circulatory systems Basic physicochemical considerations Animals without independent vascular systems Vascular systems Blood Hearts Acoelomates and pseudocoelomates Coelomates Annelida Echiura Mollusca Brachiopoda Arthropoda Echinodermata Hemichordata Chordata The vertebrate circulatory system The basic vertebrate pattern The plan The heart The blood vessels Evolutionary trends Circulation in what is the deadline for filing individual income tax returns Circulation in jawed vertebrates Modifications among the vertebrate classes Fishes Amphibians Reptiles Birds Mammals Embryonic development of the circulatory system Biodynamics of vertebrate circulation Blood pressure and blood flow Electrical activity Control of heartbeat and circulation Show more.
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External Websites. Articles from Britannica Encyclopedias for elementary and high school students. Author of Looking at Vertebrates. See Article History. Parts of the human circulatory system that highlight arterial supply and venous drainage of the organs. Get a Britannica Premium subscription and gain access to exclusive content. Subscribe Now. What type of organism has the simplest level of organization how the heart and blood vessels, helps in the circulation of blood throughout the body.
The heart and blood vessels constitute the cardiovascular system, which circulates blood throughout the body. Load Next Page.
General features of circulation
The highest level of organization for living things is the biosphere; it encompasses all other levels. The biological levels of organization of living things arranged from the simplest to most complex are: organelle, cells, tissues, organs, organ systems, organisms, populations, communities, ecosystem, and . The latest Lifestyle | Daily Life news, tips, opinion and advice from The Sydney Morning Herald covering life and relationships, beauty, fashion, health & wellbeing. May 23, · Likes, 2 Comments - Dr Raymond C Lee MD (@drrayleemd) on Instagram: “What an amazing virtual aats. Congratulations to my chairman Dr Vaughn Starnes th AATS ”.
Multicellular Organisms : A toad represents a highly organized structure consisting of cells, tissues, organs, and organ systems. All living organisms share several key characteristics or functions: order, sensitivity or response to the environment, reproduction, growth and development, regulation, homeostasis, and energy processing.
When viewed together, these eight characteristics serve to define life. Organisms are highly organized, coordinated structures that consist of one or more cells. Even very simple, single-celled organisms are remarkably complex: inside each cell, atoms make up molecules; these in turn make up cell organelles and other cellular inclusions.
In multicellular organisms, similar cells form tissues. Tissues, in turn, collaborate to create organs body structures with a distinct function. Organs work together to form organ systems. Response to Stimuli : The leaves of this sensitive plant Mimosa pudica will instantly droop and fold when touched.
After a few minutes, the plant returns to normal. Organisms can respond to diverse stimuli. For example, plants can grow toward a source of light, climb on fences and walls, or respond to touch.
Even tiny bacteria can move toward or away from chemicals a process called chemotaxis or light phototaxis. Movement toward a stimulus is considered a positive response, while movement away from a stimulus is considered a negative response. Single-celled organisms reproduce by first duplicating their DNA. They then divide it equally as the cell prepares to divide to form two new cells.
Multicellular organisms often produce specialized reproductive germline cells that will form new individuals. These genes ensure that the offspring will belong to the same species and will have similar characteristics, such as size and shape. Reproduction : Although no two look alike, these kittens have inherited genes from both parents and share many of the same characteristics. All organisms grow and develop following specific instructions coded for by their genes.
Even the smallest organisms are complex and require multiple regulatory mechanisms to coordinate internal functions, respond to stimuli, and cope with environmental stresses. Two examples of internal functions regulated in an organism are nutrient transport and blood flow. Organs groups of tissues working together perform specific functions, such as carrying oxygen throughout the body, removing wastes, delivering nutrients to every cell, and cooling the body.
Homeostasis : Polar bears Ursus maritimus and other mammals living in ice-covered regions maintain their body temperature by generating heat and reducing heat loss through thick fur and a dense layer of fat under their skin. In order to function properly, cells need to have appropriate conditions such as proper temperature, pH, and appropriate concentration of diverse chemicals.
These conditions may, however, change from one moment to the next. For example, an organism needs to regulate body temperature through a process known as thermoregulation. Organisms that live in cold climates, such as the polar bear, have body structures that help them withstand low temperatures and conserve body heat.
Structures that aid in this type of insulation include fur, feathers, blubber, and fat. In hot climates, organisms have methods such as perspiration in humans or panting in dogs that help them to shed excess body heat. Energy Processing : The California condor Gymnogyps californianus uses chemical energy derived from food to power flight. All organisms use a source of energy for their metabolic activities. Some organisms capture energy from the sun and convert it into chemical energy in food; others use chemical energy in molecules they take in as food.
Adaptation in the flat-tailed horned lizard : This lizard exhibits a flattened body and coloring that helps camouflage it, both of which are adaptive traits that help it avoid predators. As a population of organisms interacts with the environment, individuals with traits that contribute to reproduction and survival in that particular environment will leave more offspring.
Over time those advantageous traits called adaptations will become more common in the population. This process, change over time, is called evolution, and it is one of the processes that explain the diverse species seen in biology. Adaptations help organisms survive in their ecological niches, and adaptive traits may be structural, behavioral, or physiological; as such, adaptations frequently involve other properties of organisms such as homeostasis, reproduction, and growth and development.
