{"id":1349,"date":"2017-01-18T23:31:05","date_gmt":"2017-01-18T23:31:05","guid":{"rendered":"https:\/\/courses.lumenlearning.com\/wm-biology2\/?post_type=chapter&#038;p=1349"},"modified":"2024-04-25T18:48:35","modified_gmt":"2024-04-25T18:48:35","slug":"chromalveolata","status":"publish","type":"chapter","link":"https:\/\/courses.lumenlearning.com\/wm-biology2\/chapter\/chromalveolata\/","title":{"raw":"Chromalveolata","rendered":"Chromalveolata"},"content":{"raw":"<div class=\"textbox learning-objectives\">\r\n<h3>Learning Outcomes<\/h3>\r\n<ul>\r\n \t<li>Identify characteristics and examples of protists in the supergroup Chromalveolata<\/li>\r\n<\/ul>\r\n<\/div>\r\n<p id=\"fs-idp66693776\">Current evidence suggests that species classified as chromalveolates are derived from a common ancestor that engulfed a photosynthetic red algal cell, which itself had already evolved chloroplasts from an endosymbiotic relationship with a photosynthetic prokaryote. Therefore, the ancestor of chromalveolates is believed to have resulted from a secondary endosymbiotic event. However, some chromalveolates appear to have lost red alga-derived plastid organelles or lack plastid genes altogether. Therefore, this supergroup should be considered a hypothesis-based working group that is subject to change. Chromalveolates include very important photosynthetic organisms, such as diatoms, brown algae, and significant disease agents in animals and plants. The chromalveolates can be subdivided into alveolates and stramenopiles.<\/p>\r\n\r\n<section id=\"fs-idp169176416\" data-depth=\"2\"><\/section>\r\n<h2>Alveolates: Dinoflagellates, Apicomplexians, and Ciliates<\/h2>\r\n<p id=\"fs-idp57337600\">A large body of data supports that the alveolates are derived from a shared common ancestor. The alveolates are named for the presence of an alveolus, or membrane-enclosed sac, beneath the cell membrane. The exact function of the alveolus is unknown, but it may be involved in osmoregulation. The alveolates are further categorized into some of the better-known protists: the dinoflagellates, the apicomplexans, and the ciliates.<\/p>\r\n\r\n\r\n[caption id=\"attachment_1361\" align=\"alignright\" width=\"300\"]<img class=\" wp-image-1361\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/1223\/2017\/01\/18231017\/Figure_23_03_04.jpg\" alt=\"The illustration shows two dinoflagellates. The first is walnut-shaped, with a groove around the middle and another perpendicular groove that starts at the middle and extends back. Flagella fit in each groove. The second dinoflagellate is horseshoe-shaped, with the body extending from the wide part of the horseshoe toward the narrow end. Like the first dinoflagellate, this one has two perpendicular grooves, each containing a flagellum.\" width=\"300\" height=\"236\" \/> Figure 1. The dinoflagellates exhibit great diversity in shape. Many are encased in cellulose armor and have two flagella that fit in grooves between the plates. Movement of these two perpendicular flagella causes a spinning motion.[\/caption]\r\n<p id=\"fs-idp97313456\">Dinoflagellates exhibit extensive morphological diversity and can be photosynthetic, heterotrophic, or mixotrophic. The chloroplast of photosynthetic dinoflagellates was derived by secondary endosymbiosis of a red alga. Many dinoflagellates are encased in interlocking plates of cellulose. Two perpendicular flagella fit into the grooves between the cellulose plates, with one flagellum extending longitudinally and a second encircling the dinoflagellate (Figure 1). Together, the flagella contribute to the characteristic spinning motion of dinoflagellates. These protists exist in freshwater and marine habitats, and are a component of\u00a0<span id=\"term891\" data-type=\"term\">plankton<\/span>, the typically microscopic organisms that drift through the water and serve as a crucial food source for larger aquatic organisms.<\/p>\r\n<p id=\"fs-idp109186578\">Dinoflagellates have a nuclear variant called a dinokaryon. The chromosomes in the dinokaryon are highly condensed throughout the cell cycle and do not have typical histones. Mitosis in dinoflagellates is closed, that is, the spindle separates the chromosomes from outside of the nucleus without breakdown of the nuclear envelope.<\/p>\r\n<p id=\"fs-idp109187856\">Some dinoflagellates generate light, called\u00a0<strong><span id=\"term892\" data-type=\"term\">bioluminescence<\/span><\/strong>, when they are jarred or stressed. Large numbers of marine dinoflagellates (billions or trillions of cells per wave) can emit light and cause an entire breaking wave to twinkle or take on a brilliant blue color (Figure 2). For approximately 20 species of marine dinoflagellates, population explosions (also called blooms) during the summer months can tint the ocean with a muddy red color. This phenomenon is called a red tide, and it results from the abundant red pigments present in dinoflagellate plastids. In large quantities, these dinoflagellate species secrete an asphyxiating toxin that can kill fish, birds, and marine mammals. Red tides can be massively detrimental to commercial fisheries, and humans who consume these protists may become poisoned.<\/p>\r\n\r\n<div id=\"fig-ch23_03_05\" class=\"os-figure\"><\/div>\r\n\r\n[caption id=\"attachment_1362\" align=\"aligncenter\" width=\"544\"]<img class=\"size-full wp-image-1362\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/1223\/2017\/01\/18231057\/Figure_23_03_05.jpg\" alt=\"The breaking wave in this photo is an iridescent blue color.\" width=\"544\" height=\"363\" \/> Figure 2. Bioluminescence is emitted from dinoflagellates in a breaking wave, as seen from the New Jersey coast. (credit: \u201ccatalano82\u201d\/Flickr)[\/caption]\r\n<p id=\"fs-idp75140832\">The apicomplexan protists are named for a structure called an apical complex (Figure 3), which appears to be a highly modified secondary chloroplast. The apicoplast genome is similar to those of dinoflagellate chloroplasts. The apical complex is specialized for entry and infection of host cells. Indeed, all apicomplexans are parasitic. This group includes the genus\u00a0<em data-effect=\"italics\">Plasmodium<\/em>, which causes malaria in humans. Apicomplexan life cycles are complex, involving multiple hosts and stages of sexual and asexual reproduction.