Week Four: Oleander

Not-So-Fun Fact: All parts of the oleander shrub have been infamous since classical times as a lethal poison.

Common Name: Oleander

Scientific Name: Nerium oleander

Domain: Eukaryota

Kingdom: Plantae

Phylum: Magnoliophyta

Class: Magnoliopsida

Order: Gentianales

Family: Apocynaceae

Genus: Nerium

Species: N. oleander

Description: Oleander is a large woody-stemmed shrub covered by five-petaled blossoms in shades of red, yellow, pink, or white. All parts of the plant contain oleandrin, a cardiac glycoside named after the plant.

Environment: Oleander prefers warm, dry, sunny climates in temperate and tropical regions across the globe. It originated in the Mediterranean, where it was described by such prominent naturalists as Pliny the Elder.

Reproduction & Development: Oleander is an angiosperm, which means that it reproduces sexually by way of pollination of its flowers. It is capable of self-pollination, which is fortunate, since oleander is rarely visited by its insect pollinators. Those flowers that are pollinated produce spores that disperse themselves, and from these grow new shrubs. Oleander is a perennial evergreen.

Nutrition: Oleander prefers dry, sunny locations, though the young seedlings do require more water than the adults. Like all plants, it uses photosynthesis to produce sugars, which are stored in the plant; and oxygen, which is released as a waste product.

 

Week Three: Zaire Ebolavirus

Not-So-Fun Fact: This particular organism is currently wreaking havoc in Liberia, Guinea, Nigeria, and Sierra Leone. Therefore, let us understand it further by its biological characteristics.

Common Name: Zaire Ebola Virus

Scientific Name: Ebolavirus zaire

Ebola is known to be a virus. The classification of a virus as an organism is currently being debated among biologists and taxonomists. The taxonomy pertaining to Zaire Ebolavirus is listed below, after the grouping Virus.

Class: ssRNA negative-strand viruses

Order: Mononegavirales

Family: Filoviridae

Genus: Ebolavirus

Species: E. zaire

Description: The virus itself is encapsulated by a membrane built from the stolen cell membrane of its parent’s host cell. Inside this membrane is a set of nuclear proteins and a single string of RNA—the precursor to DNA—which documents the virus’s genetic code. The viral capsule measures 920 nanometers in length and 80 nanometers in diameter.

Environment: Ebolavirus must inhabit a host animal. It is found in the host’s bodily fluids. Its natural host is the fruit bat of the Pteropodidae family, but primates, including humans, have become accidental hosts. Many other animals have also been found to carry Ebola Virus Disease.

Reproduction & Development: Ebolavirus reproduces by invading an animal cell and stealing phospholipids and proteins to duplicate itself. The new ebolavirus units escape into the rest of the host to do the same to other cells. In humans the incubation period of Ebola is 2-21 days.

Nutrition: Ebola, like many viruses, feeds off of its host. It steals material from the cells of its host to help itself grow and replicate. The host cell’s cell membrane is especially damaged in the virus’s feeding frenzy.

Week Two: Human

Common Name: Human

Scientific Name: Homo sapiens

Domain: Eukaryota

Kingdom: Animalia

Phylum: Chordata

Class: Mammalia

Order: Primates

Family: Apes

Genus: Homo

Species: H. sapiens

 

Description: Humans are bipedal apes, with fine hair over most of their bodies. On the crown of the head and on the brow grows denser hair, used to block the rays of the sun. Like most apes they do not have tails, but do possess five-fingered hands with one finger jointed as a “thumb.” Humans walk vertically, with the head as the highest point and the hind set of feet—a set of apelike hands that have lost their ability to grip—as the lowest point.

Environment: Humans are found worldwide, and some individuals have even temporarily inhabited Antarctica. Humans are opportunistic and easily adapt to any new environment using tools. This species can be found in any biome.

Reproduction & Development: Humans reach maturity at around twelve to sixteen years of age. If the female has children, they will gestate for approximately forty weeks before being born. Single births are most common, but some females may give birth to two, three, or even more infants at one time. The average lifespan for a human is about eighty years of age, which has roughly doubled from its original estimate. Some humans can live for over one hundred years of age. Most human females cease being able to reproduce at around fifty years of age, though human males may continue for longer.

Nutrition: Humans are omnivores, and may eat fruit, vegetables, meat, and other animal products. Many fruits and vegetables are poisonous to the human, however. Humans are very opportunistic feeders, but their diets are self-restricted for unknown reasons.

Fun Fact: Humans are one of the most dangerous animals on earth. They even cause harm to themselves by willingly exposing themselves to or even ingesting toxins that they have created. Humans pose a severe threat to the environments they inhabit.

Week One: Assassin Bug

Common Name: Assassin Bug

Scientific Name: Triatoma infestans

 

Domain: Eukaryota

Kingdom: Animalia

Phylum: Arthropoda

Class: Insecta

Order: Hemiptera

Family: Reduviidae

Genus: Triatoma

Species: T. infestans

Description: Darwin described the assassin bug—of which he was a victim—as a “wingless…great black bug,” but in fact the assassin bug does possess a pair of dark wings folded demurely on its long abdomen. The bugs are oval in shape, with the typical insect arrangement of six long legs, three distinct body segments, and a pair of antennae. The head is small and elongated and has a slight resemblance to a black horse or cow skull, with a long, curved proboscis like an ibis’s beak. The body measures about 25 millimeters in length.

