Note: Each image source is given below in this post of respective subheadings.
Animal cell under the microscopeDirect observationObservation after staining4.
Atom under the microscopeElectron microscope6.
Bacteria under the microscopeObservation under simple stainingObservation under Gram staining7.
Blood cells under the microscopeRed blood cellsWhite blood cellsNeutrophilsEosinophilsBasophilsMast cellsLymphocytesMonocytes9.
Cheek cells under the microscopeObservation after staining10.
DNA under the microscopeObservation under Scanning Transmission Electron Microscope11.
Euglena under the microscopeObservation under the compound microscope13.
Hair under the microscopeObservation under the stereo microscopeObservation under the compound microscope14.
Plant cell under the microscopeObservation after staining16.
Pollen under the microscopeObservation under the stereo microscopeObservation under the compound microscopeObservation under the electron microscope17.
Sand under the microscopeObservation under a magnifying glassObservation under the compound microscope19.
Virus under the microscopeFluorescence microscopeTransmission electron microscope25.
Worm under the microscopeObservation under the magnifying glassObservation under the compound microscope27.
1. Amoeba under the microscope
Amoeba is a unicellular organism in the Kingdom Protozoa.
It is a eukaryote and thus has membrane-bound cell organelles and protein-bound genetic material with a nuclear membrane.
Amoeba moves with their pseudopodia, which is a specialized form of the plasma membrane that results in a crawling motion of the organism.
Because these are unicellular organisms, they cannot be seen through the naked eyes and thus are microscopic organisms.
Amoeba can be observed under the microscope either directly without staining or after staining and fixing with a particular dye.
Figure: Amoeba under the microscope.
Image Source: Onview.net Ltd. Direct observation
Direct observation allows the viewing of living organisms as they move around.
For direct observation, a sample of water can be directly observed under a microscope, or the organisms can be cultured to increase the number before the inspection.
Under direct observation, Amoeba appears like a transparent jelly-like structure that shows the crawling movement of the organism through the field.
Pseudopodia can be observed as the cell membrane protrudes, forming long finger-like projections.
Inside the organism vacuoles are seen as large empty spaces and food particles are seen as tiny black dots.
In order to observe the internal cell organelles of the organism, fixing and staining procedures are performed.
However, fixing and staining provide a better understanding of the structure and morphology of the organism.
After staining the organism, it can be observed that Amoeba’s cell organelles and cytoplasm are enclosed inside the cell membrane.
The cytoplasm is stained, which allows the observation of food vacuoles, nucleus, and other essential cell organelles.
Amoeba usually has one or more nucleus, which is present inside the nuclear membrane.
Food particles can be seen present inside vacuoles where they are stored and digested.
Similarly, to maintain the osmotic balance, contractile vacuole can also be seen throughout the cytoplasm.
2. Algae under the microscope
Algae are photosynthetic organisms that are mostly found in either freshwater or marine sources.
Most algae are provided with pigments that assist the organisms in producing food or oxygen.
The structure of algae is quite different from other organisms like plants and animals.
Some algae are microscopic whereas some are large extending up to 200 feet in length.
Based on the complexity of the algae, they can either be collected along with the water sample or by cutting the large kelps.
Algae in the soil are difficult to obtain, so it is better to culture them before observation.
Image Source: Onview.net Ltd. Based on their morphology, algae are divided into separate groups:
Under the microscope, Chlorophytas are seen as green structures enclosed into compartments arranged in the form of chains.
Inside each of such compartments, a large vacuole is observed and two layers of the cell wall can also be seen.
The shape and size of the algae vary depending on the genus.
This group of algae contains species that are barely chained and instead appear as drum-shaped, amoeboid or pear-shaped in structure.
Some species are provided with hair-like appendages or flagella that sometimes, extend longer than the body of the organism.
The shape and size of some algae might change throughout their life, depending on the stage of life and habitat.
The algae in this group appear comma-shaped with red or similar pigments.
Some species might have a groove in their cell membrane while others don’t.
The pigments are usually positioned towards the side while the nucleus is present in the center near the vacuole.
These are filamentous where the body is characterized by thallus with calcareous deposits resulting in a solid structure.
The color of the organism ranges from pink to purple, red, yellow, green, or even white.
Some species are photosynthetic and thus have green pigments deposited in the interior of the cell wall.
These are unicellular organisms that appear golden-brown due to the presence of golden-brown plastids.
They have a dented cell membrane and show distinct swimming patterns.
The nucleus is rather large with visible chromosomes.
They have two dissimilar flagella protruding from the cell membrane.
Some dinoflagellates are macroscopic and can be seen even without any microscope.
Under the microscope, they have a large elongated green structure.
In Euglena, an orange spot is seen towards the periphery that is called the eyespot of the organism.
3. Animal cell under the microscope
A typical animal cell is 10–20 μm in diameter, which is about one-fifth the size of the smallest particle visible to the naked eye.
Under the microscope, animal cells appear different based on the type of the cell.
However, the internal structure and organelles are more or less similar.
Animal cells usually are transparent and colorless, and the thickness of the cell differs throughout the cytoplasm.
Compared to the plant cell, animal cells have a more pleomorphic shape as they don’t have a cell wall and thus can change their shape throughout their life.
Because animal cells are transparent and colorless, it is challenging to observe them directly without staining.
However, under a phase-contrast microscope, the nucleus is visible as a solid structure because it is denser than other parts of the cell.
The cell membrane appears as a border enclosing all the components inside the cells.
Direct observation, however, allows the observation of living cells without any components being lost or distorted during specimen preparation.
Figure: Animal cell under the microscope.
Image Source: The Greatest Garden.
Staining allows the viewing of the cellular organelles present in the cytoplasm.
Separate stains are available for the staining of a distinct part of the cell which allows a more detailed study of different components of a cell.
Under a low-power microscope, the cell membrane is observed as a thin line, while the cytoplasm is completely stained.
The cell organelles are seen as tiny dots throughout the cytoplasm, whereas the nucleus is seen as a thick drop.
Under a higher power microscope, the organelles like mitochondria and ribosomes can also be seen.
In some cells, the chromosomes present inside the nucleus can also be seen.
In the case of tissues, other structures like microvilli and cilia can also be observed.
4. Ant under the microscope
These are macroscopic organisms and can be easily viewed without a microscope.
However, under a microscope, different parts of the ant can be seen in more detail.
The size of the ants differs depending on the stage of life as well as in different species.
Figure: Ant under the microscope.
Under the microscope, ants appear to have three main body parts; head, thorax, and abdomen.
The head is more movable than other parts while the thorax is the middle part, and the body consists of six pairs of appendages.
If viewed closely, the head has a pair of antenna and a couple of compound eyes.
The entire body of the ant is covered with an exoskeleton made up of chitin that protects the internal organs of the insect.
Ants under a light microscope
As under a magnifying glass, three body parts of the ants can also be seen under a light microscope.
Under the microscope, a small structure called petiolus can be seen between the thorax and the abdomen, which provides a range of motion to the abdomen.
In the compound eyes, numerous units called ommatidia can be seen.
Three smaller eyes can further be seen in the head arranged in a triangle.
The light microscope also provides a better view of the mouthparts of the ant.
5. Atom under the microscope
Atoms are the smallest unit of an element in that the particles within atom-like electrons and neutrons do not show the properties of the element.
The size of an atom is about 1× 10-10 m which means that the atoms are not visible with a light microscope.
However, a number of other microscopes are available through which the structure of an atom can be observed.
Figure: Atom under the microscope.
Image Source: Microscope Master.
Image Source: Microscope Master.
