Oldest and most abundant organisms

Prokaryotic (“before a nucleus”)

Unicellular & Microscopic Undergo asexual

reproduction Prokaryotes are single-celled

organisms. They are the smallest, simplest organisms

Subkingdom Archaebacteria- differ

fundamantally from eubacteria with respect to their metabolism and preference for exotic environments.

-can live in the most extreme of environments.

Is also called the true bacteria

Not classified accdg to shape as coccus, bacillus and spirillum but according to chemical composition of their cell walls and reaction to Gram stain

These bacteria live in very hot, acid habitats of 60-80 and pH 2-4, like the photo of a "Hot springs" below, the red stain on the rocks are the prokaryotic cells.

Eubacteria are more modern bacteria.

Inhabit nearly every known habitat

Consumers, producers, and decomposers

Some cause disease but most are harmless

They are found in nearly every habitat studied, including some that no other organism is able to withstand.

Bacteria have a cell wall, a cell membrane surrounds the cell but no membrane-bound organelles such as a nucleus, mitochondria, chloroplasts, Golgi apparatus, or ER. Some are covered by a layer of “slime” called a capsule. Some have flagella for locomotion.

1. Cocci – spherical (coccus)

2. Bacilli – rod-shaped (bacillus)

3. Spirilla – spiral (spirillum)

Most are heterotrophs although some are autotrophs.

The autotrophic bacteria either use chemicals as a source of energy (chemoautotrophs) or are photosynthetic (photoautotrophs).

Some are parasites which live off a living host

Leucothrix mucor

Some are saprobes, feeding off dead organisms and waste

(i.e., decomposers).

Prokaryotes have a single circular chromosome attached to the inside of the plasma membrane

Prokaryotes reproduce by simply splitting in two The DNA is copied and the cell divides into two

identical cells.