<\/p>\r\n\r\n\r\n[caption id=\"attachment_1363\" align=\"aligncenter\" width=\"1024\"]<img class=\"size-large wp-image-1363\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/1223\/2017\/01\/18231144\/Figure_23_03_05ab-1024x486.jpg\" alt=\" Illustration A shows an oval cell that has a narrow end and a wide end. The apical complex is located at the narrow end. The three branches of this complex narrow and join at the apical, or narrow, end of the cell. Illustration b shows the life cycle of Plasmodium, which causes malaria. The plasmodium life cycle begins when a mosquito takes a blood meal and injects Plasmodium into the bloodstream. The Plasmodium enters the liver where it multiplies, and eventually reenters the blood. In the blood it enters the ring stage, so called because the cell is curled into a ring shape. The Ring stage may multiply by mitosis or it may undergo meiosis, forming new 1n gametes of male or female sex types. When a mosquito takes a blood meal from an infected host the gametes are ingested. A smaller gamete sex type, called a microgamete, fertilizes a larger sex type, called a macrogamete, producting a 2n zygote. The zygote undergoes mitosis and differentiation. It enters the saliva where it can be injected into another host, completing the cycle.\" width=\"1024\" height=\"486\" \/> Figure 3. (a) Apicomplexans are parasitic protists. They have a characteristic apical complex that enables them to infect host cells. (b) Plasmodium, the causative agent of malaria, has a complex life cycle typical of apicomplexans. (credit b: modification of work by CDC)[\/caption]\r\n<p id=\"fs-idm122079280\">The ciliates, which include\u00a0<em data-effect=\"italics\">Paramecium\u00a0<\/em>and\u00a0<em data-effect=\"italics\">Tetrahymena<\/em>, are a group of protists 10 to 3,000 micrometers in length that are covered in rows, tufts, or spirals of tiny cilia. By beating their cilia synchronously or in waves, ciliates can coordinate directed movements and ingest food particles. Certain ciliates have fused cilia-based structures that function like paddles, funnels, or fins. Ciliates also are surrounded by a pellicle, providing protection without compromising agility. The genus\u00a0<em data-effect=\"italics\">Paramecium<\/em>\u00a0includes protists that have organized their cilia into a plate-like primitive mouth, called an oral groove, which is used to capture and digest bacteria (Figure 4). Food captured in the oral groove enters a food vacuole, where it combines with digestive enzymes. Waste particles are expelled by an exocytic vesicle that fuses at a specific region on the cell membrane, called the anal pore. In addition to a vacuole-based digestive system,\u00a0<em data-effect=\"italics\">Paramecium<\/em>\u00a0also uses\u00a0<strong><span id=\"term893\" data-type=\"term\">contractile vacuoles<\/span><\/strong>, which are osmoregulatory vesicles that fill with water as it enters the cell by osmosis and then contract to squeeze water from the cell. Ciliates therefore exhibit considerable structural complexity without having achieved multicellularity.<\/p>\r\n\r\n\r\n[caption id=\"attachment_1364\" align=\"aligncenter\" width=\"800\"]<img class=\"size-full wp-image-1364\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/1223\/2017\/01\/18231235\/Figure_23_03_06ab.jpg\" alt=\"The illustration on the left shows a shoe-shaped Paramecium. Short, hair-like cilia cover the outside of the cell. Inside are food vacuoles, a large macronucleus, and a small micronucleus. The Paramecium has two star-shaped contractile vacuoles. The mouth pore is an indentation located just where the foot narrows. A small opening called the anal pore is located at the wide end of the cell. The micrograph on the right is a Paramecium, which is about 50 microns across and 150 microns long.\" width=\"800\" height=\"324\" \/> Figure 4. <em>Paramecium<\/em> has a primitive mouth (called an oral groove) to ingest food, and an anal pore to excrete it. Contractile vacuoles allow the organism to excrete excess water. Cilia enable the organism to move. (credit \u201cparamecium micrograph\u201d: modification of work by NIH; scale-bar data from Matt Russell)[\/caption]\r\n\r\n<div class=\"textbox\">\r\n\r\nWatch the video of the contractile vacuole of <em>Paramecium<\/em> expelling water to keep the cell osmotically balanced.\r\n\r\n<script type=\"text\/javascript\" src=\"\/\/static.3playmedia.com\/p\/projects\/20361\/files\/1593709\/plugins\/11085.js\"><\/script><script src=\"https:\/\/www.youtube.com\/iframe_api\" type=\"text\/javascript\"><\/script>\r\n<iframe id=\"myytplayer\" src=\"https:\/\/www.youtube.com\/embed\/iG6Dd3COug4?enablejsapi=1\" width=\"440\" height=\"300\" frameborder=\"0\"><\/iframe>\r\n\r\n<\/div>\r\n<p id=\"fs-idp36250448\"><em data-effect=\"italics\">Paramecium\u00a0<\/em>has two nuclei, a macronucleus and a micronucleus, in each cell. The micronucleus is essential for sexual reproduction, and is in many ways a typical eukaryotic nucleus, except that its genes are not transcribed. The transcribed nucleus is the macronucleus, which directs asexual binary fission and all other biological functions. The macronucleus is a multiploid nucleus constructed from the micronucleus during sexual reproduction. Periodic reconstruction of the macronucleus is necessary because the macronucleus divides amitotically, and thus becomes genetically unbalanced over a period of successive cell replications.\u00a0<em data-effect=\"italics\">Paramecium<\/em>\u00a0and most other ciliates reproduce sexually by conjugation. This process begins when two different mating types of\u00a0<em data-effect=\"italics\">Paramecium<\/em>\u00a0make physical contact and join with a cytoplasmic bridge (Figure 5). The diploid micronucleus in each cell then undergoes meiosis to produce four haploid micronuclei. Three of these degenerate in each cell, leaving one micronucleus that then undergoes mitosis, generating two haploid micronuclei. The cells each exchange one of these haploid nuclei and move away from each other. Fusion of the haploid micronuclei generates a completely novel diploid pre-micronucleus in each conjugative cell. This pre-micronucleus undergoes three rounds of mitosis to produce eight copies, and the original macronucleus disintegrates. Four of the eight pre-micronuclei become full-fledged micronuclei, whereas the other four perform multiple rounds of DNA replication. The copies of the micronuclear chromosomes are severely edited to form hundreds of smaller chromosomes that contain only the protein coding genes. Each of these smaller chromosomes gets new telomeres as the macronucleus differentiates. Two cycles of cell division then yield four new\u00a0<em data-effect=\"italics\">Paramecia\u00a0<\/em>from each original conjugative cell.