Marxism and Humanism

This trend of thinking is powerfully developed in the thought of Karl Marx (a student of Hegel's thought) and his secular historical materialism. With splendid rhetoric, Marx describes the mid-19th century condition in the Communist Manifesto as follows:

"The bourgeoisie cannot exist without constantly revolutionizing the instruments of production, and thereby the relations of production, and with them the whole relations of society. Conservation of the old modes of production in unaltered form, was, on the contrary, the first condition of existence for all earlier industrial classes. Constant revolutionizing of production, uninterrupted disturbance of all social conditions, everlasting uncertainty, and agitation distinguish the bourgeois epoch from all earlier ones. All fixed, fast frozen relations, with their train of ancient and venerable prejudices and opinions, are swept away, all new-formed ones become antiquated before they can ossify. All that is solid melts into air, all which is holy is profaned, and man is at last compelled to face with sober senses his real condition of life and his relations with his kind."

The capitalist era in history is understood here very radically as a process of continual change, in which the growth of markets dissolve all fixities in human life. This is an almost absolute rejection of the conservative ethos, according to which nothing really changes in human life. Marxism further states that capitalism, in its quest for higher profits and new markets, will inevitably sow the seeds of its own destruction. Marxists believe that, in the future, capitalism will be replaced by socialism and eventually communism.

White Nile

The White Nile (Arabic: النيل الأبيض, transliterated: an-Nīl al-Ābyadˤ) is a river of Africa, one of the two main tributaries of the Nile, the other being the Blue Nile. In the strict meaning, "White Nile" refers to the river formed at Lake No at the confluence of the Bahr al Jabal and Bahr el Ghazal rivers. In the wider sense, "White Nile" refers to the approximately 3700 kilometers (2300 miles) of rivers draining from Lake Victoria into the White Nile proper. It may also, depending on the speaker, refer to the headwaters of Lake Victoria.

The 19th century search by Europeans for the source of the Nile was mainly focused on the White Nile, which disappeared into the depths of what was then known as "Darkest Africa". The discovery of the source of the White Nile thus came to symbolise European penetration of unknown jungle.

Tephritidae

Tephritidae is one of two fly families referred to as "fruit flies." Tephritidae does not include the biological model organisms of the genus Drosophila, which is often called the "common fruit fly". Drosophila is, instead, the type genus of the second "fruit fly" family, Drosophilidae. There are nearly 5,000 described species of tephritid fruit fly, categorized in almost 500 genera. Description, recategorization, and genetic analysis are constantly changing the taxonomy of the fruit fly family.

Tephritid fruit flies are of major importance in agriculture. Some have negative effects, some positive. Various species of fruit fly cause damage to fruit and other plant crops. The genus Bactrocera is of worldwide notoriety for its destructive impact on agriculture. The olive fruit fly (B. oleae), for example, feeds on only one plant: the wild or commercially cultivated olive. It has the capacity to ruin 100% of an olive crop by damaging the fruit. On the other hand, some fruit flies are used as agents of biological control, thereby reducing the populations of pest species. Several species of the fruit fly genus Urophora have been shown to be effective agents against rangeland-destroying noxious weeds such as starthistles and knapweeds.

Most fruit flies lay their eggs in plant tissues, where the larvae find their first food upon emerging. The adults usually have a very short lifespan. Some live for less than a week.

Fruit flies use an open circulatory system as their cardiovascular system.

Their behavioral ecology is of great interest to biologists. Some fruit flies have extensive mating rituals or territorial displays. Many are brightly colored and visually showy. Some fruit flies show Batesian mimicry, bearing the colors and markings of dangerous insects such as wasps because it helps the fruit flies to avoid predators; the flies, of course, lack stingers.

Six kingdoms

In the years around 1980 there was an emphasis on phylogeny and redefining the kingdoms to be monophyletic groups, groups made up of relatively closely related organisms. The Animalia, Plantae, and Fungi were generally reduced to core groups of closely related forms, and the others placed into the Protista. Based on RNA studies Carl Woese divided the prokaryotes (Kingdom Monera) into two kingdoms, called Eubacteria and Archaebacteria. Carl Woese attempted to establish a Three Primary Kingdom (or Urkingdom) system in which Plants, Animals, Protista, and Fungi were lumped into one primary kingdom of all eukaryotes. The Eubacteria and Archaebacteria made up the other two urkingdoms. The initial use of "six Kingdom systems" represents a blending of the classic Five Kingdom system and Woese's Three Kingdom system. Such six Kingdom systems have become standard in many works.

A variety of new eukaryotic kingdoms were also proposed, but most were quickly invalidated, ranked down to phyla or classes, or abandoned. The only one which is still in common use is the kingdom Chromista proposed by Cavalier-Smith, including organisms such as kelp, diatoms, and water moulds. Thus the eukaryotes are divided into three primarily heterotrophic groups, the Animalia, Fungi, and Protozoa, and two primarily photosynthetic groups, the Plantae (including red and green algae) and Chromista. However, it has not become widely used because of uncertainty over the monophyly of the latter two kingdoms.

Woese stresses genetic similarity over outward appearances and behaviour, relying on comparisons of ribosomal RNA genes at the molecular level to sort out classification categories. A plant does not look like an animal, but at the cellular level, both groups are eukaryotes, having similar subcellular organization, including cell nuclei, which the Eubacteria and Archaebacteria do not have. More importantly, plants, animals, fungi, and protists are more similar to each other in their genetic makeup at the molecular level, based on rRNA studies, than they are to either the Eubacteria or Archaebacteria. Woese also found that all of the eukaryotes, lumped together as one group, are more closely related, genetically, to the Archaebacteria than they are to the Eubacteria. This means that the Eubacteria and Archaebacteria are separate groups even when compared to the eukaryotes. So, Woese established the Three-domain system, clarifying that all the Eukaryotes are more closely genetically related compared to their genetic relationship to either the bacteria or the archaebacteria, without having to replace the "six kingdom systems" with a three kingdom system. The Three Domain system is a "six kingdom system" that unites the eukaryotic kingdoms into the Eukarya Domain based on their relative genetic similarity when compared to the Bacteria Domain and the Archaea Domain. Woese also recognized that the Protista Kingdom is not a monophyletic group and might be further divided at the level of Kingdom. Others have divided the Protista Kingdom into the Protozoa and the Chromista, for instance.