Electron microscope
The images from the transmission electron microscope show a razor-thin layer, just two atoms thick, of two atoms bonded together.
The microscope can not only distinguish between individual atoms but even see them when they were about only 0.4 angstroms apart, half the length of a chemical bond.
Some variation of this microscope can also penetrate down to the subatomic particles like electrons.
Energy-filtered transmission electron microscopes can even observe individual electrons orbiting around the nucleus.
A scanning transmission electron microscope (STEM) is often used to observe crystals or compounds that reveal the atoms present inside the compounds with some electrons being used to identify atoms of a particular element through the microscope.
The structure of an atom is visible with these microscopes.
However, the internal components like neutrons, protons, and electrons are only observed as waves.
6. Bacteria under the microscope
Bacteria are unicellular prokaryotes in which the genetic material is not enclosed inside a nuclear membrane.
These are simpler organisms consisting of membrane-less cell organelles.
The size of bacteria ranges from 0.5 to 5 µm, and therefore the bacteria are microscopic.
The bacteria are varying in shape and size and their components.
It is hard to observe bacteria directly from their source and thus need to be cultured to increase their number.
Bacteria are very hard to observe without staining as they are colorless and transparent and tiny in size.
Because of the varying shape and size of the bacteria, it is also challenging to distinguish bacteria from other dust particles without staining.
A number of different staining processes can be done to obtain a more detailed structure of these bacteria.
Some of these procedures even allow the differentiation of bacteria into separate groups based on their staining results.
Observation under simple staining
This method is usually performed to detect and observe bacteria simply.
Based on the shape of the bacteria, they are classified into cocci, bacilli, spirilla, and other groups.
Some bacteria might be seen in chains while some are observed in groups in a grape-like structure.
Under a higher power microscope, it is possible to observe the internal cellular components in the bacteria.
Figure: Bacterial cell under microscope A; Gram-negative B; Gram-positive bacteria.
Image Source: https://doi.org/10.24897/acn.64.68.503
Observation under Gram staining
Gram staining is usually performed to distinguish bacteria into groups.
Gram-positive bacteria appear purple whereas Gram-negative bacteria appear red under the microscope.
Based on the result of the staining, the thickness of the cell wall of the bacteria can be assumed.
The nucleus appears as a large black spot in the center where they are not necessarily surrounded by any membrane.
7. Blood under the microscope
7. Blood under the microscope
Blood is the liquid connective tissue in animals that transfers nutrition, water, oxygen, and carbon dioxide to different parts of the body.
Blood consists of a liquid portion called plasma and other blood cells.
The blood also consists of other particles like dissolved glucose, other nutrients, and proteins that assist in the functions of the blood.
Blood appears as a red-colored liquid due to the presence of hemoglobin.
Under the microscope at 40X, a colorless liquid is seen called plasma that occupies about half of the volume of the blood.
Other components, like blood cells, are seen suspended in the plasma.
As the power of the microscope increases (under 100X), red blood cells and white blood cells can be distinguished.
The volume of red blood cells is higher than that of white blood cells.
Red blood cells are smaller and don’t have any nucleus whereas white blood cells are larger in size with the nucleus that appears as a dark stain.
Figure: Blood under the microscope.
Image Source: MicroscopeMaster.
Under a higher power (400X), red blood cells are seen stacked on top of each other, and some granules can be seen inside the white blood cells.
At this point, platelets can also be seen between the red and white blood cells as tiny dots.
In an electron microscope, it is even possible to see other proteins and elements present in the blood other than plasma and blood cells.
8. Blood cells under the microscope
Blood cells are cellular structures found suspended in the plasma of the blood.
Human blood contains a number of blood cells on the basis of their purpose and structure.
The red blood cells are red in color due to the presence of hemoglobin.
These cells are formed in the bone marrow through erythropoiesis.
The red blood cell is responsible for the transfer of oxygen to different parts of the body.
The white blood cells, on the other hand, do not have hemoglobin and are involved in providing protection against foreign invaders.
Other cells termed platelets are also present in the blood, which helps in the clotting of the blood.
Figure: Blood cells under the microscope.
Image Source: Quizlet.
Red blood cells
Under the microscope, red blood cells appear as red-colored circular cells that are thick at the periphery and thin in the center.
The red blood cells do not have a nucleus or any other cellular organelles.
They appear as biconcave discs that are empty on the inside under a microscope.
In the case of a fresh blood sample, the red blood cells appear yellow-green in color with pale centers containing no visible internal structures.
The structure of the cells, however, might not be uniform as they get distorted while traveling through the blood capillaries.
White blood cells
White blood cells or leukocytes are comparatively fewer in blood and thus are difficult to find under the microscope.
Because they are colorless, it is also difficult to observe them without staining.
After staining, however, different types of leukocytes can be seen in the microscopic field.
They appear spherical in shape with a darkly stained nucleus which is usually segmented into 2-5 lobes.
Further, tiny granules can be seen in the cytoplasm along with small threads connecting different lobes of the nucleus.
These cells also appear spherical in shape under the microscope.
The cytoplasm contains granules along with a darkly stained nucleus with just two lobes.
Basophils are larger in size than other leukocytes and have irregular nuclei inside the spherical cell.
The nucleus of the basophil is seen bluish in color which is not as defined as in other leukocytes.
Mast cells are very few and thus difficult to detect; however, they appear enormous compared to other cells and have more granules in their cytoplasm than other cells.
Lymphocytes are the cells that are comparatively smaller in size and under the microscope appear spherical in shape with minimal cytoplasm.
The nucleus is large and round, occupying most of the volume inside the cell.
Monocytes appear larger than lymphocytes and have a kidney or bean-shaped nucleus.
These cells, like lymphocytes, don’t have granules in their cytoplasm.
9. Cheek cells under the microscope
The cells in the cheeks are eukaryotic cells with a defined nucleus enclosed inside a nuclear membrane along with other cell organelles.
These cells line the buccal cavity in humans and are usually shed during mastication and even talking.
Under direct observation, only the shape and size of the cell are visible because the cells are transparent and colorless.
After staining, however, other components like the nucleus are visible under the microscope.
Figure: Cheek cells under the microscope.
Image Source: Paul Anderson (John Abbott College).
The cells in the cheek are not uniform in shape but are more or less circular in shape.
The cell membrane is visible as a dark stained border, and the nucleus is seen as a dark spot in the center.
Similarly, the cytoplasm is also stained, which allows the differentiation of the nucleus and the cytoplasm.
Under a high-power microscope, the cell organelles are more differentiated and allow the observation of individual structures.
Because of the affinity of the stain with the DNA and RNA of the cell, the components inside the nucleus might also be visible.
DNA under the microscope
DNA (Deoxyribonucleic acid) is a molecule present inside the nucleus consisting of two polynucleotide chains coiled around each other to form a helical structure.
DNA is present in the chromosomes inside the nucleus, which is responsible for controlling all activities of a cell.
Even though the overall length of a DNA molecule is about 2 inches, it is not possible to see DNA through light microscopy as the DNA is present inside the nucleus inside the cell.
DNA that has been extracted might be seen through naked eyes as a long thread-like structure.
It is, however, possible to observe DNA through a high-resolution microscope like an electron microscope.
Figure: TEM image with intensity profile and corresponding FFT pitch calculation of λ-DNA fibers.
Image Source: Nano Lett.
Observation under Scanning Transmission Electron Microscope
This method allows the stained visualization of DNA strands inside the cell.
Without staining, the DNA appears corkscrew thread of the DNA double helix.