<\/p>\r\n\r\n<div id=\"fs-idm65614864\" class=\"visual-connection ui-has-child-title\" data-type=\"note\" data-has-label=\"true\" data-label=\"\"><\/div>\r\n\r\n[caption id=\"attachment_1365\" align=\"aligncenter\" width=\"650\"]<img class=\" wp-image-1365\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/1223\/2017\/01\/18231454\/Figure_23_03_07.png\" alt=\"The illustration shows the life cycle of Paramecium. The cycle begins when two different mating types form a cytoplasmic bridge, becoming a conjugate pair. Each Paramecium has a macronucleus and a micronucleus. The micronuclei undergo meiosis, resulting in four haploid micronuclei in each parent cell. Three of these micronuclei disintegrate. The remaining micronuclei divide once by mitosis, resulting in two micronuclei per cell. The parent cells swap one of these micronuclei. The two haploid micronuclei then fuse, forming a diploid micronucleus. The micronucleus undergoes three rounds of mitosis, resulting in eight micronuclei. The original macronucleus dissolves, and four of the micronuclei become macronuclei. Two rounds of cell division result in four daughter cell per each parent cell, each with one macronucleus and one micronucleus.\" width=\"650\" height=\"875\" \/> Figure 5. The complex process of sexual reproduction in <em>Paramecium<\/em> creates eight daughter cells from two original cells. Each cell has a macronucleus and a micronucleus. During sexual reproduction, the macronucleus dissolves and is replaced by a micronucleus. (credit \u201cmicrograph\u201d: modification of work by Ian Sutton; scale-bar data from Matt Russell)[\/caption]\r\n\r\n<div class=\"textbox exercises\">\r\n<h3>Practice\u00a0Question<\/h3>\r\nWhich of the following statements about <em>Paramecium<\/em> sexual reproduction is false?\r\n<ol style=\"list-style-type: lower-alpha;\">\r\n \t<li>The macronuclei are derived from micronuclei.<\/li>\r\n \t<li>Both mitosis and meiosis occur during sexual reproduction.<\/li>\r\n \t<li>The conjugate pair swaps macronucleii.<\/li>\r\n \t<li>Each parent produces four daughter cells.<\/li>\r\n<\/ol>\r\n[reveal-answer q=\"294017\"]Show Answer[\/reveal-answer]\r\n[hidden-answer a=\"294017\"]Statement c is false.[\/hidden-answer]\r\n\r\n<\/div>\r\n<h2>Stramenopiles: Diatoms, Brown Algae, Golden Algae and Oomycetes<\/h2>\r\n[caption id=\"attachment_1367\" align=\"alignright\" width=\"349\"]<img class=\" wp-image-1367\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/1223\/2017\/01\/18232643\/Figure_23_03_08.jpg\" alt=\"The illustration shows an egg-shaped stramenopile cell. Protruding from the narrow end of the cell is one hairless flagellum and one hairy flagellum.\" width=\"349\" height=\"346\" \/> Figure 6. This stramenopile cell has a single hairy flagellum and a secondary smooth flagellum.[\/caption]\r\n\r\nThe other subgroup of chromalveolates, the stramenopiles, includes photosynthetic marine algae and heterotrophic protists. The unifying feature of this group is the presence of a textured, or \u201chairy,\u201d flagellum. Many stramenopiles also have an additional flagellum that lacks hair-like projections (Figure 6). Members of this subgroup range in size from single-celled diatoms to the massive and multicellular kelp.\r\n\r\nThe diatoms are unicellular photosynthetic protists that encase themselves in intricately patterned, glassy cell walls composed of silicon dioxide in a matrix of organic particles (Figure 7). These protists are a component of freshwater and marine plankton. Most species of diatoms reproduce asexually, although some instances of sexual reproduction and sporulation also exist. Some diatoms exhibit a slit in their silica shell, called a <b>raphe<\/b>. By expelling a stream of mucopolysaccharides from the raphe, the diatom can attach to surfaces or propel itself in one direction.\r\n\r\n[caption id=\"attachment_1368\" align=\"aligncenter\" width=\"544\"]<img class=\"wp-image-1368 size-full\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/1223\/2017\/01\/18232720\/Figure_23_03_09.jpg\" alt=\"This micrograph shows translucent blue diatoms, which range widely in size and shape. Many are tube- or diamond-shaped. One is disk-shaped with a visible hub. Another looks like a disk viewed from the end, with grooves in it.\" width=\"544\" height=\"357\" \/> Figure 7. Assorted diatoms, visualized here using light microscopy, live among annual sea ice in McMurdo Sound, Antarctica. Diatoms range in size from 2 to 200 \u00b5m. (credit: Prof. Gordon T. Taylor, Stony Brook University, NSF, NOAA)[\/caption]\r\n\r\nDuring periods of nutrient availability, diatom populations bloom to numbers greater than can be consumed by aquatic organisms. The excess diatoms die and sink to the sea floor where they are not easily reached by saprobes that feed on dead organisms. As a result, the carbon dioxide that the diatoms had consumed and incorporated into their cells during photosynthesis is not returned to the atmosphere. Along with rhizarians and other shelled protists, diatoms help to maintain a balanced carbon cycle.\r\n<p id=\"eip-528\">Like diatoms, golden algae are largely unicellular, although some species can form large colonies. Their characteristic gold color results from their extensive use of carotenoids, a group of photosynthetic pigments that are generally yellow or orange in color. Golden algae are found in both freshwater and marine environments, where they form a major part of the plankton community.