Environment: T. infestans lives in the rainforests of South America and may be found either in the dwelling of the victim or in the fronds of palm trees.

Reproduction & Development: The mature female insect may lay between 100-600 eggs, depending on how much blood she ingests and therefore how much nutrition she has to spare.

Nutrition: the main food of the assassin bug is the blood of birds, rodents, bats, and humans. The insects typically are the uninvited guests of their hosts’ dwellings.

Not-So-Fun Fact: Assassin bugs carry Chagas disease, which is most often fatal and causes symptoms including sores, fever, swollen lymph nodes, and damage to the major organs. The disease is transmitted when the feces of the insect, deposited near the feeding site, is scratched by the victim into the bite and therefore into the bloodstream.

 

 

Week One: King Cobra

Common Name: King Cobra

Scientific Name: Ophiophagus Hannah

Domain: Eukaryota

Kingdom: Animalia

Phylum: Chordata

Class: Reptiles

Order: Squamata

Family: Elapidae

Genus: Ophiophagus

Species: O. hannah

 

Description: The king cobra may grow to a length of 16 feet, but on average it is only 13 feet long. It has a distinctive “hood” on its neck which it spreads when feeling threatened. This hood is black or a dusty olive and usually sports a double chevron marking in cream or yellow. To blend in with its habitat the cobra’s scales and skin are colored in shades of olive-green, tan, and black. Its underside is creamy yellow.

Environment: The king cobra inhabits dense, undisturbed forests and bamboo groves in Southeast Asia and the Indian subcontinent. The bamboo groves are used to provide shelter and concealment for the cobra and its eggs. Individuals are often found by humans in abandoned rural buildings and in forests in the process of being cleared, which puts both the cobra and the human in danger due to the snake’s venomous and potentially lethal bite.

Reproduction & Development: Cobras mate in January and the females lay between forty and fifty eggs approximately one month later. The eggs will gestate for seventy to seventy-seven days after they are laid in a nest on the ground. During this time they are fiercely protected by the mother, although after the eggs hatch the newborn cobras are left to fend for themselves. After about four years the cobras are ready to reproduce themselves, and may live to the age of twenty.

Nutrition: King cobras eat snakes and lizards. After the reptile has succumbed to its venom the cobra dislocates its jaw and swallows its victim whole. It uses its bite only to kill prey, and bites other animals only in self-defense.

Fun Fact: The family to which the king cobra belongs—Elapidae—also includes the equally infamous and venomous coral snake, death adder, and green mamba.

 

Week One: Black Fly

Common Name: Black Fly

Scientific Name: Simulium Damnosum

Domain: Eukaryota

Kingdom: Animalia

Phylum: Arthropoda

Class: Insecta

Order: Diptera

Family: Simuliidae

Genus: Simulium

Species: S. damnosum

Description: Black flies follow the generic design of the diptera order, which includes common houseflies and the more rotund blowfly. Unlike these cousins, however, the black fly has a distinctly divided head and thorax. The head is oriented downward toward the flesh on which it can often be found, and features large vertical oval eyes. The abdomen is fat and segmented. The wings, following the fashion of the dipteran, are colorless and transparent and two in number (“di”=two, “ptera”=wing). The black fly typically measures from 2-5 millimeters.

Environment: S. damnosum is mainly found in the fertile river valleys of West Africa. Black flies congregate in biting swarms around rivers and riverbanks, and attack any warm-blooded animal unlucky enough to stumble into a swarm. Determined swarms have been known to kill their victims by sheer exsanguination.

Reproduction & Development: Once mature, female black flies mate and afterward begin feeding on as much blood as they are able to extract from their victims. Over a month’s time they lay eggs on the surface of swiftly flowing rivers and then die. These eggs will hatch into larvae—maggots—that live in the mud of the river’s banks until they undergo metamorphosis.

Nutritional Requirements: Black flies are opportunistic and feed on the blood of any warm-blooded animal they are able to find.

Not-So-Fun Fact: West African black flies carry the nematode whose scientific name is Onchocerca volvulus. This worm’s larvae, called microfiliae, cause onchocerciasis, which is often referred to as “river blindness.” The microfiliae’s wanderings inside a human host cause infection and blindness in the eyes and provoke lesions, rashes, depigmentation, and severe irritation of the skin.

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Welcome to Organism of the Week!
Perhaps you are someone besides my professor--it sounds more sophisticated when you say professor--checking to see if I have completed this week's assignment. If you are, then you may be some combination of bored and awesome.
Thanks for reading.
This blog will post one entry most every week on an organism of my choice. These organisms will often be poisonous/venomous/disease-carrying little vectors of hate. If you are interested in microbiology and/or toxicology and/or epidemiology, then this is a good blog for you. Or maybe you just like factoids.
Or maybe you're just checking to see if I've done my homework. (Hi there Ms. L!)
--Lily