Rikunarita-ORG/Wikinium huggingface dataset:
# Protist

Different kinds of protists: . Clockwise from top left: red algae, brown algae, ciliate, golden algae, Foraminifera ; parasitic flagellate; pathogenic amoeba ; amoebozoan slime mold
**Protists** are single-celled eukaryotes (which are organisms with a nucleus). The term **Protista** was first used by Ernst Haeckel in 1866. The protists are not a natural group, or clade, since they have no common origin. Like algae or invertebrates, they are often grouped together for convenience.

The term "protist" includes microorganisms from several distantly related phyla. Some are autotrophic (which means they make their own food by photosynthesis), and others are heterotrophic (which means they eat organic material).

Most protists are very small. They are made up of one or a few cells at most – they are microscopic and usually invisible to the naked eye. Some algae are protists, if they are single-celled. Many protists are part of the plankton and are very important for the ecosystem. The cells found in protists may be extremely complex, and are often little understood. It is now possible to do DNA sequencing, and a number of protists have been analysed. The results show that the Protista is not a monophyletic group. It is paraphyletic, and not a single clade. The taxonomy of the Protista is therefore rather confused.

Some protists cause diseases. *Plasmodium falciparum* causes malaria; sleeping sickness is also caused by a protist.

An example of a single celled organism in the protist kingdom is the *Paramecium* or "slipper animalcule." The *Paramecium* moves using its small, hair-like fibers called cilia, and eats using the cilia to sweep the food into its food vacuole. Other protists can be amoebas, which move by extending pseudopods and flowing into them, or flowing around food particles and engulfing them.

Nutrition in protists| Nutritional type | Source of energy | Source of carbon | Examples |
| --- | --- | --- | --- |
|  Phototrophs  |  Sunlight  |  Organic compounds or carbon fixation |  Algae, Dinoflagellates or Euglena  |
|  Organotrophs  Heterotrophs |  Organic compounds  |  Organic compounds  |  Apicomplexa, Trypanosomes or Amoebae  |

## Origin and taxonomy

Phylogenetic and symbiogenetic tree of living organisms, showing the origins of eukaryotes
Protists are not a monophyletic clade. The term is a convenient holdall for about 20 different kinds of single-celled eukaryotes. They differ in their cell organelles, specialised units which carry out well-defined functions, like mitochondria and plastids. This proves they have made the transition from prokaryotes in different ways. It is fairly clear now that all or most of these organelles have their origin in once-independent prokaryotes (bacteria or archaea), and that the eukaryote cell is a 'community of micro-organisms' working together in 'a marriage of convenience'. Admittedly, the Protista is a collection of disparate single-celled forms, but while a more sophisticated taxonomy is in flux (changing), Protista is still a useful term.
# Actinomycetota

Actinomycetota (old name: *Actinobacteria*) are a phylum of Gram-positive bacteria. They are known for having high guanine and cytosine content (GC content) in their DNA. They include many kinds of terrestrial and aquatic bacteria.

*Actinomycetota* are very important to plants. They decompose dead plants and animals into good nutrients for plants. Although some fungi also decompose dead matter, actinomycetota are smaller and decompose where fungi can not. Some actinomycetota are nitrogen-fixing and turn nitrogen into useable ammonia for plants.

Notable genera include *Bifidobacterium*, which is important for a baby's gut microbiome. Others, like *Frankia*, live in plant roots.
# Prion

Prions infect tissues and make them look spongy. This sample is from Mad Cow disease.
A **prion** (pronounced *pree-on)* is an infectious protein. The word is short for "proteinaceous infectious particles".

All known prion diseases in mammals affect the structure of the brain or other neural tissue. Right now, they cannot be treated and always end in death.

Prions cause many forms of encephalitis, or brain disease, such as scrapie, chronic wasting disease, Creutzfeldt-Jakob Disease, bovine spongiform encephalopathy and kuru. Prions work by changing the shape of proteins in infected animals. While normal proteins have lots of alpha helices, or twisted parts, changed proteins have lots of beta sheets, or flat parts. It has also been suggested that Alzheimer's disease causes damage to the prions.

Because prions are proteins, and proteins cannot reproduce themselves, it is a mystery how prions work. A lot of molecular biology research is going on to find out how they reproduce themselves, with no clear result so far.