<\/p>\r\n<p id=\"fs-idp5288640\">The brown algae are primarily marine, multicellular organisms that are known colloquially as seaweeds. Giant kelps are a type of brown alga. Some brown algae have evolved specialized tissues that resemble terrestrial plants, with root-like holdfasts, stem-like stipes, and leaf-like blades that are capable of photosynthesis. The stipes of giant kelps are enormous, extending in some cases for 60 meters. Like the green algae, brown algae have a variety of life cycles, including alternation of generations. In the brown algae genus\u00a0<em data-effect=\"italics\">Laminaria<\/em>, haploid spores develop into multicellular gametophytes, which produce haploid gametes that combine to produce diploid organisms that then become multicellular organisms with a different structure from the haploid form (Figure 8).<\/p>\r\n\r\n<div id=\"fs-idp25278080\" class=\"visual-connection ui-has-child-title\" data-type=\"note\" data-has-label=\"true\" data-label=\"\"><\/div>\r\n\r\n[caption id=\"attachment_1366\" align=\"aligncenter\" width=\"1024\"]<img class=\"size-large wp-image-1366\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/1223\/2017\/01\/18232608\/Figure_23_03_10-1024x606.png\" alt=\"The life cycle of the brown algae, Laminaria, begins when sporangia undergo meiosis, producing 1n zoospores. The zoospores undergo mitosis, producing multicellular male and female gametophytes. The female gametophyte produces eggs, and the male gametophyte produces sperm. The sperm fertilizes the egg, producing a 2n zygote. The zygote undergoes mitosis, producing a multicellular sporophyte. The mature sporophyte produces sporangia, completing the cycle. A photo inset shows the sporophyte stage, which resembles a plant with long, flat blade-like leaves attached to green stalks via bladder-like connections. Both the blade and stalks are submerged. Sporangia are associated with the leaf-like structures.\" width=\"1024\" height=\"606\" \/> Figure 8. Several species of brown algae, such as the Laminaria shown here, have evolved life cycles in which both the haploid (gametophyte) and diploid (sporophyte) forms are multicellular. The gametophyte is different in structure than the sporophyte. (credit \u201claminaria photograph\u201d: modification of work by Claire Fackler, CINMS, NOAA Photo Library)[\/caption]\r\n\r\n<div class=\"textbox exercises\">\r\n<h3>Practice\u00a0Question<\/h3>\r\nWhich of the following statements about the <em>Laminaria<\/em> life cycle is false?\r\n<ol style=\"list-style-type: lower-alpha;\">\r\n \t<li>1<em>n<\/em> zoospores form in the sporangia.<\/li>\r\n \t<li>The sporophyte is the 2<em>n<\/em> plant.<\/li>\r\n \t<li>The gametophyte is diploid.<\/li>\r\n \t<li>Both the gametophyte and sporophyte stages are multicellular.<\/li>\r\n<\/ol>\r\n[reveal-answer q=\"65382\"]Show Answer[\/reveal-answer]\r\n[hidden-answer a=\"65382\"]Statement c\u00a0is false.[\/hidden-answer]\r\n\r\n<\/div>\r\n\r\n[caption id=\"attachment_1369\" align=\"alignright\" width=\"401\"]<img class=\" wp-image-1369\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/1223\/2017\/01\/18232808\/Figure_23_03_11.jpg\" alt=\"The photo shows a mucous-like mass, covered in white fuzz, hanging from a rock.\" width=\"401\" height=\"302\" \/> Figure 9. A saprobic oomycete engulfs a dead insect. (credit: modification of work by Thomas Bresson)[\/caption]\r\n\r\nThe water molds, oomycetes (\u201cegg fungus\u201d), were so-named based on their fungus-like morphology, but molecular data have shown that the water molds are not closely related to fungi. The oomycetes are characterized by a cellulose-based cell wall and an extensive network of filaments that allow for nutrient uptake. As diploid spores, many oomycetes have two oppositely directed flagella (one hairy and one smooth) for locomotion. The oomycetes are nonphotosynthetic and include many saprobes and parasites. The saprobes appear as white fluffy growths on dead organisms (Figure 9).\r\n\r\nMost oomycetes are aquatic, but some parasitize terrestrial plants. One plant pathogen is <em>Phytophthora infestans<\/em>, the causative agent of late blight of potatoes, such as occurred in the nineteenth century Irish potato famine.\r\n<div class=\"textbox tryit\">\r\n<h3>Try It<\/h3>\r\nhttps:\/\/assess.lumenlearning.com\/practice\/fd8aef2a-81a2-4d3f-97c0-0b41527bc2ef\r\n<\/div>","rendered":"<div class=\"textbox learning-objectives\">\n<h3>Learning Outcomes<\/h3>\n<ul>\n<li>Identify characteristics and examples of protists in the supergroup Chromalveolata<\/li>\n<\/ul>\n<\/div>\n<p id=\"fs-idp66693776\">Current evidence suggests that species classified as chromalveolates are derived from a common ancestor that engulfed a photosynthetic red algal cell, which itself had already evolved chloroplasts from an endosymbiotic relationship with a photosynthetic prokaryote. Therefore, the ancestor of chromalveolates is believed to have resulted from a secondary endosymbiotic event. However, some chromalveolates appear to have lost red alga-derived plastid organelles or lack plastid genes altogether. Therefore, this supergroup should be considered a hypothesis-based working group that is subject to change. Chromalveolates include very important photosynthetic organisms, such as diatoms, brown algae, and significant disease agents in animals and plants. The chromalveolates can be subdivided into alveolates and stramenopiles.<\/p>\n<section id=\"fs-idp169176416\" data-depth=\"2\"><\/section>\n<h2>Alveolates: Dinoflagellates, Apicomplexians, and Ciliates<\/h2>\n<p id=\"fs-idp57337600\">A large body of data supports that the alveolates are derived from a shared common ancestor. The alveolates are named for the presence of an alveolus, or membrane-enclosed sac, beneath the cell membrane. The exact function of the alveolus is unknown, but it may be involved in osmoregulation. The alveolates are further categorized into some of the better-known protists: the dinoflagellates, the apicomplexans, and the ciliates.<\/p>\n<div id=\"attachment_1361\" style=\"width: 310px\" class=\"wp-caption alignright\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-1361\" class=\"wp-image-1361\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/1223\/2017\/01\/18231017\/Figure_23_03_04.jpg\" alt=\"The illustration shows two dinoflagellates. The first is walnut-shaped, with a groove around the middle and another perpendicular groove that starts at the middle and extends back. Flagella fit in each groove. The second dinoflagellate is horseshoe-shaped, with the body extending from the wide part of the horseshoe toward the narrow end. Like the first dinoflagellate, this one has two perpendicular grooves, each containing a flagellum.