Gram-positive bacterium.
Bacillus subtilis
Bacillus subtilis
Rod-shaped cells; forms endospores.
Open profileAnother scale of the living world
Microorganisms
Explore bacteria, archaea, protozoa, microscopic algae and fungi. Compare sizes, movements and structures through visual experiences and documented reading.
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Another scale of the living world
Microorganism profiles
Microorganisms is a grouping by scale, not a biological kingdom. It brings together organisms from different branches of the tree of life; each profile retains its taxonomic classification.
Unicellular green alga.
Chlamydomonas reinhardtii
Chlamydomonas reinhardtii
It has two anterior cilia and a cup-shaped chloroplast with a pyrenoid.
Open profileGreen unicellular microalga of the group Chlorophyta.
Chlorella vulgaris
Chlorella vulgaris
Mature cells spherical, sometimes oval; the observed size varied between the two strains studied.
Open profileEuglena gracilis is a unicellular, flagellated, and photosynthetic euglenoid.
Euglena gracilis
Euglena gracilis
It stores paramylon, a β-1,3 glucan, and can produce wax esters.
Open profileArchaea (Domain Archaea, Class Halobacteria)
Halobacterium salinarum
Halobacterium salinarum
Extremophilic halophile; obligate aerobe; possesses bacteriorhodopsin.
Open profileHalophilic archaeon.
Haloferax volcanii
Haloferax volcanii
The cell envelope includes a glycoprotein surface layer.
Open profileA bacterium in the family Lactobacillaceae and the genus Lactobacillus.
Lactobacillus acidophilus
Lactobacillus acidophilus
Gram-positive and rod-shaped; produces lactic acid through fermentation.
Open profileCiliated protozoan (Ciliophora).
Paramecium caudatum
Paramecium caudatum
Cilia for locomotion and feeding; two contractile vacuoles; two nuclei (macro and micro).
Open profileRelated reading
Reading about the microscopic world
Documentary photograph
Photo by
Давид Андронов
Source: wikimedia_commons
CC BY 4.0
Explanation · 2 min
White rot and brown rot: two patterns described in wood
A Kew source contrasts two appearances of decomposed wood: pale, soft fibres in white rot and reddish, cube-shaped fragments in brown rot. The available sources describe these patterns, but are not sufficient to explain their mechanisms or identify the fungi as moulds.
Explanation · 2 min
Saccharomyces cerevisiae on Grape Skins: Presence Is Not Residency
The yeast Saccharomyces cerevisiae plays a role in wine fermentation, but it is rarely found on intact grapes. A study describes grape skin as an unsuitable environment for this species to establish a stable presence: a specific case, not a general map of where yeasts live.
Documentary photograph
Photo by
Medmyco
Source: wikimedia_commons
CC BY-SA 4.0
Explanation · 2 min
Mold Spores in a Mortar Experiment: What a Study Documents
A study involving two molds describes how it prepared a spore suspension and applied it to mortar samples. This is a laboratory case, not an explanation of how molds disperse in the environment.
Explanation · 2 min
In California wineries, fruit flies transport yeasts
A study at four wineries in the San Francisco Bay Area shows that fruit flies carry a variety of yeasts. The tests also reveal that attracting flies does not guarantee the same effect on their larvae.
Documentary photograph
Photo by
WEI, WAN-CHEN（魏琬臻）
Source: wikimedia_commons
CC BY-SA 4.0
resized and converted to WebP
Explanation · 2 min
Freshwater Under the Microscope: Possible Inhabitants, Not an Inventory of a Drop
A drop of freshwater does not have a universal roster of inhabitants. Sources describe groups that live in lakes and rivers—from photosynthetic microorganisms to zooplankton—but do not document what a particular drop contains. They also explain why a microscopic image, or a software program’s label, is not always enough to identify a species.
Explanation · 3 min
What can distinguish a plant cell from an animal cell
The cell wall, chloroplasts, and large central vacuole are useful clues when comparing plant and animal cells, but they are not an infallible checklist for identifying every sample. Cell type, organism, and what the microscope can resolve all matter.
Explanation · 1 min
Cilia and Pseudopodia: Two Forms of Cell Movement on a Microscopic Scale
Cilia and pseudopodia offer two distinct examples of locomotion described in microscopic organisms: in ciliates, cilia beat rhythmically; in amoebas, pseudopodia and cytoplasmic flow contribute to movement. The available evidence here does not reliably explain the mechanism of flagella or support a complete comparison of all three.
Explanation · 2 min
Viruses and bacteria under the microscope: what we know about scale and how they are studied
Bacteria are larger than viruses, but that difference alone does not explain which method is appropriate. The sources describe viral structures, observation with electron microscopes, and techniques that detect genetic material in samples: different ways of obtaining information, not a universal rule based on size.
Another scale of the living world
Diversity on a small scale
Microorganisms is a grouping by scale, not a biological kingdom. It brings together organisms from different branches of the tree of life; each profile retains its taxonomic classification.
Bacteria
Cellular organisms without a membrane-bound nucleus. They include cyanobacteria.
Archaea
Organisms without a cellular nucleus, evolutionarily distinct from bacteria.
Protozoa
Single-celled eukaryotes, such as amoebae and ciliates.
Microscopic algae
Microscopic forms such as diatoms and some green algae; they do not form a single kingdom.
Microscopic fungi
Yeasts and moulds, belonging to the kingdom Fungi.
These groups overlap: yeasts are also fungi. Not all algae or chromists are microscopic. Fungi
Experiences
Get closer to the microscopic world
These explorations are models and illustrations, not real samples or tools for identifying a species.
From landscapes to the microscopic worldChange scale and explore tiny structures.
How microorganisms moveExplore models of cilia, flagella and pseudopods.
Microorganisms to scaleCompare sizes and discover another scale of life.
Life in a drop of waterExplore an illustrated freshwater sample.
Inside a cellCompare cellular models and their structures.