Usually, through this method, rather small segments of DNA are visible as the electron breaks up the entire DNA into shorter strands.
Under Cryo-electron tomography, DNA strands are visible in a 3-D structure that allows the visualization of DNA from different angles.
coli) is a bacterium commonly found in various ecosystems like land and water.
coli is commonly studied as they are considered as a standard for the study of different bacteria.
Because E.coli is a motile organism, it is beneficial to observe E.
coli directly without staining.
E. coli being a prokaryote, doesn’t have a membrane-bound nucleus and has primitive cell organelles.
E. coli is a bacillus and has an elongated structure with round edges.
coli under the microscope.
coli under the microscope.
Image Source: bacteriainphotos.
This technique is performed to observe the motility of the organism.
Under this method, the living organisms are observed, which allows a more life-like observation of the organism.
The structure of the organism can be observed with this technique in which E.
coli is seen as a bacillus arranged in chains.
The internal structure and organelles are not visible through this method as the organism itself is colorless.
The motility of the organism is, however, possible to observe where the organism moves in a different direction while changing position rather than showing a Brownian movement.
This method is usually performed to detect and observe E.
Here, the organism is stained with a distinct colored stain which causes the entire surface of the bacteria to be stained with that color.
E. coli is seen as a rod-shaped organism ranging in size from 1-2 µm.
The bacteria are seen mostly in chains.
Under a higher power microscope, it is possible to observe the internal cellular components in the organism.
For a more detailed structure of the cellular organelles, however, separate staining of the internal organelles is to be performed.
For a more detailed structure of the cellular organelles, however, separate staining of the internal organelles is to be performed.
coli appears pink in color under the compound microscope.
This indicates that the bacteria are Gram-negative and have an additional layer in the cell membrane made up of phospholipids and lipopolysaccharides.
Under a high-power microscope like the scanning transmission electron microscope, it is possible even to stain and observe the detailed structure of the cellular organelles.
Under a high-power microscope like the scanning transmission electron microscope, it is possible even to stain and observe the detailed structure of the cellular organelles.
The nucleus appears as a large black spot in the center where they are not surrounded by any membrane.
The cytoplasm is also stained, which reveals other structures as tiny dots or long filamentous structures.
The cytoplasm is also stained, which reveals other structures as tiny dots or long filamentous structures.
On the surface of the cell membrane, a long filamentous structure called flagellum is seen.
Euglena under the microscope
Euglena is a single-celled organism that belongs in the kingdom Protista.
These are usually found in pond water or marshy places.
As they are easily found in water and other areas, they are easy to collect and observe.
Because they are unicellular organisms, they cannot be viewed through the naked eyes but can be easily seen through a compound microscope.
Figure: Euglena mutabilis under the microscope.
Image Source: djpmapfer.
As the sample is usually collected from pond water, it might be contaminated with Amoeba and other such organisms.
It is possible to distinguish between Amoeba and Euglena as the latter is an elongated organism while Amoeba has a more irregular shape.
Under 40X magnification, Euglena is seen as tiny particles making sudden movement in the field as they are motile.
As the resolution increases, green spots are seen in the organisms indicating the presence of chloroplast.
Inside the organisms, dark spots are also observed which refer to the nuclear material of the organism along with a whip-like flagellum at the end.
As the resolution increases, the orange-colored spot is seen at the periphery of the organism, which indicates the eyespot of Euglena known to detect light.
Hair under the microscope
Hair is a keratinized structure that is characteristic of mammals.
The entire skin surface of humans except some glabrous skin is covered with hair.
The hair has two parts; root present inside the skin and shaft present above the surface.
New cells are formed at the root when then add up and reach the outside of the skin, where they become keratinized and convert into dead cells.
Over time, the microscopic examination of hair has become very important as it allows the distinction of color, shape, structure, and texture of the hair.
Through observation under microscopic, it is possible to examine the condition of the scalp, its pigmentation, and its condition.
Figure: Hair under the microscope.
Image Source: Microscope World.
Stereo microscopes allow up to 90X magnification for the observation of the general structure and condition of the hair.
The external characteristics like color, shape, texture, and length of hair can be seen easily through a stereomicroscope.
Under this microscope, the hair will appear to have tiny fragments or fiber on its surface.
It allows the observation of how uniform the thickness and pigmentation of the hair are.
When placed on the scalp, the microscope also provides information on the condition and composition of the scalp.
The outer scales on the hair can be observed to some extent through this microscope.
The compound microscope provides a more detailed visualization of the hair fragment.
Through the compound microscope, it is possible to distinguish hairs on the basis of their thickness and also allows the differentiation of different scales present on the hair.
The scales are seen to be present in an annular pattern which is usually different in different animals.
Through a compound microscope, it is possible to distinguish the three layers of hair; cuticle, medulla, and cortex.
The cuticle consists of scales made up of keratinized structures in the form of rings followed by the cortex that provides moisture and pigmentation to the hair.
The medulla, in turn, is seen either as a long continuous thread or is fragmented or even absent in some hair.
Paramecium under the microscope
Paramecium is a single-celled organism resembling in shape to that of the sole of a shoe.
It is a eukaryote that has developed cellular organelles with a nucleus enclosed inside a nuclear membrane.
It is a ciliated organism with cilia present throughout the body of the organism.
Paramecium is a freshwater protist that can be easily collected along with the water sample.
Figure: Paramecium under the microscope.
Image Source: Office for Science and Society, McGill University.
When observed directly under the microscope, this organism appears like the sole of a shoe and thus is named “slipper animalcules”.
The movement can be seen under the microscope if observed directly.
The body of the organism is transparent and thus is very difficult to observe without staining.
The cytoplasm of the organisms is seen as a transparent jelly that moves throughout the microscopic field.
After staining, it is easier to distinguish the organism from other particles.
The cytoplasm of the organism is stained, revealing the contents of the cytoplasm as tiny colored dots.
The nucleus is seen as a dark stained elongated structure at the center of the cytoplasm.
On the surface of the cell membrane of the organism, tiny hair-like projections are seen throughout the body.
A folded structure is observed on the side of the cell membrane, which is the oral groove.
Plant cell under the microscope
Plants cells are larger than animal cells ranging in size from 10-100 µm in length.
The structure and shape of the cell are more rigid when compared to animal cells as plant cells have a rigid cell wall that provides a more solid structure to the plant cell.
Green plants have pigment deposits on their cell, which might provide some color to the cell.
It is difficult to differentiate a single plant cell from others, and thus these are usually observed in the form of tissues.
Because the structure of living and dead plant cells is not much different, plant cells are mostly observed after staining.
Figure: Plant cell under the microscope.
Image Source: Glenda Stovall (Puplbits).
Under the microscope, plant cells are seen as large rectangular interlocking blocks.
The cell wall is somewhat thick and is seen rightly when stained.
The cytoplasm is also lightly stained containing a darkly stained nucleus at the periphery of the cell.
Similarly, a large empty vacuole occupies most of the cell.
Throughout the cytoplasm, tiny dots or granules are seen indicating the presence of starch granules.
The plant cells from the green parts of the plant might even have some green pigments deposited on some parts of the cytoplasm.
Pollen under the microscope
Pollen is a small grain consisting of few cells.
These are macroscopic structures that can be observed with naked eyes.
Macroscopically, they appear as yellow dust-like particles that can be easily moved by wind or water.
These are haploid having half the number of chromosomes as in regular plant cells.
Because these are macroscopic structures, they can be observed easily even through a stereomicroscope.
Figure: Pollen under the microscope.
Image Source: Hanny van Arkel.