\" width=\"300\" height=\"236\" \/><\/p>\n<p id=\"caption-attachment-1361\" class=\"wp-caption-text\">Figure 1. The dinoflagellates exhibit great diversity in shape. Many are encased in cellulose armor and have two flagella that fit in grooves between the plates. Movement of these two perpendicular flagella causes a spinning motion.<\/p>\n<\/div>\n<p id=\"fs-idp97313456\">Dinoflagellates exhibit extensive morphological diversity and can be photosynthetic, heterotrophic, or mixotrophic. The chloroplast of photosynthetic dinoflagellates was derived by secondary endosymbiosis of a red alga. Many dinoflagellates are encased in interlocking plates of cellulose. Two perpendicular flagella fit into the grooves between the cellulose plates, with one flagellum extending longitudinally and a second encircling the dinoflagellate (Figure 1). Together, the flagella contribute to the characteristic spinning motion of dinoflagellates. These protists exist in freshwater and marine habitats, and are a component of\u00a0<span id=\"term891\" data-type=\"term\">plankton<\/span>, the typically microscopic organisms that drift through the water and serve as a crucial food source for larger aquatic organisms.<\/p>\n<p id=\"fs-idp109186578\">Dinoflagellates have a nuclear variant called a dinokaryon. The chromosomes in the dinokaryon are highly condensed throughout the cell cycle and do not have typical histones. Mitosis in dinoflagellates is closed, that is, the spindle separates the chromosomes from outside of the nucleus without breakdown of the nuclear envelope.<\/p>\n<p id=\"fs-idp109187856\">Some dinoflagellates generate light, called\u00a0<strong><span id=\"term892\" data-type=\"term\">bioluminescence<\/span><\/strong>, when they are jarred or stressed. Large numbers of marine dinoflagellates (billions or trillions of cells per wave) can emit light and cause an entire breaking wave to twinkle or take on a brilliant blue color (Figure 2). For approximately 20 species of marine dinoflagellates, population explosions (also called blooms) during the summer months can tint the ocean with a muddy red color. This phenomenon is called a red tide, and it results from the abundant red pigments present in dinoflagellate plastids. In large quantities, these dinoflagellate species secrete an asphyxiating toxin that can kill fish, birds, and marine mammals. Red tides can be massively detrimental to commercial fisheries, and humans who consume these protists may become poisoned.<\/p>\n<div id=\"fig-ch23_03_05\" class=\"os-figure\"><\/div>\n<div id=\"attachment_1362\" style=\"width: 554px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-1362\" class=\"size-full wp-image-1362\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/1223\/2017\/01\/18231057\/Figure_23_03_05.jpg\" alt=\"The breaking wave in this photo is an iridescent blue color.\" width=\"544\" height=\"363\" \/><\/p>\n<p id=\"caption-attachment-1362\" class=\"wp-caption-text\">Figure 2. Bioluminescence is emitted from dinoflagellates in a breaking wave, as seen from the New Jersey coast. (credit: \u201ccatalano82\u201d\/Flickr)<\/p>\n<\/div>\n<p id=\"fs-idp75140832\">The apicomplexan protists are named for a structure called an apical complex (Figure 3), which appears to be a highly modified secondary chloroplast. The apicoplast genome is similar to those of dinoflagellate chloroplasts. The apical complex is specialized for entry and infection of host cells. Indeed, all apicomplexans are parasitic. This group includes the genus\u00a0<em data-effect=\"italics\">Plasmodium<\/em>, which causes malaria in humans. Apicomplexan life cycles are complex, involving multiple hosts and stages of sexual and asexual reproduction.<\/p>\n<div id=\"attachment_1363\" style=\"width: 1034px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-1363\" class=\"size-large wp-image-1363\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/1223\/2017\/01\/18231144\/Figure_23_03_05ab-1024x486.jpg\" alt=\"Illustration A shows an oval cell that has a narrow end and a wide end. The apical complex is located at the narrow end. The three branches of this complex narrow and join at the apical, or narrow, end of the cell. Illustration b shows the life cycle of Plasmodium, which causes malaria. The plasmodium life cycle begins when a mosquito takes a blood meal and injects Plasmodium into the bloodstream. The Plasmodium enters the liver where it multiplies, and eventually reenters the blood. In the blood it enters the ring stage, so called because the cell is curled into a ring shape. The Ring stage may multiply by mitosis or it may undergo meiosis, forming new 1n gametes of male or female sex types. When a mosquito takes a blood meal from an infected host the gametes are ingested. A smaller gamete sex type, called a microgamete, fertilizes a larger sex type, called a macrogamete, producting a 2n zygote. The zygote undergoes mitosis and differentiation. It enters the saliva where it can be injected into another host, completing the cycle.\" width=\"1024\" height=\"486\" \/><\/p>\n<p id=\"caption-attachment-1363\" class=\"wp-caption-text\">Figure 3. (a) Apicomplexans are parasitic protists. They have a characteristic apical complex that enables them to infect host cells. (b) Plasmodium, the causative agent of malaria, has a complex life cycle typical of apicomplexans. (credit b: modification of work by CDC)<\/p>\n<\/div>\n<p id=\"fs-idm122079280\">The ciliates, which include\u00a0<em data-effect=\"italics\">Paramecium\u00a0<\/em>and\u00a0<em data-effect=\"italics\">Tetrahymena<\/em>, are a group of protists 10 to 3,000 micrometers in length that are covered in rows, tufts, or spirals of tiny cilia. By beating their cilia synchronously or in waves, ciliates can coordinate directed movements and ingest food particles. Certain ciliates have fused cilia-based structures that function like paddles, funnels, or fins. Ciliates also are surrounded by a pellicle, providing protection without compromising agility. The genus\u00a0<em data-effect=\"italics\">Paramecium<\/em>\u00a0includes protists that have organized their cilia into a plate-like primitive mouth, called an oral groove, which is used to capture and digest bacteria (Figure 4). Food captured in the oral groove enters a food vacuole, where it combines with digestive enzymes. Waste particles are expelled by an exocytic vesicle that fuses at a specific region on the cell membrane, called the anal pore. In addition to a vacuole-based digestive system,\u00a0<em data-effect=\"italics\">Paramecium<\/em>\u00a0also uses\u00a0<strong><span id=\"term893\" data-type=\"term\">contractile vacuoles<\/span><\/strong>, which are osmoregulatory vesicles that fill with water as it enters the cell by osmosis and then contract to squeeze water from the cell. Ciliates therefore exhibit considerable structural complexity without having achieved multicellularity.