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Cercozoa
Filosa Chlorarachnea
Chlorarachnea
/ Chlorarachniophyta Spongomonadea Sarcomonadea
Sarcomonadea
(Cercomonada) Thecofilosea
Thecofilosea
(Tectofilosida, Cryomonadida) Imbricatea
Imbricatea
/ Silicofilosea
Silicofilosea
(Euglyphida, Thaumatomonadida) Phaeodarea[2] Ebridea, etc[3] Granofilosea
Granofilosea
(Heliomonadida, Desmothoracida, Gymnosphaerida)Endomyxa Proteomyxidea
Proteomyxidea
(Reticulosida, Vampyrellida, etc) Phytomyxea Ascetosporea Gromiidea
Gromiidea
(Gromia)The Cercozoa
Cercozoa
are a group of single-celled eukaryotes
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Eukaryote
Eukaryotic organisms that cannot be classified under the kingdoms Plantae, Animalia
Animalia
or Fungi
Fungi
are sometimes grouped in the kingdom Protista.Eukaryotes (/juːˈkærioʊt, -ət/) are organisms whose cells have a nucleus enclosed within membranes, unlike prokaryotes ( Bacteria
Bacteria
and Archaea), which have no membrane-bound organelles.[3][4][5] Eukaryotes belong to the domain Eukaryota
Eukaryota
or Eukarya. Their name comes from the Greek εὖ (eu, "well" or "true") and κάρυον (karyon, "nut" or "kernel").[6] Eukaryotic cells also contain other membrane-bound organelles such as mitochondria and the Golgi apparatus, and in addition, some cells of plants and algae contain chloroplasts
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Green Alga
The green algae (singular: green alga) are a large, informal grouping of algae consisting of the Chlorophyte and Charophyte/Streptophyta, which are now placed in separate divisions, as well as the more basal Mesostigmatophyceae and Chlorokybophyceae.[1] The land plants, or embryophytes, are thought to have emerged from the charophytes.[2] Therefore, cladistically, embryophytes belong to green algae as well. However, because the embryophytes are traditionally classified as neither algae nor green algae, green algae are a paraphyletic group. Since the realization that the embryophytes emerged from within the green algae, some authors are starting to include them.[3][4][5][6] The clade that includes both green algae and embryophytes is monophyletic and is referred to as the clade Viridiplantae
Viridiplantae
and as the kingdom Plantae
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Eukaryota
Eukaryotic organisms that cannot be classified under the kingdoms Plantae, Animalia
Animalia
or Fungi
Fungi
are sometimes grouped in the kingdom Protista.Eukaryotes (/juːˈkærioʊt, -ət/) are organisms whose cells have a nucleus enclosed within membranes, unlike prokaryotes ( Bacteria
Bacteria
and Archaea), which have no membrane-bound organelles.[3][4][5] Eukaryotes belong to the domain Eukaryota
Eukaryota
or Eukarya. Their name comes from the Greek εὖ (eu, "well" or "true") and κάρυον (karyon, "nut" or "kernel").[6] Eukaryotic cells also contain other membrane-bound organelles such as mitochondria and the Golgi apparatus, and in addition, some cells of plants and algae contain chloroplasts
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Actin
Actin
Actin
is a family of globular multi-functional proteins that form microfilaments. It is found in essentially all eukaryotic cells (the only known exception being nematode sperm), where it may be present at a concentration of over 100 μM; its mass is roughly 42-kDa, with a diameter of 4 to 7 nm. An actin protein is the monomeric subunit of two types of filaments in cells: microfilaments, one of the three major components of the cytoskeleton, and thin filaments, part of the contractile apparatus in muscle cells
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Paraphyletic
In taxonomy, a group is paraphyletic if it consists of the group's last common ancestor and all descendants of that ancestor excluding a few—typically only one or two—monophyletic subgroups. The group is said to be paraphyletic with respect to the excluded subgroups. The arrangement of the members of a paraphyletic group is called a paraphyly. The term is commonly used in phylogenetics (a subfield of biology) and in linguistics. The term was coined to apply to well-known taxa like Reptilia (reptiles) which, as commonly named and traditionally defined, is paraphyletic with respect to mammals and birds. Reptilia contains the last common ancestor of reptiles and all descendants of that ancestor—including all extant reptiles as well as the extinct synapsids—except for mammals and birds. Other commonly recognized paraphyletic groups include fish, monkeys, and lizards.[1] If many subgroups are missing from the named group, it is said to be polyparaphyletic