Observation under the stereo microscope
Observation under the stereo microscope
In the stereo microscope, pollen appears irregularly shaped with random structures.
They are yellow in color, and each pollen is different from the other in structure and shape.
Different structures within the pollen appear better under staining as it provides contrast.
Under a compound microscope, pollen appears ovoid and is provided on the surface with scales or similar structures.
The structure of the pollen also depends on the type of plant.
Observation under the electron microscope
Under the electron microscope, pollens appear as inflated or deflated ovoid structures.
Figure: Pollen under the microscope (SEM).
Image Source: Dartmouth College.
Salt under the microscope
Salt under the microscope
Salt is essential for the living being as it provides the necessary minerals to the body.
Salt exists in the form of a crystal and is made up of two or more electrons.
Figure: Salt under the microscope (SEM).
Image Source: ZEISS (Flickr).
The shape of different salt crystals may not be the same as they go through wear and tear.
The internal structure or chemical makeup, however, is the same in all salt crystals.
Salt crystals are macroscopic structures and thus can easily be viewed through a compound microscope.
Under the microscope, salt crystals appear cubical in shape.
Since they are 3-Dimensional, with a compound microscope, you will see a fuzzy outline on the edge where there is an out-of-focus section.
Sand under the microscope
Sand is a loose granular material consisting of finely divided rocks and other mineral particles.
Sand is made up of fine particles called sand grains having a diameter ranging from 0.06 mm to 2 mm.
Sand particles are microscopic particles that can be seen with our naked eyes.
Macroscopically, the color of the sand particles and their size can be determined.
However, in order to determine other physical properties of sand particles, we can observe these particles either with a magnifying glass or with a compound microscope.
Figure: Nine Sand grains under the microscope.
Image Source: Gary Greenberg (Sand Grains).
Under a magnifying glass, it is possible to observe individual grains of sand particles and distinguish the color of these particles.
Based on the color and size of these particles, their place of origin can be determined.
While observing sand particles under a magnifying glass, we can see that the size and color of the particles are not always uniform which might be because the sand particles are moved around because of wind and other environmental factors.
Under a compound microscope, the differences between the sand particles become more apparent.
It is visible that the shape, size color, and texture of individual particles vary within the sand collected from the same place.
Pink, peach, or such light-colored sand particles tends to have granite as their main component.
Sand particles with holes or some texture on the surface indicate the remains of some marine life forms.
Skeletal muscle under the microscope
The shape, size, and arrangement of fibers in skeletal muscle vary according to the position of the muscle in the body.
An individual cell of the skeletal muscle is a unicellular unit; however, the muscle formed by the bundle of these cells is multicellular and can be seen with naked eyes.
The skeletal muscles are red in color because of the presence of myoglobin and a large number of mitochondria.
Figure: Skeletal muscle under the microscope.
Image Source: School of Biomedical Sciences, Newcastle University.
Under the microscope at the magnification of 40X, bundles of muscle fibers termed fascicles are seen where each of such bundles is separated by connective tissue, perimysium.
Similarly, nuclei of the cells might also be visible, which appear like tiny dots.
Under a higher magnification of 100X, nuclei of the cells appear towards the periphery because of the proteins present in the cytoplasm of the muscle cells.
With the increased magnification, we can observe individual muscle cells connected to each other through another connective tissue, the endomysium.
The nuclei of the cells of the connective tissue might also be seen that are smaller and more rounded than that of the muscle cells.
In this case, the nucleus appears more flat and oval if the muscle sample taken is sectioned transversely.
Faint lines are seen across each of the muscle cells, which are termed striations.
These striations, however, are not actual structures inside the cell but are the reflection of light caused by the proteins present inside the cells.
Skin under the microscope
Skin under the microscope
Skin is the largest and one of the most important organs of our body.
The most predominant cell type in the epidermis is the keratinocyte and several morphologically distinct epidermis layers are formed as the keratinocytes move from the basement membrane to the skin surface.
Skin, as an organ, is a multicellular structure; however, individual skin cells are microscopic and can only be viewed under a microscope.
Figure: Skin under the microscope.
Image Source: PS micrographs.
The general surface of the sin can be viewed through a hand-held stereo microscope.
This reveals the outer surface of the skin arranged in the form of scales and pores are seen throughout the skin.
In addition, individual hair strands are also visible, which are present close to the pores.
Under a high-power microscope, the different layers of the skin are seen.
The outermost epidermis and inner dermis are visible through the compound microscope.
The cells on the epidermis appear more irregular and are formed of fewer layers, whereas the cells in the dermis are more uniform and have more layers.
The nucleus of the cells is visible towards the base of the cells.
The projection of hair strands can also be seen origination from the roots present inside the skin.
Besides, ducts of the different glands can be seen passing through the cell and opening on the surface of the skin.
Snowflake under the microscope
Snowflake under the microscope
These flakes are formed from water vapor as they freeze under lower temperatures and the snowflakes take shapes as more water molecule freezes on the surface of the seed crystal.
Each snowflake might have an individual shape and structure as well as patterns on its surface.
Snowflakes are macroscopic and can be seen with naked eyes; however, the structure and pattern present cannot be viewed without a microscope.
Figure: Snowflake under the microscope.
Image Source: Michael Peres.
Under a magnifying glass or a stereo microscope, the shape and structure of the snowflake can be determined.
For the pattern present on the surface, however, a compound microscope is to be used.
Under a compound microscope, all snowflakes have a geometric crystalline shape.
In addition, different patterns can be seen on the surface, which is different in different flakes.
Sperm under the microscope
Sperms are male gametes that are formed in the testes of the male reproductive system in humans and other animals.
The general morphology of a sperm cell is composed of a clear head, midpiece, and tail.
Sperms are highly motile and thus require a large amount of energy which is provided by a large number of mitochondria present in the cell.
One of the most distinctive characters of sperms is their motility, and thus, direct observation of sperms is usually done before staining to ensure the presence of sperms.
Through direct observation, it is possible to detect the motility of sperm, which is rapid and random.
Similarly, the basic structure of sperm can also be identified through the microscope.
The head and body of the sperm appear as one under direct observation whereas the tail is distinguishable as a long flagella-like structure.
Figure: Sperm under the microscope.
Image Source: Zeiss.
Observation after staining
Observation after staining
Observation after staining
Observation after staining
Observation after staining
Observation after staining
After staining the sperm with appropriate dye, the body of the sperm appears red while the acrosome and the tail appear green.
The head appears as a smooth oval structure that resembles an egg.
The acrosome and acrosome cap are present together at the top of the head that appear conical in shape.
The nucleus is seen as a stained dot and also has a nucleus vacuole.
At last, the tail appears a long elongated structure that occupies about 80%of the entire sperm.
The tail is transparent and thus is difficult to detect under a low-power microscope.
Spirogyra under the microscope
Spirogyra under the microscope
Spirogyra is a green alga found mostly in freshwater in the form of green clumps.
Spirogyra is unicellular, but because it clumps together, it can be seen in the pond even with our naked eyes.
These organisms have green pigments that are arranged in the form of ribbons in the cytoplasm.
Spirogyra exists in chains where individual cells are stacked on top of another.
The name spirogyra is given because of the spiral/ helical structure of chloroplasts present in the cytoplasm.
Because they are pigmented, they can be easily viewed directly without any staining.
Figure: Spirogyra under the microscope.
Image Source: Motherdragonair.
Under the microscope, spirogyras appear surrounded by a slimy jelly-like substance which is the outer wall of the organism dissolved in water.
The next layer of the cell wall is present on the outside of the cell that appears transparent.
