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Answers:or amoeba (both: symbolm bsymbol) , common name for certain one-celled organisms belonging to the phylum Sarcodina of the kingdom Protista. Amebas were previously classified as members of the animal kingdom. Most amebas are very small (from 5 to 20 microns in diameter) and contain a single nucleus. A. proteus averages 0.25 mm in length. Members of the genus Pelomyxa, however, may be well over a millimeter (up to 8 mm) in diameter and may contain hundreds of nuclei. Amebas constantly change the shape of their bodies as a result of the phenomenon known as ameboid movement, involving the formation of temporary extensions (pseudopodia, or false feet) of the body. Pseudopodia, used in locomotion and feeding, may be rounded at the tip (lobopodia), pointed (filopodia), branched and fused together (rhizopodia), or somewhat rigid and pointed (axopodia). Although simple in form, amebas are very successful organisms and are found abundantly in a variety of habitats all over the world. Amebas live in freshwater, the oceans, and in the upper layers of the soil, and many have adapted to a parasitic life on the body surface of aquatic animals or in the internal organs of both aquatic and terrestrial animals. Few animals escape invasion by some type of ameba. Some are harmless, but others are pathogenic and cause serious diseases; e.g., Entamoeba histolytica causes amebic dysentery, which is fatal if untreated. The many genera of amebas were given their common name because of their resemblance to the genus Amoeba (order Amoebida), which includes several large, common species of which the freshwater Amoeba proteus is the most familiar. The term ameba is sometimes also used to refer to other unicellular protists (e.g., slime molds) that have ameboid features such as pseudopodia. Other ameboid protozoans of the phylum Sarcodina include the marine radiolarians, which form silicate skeletons; their freshwater counterparts, the heliozoans; and the shell-bearing foraminiferans. Digestion and Respiration In a process known as phagocytosis, amebas engulf their prey, or particles of appropriate size, with their pseudopodia, forming food vacuoles. Digestive enzymes, manufactured and secreted by the organism, are then poured into these vacuoles, and the particles are digested. Useful compounds are subsequently absorbed into the ameba's body. Useless residues remain in the vacuoles and are ultimately expelled (egested) as the vacuole comes in contact with the membrane at the body surface. Amebas can distinguish food (e.g., algae, diatoms, bacteria, and other protozoans) from other material and use different tactics in approaching different food. Freshwater amebas take up water constantly through the process of osmosis, and water content is regulated with a pulsating contractile vacuole. Marine amebas lack a contractile vacuole. Respiration is by diffusion of gases through the cell membrane. Reproduction Under favorable conditions amebas divide by binary fission (splitting) to produce two daughter amebas, the nucleus dividing by mitosis. When an ameba is divided artificially, the portion containing the nucleus forms a new cell membrane and continues as a whole animal, while the other portion lives only as long as its present food supply lasts, ultimately dying, since it cannot ingest food or reproduce. If conditions are unfavorable, e.g., in the absence of food and water, amebas secrete a firm protective covering and encyst until conditions are again favorable to active division.
Answers:amoeba - The amoeba is a tiny, one-celled organism. You need a microscope to see most amoebas - the largest are only about 1 mm across. Amoebas live in fresh water (like puddle and ponds), in salt water, in wet soil, and in animals (including people). There are many different types of amoebas. The name amoeba comes from the Greek word amoibe, which means change. (Amoeba is sometimes spelled ameba.) diatom - Diatoms are unique forms of algae that grow a silica shell that is preserved in underwater sediments after they die. The diatom shell, called a frustule, is different for each species, so you can identify them through a microscope. By looking at the fossil frustules in the layers of sediment, you can see which kind of diatoms lived when that layer was deposited. If you figure out the date corresponding to each layer of sediment, and you know what water conditions each diatom species prefers, you will know what the water quality was like through history. euglena - Euglena Gracilis (genus) commonly known as Euglena (species name) live in fresh water. They are found in the warmer seasons, sometimes they create a layer of green "scum" on the top of a lake or pond. Euglena uses photosynthesis to get its energy and food. Some Euglena also eact little particles of living creatures. paramecium - Paramecium use cilia to move around Paramecium are unicellular like all the other protests Parameciums have nucleus, a large one and a small one Parameciums have a shell like covering called the pellicle Parameciums have food vacuoles Paramecium belongs to the animal like group of protests called ciliates Paramecium has an anal pore which empties waste materials into the waters Paramecium live in any watery environment Parameciums are very small and can only be seen by a microscope Paramecium cilia acts like a sensor and also sweep food toward the paramecium Paramecium reproduces by dividing in half unicellular algae - These are the simplest algae. Except for a few that live in damp terrestrial habitats, these organisms are mainly confined to aquatic environments which provide an adequate supply of nutrients, water, a means of dispersal and a degree of support. Thus, these simple organisms can survive and even thrive in this environment. Although they consist of a single cell, botanists are able to place them in literally thousands of different genera and species. The range of cellular morphology is, at least in part, an adaptation for floatation or for predation avoidance. These organisms must have some ability to float at least through a portion of their life cycle because they must remain near enough to the surface to obtain sufficient light for photosynthesis. Large irregular shaped cells have the advantage of being avoided by herbivores in the water. Most of the animals, which eat algae, are very tiny and these cells would be difficult for them to ingest.