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Cytostome
A cytostome (from cyto-, cell and stome-, mouth) or cell mouth is a part of a cell specialized for phagocytosis, usually in the form of a microtubule-supported funnel or groove. Food is directed into the cytostome, and sealed into vacuoles. Only certain groups of protozoa, such as the ciliates and excavates, have cytostomes.[1] An example is Balantidium coli, a ciliate. In other protozoa, and in cells from multicellular organisms, phagocytosis takes place at any point on the cell or feeding takes place by absorption.Contents1 Structure1.1 Cytopharynx2 Location 3 Function3.1 Associations 3.2 Related structures4 Visualization methods 5 ReferencesStructure[edit] The cytostome forms an invagination on the cell surface and is typically directed towards the nucleus of the cell.[2] The cytostome is often labeled as the entire invagination, but in fact the cytostome only constitutes the opening of the invagination at the surface of the cell
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Taxon
In biology, a taxon (plural taxa; back-formation from taxonomy) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit.[clarification needed] Although neither is required, a taxon is usually known by a particular name and given a particular ranking, especially if and when it is accepted or becomes established. It is not uncommon, however, for taxonomists to remain at odds over what belongs to a taxon and the criteria used for inclusion. If a taxon is given a formal scientific name, its use is then governed by one of the nomenclature codes specifying which scientific name is correct for a particular grouping. Initial attempts at classifying and ordering organisms (plants and/or animals) was set forth in Linnaeus's system in Systema Naturae, 10th edition, (1758)[1] as well as an unpublished work by Bernard and Antoine Laurent de Jussieu
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Taxonomy (biology)
In biology, taxonomy (from Ancient Greek τάξις (taxis), meaning 'arrangement', and -νομία (-nomia), meaning 'method') is the science of defining and naming groups of biological organisms on the basis of shared characteristics. Organisms are grouped together into taxa (singular: taxon) and these groups are given a taxonomic rank; groups of a given rank can be aggregated to form a super-group of higher rank, thus creating a taxonomic hierarchy. The principal ranks in modern use are domain, kingdom, phylum (division is sometimes used in botany in place of phylum), class, order, family, genus, and species
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RRNA
Ribosomal ribonucleic acid (rRNA) is the RNA
RNA
component of the ribosome, and is essential for protein synthesis in all living organisms. It constitutes the predominant material within the ribosome, which is approximately 60% r RNA
RNA
and 40% protein by weight, or 3/5 of ribosome mass. Ribosomes contain two major rRNAs and 50 or more proteins. The ribosomal RNAs form two subunits, the large subunit (LSU) and small subunit (SSU). The LSU r RNA
RNA
acts as a ribozyme, catalyzing peptide bond formation
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Monophyletic
In cladistics, a monophyletic group, or clade, is a group of organisms that consists of all the descendants of a common ancestor. Monophyletic groups are typically characterised by shared derived characteristics (synapomorphies), which distinguish organisms in the clade from other organisms. The arrangement of the members of a monophyletic group is called a monophyly. Monophyly
Monophyly
is contrasted with paraphyly and polyphyly as shown in the second diagram. A paraphyletic group consists of all of the descendants of a common ancestor minus one or more monophyletic groups. A polyphyletic group is characterized by convergent features or habits of scientific interest (for example, night-active primates, fruit trees, aquatic insects). The features by which a polyphyletic group is differentiated from others are not inherited from a common ancestor. These definitions have taken some time to be accepted
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Chloroplast
