Answers...

Bacteria (formerly known as eubacteria) and Archaea (formerly called archaebacteria) share the procaryotic type of cellular configuration, but otherwise are not related to one another any more closely than they are to the eukaryotic domain, Eukarya. Between the two procaryotes, Archaea are apparently more closely related to Eukarya than are the Bacteria. Eukarya consists of all eukaryotic cell-types, including protista, fungi, plants and animals.

Archaea are the least evolved type of cell (they remain closest to the common point of origin). This helps explain why contemporary Archaea are inhabitants of environments that are something like the earth 3.86 billion years ago (hot, salty, acidic, anaerobic, low in organic material, etc.).

Eucaryotes (Eucarya) are the most evolved type of cell (they move farthest from the common point of origin). However, the eucaryotes do not begin to diversify (branch) until relatively late in evolution, at a time when the Bacteria diversify into oxygenic photosynthesis (Synechococcus) and aerobic respiration (Agrobacterium).

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Leeuwenhoek, Antoni van
Although Leeuwenhoek's family was fairly well off, he received little formal education. After completing grammar school in Delft, Netherlands, he moved to Amsterdam to work as a draper's apprentice (a draper was a person who made and sold clothing). In 1654 he returned to Delft to establish his own shop and worked as a draper for the rest of his life. His medical achievements in lens grinding were actually a hobby rather than his main work. Lenses were an important tool in Leeuwenhoek's profession, since cloth merchants often used small lenses to inspect their products. His hobby soon turned to obsession, however, as he searched for more and more powerful lenses.

In 1671 Leeuwenhoek made his first simple microscope. It had a tiny lens that he had ground by hand from a globule (small ball) of glass and had placed in a brass holder. To this he had attached a series of pins designed to hold the specimen. It was the first of nearly six hundred lenses ranging from 50 to 500 times magnifications that he would grind during his lifetime.
Through his microscope Leeuwenhoek examined such substances as skin, hair, and his own blood. He studied the structure of ivory as well as the physical composition of the flea, discovering that fleas, too, had even smaller parasites on them.