The cytoplasm is also transparent except the chloroplast arranged in the form of ribbons.
These ribbons are observed as helical structures in the cytoplasm.
For the differentiation of the nucleus and other cell organelles, staining has to be performed.
After staining, the nucleus is visible as a stained spot at the side of the cytoplasm beside the ribbons of chloroplasts.
Virus under the microscope
Viruses are particles that are considered obligatory parasites as they don’t grow or survive outside a living organism.
Because viruses are tiny as compared to bacteria, they cannot be viewed with a compound microscope.
Instead, high-power microscopes like fluorescence microscopes or transmission electron microscopes are to be used.
Fluorescence microscope
Under fluorescence microscopes, the viruses appear the color of the fluorescent particle used.
Figure: Virus (SARS-CoV-2) under the microscope (TEM).
Image Source: NIAID (Flickr).
Transmission electron microscope
Transmission electron microscopes are better for the observation of viruses as they provide up to 1000X magnification of particles.
Through this type of microscope, it is possible to observe viruses inside the cells of living beings.
Like in fluorescent microscopy, this technique also utilizes dyes that are specific for the proteins in the viruses which allow the visualization of the viruses.
When the structure of a virus is viewed under a powerful microscope, it may be icosahedral or helical.
The shape and structure of each virus are different from the other, but the composition is similar.
If glycoprotein spikes are present like in the influenza virus, those can also be visible.
In the case of bacteriophage viruses, the tail and tail fibers are also visible and are found attached on the surface of bacterial cells.
The protein head can be seen as a hexagonal capsid inside which the genetic material is present in the form of coiled strands.
Volvox under the microscope
Volvox under the microscope
Volvox is an alga usually found in ponds, ditches, and shallow puddles.
These are unicellular organisms and thus cannot be seen through naked eyes.
These organisms like spirogyra have chloroplasts deposited in the cytoplasm of the organism.
Volvox exists in colonies and thus appears larger than their cells.
Their size ranges from 350-500 µm but appears larger as they exist in the form of colonies.
Figure: Volvox under the microscope.
Image Source: Wim van Egmond.
Under the microscope, about 200-50,000 individual cells are arranged in the form of a hollow sphere.
Each volvox cell appears to have two flagella that beat together to move around in the water.
Individual volvox cell is spherical and occupies cytoplasm, a transparent nucleus, and green colored granules.
Towards the periphery, a red eyespot can be seen that receives sunlight for the preparation of food.
Worm under the microscope
Although the shape and structure of worms vary, worms are generally characterized by an elongated, legless body where the organisms move by crawling movement.
Worms are macroscopic organisms; however, the internal structure and components are not visible with the naked eyes.
Figure: Worm under the microscope.
Image Source: Philippe Crassous.
Observation under the magnifying glass
Observation under the magnifying glass
Under the magnifying glass, segmented worms like earthworms appear visible.
The dorsal part of the body might appear dark due to the epidermis whereas the ventral surface is lighter in color and thus more clearly visible.
A more distinct and thick segment is present in the upper part of the body called the clitellum.
In addition, fine hair-like projections called setae are also visible in each segment.
The flatworms, in turn, are smaller than segmented worms and have a flattened leaf-like body.
The anterior part of the body appears broader than the posterior end.
A closer look may also reveal eyespots at the head region as well as a pharynx located near the middle (central part of the body).
Observation under the compound microscope
Observation under the compound microscope
Observation under the compound microscope
Observation under the compound microscope
Observation under the compound microscope
Under a high-power microscope, a muscular flap might be visible at the anterior end of the body, which is the prostomium.
A septum is also visible, separating each segment on the body of the worm.
The setae or hairs will be more visible than with the magnifying glass.
Apart from the hair, pores are also visible on the surface of the worm.
Additionally, to observe the internal organs of the worm, worms can be dissected.
Yeast under microscope
Yeasts are unicellular eukaryotic organisms that are mostly found in plants and soil.
Some yeasts are also found on the surface of the skin and even inside the body of some animals.
Yeasts mostly exist in a budding form with few cells found as single or pairs.
These are microscopic organisms but are visible with naked eyes when present in large numbers.
Some yeast cells are visible without staining under bright field microscopes.
In a bright field microscope, yeast appears as oval-shaped cells with tiny buds visible in some cells.
These are colorless but under a bright-field microscope might appear creamy to off-white in color.
For the observation of cellular organelles, yeast cells have to be stained.
In fluorescent microscopes, different dyes can be used for different organelles to obtain a more detailed structure of the organelles.
Figure: Yeast under the microscope.
Image Source: microbiological garden.
Read Also:Plant Cell- Definition, Structure, Parts, Functions, Labeled DiagramAnimal Cell- Definition, Structure, Parts, Functions, Labeled DiagramCell Organelles- Definition, Structure, Functions, DiagramBacteria- Definition, Structure, Shapes, Sizes, ClassificationProkaryotes vs Eukaryotes- Definition, 47 Differences, Structure, Examples
Molecular Biology of the Cell.
Looking at the Structure of Cells in the Microscope.
Available from: https://www.ncbi.nlm.nih.gov/books/NBK26880/
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You can find simple life forms such as bacteria, great oxygen-producers like algae, all kinds of alien-like protozoans, and cute microscopic animals like water bears.With the help of this guide and a microscope, you can bring these tiny creatures into focus and discover the secrets in which they live.Let’s see what you will find in a drop of pond water!
What are microorganisms?How small are these microorganisms?Why are microorganisms important?How do we name and classify these microorganisms?Where can you find microorganisms for microscopic projects?What kinds of microorganisms can we find in freshwater?I.
Microscopic autotrophic organismsIII.
Microscopic animalsV.
Arthropods (crustaceans and insects)Introduction of pond microorganisms – Definition, biology, and fun factsBacteriaCyanobacteriaProtophytaGreen algaeDiatomSynuraEuglenaDinoflagellateProtozoaAmoebaShelled AmoebaHeliozoa CiliateParameciumDidiniumStentorVorticellaSuctoriaColepsLacrymariaMicro-animalRotifersHydraPlanarianNeonatesGastrotrichTardigradesOligochaetaArthropodsDaphniaCopepodOstracodAmphipodMosquito larvaHomeworkSuggested BooksReferences
Microorganisms or microbes are microscopic organisms that can be found all around the world.
They can be unicellular or cell clusters.
As such, they are only visible under a microscope.They are largely composed of the members of the Archaea and Bacteria kingdoms (both are prokaryotic cells) and unicellular Protists (belong to eukaryotes).
Within the umbrella of Protist, the members can be further divided into:• Protozoa – “animal-like”, like Paramecium and Amoeba;• Protophyta – “plant-like”, like Diatom, green, red, and brown algae;• Molds – “fungus-like”, like water mold and slime mold.Typically, pond water contains a variety of microorganisms.
They could be free-living single cells or microorganisms that cluster together in large numbers (colonies).
Sometimes, you will find microscopic animals and plants that consist of hundreds or even thousands of cells.
[In this figure] Many pond creatures fall in the size range between 100-500 micrometers (μm).
Some microorganisms (such as Euglena, Paramecium, and Amoeba) contain only one gigantic cell (called unicellular or single-cellular) and are classified as protists.
Others (such as Rotifer and Tardigrade), however, contain thousands of cells and belong to multicellular animals.
Before we start hunting for microorganisms, we should have a good idea of how small they are and the relative biology scale.
To express numbers that are too large or too small to be conveniently written in decimal form, it is common to use “Scientific notation” in biology and other science branches.