Chloroplasts /ˈklɔːrəˌplæsts, -plɑːsts/[1][2] are organelles, specialized compartments, in plant and algal cells. The main role of chloroplasts is to conduct photosynthesis, where the photosynthetic pigment chlorophyll captures the energy from sunlight and converts it and stores it in the energy-storage molecules ATP and NADPH
NADPH
while freeing oxygen from water. They then use the ATP and NADPH
NADPH
to make organic molecules from carbon dioxide in a process known as the Calvin cycle. Chloroplasts carry out a number of other functions, including fatty acid synthesis, much amino acid synthesis, and the immune response in plants. The number of chloroplasts per cell varies from one, in unicellular algae, up to 100 in plants like Arabidopsis
Arabidopsis
and wheat. A chloroplast is a type of organelle known as a plastid, characterized by its two membranes and a high concentration of chlorophyll
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Heliozoa
Heliozoa, commonly known as sun-animalcules, are microbial eukaryotes (protists) with stiff arms (axopodia) radiating from their spherical bodies, which are responsible for their common name.[1][2][3] The axopodia are microtubule-supported projections from the amoeboid cell body, and are variously used for capturing food, sensation, movement, and attachment. They are similar to Radiolaria, but they are distinguished from them by lacking central capsules and other complex skeletal elements, although some produce simple scales and spines.[4] They may be found in both freshwater and marine environments. Classification[edit] Originally the heliozoa were treated together as a formal taxon Heliozoa
Heliozoa
or Heliozoea, with the rank of class or phylum, but it has been realised that they are polyphyletic, as the various orders show notable differences and are no longer believed to be descended from a single common ancestor
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SAR Supergroup
Sar or Harosa (informally the SAR supergroup) is a clade that includes stramenopiles (heterokonts), alveolates, and Rhizaria.[2][3][4][5] The first letter of each group provides the "SAR" in the name (alternatively spelled "RAS").[6][7] The term "Harosa" (at the subkingdom level) has also been used for this grouping by Cavalier-Smith
Cavalier-Smith
(2010).[8] Adl et al. (2012) formalized the SAR supergroup
SAR supergroup
as the node-based taxon Sar. They defined it as:[6]Sar: the least inclusive clade containing Bigelowiella natans Moestrup & Sengco 2001 (Rhizaria), Tetrahymena thermophila
Tetrahymena thermophila
Nanney & McCoy 1976 (Alveolata), and Thalassiosira pseudonana
Thalassiosira pseudonana
Cleve 1873 (Stramenopiles)
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Thomas Cavalier-Smith
Thomas (Tom) Cavalier-Smith, FRS, FRSC, NERC Professorial Fellow (born 21 October 1942), is a Professor of Evolutionary Biology
Evolutionary Biology
in the Department of Zoology, at the University of Oxford.[1] His research has led to discovery of a number of unicellular organisms (protists) and definition of taxonomic positions, such as introduction of the kingdom Chromista, and other groups including Chromalveolata, Opisthokonta, Rhizaria, and Excavata. He is well known for his system of classification of all organisms.Contents1 Life and career 2 Awards and honours 3 Contributions3.1 Eight kingdoms model 3.2 Six kingdoms models 3.3 Seven kingdoms model 3.4 Rooting the tree of life4 References 5 External linksLife and career[edit] Cavalier-Smith was born on 21 October 1942 in London
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Flagellate
A flagellate is a cell or organism with one or more whip-like appendages called flagella. The word flagellate also describes a particular construction (or level of organization) characteristic of many prokaryotes and eukaryotes and their means of motion. The term presently does not imply any specific relationship or classification of the organisms that possess flagellae. However, the term "flagellate" is included in other terms (such as "dinoflagellate" and "choanoflagellata") which are more formally characterized.[1]Contents1 Form and behavior 2 Flagellates
Flagellates
as specialized cells or life cycle stages 3 Flagellates
Flagellates
as organisms: the Flagellata 4 References 5 External linksForm and behavior[edit] Eukaryotic flagella are supported by microtubules in a characteristic arrangement, with nine fused pairs surrounding two central singlets. These arise from a basal body
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