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Multicellular
A multicellular organism is an organism that consists of more than one cell, in contrast to unicellular organism. All species of animals, land plants and most fungi are multicellular, as are many algae, whereas a few organisms are partially uni- and partially multicellular, like slime molds and social amoebae such as the genus ''Dictyostelium''. Multicellular organisms arise in various ways, for example by cell division or by aggregation of many single cells. Colonial organisms are the result of many identical individuals joining together to form a colony. However, it can often be hard to separate colonial protists from true multicellular organisms, because the two concepts are not distinct; colonial protists have been dubbed "pluricellular" rather than "multicellular". There are also multinucleate though technically unicellular organisms that are macroscopic, such as the xenophyophorea that can reach 20 cm. Evolutionary history Occurrence Multicellularity has evolved ind ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cell (biology)
The cell is the basic structural and functional unit of life forms. Every cell consists of a cytoplasm enclosed within a membrane, and contains many biomolecules such as proteins, DNA and RNA, as well as many small molecules of nutrients and metabolites.Cell Movements and the Shaping of the Vertebrate Body in Chapter 21 of Molecular Biology of the Cell '' fourth edition, edited by Bruce Alberts (2002) published by Garland Science. The Alberts text discusses how the "cellular building blocks" move to shape developing embryos. It is also common to describe small molecules such as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organism
In biology, an organism () is any living system that functions as an individual entity. All organisms are composed of cells (cell theory). Organisms are classified by taxonomy into groups such as multicellular animals, plants, and fungi; or unicellular microorganisms such as protists, bacteria, and archaea. All types of organisms are capable of reproduction, growth and development, maintenance, and some degree of response to stimuli. Beetles, squids, tetrapods, mushrooms, and vascular plants are examples of multicellular organisms that differentiate specialized tissues and organs during development. A unicellular organism may be either a prokaryote or a eukaryote. Prokaryotes are represented by two separate domains – bacteria and archaea. Eukaryotic organisms are characterized by the presence of a membrane-bound cell nucleus and contain additional membrane-bound compartments called organelles (such as mitochondria in animals and plants ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eukaryote
Eukaryotes () are organisms whose cells have a nucleus. All animals, plants, fungi, and many unicellular organisms, are Eukaryotes. They belong to the group of organisms Eukaryota or Eukarya, which is one of the three domains of life. Bacteria and Archaea (both prokaryotes) make up the other two domains. The eukaryotes are usually now regarded as having emerged in the Archaea or as a sister of the Asgard archaea. This implies that there are only two domains of life, Bacteria and Archaea, with eukaryotes incorporated among archaea. Eukaryotes represent a small minority of the number of organisms, but, due to their generally much larger size, their collective global biomass is estimated to be about equal to that of prokaryotes. Eukaryotes emerged approximately 2.3–1.8 billion years ago, during the Proterozoic eon, likely as flagellated phagotrophs. Their name comes from the Greek εὖ (''eu'', "well" or "good") and κάρυον (''karyon'', "nut" or "kernel"). Euka ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brown Algae
Brown algae (singular: alga), comprising the class Phaeophyceae, are a large group of multicellular algae, including many seaweeds located in colder waters within the Northern Hemisphere. Brown algae are the major seaweeds of the temperate and polar regions. They are dominant on rocky shores throughout cooler areas of the world. Most brown algae live in marine environments, where they play an important role both as food and as a potential habitat. For instance, ''Macrocystis'', a kelp of the order Laminariales, may reach in length and forms prominent underwater kelp forests. Kelp forests like these contain a high level of biodiversity. Another example is ''Sargassum'', which creates unique floating mats of seaweed in the tropical waters of the Sargasso Sea that serve as the habitats for many species. Many brown algae, such as members of the order Fucales, commonly grow along rocky seashores. Some members of the class, such as kelps, are used by humans as food. Between 1,500 and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unicellular Organism
A unicellular organism, also known as a single-celled organism, is an organism that consists of a single cell, unlike a multicellular organism that consists of multiple cells. Organisms fall into two general categories: prokaryotic organisms and eukaryotic organisms. All prokaryotes are unicellular and are classified into bacteria and archaea. Many eukaryotes are multicellular, but some are unicellular such as protozoa, unicellular algae, and unicellular fungi. Unicellular organisms are thought to be the oldest form of life, with early protocells possibly emerging 3.8–4.0 billion years ago. Although some prokaryotes live in colonies, they are not specialised cells with differing functions. These organisms live together, and each cell must carry out all life processes to survive. In contrast, even the simplest multicellular organisms have cells that depend on each other to survive. Most multicellular organisms have a unicellular life-cycle stage. Gametes, for example, are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fungi
A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately from the other eukaryotic kingdoms, which by one traditional classification include Plantae, Animalia, Protozoa, and Chromista. A characteristic that places fungi in a different kingdom from plants, bacteria, and some protists is chitin in their cell walls. Fungi, like animals, are heterotrophs; they acquire their food by absorbing dissolved molecules, typically by secreting digestive enzymes into their environment. Fungi do not photosynthesize. Growth is their means of mobility, except for spores (a few of which are flagellated), which may travel through the air or water. Fungi are the principal decomposers in ecological systems. These and other differences place fungi in a single group of related organisms, named the ''Eumycota'' (''t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Slime Mold