<\/p>\n<div id=\"attachment_1364\" style=\"width: 810px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-1364\" class=\"size-full wp-image-1364\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/1223\/2017\/01\/18231235\/Figure_23_03_06ab.jpg\" alt=\"The illustration on the left shows a shoe-shaped Paramecium. Short, hair-like cilia cover the outside of the cell. Inside are food vacuoles, a large macronucleus, and a small micronucleus. The Paramecium has two star-shaped contractile vacuoles. The mouth pore is an indentation located just where the foot narrows. A small opening called the anal pore is located at the wide end of the cell. The micrograph on the right is a Paramecium, which is about 50 microns across and 150 microns long.\" width=\"800\" height=\"324\" \/><\/p>\n<p id=\"caption-attachment-1364\" class=\"wp-caption-text\">Figure 4. <em>Paramecium<\/em> has a primitive mouth (called an oral groove) to ingest food, and an anal pore to excrete it. Contractile vacuoles allow the organism to excrete excess water. Cilia enable the organism to move. (credit \u201cparamecium micrograph\u201d: modification of work by NIH; scale-bar data from Matt Russell)<\/p>\n<\/div>\n<div class=\"textbox\">\n<p>Watch the video of the contractile vacuole of <em>Paramecium<\/em> expelling water to keep the cell osmotically balanced.<\/p>\n<p><script type=\"text\/javascript\" src=\"\/\/static.3playmedia.com\/p\/projects\/20361\/files\/1593709\/plugins\/11085.js\"><\/script><script src=\"https:\/\/www.youtube.com\/iframe_api\" type=\"text\/javascript\"><\/script><br \/>\n<iframe loading=\"lazy\" id=\"myytplayer\" src=\"https:\/\/www.youtube.com\/embed\/iG6Dd3COug4?enablejsapi=1\" width=\"440\" height=\"300\" frameborder=\"0\"><\/iframe><\/p>\n<\/div>\n<p id=\"fs-idp36250448\"><em data-effect=\"italics\">Paramecium\u00a0<\/em>has two nuclei, a macronucleus and a micronucleus, in each cell. The micronucleus is essential for sexual reproduction, and is in many ways a typical eukaryotic nucleus, except that its genes are not transcribed. The transcribed nucleus is the macronucleus, which directs asexual binary fission and all other biological functions. The macronucleus is a multiploid nucleus constructed from the micronucleus during sexual reproduction. Periodic reconstruction of the macronucleus is necessary because the macronucleus divides amitotically, and thus becomes genetically unbalanced over a period of successive cell replications.\u00a0<em data-effect=\"italics\">Paramecium<\/em>\u00a0and most other ciliates reproduce sexually by conjugation. This process begins when two different mating types of\u00a0<em data-effect=\"italics\">Paramecium<\/em>\u00a0make physical contact and join with a cytoplasmic bridge (Figure 5). The diploid micronucleus in each cell then undergoes meiosis to produce four haploid micronuclei. Three of these degenerate in each cell, leaving one micronucleus that then undergoes mitosis, generating two haploid micronuclei. The cells each exchange one of these haploid nuclei and move away from each other. Fusion of the haploid micronuclei generates a completely novel diploid pre-micronucleus in each conjugative cell. This pre-micronucleus undergoes three rounds of mitosis to produce eight copies, and the original macronucleus disintegrates. Four of the eight pre-micronuclei become full-fledged micronuclei, whereas the other four perform multiple rounds of DNA replication. The copies of the micronuclear chromosomes are severely edited to form hundreds of smaller chromosomes that contain only the protein coding genes. Each of these smaller chromosomes gets new telomeres as the macronucleus differentiates. Two cycles of cell division then yield four new\u00a0<em data-effect=\"italics\">Paramecia\u00a0<\/em>from each original conjugative cell.<\/p>\n<div id=\"fs-idm65614864\" class=\"visual-connection ui-has-child-title\" data-type=\"note\" data-has-label=\"true\" data-label=\"\"><\/div>\n<div id=\"attachment_1365\" style=\"width: 660px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-1365\" class=\"wp-image-1365\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/1223\/2017\/01\/18231454\/Figure_23_03_07.png\" alt=\"The illustration shows the life cycle of Paramecium. The cycle begins when two different mating types form a cytoplasmic bridge, becoming a conjugate pair. Each Paramecium has a macronucleus and a micronucleus. The micronuclei undergo meiosis, resulting in four haploid micronuclei in each parent cell. Three of these micronuclei disintegrate. The remaining micronuclei divide once by mitosis, resulting in two micronuclei per cell. The parent cells swap one of these micronuclei. The two haploid micronuclei then fuse, forming a diploid micronucleus. The micronucleus undergoes three rounds of mitosis, resulting in eight micronuclei. The original macronucleus dissolves, and four of the micronuclei become macronuclei. Two rounds of cell division result in four daughter cell per each parent cell, each with one macronucleus and one micronucleus.\" width=\"650\" height=\"875\" \/><\/p>\n<p id=\"caption-attachment-1365\" class=\"wp-caption-text\">Figure 5. The complex process of sexual reproduction in <em>Paramecium<\/em> creates eight daughter cells from two original cells. Each cell has a macronucleus and a micronucleus. During sexual reproduction, the macronucleus dissolves and is replaced by a micronucleus. (credit \u201cmicrograph\u201d: modification of work by Ian Sutton; scale-bar data from Matt Russell)<\/p>\n<\/div>\n<div class=\"textbox exercises\">\n<h3>Practice\u00a0Question<\/h3>\n<p>Which of the following statements about <em>Paramecium<\/em> sexual reproduction is false?<\/p>\n<ol style=\"list-style-type: lower-alpha;\">\n<li>The macronuclei are derived from micronuclei.