Amoeba or amoeboid is a unicellular organism particularly known for its ability to change its body size by retracting and extending its pseudopods.Amoeba is a microscopic organism and cannot be seen with the naked eye, and being a single-cell organism, it is regarded as one of the simplest organisms on the planet. Amoeba is found in multiple environments as it can be found in freshwater streams, soil, and also on the bodies of animals.Amoeba is classified under the family Amoebidae. As amoeba can change its body shape at any point in time, it often seems like a jelly. There are several species of amoeba that are cultivated and studied, and one such common amoeboid organism is Amoeba proteus. Some of the other amoebas include the intestinal parasite, Entamoeba histolytica, and Naegleria fowleri, or the ‘brain-eating amoeba’. There are several cells in our body that replicate the shape-changing characteristic of amoeba and they are known as amoeboid cells. The white blood cells present in our body are the perfect example of amoeboid cells, and they engulf organisms like bacteria by the process of phagocytosis. These cells can be found in algae, fungi, as well as in animals.As amoeba doesn’t have a fixed shape, and the pseudopods play a key role in its locomotion, as well as in helping the amoeba gather food. A fact about the Amoeba proteus is that its favorite food is most likely Paramecium. There are several unicellular organisms in the world, and all these organisms contain only the nucleus, vacuole, and cytoplasm within their cell structure. Interestingly, amoebas can also be divided into two categories known as naked amoebas and shelled amoebas.If you enjoy this article, why not also read about why cells need oxygen and cell division facts here on Kidadl?Shape, Movement, And NutritionContrary to most other organisms, amoebas do not have a fixed shape and also lack cell walls but this helps them in easy body movement. The cytoplasm which is all the cell material present inside eukaryotic cells and further enclosed within the cell membrane plays a key role here. The pseudopods which are projections of a eukaryotic cell membrane are filled with cytoplasm which helps the organism to move and eat food.Interestingly, scientists observe the internal structure of pseudopodia to distinguish between different species of amoeba. In order to move from one place to another, the amoebas form a coordinated action of the microfilaments pushing out the cytoplasm which makes the pseudopods move, and thus, the whole amoeba itself. Researches were then undertaken to calculate the speed of the movement of amoeba and it was found that, on average, amoebas move at a rate of 0.078-0.196 in (2-5 mm) per minute. The amoeba cells which cover its outer body are made up of calcium. The amoeba synthesizes all the materials including protein within its cell and then exports it just outside the cell membrane. Although amoeba is found in soil, animal bodies, the most prominent kind of amoeba, Amoeba proteus, is mostly found in water bodies especially freshwater bodies like freshwater ponds or in the bottom of some still water lakes.Interestingly, Amoeba proteus is relatively quite large in size. An Amoeba proteus, a large protozoan can grow up to 0.039 in (1 mm) long. Now the pseudopods which have played a key role in movement and body shape also help the amoeba in the process of nutrition consumption. Amoebas being single-celled organisms do not have a dedicated organ for nutrition, and they consume the required amount of nutrition via a process known as holozoic nutrition. Under this process, the ingestion, digestion, as well as egestion of the food particles are carried through the cell surface of the amoeba with some assistance of the pseudopods.Pathogenic Interactions With Other OrganismsMany of you might not be aware of this but amoebas can be harmful to us human beings when they become host to microscopic organisms that are pathogenic to us. It can be viewed under an optical microscope and can be found by increasing the illumination and scanning the field by low magnification. Amoebas can release disease-causing agents and if they come in contact with humans or animals under certain conditions, they can affect their health.Researchers have found that amoebas play the role of host to bacteria which have been found responsible for the plague. Additionally, the commonly known as ‘brain-eating amoeba’ or Naegleria fowleri is a bacteria-eating organism usually found in freshwater lakes or ponds but if they enter the human body via the nose, they can prove to be fatal. Acanthamoeba is another organism belonging to the genus of amoeba which can harm people by causing encephalitis or amoebic keratitis in human beings. All the researches up until this day have shown that Dictyostelium discoideum and Acanthamoeba castellanii are the best-explored amoebas that are capable of hosting other organisms which can then prove to be fatal.Life Cycle StagesStudying the life cycle of amoebas lets scientists know how these single-celled creatures live under extreme conditions and have successfully survived all notable events on Earth. Amoebas reproduce using two processes, binary fission, and multiple fission. The latter is used only under special conditions when all the necessary nutrients are not available in the environment. It breathes with the help of its cell membrane as it allows oxygen and carbon dioxide to diffuse easily.In binary fission, the Amoeba proteus begins by forming a spherical shape by changing the shape of its pseudopods. It is then followed by the cell division which leads to the formation of the daughter cells. In the formation of the daughter cells, the nucleus of the existing amoeba is divided into the daughter cells along with the cytoplasm. The nucleus contains all the genetic material which is responsible for making the daughter cells identical. This entire process of binary fission takes a duration of almost 30 minutes to an hour under ideal conditions. Let us now look at how multiple fission is different from binary fission.Multiple fission takes place when it is difficult for the Amoeba proteus to survive due to unideal conditions. This is when the Amoeba proteus has a cyst form around the cell like a wall, and this cyst is able to survive in tough conditions and protect the amoeba. Now the process of cell division or mitosis takes place within the cyst. The newly formed daughter cells stay within the cyst until the amoeba is in a stable and ideal environment. The amoeba cannot stay inside the cyst for long and needs to find a suitable environment quickly else it will die of lack of food and at times become incapable to reproduce.Studying AmoebaAn amoeba is a unicellular organism that was first discovered in the mid-1700s by a German scientist, naturalist named Johann Rösel von Rosenhof. Amoeba is most notably known for its ability to change its shape as it has no fixed body shape and its size depends upon how much food engulfs. Amoeba can be found anywhere whether it is a ground or a living organism or underwater as this organism is capable of surviving under any conditions and is arguably the oldest living organism on the Earth.Amoeba is most commonly found in stagnant lakes or deep in freshwater ponds, and lakes. The size of an amoeba varies depending upon its species, as it is a microscopic organism, its body size is measured in the units of a micrometer. Some species of amoeba have a body size of as small as 0.000118 in (3 μm). The commonly found amoeba species, Amoeba proteus has a body size ranging from 0.0086-0.0299 in (220-760 μm). As a fact about the body size of amoeba, some recently found giant amoebae had a body size of 4 in (10 cm) found some miles within the earth.Amoeba DietThere is no fixed diet of amoeba as the food sources of amoeba vary depending upon the species. Some species of amoeba prefer to consume bacteria, whereas some on the contrary eat dead organic material. The pseudopods of amoeba once again play a very important role in consuming food by performing the process of phagocytosis.Amoebas do not have a designated mouth or a particular place from which they consume food. The pseudopods are extended using cytoplasm in the direction of the food and they engulf the bacteria or the other food material as applicable. Some amoebas also eat plant cells, metazoa, and protozoa. We have been talking about amoeba all this while but do you know where the word ‘amoeba’ comes from? Well, the word ‘amoeba’ has been derived from the Greek word which means ’to change’ signifying its ability to change its shape. Moreover, this organism belongs to the family Amoebidae. These organisms don’t have eyes and some amoebae look different from Amoeba proteus.Here at Kidadl, we have carefully created lots of interesting family-friendly facts for everyone to enjoy! If you liked our suggestions for amoeba facts, then why not take a look at where cells come from, or why cells divide?
Amoeba or amoeboid is a unicellular organism particularly known for its ability to change its body size by retracting and extending its pseudopods.
