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47-620: Alien Planet is a 2005 docufiction TV special created for the Discovery Channel . Based on the 1990 book Expedition by the artist and writer Wayne Barlowe , Alien Planet explores the imagined extraterrestrial life of the fictional planet Darwin IV in the style of a nature documentary . Although closely following Barlowe's depiction of Darwin IV, Alien Planet features a team of scientists and science fiction figures discussing Darwin IV as if it had actually been discovered. Among

94-469: A fictionalized scenario. In this sense, docufiction may overlap to an extent with some aspects of the mockumentary format, but the terms are not synonymous. A film genre in expansion, it is adopted by a number of experimental filmmakers. The neologism docufiction appeared at the beginning of the 21st century. It is now commonly used in several languages and widely accepted for classification by international film festivals. The term involves

141-424: A mouth or cytostome , and there is no fixed place on the cell at which phagocytosis normally occurs. Some amoebae also feed by pinocytosis , imbibing dissolved nutrients through vesicles formed within the cell membrane. The size of amoeboid cells and species is extremely variable. The marine amoeboid Massisteria voersi is just 2.3 to 3 micrometres in diameter, within the size range of many bacteria. At

188-518: A secondary loss of the amoeboid phase. In his scheme, the Sarcodina were divided into the more primitive Eosarcodina (with the phyla Reticulosa and Mycetozoa) and the more derived Neosarcodina (with the phyla Amoebozoa for lobose amoebae and Rhizopoda for filose amoebae). Shortly after, phylogenetic analyses disproved this hypothesis, as non-amoeboid zooflagellates and amoeboflagellates were found to be completely intermingled with amoebae. With

235-428: A series of molecular phylogenetic analyses confirmed that Sarcodina was not a monophyletic group, and that amoebae evolved from flagellate ancestors. The protozoologist Thomas Cavalier-Smith proposed that the ancestor of most eukaryotes was an amoeboflagellate much like modern heteroloboseans , which in turn gave rise to a paraphyletic Sarcodina from which other groups (e.g., alveolates, animals, plants) evolved by

282-433: A way of making films already practiced by such authors as Robert Flaherty , one of the fathers of documentary, and Jean Rouch , later in the 20th century. Being both fiction and documentary , docufiction is a hybrid genre, raising ethical problems concerning truth , since reality may be manipulated and confused with fiction (see Ethics at creative non-fiction ). In the domain of visual anthropology ,

329-558: Is a type of cell or unicellular organism with the ability to alter its shape, primarily by extending and retracting pseudopods . Amoebae do not form a single taxonomic group ; instead, they are found in every major lineage of eukaryotic organisms. Amoeboid cells occur not only among the protozoa , but also in fungi , algae , and animals . Microbiologists often use the terms "amoeboid" and "amoeba" interchangeably for any organism that exhibits amoeboid movement . In older classification systems, most amoebae were placed in

376-440: Is also a film or television show in which fictitious events are presented in documentary format, sometimes a recreation of factual events after they took place or a comment on current events , typically satirical, comedic or even dramatic. Whereas mockumentaries are usually fully scripted comedies or dramas that merely adopt some aspects of documentary format as a framing device, docufictions are usually not scripted, instead placing

423-405: Is finished, a massive hurricane -like storm hits and Ike must take to the sky, launching weather balloons . Leo goes to the mountain ranges and finds a herd of Unths engaged in rutting -like behavior. Afterward, Leo finds a pair of Bladderhorns engaging in combat, and tries to present the holographic message to one, but a sonic ping interrupts the conversation and scares off the animal before

470-413: Is ordered by the mothership to search for Leo. Ike's route takes him over perilous terrain, including the planet’s only sea, and find the entire aforementioned sea is Amoebic in nature (and attempts to attack him), making it a source of food to giant Sea Striders. Ike manages to find Leo’s last known location, where a Skewer tries to attack him, but is killed by a spear . Investigating, Ike finds Leo and

517-466: Is shown of the actual planet and its life follows what is described in Expedition . Though much of Darwin IV and its creatures is identical to what was presented in the book, Alien Planet diverges from Expedition in several ways. Unlike Expedition , which is set in the mid-24th century, Alien Planet is set at an unspecified point in the near future , and unlike in the book, when the expedition

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564-675: Is transferred across the amoeba's cell membrane by osmosis . Without a contractile vacuole, the cell would fill with excess water and, eventually, burst. Marine amoebae do not usually possess a contractile vacuole because the concentration of solutes within the cell are in balance with the tonicity of the surrounding water. The food sources of amoebae vary. Some amoebae are predatory and live by consuming bacteria and other protists . Some are detritivores and eat dead organic material. Amoebae typically ingest their food by phagocytosis , extending pseudopods to encircle and engulf live prey or particles of scavenged material. Amoeboid cells do not have