Answers:u can take fresh water from river or stream. U can observe many organisms in it as "amoeba,paramecium,chlaydomnas,spirogyra,fresh water mussel, leech,bacteria,hydra,sponge,cyanobacteria" CLASSIFICATION: amoeba and paramecium r PROTOZOANS chlaydomonas and spirogyra r ALGAE mussel is a MULLUSCA leech is an ANNELIDA bacteria and cyanobacteria r PROKARYOTIC hydra is a COELENTRATE sponge belongs to PHYLUM PORIFERA
Answers:BACTERIA The bacteria ( [b k t ri ] (help info); singular: bacterium)[ ] are a large group of unicellular, prokaryote microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals. Bacteria are ubiquitous in every habitat on Earth, growing in soil, acidic hot springs, radioactive waste, water, and deep in the Earth's crust, as well as in organic matter and the live bodies of plants and animals. There are typically 40 million bacterial cells in a gram of soil and a million bacterial cells in a millilitre of fresh water; in all, there are approximately five nonillion (5 1030) bacteria on Earth, forming much of the world's biomass. Bacteria are vital in recycling nutrients, with many steps in nutrient cycles depending on these organisms, such as the fixation of nitrogen from the atmosphere and putrefaction. However, most bacteria have not been characterized, and only about half of the phyla of bacteria have species that can be grown in the laboratory. The study of bacteria is known as bacteriology, a branch of microbiology. FUNGI The organisms of the fungal lineage include mushrooms, rusts, smuts, puffballs, truffles, morels, molds, and yeasts, as well as many less well-known organisms (Alexopoulos et al., 1996). More than 70,000 species of fungi have been described; however, some estimates of total numbers suggest that 1.5 million species may exist (Hawksworth, 1991; Hawksworth et al., 1995). As the sister group of animals and part of the eukaryotic crown group that radiated about a billion years ago, the fungi constitute an independent group equal in rank to that of plants and animals. They share with animals the ability to export hydrolytic enzymes that break down biopolymers, which can be absorbed for nutrition. Rather than requiring a stomach to accomplish digestion, fungi live in their own food supply and simply grow into new food as the local environment becomes nutrient depleted. Most biologists have seen dense filamentous fungal colonies growing on rich nutrient agar plates, but in nature the filaments can be much longer and the colonies less dense. When one of the filaments contacts a food supply, the entire colony mobilizes and reallocates resources to exploit the new food. Should all food become depleted, sporulation is triggered. Although the fungal filaments and spores are microscopic, the colony can be very large with individuals of some species rivaling the mass of the largest animals or plants. Algae (pronounced / ld i / or / l i /; singular alga / l /, Latin for "seaweed") are a large and diverse group of simple, typically autotrophic organisms, ranging from unicellular to multicellular forms. The largest and most complex marine forms are called seaweeds. They are photosynthetic, like plants, and "simple" because they lack the many distinct organs found in land plants. ALGAE Though the prokaryotic Cyanobacteria (commonly referred to as blue-green algae) were traditionally included as "algae" in older textbooks, many modern sources regard this as outdated as they are now considered to be closely related to bacteria. The term algae is now restricted to eukaryotic organisms. All true algae therefore have a nucleus enclosed within a membrane and plastids bound in one or more membranes. Algae constitute a paraphyletic and polyphyletic group, as they do not include all the descendants of the last universal ancestor nor do they all descend from a common algal ancestor, although their plastids seem to have a single origin. Diatoms are also examples of algae. PROTOZOA Protozoa (from the Greek words proton, meaning "first", and zoa, meaning "animals") is a subkingdom of microorganisms that are generally classified as unicellular non-fungal eukaryotes. Protozoans play a key role in maintaining the balance of the ecosystem. The word protozoan is originally an adjective and is used as a noun. While there is no exact definition for the term protozoan, most scientists use the word to refer to a unicellular heterotrophic protist, such as the amoeba and ciliate. The term algae is used for microorganisms that photosynthesize. However, the distinction between protozoa and algae is often vague. For example, the algae Dinobryon has chloroplasts for photosynthesis, but it can also feed on organic matter and is motile. Protozoans are generally referred to as animal-like protists. Protozoa are paraphyletic. They constitute their own kingdom under the Integrated Taxonomic Information System 2009 classification.