Slime mold or slime mould is an informal name given to several kinds of unrelated eukaryotic organisms with a life cycle that includes a free-living single-celled stage and the formation of spores. Spores are often produced in macroscopic multicellular or multinucleate fruiting bodies which may be formed through aggregation or fusion. Slime molds were formerly classified as fungi but are no longer considered part of that kingdom. Although not forming a single monophyletic clade, they are grouped within the paraphyletic group Protista. More than 900 species of slime mold occur globally. Their common name refers to part of some of these organisms' life cycles where they can appear as gelatinous "slime". This is mostly seen with the Myxogastria, which are the only macroscopic slime molds. Most slime molds are smaller than a few centimetres, but some species may reach sizes up to several square metres and masses up to 20 kilograms. They feed on microorganisms that live in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Myxobacteria
The myxobacteria ("slime bacteria") are a group of bacteria that predominantly live in the soil and feed on insoluble organic substances. The myxobacteria have very large genomes relative to other bacteria, e.g. 9–10 million nucleotides except for '' Anaeromyxobacter'' and ''Vulgatibacter''. One species of myxobacteria, ''Minicystis rosea'', has the largest known bacterial genome with over 16 million nucleotides. The second largest is another myxobacteria ''Sorangium cellulosum''. Myxobacteria can move by gliding. They typically travel in ''swarms'' (also known as ''wolf packs''), containing many cells kept together by intercellular molecular signals. Individuals benefit from aggregation as it allows accumulation of the extracellular enzymes that are used to digest food; this in turn increases feeding efficiency. Myxobacteria produce a number of biomedically and industrially useful chemicals, such as antibiotics, and export those chemicals outside the cell. Myxobacteria are u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cell Division
Cell division is the process by which a parent cell (biology), cell divides into two daughter cells. Cell division usually occurs as part of a larger cell cycle in which the cell grows and replicates its chromosome(s) before dividing. In eukaryotes, there are two distinct types of cell division: a vegetative division (mitosis), producing daughter cells genetically identical to the parent cell, and a cell division that produces Haploidisation, haploid gametes for sexual reproduction (meiosis), reducing the number of chromosomes from two of each type in the diploid parent cell to one of each type in the daughter cells. In cell biology, mitosis (Help:IPA/English, /maɪˈtoʊsɪs/) is a part of the cell cycle, in which, replicated chromosomes are separated into two new Cell nucleus, nuclei. Cell division gives rise to genetically identical cells in which the total number of chromosomes is maintained. In general, mitosis (division of the nucleus) is preceded by the S stage of interph ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Colonial Organism
In biology, a colony is composed of two or more conspecific individuals living in close association with, or connected to, one another. This association is usually for mutual benefit such as stronger defense or the ability to attack bigger prey. Colonies can form in various shapes and ways depending on the organism involved. For instance, the bacterial colony is a cluster of identical cells (clones). These colonies often form and grow on the surface of (or within) a solid medium, usually derived from a single parent cell. Colonies, in the context of development, may be composed of two or more unitary (or solitary) organisms or be modular organisms. Unitary organisms have determinate development (set life stages) from zygote to adult form and individuals or groups of individuals (colonies) are visually distinct. Modular organisms have indeterminate growth forms (life stages not set) through repeated iteration of genetically identical modules (or individuals), and it can be diffic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Colony (biology)
In biology, a colony is composed of two or more conspecific individuals living in close association with, or connected to, one another. This association is usually for mutual benefit such as stronger defense or the ability to attack bigger prey. Colonies can form in various shapes and ways depending on the organism involved. For instance, the bacterial colony is a cluster of identical cells (clones). These colonies often form and grow on the surface of (or within) a solid medium, usually derived from a single parent cell. Colonies, in the context of development, may be composed of two or more unitary (or solitary) organisms or be modular organisms. Unitary organisms have determinate development (set life stages) from zygote to adult form and individuals or groups of individuals (colonies) are visually distinct. Modular organisms have indeterminate growth forms (life stages not set) through repeated iteration of genetically identical modules (or individuals), and it can be diffic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deltaproteobacteria
The Myxococcota are a phylum of bacteria known as the fruiting gliding bacteria. All species of this group are Gram-negative. They are predominantly aerobic genera that release myxospores in unfavorable environments. Phylogeny The currently accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature (LSPN) and the National Center for Biotechnology Information (NCBI). See also * List of bacterial orders * List of bacteria genera * Bacterial taxonomy Bacterial taxonomy is the taxonomy, i.e. the rank-based classification, of bacteria. In the scientific classification established by Carl Linnaeus, each species has to be assigned to a genus ( binary nomenclature), which in turn is a lower level ... References External links * {{Taxonbar, from=Q307535 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