## Related pages

* Prion disease
# Acellular

Covid, a speceis of virus
**Acellular** or **non-cellular life** is life that exists without a cellular structure. Some scientists say that a virus is a type of life form. The 2 types of non-celluar life are viroids and viruses.
# Nucleic acid

**Nucleic acids** are large molecules where genetic information is stored. There are two types of nucleic acids: deoxyribonucleic acid, better known as **DNA** and ribonucleic acid, better known as **RNA**.

The nucleic acids are made of nucleotides. A nucleotide is made of a nitrogenous base, sugar with five carbon atoms and a phosphate group.

Nucleic acids allow organisms to transfer genetic information from one generation to the next. When a cell divides, its DNA is copied and passed from one cell generation to the next generation.

DNA is organized into chromosomes and found within the nucleus of our cells. Its function in any cell is to carry the sequence of bases which will be transcribed into RNA. The function of RNA is much more difficult to explain. One well-known function is for messenger RNA to be translated into proteins, mainly enzymes. But there are other types of RNA, and these are called non-coding RNAs.
# Ernst Haeckel

| Ernst Haeckel |
| --- |
|  |
| Born | (1834-02-16)16 February 1834 Potsdam |
| Died | 9 August 1919(1919-08-09) (aged 85) Jena |
| Nationality |  Prussia (later  German Empire) |
| Awards | Linnean Medal (1894) Darwin–Wallace Medal (Silver, 1908) |
| **Scientific career** |
| Author abbrev. (zoology) | Haeckel |
|  |

**Ernst Heinrich Philipp August Haeckel** (16 February 1834 – 9 August 1919) was an influential German zoologist, naturalist, and artist. He was also a philosopher and physician, but in those fields he is not regarded as particularly notable. He was an atheist. He left the Lutheran church in 1910. He is regarded as a pioneer of eugenics and Nazi eugenics in Germany.

## Works

Haekel was professor of comparative anatomy at the University of Jena, where he worked for 47 years, from 1862 to 1909. Haekel discovered, described and named thousands of new species, mapped a tree of life relating all life forms. He coined many terms in biology, including *ecology*, *phylum*, *phylogeny*, *stem cell*, and the kingdom *Protista.* Haeckel promoted and popularised Charles Darwin's work in Germany and developed the controversial recapitulation theory ("ontogeny recapitulates phylogeny"). This claimed that an individual organism's biological development, or ontogeny, parallels and summarises its species' evolutionary development.

The published artwork of Haeckel includes over 100 detailed, multi-colour illustrations of animals and sea creatures. As a philosopher, Ernst Haeckel wrote *Die Welträtsel* (1895–1899, *The Riddle of the Universe*, 1901), and *Freedom in Science and Teaching* to support teaching evolution.

Haeckel was a member of the nationalist and antisemitic Pan-German League (German: *Altdeutscher Verband*) and of the peace organization Verband für internationale Verständigung.

## Books

Haekel wrote many books, some of them in multi-volumes. Among the most notable are:

* *Die Radiolarien*, four parts in five volumes. 1862–1888. (Rhizopoda Radiaria) Eine Monographie. Georg Reimer, Berlin.
* *Generelle Morphologie der Organismen*. 1866. Allgemeine Grundzüge der organischen Formen-Wissenschaft, mechanisch begründet durch die von Charles Darwin reformirte Descendenz-Theorie. Georg Reimer, Berlin.
* *Das Protistenreich*. 1878. Eine populäre Uebersicht über das Formengebiet der niedersten Lebewesen. Mit einem wissenschaftlichen Anhange: System der Protisten. Mit zahlreichen Holzschnitten. Ernst Günther’s Verlag, Leipzig.
* *Monographie der Medusen*. Six parts, some in two volumes. Gustav Fischer, Jena 1879–1881.
* *The history of creation* (1868) 1993, translated by E. Ray Lankester, Kegan Paul, Trench, London, 3rd edition, volume 1. His best-known work, translated into English.
* *Art forms from the ocean: the Radiolarian atlas of 1862*. Prestel Verlag, 2005. A reprint of his artwork for the Radiolaria. ISBN 3-7913-3327-5