<\/li>\n<li>Both mitosis and meiosis occur during sexual reproduction.<\/li>\n<li>The conjugate pair swaps macronucleii.<\/li>\n<li>Each parent produces four daughter cells.<\/li>\n<\/ol>\n<div class=\"qa-wrapper\" style=\"display: block\"><span class=\"show-answer collapsed\" style=\"cursor: pointer\" data-target=\"q294017\">Show Answer<\/span><\/p>\n<div id=\"q294017\" class=\"hidden-answer\" style=\"display: none\">Statement c is false.<\/div>\n<\/div>\n<\/div>\n<h2>Stramenopiles: Diatoms, Brown Algae, Golden Algae and Oomycetes<\/h2>\n<div id=\"attachment_1367\" style=\"width: 359px\" class=\"wp-caption alignright\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-1367\" class=\"wp-image-1367\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/1223\/2017\/01\/18232643\/Figure_23_03_08.jpg\" alt=\"The illustration shows an egg-shaped stramenopile cell. Protruding from the narrow end of the cell is one hairless flagellum and one hairy flagellum.\" width=\"349\" height=\"346\" \/><\/p>\n<p id=\"caption-attachment-1367\" class=\"wp-caption-text\">Figure 6. This stramenopile cell has a single hairy flagellum and a secondary smooth flagellum.<\/p>\n<\/div>\n<p>The other subgroup of chromalveolates, the stramenopiles, includes photosynthetic marine algae and heterotrophic protists. The unifying feature of this group is the presence of a textured, or \u201chairy,\u201d flagellum. Many stramenopiles also have an additional flagellum that lacks hair-like projections (Figure 6). Members of this subgroup range in size from single-celled diatoms to the massive and multicellular kelp.<\/p>\n<p>The diatoms are unicellular photosynthetic protists that encase themselves in intricately patterned, glassy cell walls composed of silicon dioxide in a matrix of organic particles (Figure 7). These protists are a component of freshwater and marine plankton. Most species of diatoms reproduce asexually, although some instances of sexual reproduction and sporulation also exist. Some diatoms exhibit a slit in their silica shell, called a <b>raphe<\/b>. By expelling a stream of mucopolysaccharides from the raphe, the diatom can attach to surfaces or propel itself in one direction.<\/p>\n<div id=\"attachment_1368\" style=\"width: 554px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-1368\" class=\"wp-image-1368 size-full\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/1223\/2017\/01\/18232720\/Figure_23_03_09.jpg\" alt=\"This micrograph shows translucent blue diatoms, which range widely in size and shape. Many are tube- or diamond-shaped. One is disk-shaped with a visible hub. Another looks like a disk viewed from the end, with grooves in it.\" width=\"544\" height=\"357\" \/><\/p>\n<p id=\"caption-attachment-1368\" class=\"wp-caption-text\">Figure 7. Assorted diatoms, visualized here using light microscopy, live among annual sea ice in McMurdo Sound, Antarctica. Diatoms range in size from 2 to 200 \u00b5m. (credit: Prof. Gordon T. Taylor, Stony Brook University, NSF, NOAA)<\/p>\n<\/div>\n<p>During periods of nutrient availability, diatom populations bloom to numbers greater than can be consumed by aquatic organisms. The excess diatoms die and sink to the sea floor where they are not easily reached by saprobes that feed on dead organisms. As a result, the carbon dioxide that the diatoms had consumed and incorporated into their cells during photosynthesis is not returned to the atmosphere. Along with rhizarians and other shelled protists, diatoms help to maintain a balanced carbon cycle.<\/p>\n<p id=\"eip-528\">Like diatoms, golden algae are largely unicellular, although some species can form large colonies. Their characteristic gold color results from their extensive use of carotenoids, a group of photosynthetic pigments that are generally yellow or orange in color. Golden algae are found in both freshwater and marine environments, where they form a major part of the plankton community.<\/p>\n<p id=\"fs-idp5288640\">The brown algae are primarily marine, multicellular organisms that are known colloquially as seaweeds. Giant kelps are a type of brown alga. Some brown algae have evolved specialized tissues that resemble terrestrial plants, with root-like holdfasts, stem-like stipes, and leaf-like blades that are capable of photosynthesis. The stipes of giant kelps are enormous, extending in some cases for 60 meters. Like the green algae, brown algae have a variety of life cycles, including alternation of generations. In the brown algae genus\u00a0<em data-effect=\"italics\">Laminaria<\/em>, haploid spores develop into multicellular gametophytes, which produce haploid gametes that combine to produce diploid organisms that then become multicellular organisms with a different structure from the haploid form (Figure 8).<\/p>\n<div id=\"fs-idp25278080\" class=\"visual-connection ui-has-child-title\" data-type=\"note\" data-has-label=\"true\" data-label=\"\"><\/div>\n<div id=\"attachment_1366\" style=\"width: 1034px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-1366\" class=\"size-large wp-image-1366\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/1223\/2017\/01\/18232608\/Figure_23_03_10-1024x606.png\" alt=\"The life cycle of the brown algae, Laminaria, begins when sporangia undergo meiosis, producing 1n zoospores. The zoospores undergo mitosis, producing multicellular male and female gametophytes. The female gametophyte produces eggs, and the male gametophyte produces sperm. The sperm fertilizes the egg, producing a 2n zygote. The zygote undergoes mitosis, producing a multicellular sporophyte. The mature sporophyte produces sporangia, completing the cycle. A photo inset shows the sporophyte stage, which resembles a plant with long, flat blade-like leaves attached to green stalks via bladder-like connections. Both the blade and stalks are submerged. Sporangia are associated with the leaf-like structures.\" width=\"1024\" height=\"606\" \/><\/p>\n<p id=\"caption-attachment-1366\" class=\"wp-caption-text\">Figure 8. Several species of brown algae, such as the Laminaria shown here, have evolved life cycles in which both the haploid (gametophyte) and diploid (sporophyte) forms are multicellular. The gametophyte is different in structure than the sporophyte. (credit \u201claminaria photograph\u201d: modification of work by Claire Fackler, CINMS, NOAA Photo Library)<\/p>\n<\/div>\n<div class=\"textbox exercises\">\n<h3>Practice\u00a0Question<\/h3>\n<p>Which of the following statements about the <em>Laminaria<\/em> life cycle is false?