Generally, the microorganisms we can find and see under a light microscope fall in the range between 0.5 – 1000 µm.
Every organism plays an essential role in the ecosystem and it is also true for microscopic organisms.
Autotrophic microorganisms like algae are the foundation and producers of nutrients for all other living creatures.
They are eaten by primary consumers like protozoans, which then become the food of larger predators.
[In this figure] Food web of the aquatic ecosystem.
To classify, categorize, and organize all the microorganisms, we need a naming system that everyone can follow.
Taxonomy is the science of biological classification that provides species with names.
It can help to distinguish how similar or different living organisms are to each other.Taxonomy works very similarly to the library.
At the top, there are the Kingdoms (animal, plant, or bacteria).
In the figure below, you can see how this system classifies the human, orange, and gut bacterium (called E.
Some species, like Euglena, are difficult to classify.
Where can you find microorganisms for microscopic projects?
Microorganisms stay with their source of food.
Ponds or slow-flowing creeks with decayed organic materials in the bottom sediments (like leaves) are ideal habitations to find all kinds of microorganisms.
[In this figure] Places to collect microorganisms.(A-C) Nutrient-rich ponds or slow-flowing creeks are ideal habitations to find all kinds of microorganisms, like paramecia, amoebas, rotifers, water bears, daphnia, and diatoms.
I brought them home to look for microorganisms under my microscope.
Plankton is the diverse collection of organisms found floating in water that is unable to propel themselves against a current.
Phytoplankton is referred to as autotrophic algae near the water surface where there is sufficient light to support photosynthesis.
Planktonic microorganisms can be collected by sampling water or using a plankton net.Some microorganisms like to anchor on the surface of other objects like rocks and leaves of aquatic plants.
There are plenty of microorganisms (called Benthos) that like to stay in this benthic zone where decayed organic materials are rich as food sources.
[In this figure] The habitation of microorganisms.
They can be found (1) free-floating in water; (2) staying at the bottom or in sediments; (3) attaching on the surface of rocks or aquatic plants.
Within a drop of pond water, we may find species coming from all kingdoms of Earth’s life.
Archaea or ancient bacteria may be difficult to identify because they are very small and usually live in harsh environments like hot springs.
[In this figure] Tree of living organisms showing the origins of eukaryotes and prokaryotes.
See where the microorganisms belong when you find them under your microscope.Modified from wiki.
Let’s see what we can find under the microscope!
These microorganisms are prokaryotes, meaning they do not have a membrane-bound cell nucleus and other organelles.
NameCharacteristicTaxonomySizeBacteria– Prokaryotes – Single cells – Rod, sphere, or filament-shapedKingdom: Bacteria1µm or lessCyanobacteria (blue-green algae)– Prokaryotes – Free-living photosynthetic bacteria– Produce the oxygen on EarthKingdom: Bacteria Phylum: Cyanobacteria0.5 – 60µm
Microscopic autotrophic organisms
These microorganisms are single-cellular eukaryotes that can produce food through sunlight by photosynthesis (i.e., algae).
NameCharacteristicTaxonomySizeChlamydomonas– Green algae with two flagella – Small single cells or clusters – Rapid movementClass: Chlorophyceae i.e., Chlamydomonas sp.< 50 µmVolvox– Green algae with two flagella – Spherical colony formed by single cellsClass: Chlorophyceae i.e., Volvox sp.500µm – 2mmPediastrum– Green algae (no flagella) – Single cells or clusters in arrangement – No movementClass: Chlorophyceae i.e., Pediastrum sp.< 500 µmSpirogyra (water silk)– Filamentous green algae – Non-branching chains of single cellular units– No movementClass: Zygnematophyceae i.e., Spirogyra sp.100µm – several cmClosterium– Green algae (no flagella) – Single cells, new moon-shaped – No movementClass: Zygnematophyceae i.e., Closterium sp.100 -1000 µmDesmidium– Green algae (no flagella) – Single cells or assembled into long filaments – Various shapesClass: Zygnematophyceae i.e., Desmidium sp.100 -1000 µmDiatom– Brown algae – Slow gliding motion– Cell wall (frustules) made of silicaClass: Bacillariophyceae i.e., Pennales< 500 µmSynura– Brown algae – Cluster of cells – Rotating with flagellaClass: Synurophyceae i.e., Synura sp.< 500 µmEuglena– Contain chloroplasts– Move by flagella – Red eye spot – Have features of animal and plantPhylum: Euglenozoa i.e., Euglena sp.< 400 µmDinoflagellate– Free swimming with flagella – Tough armorClass: Dinoflagellata i.e., Ceratium sp.< 400 µm These microorganisms are singled cellular eukaryotes that obtain nutrition from outside sources. NameCharacteristicTaxonomySizeAmoeba– Slow movement by pseudopodia – Engulfs food by phagocytosisPhylum: Amoebozoa i.e., Amoeba proteus250 -750 µmShelled Amoeba– Testate amoeba with a shell – Slow movement by pseudopodiaPhylum: Amoebozoa i.e., Arcella sp.50 – 300 µmHeliozoa– Spherical – Radiating hair-like pseudopodsPhylum: Sacrodina Order: Heliozoa50 – 1000 µmParamecium– Free-living ciliates – Movement by waving ciliaPhylum: Ciliophora Order: Peniculida i.e., Paramecium sp.50 – 300 µmDidinium– Free-living ciliates – Capture paramecia using the mouthPhylum: Ciliophora Order: Haptorida i.e., Didinium nasutum50-150 µmStentor– Large, free-living ciliates – Contractile – Collect food by cilia on the mouth endPhylum: Ciliophora Order: Heterotrichea i.e., Stentor sp.100 µm – 4 mmSuctoria– Ciliates with sticky tentacles – Attached to a surface of a substratePhylum: Ciliophora Order: Eridogenida i.e., Tokophyra sp.<500 µmVorticella– Bell-shaped ciliates – Cilia around the mouth– Often colonial – Attached to a surface of a substratePhylum: Ciliophora Order: Peritrichida i.e., Vorticella sp.<500 µmColeps– Barrel-shaped ciliates – Bodies covered by platesPhylum: Ciliophora Order: Prostomatea i.e., Coleps sp.<100 µmLacrymaria– Ciliates with a long neckPhylum: Ciliophora Class: Litostomatea i.e., Lacrymaria olor100-150 µm Microscopic animals These organisms are tiny animals. They have functional organ systems consisting of many specialized cells. However, many of them may be smaller than some giant single-celled protozoans. NameCharacteristic TaxonomySizeRotifer (Bdelloid)– Corona with cilia– Attached on a surface– Move like a leech – Filter-feedingPhylum: Rotifera Class: Bdelloided100-500 µmRotifer (Monogononta)– Free swimming rotifers– Filter-feedingPhylum: Rotifer Class: Monogononta50-150 µmHydra– Green, brown or colorless body – Use tentacles to catch preys – Attached on a surfacePhylum: Cnidaria Class: Hydrozoa i.e., Hydra sp.200 µm – several cmPlanarian (flatworm)– Flattened body – Two eyespots – Move in gliding motionPhylum: Platyhelminthes Class: Turbellaria i.e., Planaria sp.500 µm – 2 cmNematode (roundworm)– Round body – Move in rapid “s” form– Has anterior and posterior openingsPhylum: Nematodes Class: Chromadorea i.e., C. elegans1-10 mmGastrotrich (hairyback)– Mainly benthic – Hair-like bristles – Eat algae, bacteria, protozoaPhylum: Gastrotricha i.e., Lepidodermella sp.100 µm – 3 mmTardigrade (water bear)– Head and 4 trunk segments – 4 pairs of legs – Two eyespots– Survive harsh conditions by CryptobiosisPhylum: Tardigrada Class: Eutardigrada, Heterotardigrada0.5 – 1.5 mmOligochaeta (earthworm)– Segmented– Worm motion– Hair bundlesPhylum: Annelida Class: Oligochaetafew mm to 1 cm There are a huge variety of microscopic arthropods in freshwater that are worth discussing separately. They are multicellular animals with segmented bodies covered by exoskeletons.