## Related pages

* List of ecologists
# Robert Whittaker

**Robert Harding Whittaker** (December 27, 1920 – October 20, 1980) was a distinguished American plant ecologist

In 1969 Whittaker proposed a "five kingdom" system in which three kingdoms were added to the animals and plants: Monera, Protista, and Fungi. Whittaker defined the kingdoms by a number of special characteristics.
# Prokaryote

Structure of a prokaryotic bacteria cell
**Prokaryotes** (or *Monera*) are some of the simplest living things. They are unicellular organisms and they include two major divisions of simple living beings: bacteria, and Archaea. They generally do not have a cell nucleus, nuclear membrane or cell organelles, however a small number of exceptions have been found. Prokaryotes possess genetic material in the form of a single DNA loop called a Nucleoid that floats around freely inside the cell. Bacteria include the Cyanobacteria (formerly known as blue-green algae due to their photosynthetic capacity).

Some form biofilms that are somewhat like multicellular organisms.

Besides a nucleus, prokaryotes lack other things eukaryotes (cells with a true nucleus) have. They reproduce without fusion of gametes. They do not have membranes. This means that there are no vacuoles, Golgi apparatus, endoplasmic reticula or other organelles inside the cell. However, they do have ribosomes, though of a simpler kind than eukaryotes. Eukaryote cells include organelles which were once free-living prokaryotes.

## Taxonomy

In 1977, Carl Woese proposed dividing prokaryotes into the Bacteria and Archaea (originally Eubacteria and Archaebacteria) because of the major differences in the structure and genetics between the two groups of organisms. This arrangement of Eukaryota (also called "Eukarya"), Bacteria, and Archaea is called the three-domain system, replacing the traditional two-empire system.

The Archaea include simple organisms which were first discovered in extreme environments. Most of them can survive at very high or very low temperatures. Some of them can also survive in highly salty, acidic or alkaline water. Some have been found in geysers, black smokers or oil wells.

The prokaryotes may not be a monophyletic, taxonomic group of common descent, but merely a group of similar organisms. The relationships between Archaea, Eubacteria and Eukaryota are assessed differently by different scientists. The three-domain system of Carl Woese treats them as one monophyletic group.
# Protozoa

*Giardia lamblia* is a parasitic flagellate protozoan which causes 'beaver fever'.
**Protozoa** are microorganisms. They are single-celled heterotrophic eukaryotes, which eat bacteria and other food sources.

It is an old term, and the wider term protist is generally preferred today. However, 'protozoa' is often used for convenience, especially in junior education. It is a convenient hold-all term, and most systems of taxonomy classify 'protozoa' into several different phyla.

The term is problematic because modern biochemical and genetic techniques show that it includes several quite different kinds of cells. They are found only in moist or aquatic habitats. Many protozoan species are symbionts, some are parasites, and some are predators of soil bacteria and algae. About 30,000 protozoan species are known. The study of protists is called "protistology".

## Related pages

* Protist
* Eukaryote
* Amoeba
* Paramecium
# Natural history

Henry Walter Bates in the Amazon
HMS Rattlesnake
In the 19th century, naturalists travelled on ships like this! Thomas Henry Huxley went round the world on this ship. He found his wife in Sydney, Australia
**Natural history** is the study of plants and animals in the wild, and the environments they live in. This includes the geology of the places in which they live.

The work of naturalists is observation, interpretation, collecting and classification, rather than experiments. People who study natural history are called **naturalists**. They were among the first to explore the world. They were the first to study the Amazon and other tropical places. Naturalists find new species and classify plants and animals. They study ecology.

Naturalists developed some theoretical ideas which were valuable. They noticed that living things fitted the lives they led. This was adaptation. They noticed a struggle for existence between animals. They thought they could see a chain of being from lower animals to higher, which they thought was the work of God. The idea that such things might happen by natural means began to surface in the 18th century, and become the majority view in time of Charles Darwin.

Before Darwin, most naturalists did not think of themselves as scientists. When they looked at nature, perhaps as explorers, they looked at everything. They looked at the land, the people, the plants and animals. After Darwin, they did see themselves as scientists. Early on, Darwin called himself a geologist. Thomas Henry Huxley was an anatomist. Joseph Dalton Hooker was a botanist. Charles Lyell was a geologist. They changed the way in which they were educated as well. They often took degrees in science. That sort of education was rare before Darwin.