611-798: The Acanthamoeba genome . These genes included Spo11 , Mre11 , Rad50 , Rad51 , Rad52 , Mnd1, Dmc1 , Msh and Mlh . This finding suggests that the ‘'Acanthamoeba'’ are capable of some form of meiosis and may be able to undergo sexual reproduction. The meiosis-specific recombinase , Dmc1 , is required for efficient meiotic homologous recombination , and Dmc1 is expressed in Entamoeba histolytica . The purified Dmc1 from E. histolytica forms presynaptic filaments and catalyses ATP -dependent homologous DNA pairing and DNA strand exchange over at least several thousand base pairs . The DNA pairing and strand exchange reactions are enhanced by

658-522: The Radiolaria and Heliozoa , have stiff, needle-like, radiating axopodia (actinopoda) supported from within by bundles of microtubules . Free-living amoebae may be " testate " (enclosed within a hard shell), or "naked" (also known as gymnamoebae , lacking any hard covering). The shells of testate amoebae may be composed of various substances, including calcium , silica , chitin , or agglutinations of found materials like small grains of sand and

705-559: The class or subphylum Sarcodina, a grouping of single-celled organisms that possess pseudopods or move by protoplasmic flow. However, molecular phylogenetic studies have shown that Sarcodina is not a monophyletic group whose members share common descent . Consequently, amoeboid organisms are no longer classified together in one group. The best known amoeboid protists are Chaos carolinense and Amoeba proteus , both of which have been widely cultivated and studied in classrooms and laboratories. Other well known species include

752-817: The eukaryotic family tree, these results suggest that meiosis was present early in eukaryotic evolution. Furthermore, these findings are consistent with the proposal of Lahr et al. that the majority of amoeboid lineages are anciently sexual. Some amoebae can infect other organisms pathogenically , causing disease: Amoeba have been found to harvest and grow the bacteria implicated in plague . Amoebae can likewise play host to microscopic organisms that are pathogenic to people and help in spreading such microbes. Bacterial pathogens (for example, Legionella ) can oppose absorption of food when devoured by amoebae. The currently generally utilized and best-explored amoebae that host other organisms are Acanthamoeba castellanii and Dictyostelium discoideum. Microorganisms that can overcome

799-406: The frustules of diatoms . To regulate osmotic pressure , most freshwater amoebae have a contractile vacuole which expels excess water from the cell. This organelle is necessary because freshwater has a lower concentration of solutes (such as salt) than the amoeba's own internal fluids ( cytosol ). Because the surrounding water is hypotonic with respect to the contents of the cell, water

846-567: The plasma membrane that surrounds the cell. The appearance and internal structure of pseudopods are used to distinguish groups of amoebae from one another. Amoebozoan species, such as those in the genus Amoeba , typically have bulbous (lobose) pseudopods, rounded at the ends and roughly tubular in cross-section. Cercozoan amoeboids, such as Euglypha and Gromia , have slender, thread-like (filose) pseudopods. Foraminifera emit fine, branching pseudopods that merge with one another to form net-like (reticulose) structures. Some groups, such as

893-569: The speed of light (37,000 miles/s), it reaches Darwin IV, a planet 6.5 light-years away, in 42 years. Upon reaching orbit , it deploys the Darwin Reconnaissance Orbiter , which looks for potential landing sites for the probes . The first probe, Balboa , explodes along with its lifting body transport during entry, because one of its wings failed to unfold. Two backup probes, Leonardo da Vinci (nicknamed Leo) and Isaac Newton (nicknamed Ike), successfully land on

940-529: The 20th century. For convenience, all amoebae were grouped as Sarcodina and generally divided into morphological categories , on the basis of the form and structure of their pseudopods . Amoebae with pseudopods supported by regular arrays of microtubules (such as the freshwater Heliozoa and marine Radiolaria ) were classified as Actinopoda , whereas those with unsupported pseudopods were classified as Rhizopoda . The Rhizopods were further subdivided into lobose, filose, plasmodial and reticulose, according to

987-455: The Austrian zoologist Ludwig Karl Schmarda used "sarcode" as the conceptual basis for his division Sarcodea, a phylum -level group made up of "unstable, changeable" organisms with bodies largely composed of "sarcode". Later workers, including the influential taxonomist Otto Bütschli , amended this group to create the class Sarcodina, a taxon that remained in wide use throughout most of

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1034-570: The Darwinian creatures are thought-provoking and that their strangeness is a good departure from the typical science fiction approach of making alien life look much like Earth life (such as using humanoid aliens). According to Day, the life of Darwin IV "makes the point that alien life, if it is detected, will challenge our abilities to understand and even comprehend it". A review in The Washington Post stated that "a few too many of