NameCharacteristicTaxonomySizeDaphnia (water flea)– Antennae – Large compound eyes – HoloplanktonClass: Crustacea Order: Cladocera i.e. Daphnia sp.0.2 – 3 mmCopepod– Long antennae – Tiny eyespots– HoloplanktonClass: Crustacea Order: Copepoda1 – 2 mmOstracod (seed shrimp)– Bean-like shell – Filter feeders– Bivalve carapaceClass: Crustacea Order: Ostracoda i.e. Cypris sp.1 – 5 mmAmphipod– Curved, compressed body – Humped back – ScavengersClass: Crustacea Order: Amphipoda<10 mmMosquito larva (wiggler)– Long slender body– Move in undulating “s” curvesClass: Insecta Order: Diptera<10 mm Introduction of pond microorganisms – Definition, biology, and fun facts Bacteria (singular: bacterium) are single-celled organisms that thrive in diverse environments, including a freshwater pond, lake, and swamp. Bacteria are prokaryotes (pro-KAR-ee-ot-es) that don’t have the membrane-bound nucleus and other organelles. Bacteria are small, simple cells, measuring around 0.1-5 μm in diameter. Some of them can swim around by waving their tail-like flagella. [In this figure] Anatomy of a bacterium.The key structures in a prokaryote cell are nucleoid, plasmid, cytoplasm, flagellum, pilus, ribosome, capsule, cell membrane, and cell wall. Bacteria – Definition, Structure, Types & Infections Cyanobacteria, also known as “blue-green algae,” are a phylum of prokaryotes consisting of free-living photosynthetic bacteria. Cyanobacteria produce a range of toxins known as cyanotoxins that can pose a danger to humans and animals. Cyanobacteria range in size from 0.5 to 60 μm, which represents the largest prokaryotic organism. [In this figure] Left: Microscopic images of Cyanobacteria, showing many single cells assembled into long chains. Common examples include green, red, brown algae, and diatoms. Algae (singular alga) is an informal term for a large, diverse group of organisms that can obtain the energy to grow through photosynthesis (similar to plants). Algae include members ranging from unicellular microalgae, such as Chlorella and Diatoms, to multicellular forms, such as the giant kelp (a large brown seaweed that may grow up to 50 m in length)! They also lack the various structures that characterize land plants, such as the roots, leaves, stomata, and vascular bundles. Most algae belong to the Protist kingdom, which includes any eukaryotic organism that is not an animal, plant, or fungus.Green algae are excellent examples to learn the diversity of living organisms in nature and they are also easy to collect. You can collect different types of algae from a pool or lake. For instance, Spirogyra and Zygnema are filamentous green algae like a brush of green hairs. Under the microscope, you can easily see how their cells arrange into the long fiber shape. [In this figure] Spirogyra under a microscope.One of the spirogyra’s characteristics is its helical arrangement of chloroplast strands. You can also collect free-floating green algae that are in the form of single cells or colonies with a beautiful arrangement. [In this figure] Pediastrum under a light microscope. [In this figure] Closterium under a light microscope. [In this video] Volvox forms spherical colonies of up to 50,000 cells. [In this video] Chlamydomonas are single-cellular green algae with two flagella. They are free-floating unicellular algae found in both the oceans and freshwater. A unique feature of diatom cells is that they are enclosed within a cell wall made of silica (like glass) called a frustule. The photonic structures in the frustules such as pores and chambers on the micro to nanoscale interact with the visible light spectrum, creating colorful, shining, and opal-like appearances. [In this figure] The beauty of diatoms on a microscopic slide.Photo credit: micromagus.net Synura is a small group of golden-brown algae containing chloroplasts, found mostly in freshwater. A group of Synura cells tends to aggregate and assemble into a cluster. Each cell has its two flagella facing outward. I called them microscopic “Roasted Corn on the Cob.”Synura sometimes forms blooms (usually in the spring) and releases ketones and aldehydes that can give the water an unpleasant fish-like odor or taste. Euglena (Greek: “eu” = true, “glene” = eye-ball) is a genus of single-cell eukaryotes with flagella and chloroplasts. Euglena shares both characteristics of plants and animals. For example, euglena contains chloroplasts; thus, they can make their own food, a characteristic of plants. In contrast, euglena can also move using its flagella and consume food through phagocytosis, which is animals’ characteristic. Euglena also lacks a cell wall. [In this figure] Euglena anatomy and its organelles. [In this video] Euglena under a microscope. Scientists suggested that Euglena may become a future food source due to its high nutrient value. Dinoflagellate is another organism like Euglena that gives the scientists big trouble. Many dinoflagellates are photosynthetic, manufacturing their own food using the energy from sunlight, and providing a food source for other organisms.
So, are they plants or animals?
[In this figure] Electron microscopic images showing various types of Dinoflagellates.Photo source: medium.com
When this happens, many surrounding marine lives suffer, from the dinoflagellates producing a neurotoxin that affects muscle function.
[In this figure] Red tide caused by Dinoflagellate bloom.Photo source: Dinoflagellate bloom.
They are heterotrophic and have to eat other microorganisms like bacteria to obtain energy.
Amoeba proteus does not have a fixed shape – it constantly changes because it extends its pseudopods.
[In this figure] The structure of Amoeba.An amoeba has a single granular nucleus, containing most of the organism’s DNA.
Amoeba is a giant eukaryotic cell.
It has a membrane-bound nucleus and many organelles such as contractile vacuole and food vacuole.
Amoeba can eat, reproduce, and even sense its environment (i.e., light, temperature, and electric field).
Do all amoebas look like Amoeba proteus?
The answer is no.Surprisingly, some species of Amoebas make protective shells, called “tests,” around their cells.
Some shelled Amoebas make the tests entirely by themselves, and the materials could be organics, siliceous (containing silica), or calcareous (containing calcium carbonate) components produced by the Amoebas.
Some shelled Amoebas prepare their tests by collecting particles of sediment around them and gluing these mineral particles together with slime ingredients secreted from the cells.
[In this video] A shelled amoeba called Arcella.
I personally like to call Heliozoa a microscopic “Uni” (sea urchin in Japanese)!
[In this figure] Two Heliozoans under the microscope.
Many microorganisms you can find in pond water belong to “ciliates.” The ciliates are a group of protozoans characterized by the presence of hair-like organelles called cilia.
Cilia are structurally similar to flagella but are in general shorter and present in much larger numbers.
Paramecium (pair-ah-me-see-um; plural, Paramecia) is a unicellular ciliate with a shape resembling a slipper.
Although paramecium is small and has only one cell, it can do everything that a living creature can do: Paramecium can swim, digest food, and reproduce.
Paramecium’s cell contains several complex organelles performing specific functions to make its survival possible.Paramecium collects foods via its mouth, called the oral groove.
The food materials enter the cell body and then are digested in food vacuoles.
Paramecia eat other microorganisms such as bacteria, yeasts, and algae.
[In this figure] The organelles of a paramecium.
Paramecium constantly moves by beating rows of microscopic hairs, called cilia.