Naturalists were educated amateurs; scientists are trained professionals. The change happened slowly, during the 19th century. The very word *scientist* was invented in 1837 by William Whewell. Before then, the term was *natural philosopher* (for the physical sciences) or *natural historian* (for the biological sciences and geology). *Naturalist* is short for *natural historian*.

## Important naturalists

Some of the people who are important because they were interested in natural history are:

* Aristotle
* Pliny the Elder
* Conrad Gessner
* John Ray
* Georges-Louis Leclerc, Comte de Buffon
* Gilbert White
* Alexander von Humboldt
* Charles Darwin
* Alfred Russel Wallace
# Strain (biology)

In biology, a **strain** is a low-level taxonomic rank below the rank of species. This is seen in microbiology where strains are got from a single cell colony, and are quarantined by being in a Petri dish. Strains are also commonly referred to in virology, in horticulture, and with rodents used in experimental studies.

## Microbiology/Virology

A strain is a genetic variant or subtype of a microorganism, that is to say a virus or bacterium or fungus. For example, a "flu strain" is a certain biological form of the influenza or "flu" virus. Properly speaking, bacteria, archaea and viruses do not have species, because they do not have eukaryote-type sexual reproduction. Bacteria do exchange DNA, but they may exchange it between different kinds of bacteria, which shows their difference from eukaryotes. Strains are therefore an essential part of bacterial identification.

## Plants

In botany, the term is not used to rank plants. It is sometimes used to refer to all the descendants produced from a common ancestor that share a uniform morphological or physiological character. A strain is a designated group of offspring that have descended from a modified plant, produced ether by conventional breeding or by biotechnological means or result from genetic mutation.

For example, some rice strains are made by inserting new genetic material into a rice plant, all the descendants of the genetically modified rice plant are a strain with a unique genetic code that is passed on to later generations. The strain designation, a number or a formal name, covers all the plants that descend from the originally modified plant. The rice plants in the strain can be breed to other rice strains or cultivars, and if desirable plants are produced, these are further breed to stabilize the desirable traits; the stabilized plants that can be propagated and come true, are given a cultivar name and released into production to be used by farmers.

## Rodents

A mouse or a rat strain is a group of animals that is genetically uniform. Strains are used in laboratory experiments. Mouse strains can be inbred or genetically engineered, while rat strains are usually produced by inbreeding.

## Other websites

* International Mouse Strain Resource (IMSR)
* Rat strain index
# Conservation biology

Efforts are being taken to preserve the natural characteristics of Hopetoun Falls, Australia while continuing to allow visitor access
**Conservation biology** is the study of the nature and status of Earth's biodiversity, aimed to protect species, their habitats, and ecosystems from threatening to extinction. It combines subjects ranged from sciences to economics and the practice of natural resource management. The name *conservation biology* was introduced as the title of a meeting held at the University of California in 1978. Both conservation biology and the concept of biodiversity influence conservation policy.

## Related pages

* Conservation movement
* Reforesting
# Species description

When a new species is discovered, it needs to be described. This is known as **species description**. Today, this description is done in the form of an article or paper, published in a scientific journal. The scientific description has to follow strict rules. The person who is the author of the scientific article is also the person who is seen as the one who discovered the species. Usually, he or she can propose a name for the species. If the article has many authors, all of them are seen as discoverers of the species. Describing a species belongs to taxonomy.

## History

Species descriptions have also been done in historic times. That way, Aristotle's History of Animals is probably among the first such publications. The book was published around 343 BC. In it, Aristole describes some of the creatures of his homeland, mostly fish and invertebrates. He also included a few mythical creatures, such as the manticore.

In the year 77 AD, Pliny the Elder described several species, in his work Natural History. He probably read Aristonle's work, as he also describes many of the mythical creatures Aristole does.

In the 13th century, the didactic text *Konungs skuggsjá* was written. It had many descriptions of whales, seals, and monsters of the Icelandic seas. The descriptions were short, and often contained errors. The descriptions include those of a mermaid, and of a large sea monster called Hafgufa. At first, the author did not want it, because he thought it was too big, but felt it was important enough to be included in his descriptions. Today, we know that the Hafgufa does not exist.