1081-517: The Eosapiens mistakes it as a deliberate attack, and destroys the camera disk while the others are prompted to directly attack Ike. Before shutting down, the wrecked camera disk records the Eosapien tribe carrying Ike away. Commentary from notable people discussing the details behind the fictional world of Darwin IV and the likelihood of extraterrestrial life, in general, is interspersed throughout

1128-480: The TV special, Dwayne A. Day stated that "the animals are bizarre and frequently border on the implausible" and that "they do not appear to have been developed with a single biological theory in mind". Day also noted, concerning the scientists who talk about the animals as if they were real, "clearly some of them think that the animals that they are supposed to report about are barely plausible". However, Day also stated that

1175-676: The addition of many flagellates to Rhizopoda and the removal of some amoebae, the name was rejected in favour of a new name Cercozoa . As such, both names Rhizopoda and Sarcodina were finally abandoned as formal taxa, but they remained useful as descriptive terms for amoebae. The phylum Amoebozoa was conserved, as it still primarily included amoeboid organisms, and now included the Mycetozoa. Today, amoebae are dispersed among many high-level taxonomic groups. The majority of traditional sarcodines are placed in two eukaryote supergroups : Amoebozoa and Rhizaria . The rest have been distributed among

1222-568: The common species now known as Amoeba proteus . The term "Proteus animalcule" remained in use throughout the 18th and 19th centuries, as an informal name for any large, free-living amoeboid. In 1822, the genus Amiba (from the Greek ἀμοιβή amoibe , meaning "change") was erected by the French naturalist Bory de Saint-Vincent . Bory's contemporary, C. G. Ehrenberg , adopted the genus in his own classification of microscopic creatures, but changed

1269-485: The creatures seem like cartoonish monsters", though stated "but around almost every corner one encounters some sort of nutritious food for thought". Docufiction More precisely, it is a documentary mixed with fictional elements, in real time , filmed when the events take place, and in which the main character or characters—often portrayed by non-professional or amateur actors—are essentially playing themselves, or slightly fictionalized versions of themselves, in

1316-478: The defenses of one-celled organisms can shelter and multiply inside them, where they are shielded from unfriendly outside conditions by their hosts. The earliest record of an amoeboid organism was produced in 1755 by August Johann Rösel von Rosenhof , who named his discovery "Der Kleine Proteus" ("the Little Proteus"). Rösel's illustrations show an unidentifiable freshwater amoeba, similar in appearance to

1363-430: The eukaryotic meiosis-specific recombination accessory factor (heterodimer) Hop2-Mnd1. These processes are central to meiotic recombination, suggesting that E. histolytica undergoes meiosis. Studies of Entamoeba invadens found that, during the conversion from the tetraploid uninucleate trophozoite to the tetranucleate cyst, homologous recombination is enhanced. Expression of genes with functions related to

1410-399: The innovating role of Jean Rouch allows one to consider him as the father of a subgenre called ethnofiction . This term means: ethnographic documentary film with natives who play fictional roles. Making them play a role about themselves will help portray reality, which will be reinforced with imagery . A non-ethnographic documentary with fictional elements uses the same method and, for

1457-441: The life on Darwin IV, or to make general statements on life on Earth or out in the universe . Some of the people featured include physicists Michio Kaku and Stephen Hawking , paleontologist Jack Horner , NASA chief scientist James B. Garvin and director , screenwriter and producer George Lucas . Though the documentary gives the appearance of the featured scientists having designed Darwin IV and its animals, most of what

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1504-520: The major steps of meiotic recombination also increase during encystations. These findings in E. invadens , combined with evidence from studies of E. histolytica indicate the presence of meiosis in the Entamoeba . Dictyostelium discoideum in the supergroup Amoebozoa can undergo mating and sexual reproduction including meiosis when food is scarce. Since the Amoebozoa diverged early from

1551-407: The morphology of their pseudopods. During the 1980s, taxonomists reached the following classification, based exclusively on morphological comparisons: Archezoa Percolozoa (Heterolobosea)   other excavates Eosarcodina Neosarcodina Apusozoa → Choanozoa → Animals , Fungi Actinopoda Alveolata → Plants , Chromista In the final decades of the 20th century,

1598-399: The mysterious, evasive and sapient species that has been trailing the two probes, the floating Eosapiens. Ike presents the holographic message to the Eosapien tribe and discovers they are truly intelligent , at a level estimated to be comparable to early humans . Ike launches a camera disk to record the moment, or perhaps "to assess the threat" due to a third Eosapien appearing; however one of

1645-540: The other extreme, the shells of deep-sea xenophyophores can attain 20 cm in diameter. Most of the free-living freshwater amoebae commonly found in pond water , ditches, and lakes are microscopic , but some species, such as the so-called "giant amoebae" Pelomyxa palustris and Chaos carolinense , can be large enough to see with the naked eye. Recent evidence indicates that several Amoebozoa lineages undergo meiosis . Orthologs of genes employed in meiosis of sexual eukaryotes have recently been identified in