<\/p>\n<ol style=\"list-style-type: lower-alpha;\">\n<li>1<em>n<\/em> zoospores form in the sporangia.<\/li>\n<li>The sporophyte is the 2<em>n<\/em> plant.<\/li>\n<li>The gametophyte is diploid.<\/li>\n<li>Both the gametophyte and sporophyte stages are multicellular.<\/li>\n<\/ol>\n<div class=\"qa-wrapper\" style=\"display: block\"><span class=\"show-answer collapsed\" style=\"cursor: pointer\" data-target=\"q65382\">Show Answer<\/span><\/p>\n<div id=\"q65382\" class=\"hidden-answer\" style=\"display: none\">Statement c\u00a0is false.<\/div>\n<\/div>\n<\/div>\n<div id=\"attachment_1369\" style=\"width: 411px\" class=\"wp-caption alignright\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-1369\" class=\"wp-image-1369\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/1223\/2017\/01\/18232808\/Figure_23_03_11.jpg\" alt=\"The photo shows a mucous-like mass, covered in white fuzz, hanging from a rock.\" width=\"401\" height=\"302\" \/><\/p>\n<p id=\"caption-attachment-1369\" class=\"wp-caption-text\">Figure 9. A saprobic oomycete engulfs a dead insect. (credit: modification of work by Thomas Bresson)<\/p>\n<\/div>\n<p>The water molds, oomycetes (\u201cegg fungus\u201d), were so-named based on their fungus-like morphology, but molecular data have shown that the water molds are not closely related to fungi. The oomycetes are characterized by a cellulose-based cell wall and an extensive network of filaments that allow for nutrient uptake. As diploid spores, many oomycetes have two oppositely directed flagella (one hairy and one smooth) for locomotion. The oomycetes are nonphotosynthetic and include many saprobes and parasites. The saprobes appear as white fluffy growths on dead organisms (Figure 9).<\/p>\n<p>Most oomycetes are aquatic, but some parasitize terrestrial plants. One plant pathogen is <em>Phytophthora infestans<\/em>, the causative agent of late blight of potatoes, such as occurred in the nineteenth century Irish potato famine.<\/p>\n<div class=\"textbox tryit\">\n<h3>Try It<\/h3>\n<p>\t<iframe id=\"assessment_practice_fd8aef2a-81a2-4d3f-97c0-0b41527bc2ef\" class=\"resizable\" src=\"https:\/\/assess.lumenlearning.com\/practice\/fd8aef2a-81a2-4d3f-97c0-0b41527bc2ef?iframe_resize_id=assessment_practice_id_fd8aef2a-81a2-4d3f-97c0-0b41527bc2ef\" frameborder=\"0\" style=\"border:none;width:100%;height:100%;min-height:300px;\"><br \/>\n\t<\/iframe>\n<\/div>\n\n\t\t\t <section class=\"citations-section\" role=\"contentinfo\">\n\t\t\t <h3>Candela Citations<\/h3>\n\t\t\t\t\t <div>\n\t\t\t\t\t\t <div id=\"citation-list-1349\">\n\t\t\t\t\t\t\t <div class=\"licensing\"><div class=\"license-attribution-dropdown-subheading\">CC licensed content, Shared previously<\/div><ul class=\"citation-list\"><li>Biology 2e. <strong>Provided by<\/strong>: OpenStax. <strong>Located at<\/strong>: <a target=\"_blank\" href=\"http:\/\/cnx.org\/contents\/185cbf87-c72e-48f5-b51e-f14f21b5eabd@10.8\">http:\/\/cnx.org\/contents\/185cbf87-c72e-48f5-b51e-f14f21b5eabd@10.8<\/a>. <strong>License<\/strong>: <em><a target=\"_blank\" rel=\"license\" href=\"https:\/\/creativecommons.org\/licenses\/by\/4.0\/\">CC BY: Attribution<\/a><\/em>. <strong>License Terms<\/strong>: Access for free at https:\/\/openstax.org\/books\/biology-2e\/pages\/1-introduction<\/li><\/ul><div class=\"license-attribution-dropdown-subheading\">All rights reserved content<\/div><ul class=\"citation-list\"><li>Paramecium and Osmosis. <strong>Authored by<\/strong>: ppornelubio. <strong>Located at<\/strong>: <a target=\"_blank\" href=\"https:\/\/youtu.be\/iG6Dd3COug4\">https:\/\/youtu.be\/iG6Dd3COug4<\/a>. <strong>License<\/strong>: <em>All Rights Reserved<\/em>. <strong>License Terms<\/strong>: Standard YouTube License<\/li><\/ul><\/div>\n\t\t\t\t\t\t <\/div>\n\t\t\t\t\t <\/div>\n\t\t\t <\/section>","protected":false},"author":17,"menu_order":8,"template":"","meta":{"_candela_citation":"[{\"type\":\"cc\",\"description\":\"Biology 2e\",\"author\":\"\",\"organization\":\"OpenStax\",\"url\":\"http:\/\/cnx.org\/contents\/185cbf87-c72e-48f5-b51e-f14f21b5eabd@10.8\",\"project\":\"\",\"license\":\"cc-by\",\"license_terms\":\"Access for free at https:\/\/openstax.org\/books\/biology-2e\/pages\/1-introduction\"},{\"type\":\"copyrighted_video\",\"description\":\"Paramecium and Osmosis\",\"author\":\"ppornelubio\",\"organization\":\"\",\"url\":\"https:\/\/youtu.be\/iG6Dd3COug4\",\"project\":\"\",\"license\":\"arr\",\"license_terms\":\"Standard YouTube License\"}]","CANDELA_OUTCOMES_GUID":"c46d9ba9-6e05-4cb1-b248-9a0c6a8dfbad, 62f1cf88-9a54-4f5d-ba6e-d98546ecd112","pb_show_title":"on","pb_short_title":"","pb_subtitle":"","pb_authors":[],"pb_section_license":""},"chapter-type":[],"contributor":[],"license":[],"class_list":["post-1349","chapter","type-chapter","status-publish","hentry"],"part":19,"_links":{"self":[{"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/pressbooks\/v2\/chapters\/1349","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/pressbooks\/v2\/chapters"}],"about":[{"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/wp\/v2\/types\/chapter"}],"author":[{"embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/wp\/v2\/users\/17"}],"version-history":[{"count":17,"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/pressbooks\/v2\/chapters\/1349\/revisions"}],"predecessor-version":[{"id":8321,"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/pressbooks\/v2\/chapters\/1349\/revisions\/8321"}],"part":[{"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/pressbooks\/v2\/parts\/19"}],"metadata":[{"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/pressbooks\/v2\/chapters\/1349\/metadata\/"}],"wp:attachment":[{"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/wp\/v2\/media?parent=1349"}],"wp:term":[{"taxonomy":"chapter-type","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/pressbooks\/v2\/chapter-type?post=1349"},{"taxonomy":"contributor","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/wp\/v2\/contributor?post=1349"},{"taxonomy":"license","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/wp\/v2\/license?post=1349"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}