The cilia of paramecium move like many tiny oars, propelling the organism through the water at a rate that is “four times its body length per second”.
[In this video] The movement of Paramecium caudatum under a microscope.
The Structure of Paramecium Cell
Didinium is a genus of free-living ciliates that are well-known predators of paramecia.
Didinium has a barrel-shaped body encircled by two ciliary bands, which can move Didinium through water by rotating the cell around its axis.
Didinium has a cone-shaped mouth that can capture and paralyze its paramecium prey.
Stentor, sometimes called trumpet animalcules, are a genus of filter-feeding ciliates.
Stentors can reach lengths of two millimeters; as such, they are among the biggest known unicellular organisms.
Their bodies are generally horn-shaped.
[In this video] Stentors under a dark-field microscope.
Stentor – The Trumpeter of the Microscopic Symphony Orchestra
Vorticella is a genus of bell-shaped ciliates that have a stalk to attach itself to a surface of a substrate.
The stalk can contract, allowing it to pull the cell body back when sensing danger.
They both use cilia to collect food particles.
[In this video] Vorticella looks like tiny tulips under the microscope.
Vorticella – The Miniature Tulip Bouquet in the Microscopic World
Suctoria looks like Vorticella, which also has a stalk to attach itself to substrates.
Suctoria uses its tentacles to catch prey and then sucks the prey’s cytoplasm directly into a food vacuole inside the cell, where it digests and absorbs the contents.
Functionally, Suctoria hunts like a hydra (will discuss later).
However, a hydra consists of hundreds of cells, but Suctoria is only a single cell!
[In this video] Suctoria preys and paralyzes a rotifer by its tentacles.
Coleps is a genus of ciliates with barrel-shaped bodies and a shell made of mineralized plates.
Coleps swim around by cilia and feed on bacteria, algae, flagellates, and other ciliates.
Like Suctoria, Coleps can paralyze and capture the prey by toxicysts, which are organelles containing poison from their oral area.
Lacrymaria is a group of ciliates found in freshwater ponds.
Its name means “swan tear” in Latin and refers to its general shape: namely, a teardrop-shaped cell with a small “head” at the end of a long slender “neck.” This protist is notable for its ability to extend the “neck” of the cell up to 7 times its body length and manipulate it in many directions — even around obstacles — to capture its food.
Micro-animals are animals so small that they can be visually observed only under a microscope.
Unlike most other microorganisms, that are unicellular, micro-animals are unique because they are multicellular, like all other animals.
[In this figure] The animal kingdom Animalia contains approximately 35 phyla (singular: phylum).
Rotifers are microscopic aquatic animals.
Rotifers got their name from the corona: a rotating, wheel-like structure that is covered with cilia at their heads.
Rotifers also have a jawed mouth and complete digestive, sensory, and reproductive organ systems.
Rotifers are filter-feeders that eat dead material, algae, bacteria, and other microscopic living organisms, and are therefore very important components of aquatic food webs.
[In this figure] Don’t underestimate a rotifer.
It has a complete set of the digestive organ system that is very similar to ours packed in a tiny body.
[In this image] Examples from three classes of rotifers.Species from the class Bdelloidea are characterized by a large corona and telescopic body.
Rotifers from the class Monogononta have a smaller corona than Bdelloid rotifers and a single gonad (body segment), which gives the class its name.
They have a large body and elongate neck with reduced corona.Photo source: Monogononta.
Facts about Rotifers – Amazing Microscopic Animals under the Microscope
The name “Hydra” came from a snake-like water monster in Greek and Roman mythology, called The Lernaean Hydra.
Hydra has a cylindrical, radially symmetric body with a mouth opening surrounded by several (6-10) tentacles.
These tentacles can extend and capture the prey by specialized stinging cells called cnidocytes.
[In this figure] An anatomy structure scheme of hydra.
Hydra – Biology, Classification, Characteristics, and Reproduction
For example, a planarian cut into three pieces (head, body, tail) will regenerate into three separate individuals.
[In this figure] Planarian regeneration.
Planarian – Biology, Classification, Characteristics, and Regeneration
Although many nematode worms are parasitic, you still can find free-living nematodes like Caenorhabditis elegans (or C.
elegans) in the pond water.
C. elegans is a transparent nematode about 1 mm in length that lives in temperate soil environments.
It moves like a snake and feeds on bacteria.
Because of its transparent body, the internal cells of C.
elegans are easy to observe under a microscope.
elegans, including gene regulation, programmed cell death, and aging.
elegans is a model organism studied in many laboratories around the world.
elegans under a stereo microscope.
Because of the transparent body, the cells inside the worm can be easily studied.
elegans was genetically labeled with green fluorescent proteins (GFP) in all the cells.
GFP labeling with the fluorescence microscope is a very powerful tool to study the function of specific cell types in biomedical research.
Gastrotrichs, commonly referred to as hairybellies or hairybacks, are a group of microscopic, worm-like, animals.
Gastrotrich has a head with a brain and sensory organs, a body with a simple gut, and skin covered by many cilia.
They are mostly benthic (living at the bottom) and feed on detritus, sucking up organic particles with their muscular pharynx.
[In this video] Gastrotrich under a microscope.
Tardigrades, also known as water bears or moss piglets, are fascinating organisms.
Tardigrades look like chubby, microscopic bears walking slowly with eight short legs.
Of no doubt, Tardigrades are the cutest tiny creatures you can find under a microscope.Tardigrades represent a very successful group of animals.
[In this figure] A colored scanning electron microscopic (SEM) image of a Eutardigrada tardigrade (Macrobiotus sapiens) on a piece of moss.
There are some species of smaller aquatic worms that you may encounter under the microscope.
These worms are usually semi-transparent and have “bristles” on their outer body surfaces.
[In this video] A worm (Oligochaeta) under a microscope.
An arthropod (from Ancient Greek “arthron” = joint and “pous” = foot) is an invertebrate animal having an exoskeleton, a segmented body, and paired jointed appendages.
They could be microscopic crustaceans like Daphnia or juvenile larva of aquatic insects and large crustaceans.
[In this figure] Three major characteristics of arthropods are exoskeleton, a segmented body, and paired jointed appendages.Photo source: Slideplayer.
Daphnia (also known as water flea) is a genus of small planktonic crustaceans.
The daphnia body is usually 0.2-3 millimeters long, which is pretty tiny compared to their cousins in the Class Crustaceans like crabs and lobsters.
This is why we classify daphnia as a planktonic animal, meaning they live mainly by drifting in the body of water.
[In this figure] Left: An illustration of body parts of a Daphnia pulex.
Right: A dark-field microscopic picture of a Daphnia pulex.
Copepods (meaning “oar-feet”) are a group of small crustaceans found in nearly every freshwater habitat.
[In this figure] Copepods of different species imaged by a darkfield microscope with polarized light.Photo source: wiki.
They are small crustaceans, typically around 1 mm in size.
[In this video] Ostracods under the microscope.
Amphipod is a shrimp-like microscopic crustacean with no carapace (real shrimps have carapaces or shells on the back) and generally with laterally compressed bodies.
Amphipods are scavengers and mostly marine animals but are also found in freshwater habitats.
Amphipods are popular organisms that can live in a closed Ecosphere.
Mosquito larvae commonly called “wigglers,” live in water for 4 -14 days, depending on the water temperature.
When the 4th instar larva molts, it becomes a pupa, which also lives in water.A mosquito larva eats constantly since it needs a lot of energy to grow.
Mosquito larvae eat algae, bacteria, fungi, and other microorganisms in the water.
Tiny fan-like brushes filter small food particles toward their mouth.