The biological levels of organization range from a single organelle all the way up to the biosphere in a highly structured hierarchy. Living things are highly organized and structured, following a hierarchy that can be examined on a scale from small to large.
The atom is the smallest and most fundamental unit of matter. It consists of a nucleus surrounded by electrons. Atoms form molecules which are chemical structures consisting of at least two atoms held together by one or more chemical bonds.
Many molecules that are biologically important are macromolecules, large molecules that are typically formed by polymerization a polymer is a large molecule that is made by combining smaller units called monomers, which are simpler than macromolecules. An example of a macromolecule is deoxyribonucleic acid DNA , which contains the instructions for the structure and functioning of all living organisms. Macromolecules can form aggregates within a cell that are surrounded by membranes; these are called organelles.
Organelles are small structures that exist within cells. Examples of these include: mitochondria and chloroplasts, which carry out indispensable functions.
Mitochondria produce energy to power the cell while chloroplasts enable green plants to utilize the energy in sunlight to make sugars. All living things are made of cells, and the cell itself is the smallest fundamental unit of structure and function in living organisms. This requirement is why viruses are not considered living: they are not made of cells. To make new viruses, they have to invade and hijack the reproductive mechanism of a living cell; only then can they obtain the materials they need to reproduce.
Some organisms consist of a single cell and others are multicellular. Cells are classified as prokaryotic or eukaryotic. Prokaryotes are single-celled or colonial organisms that do not have membrane-bound nuclei; in contrast, the cells of eukaryotes do have membrane-bound organelles and a membrane-bound nucleus.
In larger organisms, cells combine to make tissues, which are groups of similar cells carrying out similar or related functions.
Organs are collections of tissues grouped together performing a common function. Organs are present not only in animals but also in plants. An organ system is a higher level of organization that consists of functionally related organs. Mammals have many organ systems. For instance, the circulatory system transports blood through the body and to and from the lungs; it includes organs such as the heart and blood vessels.
Furthermore, organisms are individual living entities. For example, each tree in a forest is an organism. Single-celled prokaryotes and single-celled eukaryotes are also considered organisms and are typically referred to as microorganisms. All the individuals of a species living within a specific area are collectively called a population. For example, a forest may include many pine trees. All of these pine trees represent the population of pine trees in this forest.
Different populations may live in the same specific area. For example, the forest with the pine trees includes populations of flowering plants and also insects and microbial populations. A community is the sum of populations inhabiting a particular area. The forest itself is an ecosystem. An ecosystem consists of all the living things in a particular area together with the abiotic, non-living parts of that environment such as nitrogen in the soil or rain water.
At the highest level of organization, the biosphere is the collection of all ecosystems, and it represents the zones of life on earth.
It includes land, water, and even the atmosphere to a certain extent. Taken together, all of these levels comprise the biological levels of organization, which range from organelles to the biosphere. Biological Levels of Organization : The biological levels of organization of living things follow a hierarchy, such as the one shown.
From a single organelle to the entire biosphere, living organisms are part of a highly structured hierarchy. The diversity of life can be classified within the three major domains Bacteria, Eukarya and Archaea using phylogenetic trees. The fact that biology has such a broad scope as a science has to do with the tremendous diversity of life on Earth. The source of this diversity is evolution, the process of gradual change during which new species arise from older species.
Evolutionary biologists study the evolution of living things in everything from the microscopic world to ecosystems. The evolution of various life forms on Earth can be summarized in a phylogenetic tree using phylogeny. A phylogenetic tree is a diagram showing the evolutionary relationships among biological species based on similarities and differences in genetic or physical traits or both.
A phylogenetic tree is composed of nodes and branches. The internal nodes represent ancestors and are points in evolution when, based on scientific evidence, an ancestor is thought to have diverged to form two new species. The length of each branch is proportional to the time elapsed since the split.
Phylogenetic Tree of Life : This phylogenetic tree was constructed by microbiologist Carl Woese using data obtained from sequencing ribosomal RNA genes. The tree shows the separation of living organisms into three domains: Bacteria, Archaea, and Eukarya. Bacteria and Archaea are prokaryotes, single-celled organisms lacking intracellular organelles. In the past, biologists grouped living organisms into five kingdoms: animals, plants, fungi, protists, and bacteria.
The organizational scheme was based mainly on physical features, as opposed to physiology, biochemistry, or molecular biology, all of which are used by modern systematics. The pioneering work of American microbiologist Carl Woese in the early s has shown, however, that life on Earth has evolved along three lineages, now called domains—Bacteria, Archaea, and Eukarya. The first two are prokaryotic cells with microbes that lack membrane-enclosed nuclei and organelles. The third domain contains the eukaryotes and includes unicellular microorganisms together with the four original kingdoms excluding bacteria.
Woese defined Archaea as a new domain, and this resulted in a new taxonomic tree. Many organisms belonging to the Archaea domain live under extreme conditions and are called extremophiles. To construct his tree, Woese used genetic relationships rather than similarities based on morphology shape.
The comparison of homologous DNA and RNA sequences provided Woese with a sensitive device that revealed the extensive variability of prokaryotes, and which justified the separation of the prokaryotes into two domains: bacteria and archaea. DNA, the universal genetic material, contains the instructions for the structure and function of all living organisms and can be divided into genes whose expression varies between organisms.