1692-440: The participants in a fictionalized scenario while portraying their own genuine reactions and their own improvisational dialogue and character development. THESES online ARTICLES and ESSAYS CITATIONS Amoeba An amoeba ( / ə ˈ m iː b ə / ; less commonly spelled ameba or amœba ; pl. : amoebas (less commonly, amebas ) or amoebae ( amebae ) / ə ˈ m iː b i / ), often called an amoeboid ,

1739-453: The people featured are Michio Kaku , Stephen Hawking , Jack Horner , James B. Garvin and George Lucas . Alien Planet garnered positive reviews as a thought-provoking programme, though some criticism was raised concerning the strange creatures featured, which some reviewers saw as bordering on implausible. Alien Planet starts out with an unmanned interstellar spacecraft named Von Braun , leaving Earth 's orbit . Traveling at 20%

1786-481: The planet, and learn much about its bizarre indigenous lifeforms, including an apparently sapient species. The robotic probes sent out to research on Darwin IV are called Horus Probes. Each Horus probe consists of an 8-foot-high (2.4 m), 40-foot-long (12 m) inflatable, hydrogen -filled balloon, which is covered with solar receptors , a computer 'brain', a 'head' covered with sensors , and several smaller robots that can be sent to places too dangerous for

1833-420: The probe is suddenly knocked out. Ike ventures to the meadows and gullies of Darwin IV, encountering massive Grovebacks, a herd of Littoralopes, the dangerous airborne predatory Skewers, a Groveback falling victim to a swarm of Beach Quills, and a pack of Prongheads hunting a Gyrosprinter. Leo briefly re-establishes contact with Von Braun until a mysterious and evasive creature suddenly interferes, and Ike

1880-466: The probes themselves. The probes have a limited degree of artificial intelligence , very similar to the ' processing power ' of a four-year-old. All the real thinking is done by a supercomputer in the orbiting Von Braun . The probes are programmed with different personalities; Ike is more cautious, while Leo is the risk-taker. The two probes are also equipped with a holographic message that will be projected to any sentient life found on Darwin. After

1927-402: The same reasons, may be called docufiction. In contrast, docudrama is usually a dramatized recreation of factual events in form of a documentary, at a time subsequent to the "real" events it portrays. While docudrama can be confused with docufiction, "docudrama" refers specifically to film or other television recreations that dramatize certain events, often with actors. A mockumentary

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1974-440: The so-called "brain-eating amoeba" Naegleria fowleri , the intestinal parasite Entamoeba histolytica , which causes amoebic dysentery , and the multicellular "social amoeba" or slime mould Dictyostelium discoideum . Amoeba do not have cell walls, which allows for free movement. Amoeba move and feed by using pseudopods, which are bulges of cytoplasm formed by the coordinated action of actin microfilaments pushing out

2021-487: The space historian Dwayne A. Day gave the special a positive review and concluded that "the writers and producers of Alien Planet have managed to successfully transcend current definitions of biology and yet still remained within the realm of the possible". As also happened with the 1990 book, some criticism was leveled by reviewers at the strangeness of the creatures showcased in Alien Planet . In his review of

2068-481: The special. Alien Planet is based on Expedition (1990) by the American artist and writer Wayne Barlowe , a heavily illustrated book which aimed to explore and describe a fictional extraterrestrial ecosystem as if it was as real as that of Earth. Barlowe served as one of the executive producers of the adaptation. For the TV version, a broad team of scientists , and other figures, were assembled to comment on

2115-427: The spelling to Amoeba . In 1841, Félix Dujardin coined the term " sarcode " (from Greek σάρξ sarx , "flesh," and εἶδος eidos , "form") for the "thick, glutinous, homogeneous substance" which fills protozoan cell bodies. Although the term originally referred to the protoplasm of any protozoan, it soon came to be used in a restricted sense to designate the gelatinous contents of amoeboid cells. Thirty years later,

2162-490: The two probes inflate their gas-bags, they encounter a voracious Arrowtongue and watch it pursue a Gyrosprinter. Later that night, the twins find the wreckage of Balboa and are ordered to split up, Ike studying the unique plant life and Leo going after big game. Ike's voyage takes him to one of Darwin IV's pocket forests , where he encounters a flock of Trunk Suckers and their predator , the Daggerwrist. Before his research

2209-477: Was a crewed mission, the planet is explored using sophisticated probes. The technology featured is more advanced than present-day technology , but is based on current trends and informed speculation. Technologies such as autonomous probes and controlled 'miniprobes' are similar to technologies proposed by, or under development, by modern militaries and space agencies . Writing in The Space Review ,

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