Carl Linnaeus wrote *Systema Naturae* in 1735. He was the first to use the modern system of taxonomy, which is still used today.
# Pitcher plant

The pitcher plants of Asia, the *Nepenthes*, grow pitchers from the ends of the leaves
The pitcher plants of America, the *Sarracenia*, grow pitchers up from the roots
A **pitcher plant** is a carnivorous plant (an insectivorous plant). Carnivorous plants are plants which eat insects and other small animals. Carnivorous plants grow in soil which has little nitrogen. All living things must have nitrogen. Carnivorous plants get their nitrogen from the insects they eat. They are adapted to areas with little nitrogen in the soil.

The pitcher of the pitcher plant is actually a modified leaf. The apex of the leaf is always the lid. Pitcher plants catch (get) insects in a cup of liquid. The walls of the cup make nectar (sweet liquid). The nectar attracts insects. When an insect lands on the wall, it falls down into the liquid. The insect cannot get out of the cup because the walls are smooth and slippery and the walls have hairs pointing down.

After the insect is dead, its body rots. Rotting releases (lets loose) the nitrogen from the insect's body. The nitrogen then goes into the liquid and the plant takes in the nitrogen from the liquid.
# Zoology

**Zoology** is the science of studying animal life. It is part of biology*.* Animal life is classified into groups called *phyla*, of which there are at least thirty.

**Zoologists** are scientists who study animals. They may work in laboratories, or do field research. The methods are many and various. At the heart, they cover the structure, function, ecology and evolution of animals. The structure is investigated by dissection, and microscopic examination. The function is investigated by observation and experiment. Palaeontology gives information about extinct animals. Zoologists may have jobs in zoos, museums, universities, and/or non-profit organizations.

## Select zoologists

* Aristotle
* John Ray
* Julian Huxley
* Ernst Haeckel
* Jennifer Clack
* Charles Darwin
* Conrad Gessner
* Richard Dawkins
* Stephen Jay Gould
* Henry Walter Bates
* Thomas Henry Huxley
* John Gould (ornithology)
* Theodosius Dobzhansky
* Dian Fossey (primatology)
* Jane Goodall (primatology)
* Étienne Geoffroy Saint-Hilaire
* Fritz Müller
* Gilbert White
* James D. Watson
* August Weismann
* John Maynard Smith
* Alfred Russel Wallace
* Konrad Lorenz (ethology)
* Jean-Baptiste de Lamarck
* Louis Leakey (palaeoanthropology)
* Louis Agassiz (malacology, ichthyology)
* Carolus Linnaeus (father of systematics)
* Richard Owen (Natural History Museum)
* Georges-Louis Leclerc, Comte de Buffon
* E.O. Wilson, (entomology, founder of sociobiology)

## Related pages

* Cell
* Botany
* Physics
* Ecology
* Cytology
* Genetics
* Evolution
* Chemistry
* Biophysics
* Biochemistry
* Louis Pasteur
* Gregor Mendel
* Molecular biology
* List of animal phyla
* Classical mechanics
* Quantum mechanics
* Mendelian inheritance

## Other websites

* Media related to Zoology at Wikimedia Commons
# Subspecies

Two subspecies of crow. The left one is Corvus corone cornix; the picture was taken in Helsinki. The right one is Corvus corone corone; picture taken in Brussels.
**Subspecies** is a classification (taxonomy) in biology. It is directly below species. When looking at the Latin name, subspecies are indicated by the third name. Subspecies can mix with each other; animals or plants from different subspecies can have offspring together (This is usually not the case with animals from different species).

When looking at subspecies, they can also be told apart sufficiently by looking at the appearance or DNA of an animal or plant.

Very often, there are populations that are between two subspecies; this is because evolution is a continuous process. Subspecies can often be recognised by *subsp* or *ssp* (before the third part of the name) especially in botany.

Examples of subspecies are:

* The dog (*Canis lupus familiaris*) and the dingo (*Canis lupus dingo*) are both subspecies of the wolf (*Canis lupus*)
* The domestic cat (*Felis silvestris catus*) is a subspecies of the wildcat (*Felis silvestris*)

## Nominate subspecies

In zoology, when a species is split into subspecies, the first described population is known as the "nominate subspecies", and it repeats the same name as the species. For example, the "Daboia russelii russelii" (known as the Indian Russell's Viper) is a nominate subspecies of the species "Daboia russelii" (known as the Russell's Viper).