Living Things 1.7 million species been classified suggested around 8.8 million species all are put into groups based on genetics 3 main domains (groups) are: Archaea & Eubacteria – prokaryotes Eukaryotes BiologySource

Prokaryotes – 2 Kingdoms Formerly 1 kingdom - Monera Archea – primitive bacteria Eubacteria – more developed earliest life on earth diverged from common ancestor ~ 4 bya eukaryotes diverged millions yrs later

Eukaryotes – 4 Kingdoms Plant, Animal, Fungi, Protists

1. Archea can live in extreme conditions thermophiles – hot temp like hydrothermal vent halophile – salty environments like Dead Sea

psycrophiles – live at cold temp (Antarctic lakes) acidophiles – can tolerate pH 0 some live in normal temp and environments most are methanogens – absorb CO 2, N 2, or H 2 S and give off methane doesn’t require sunlight or oxygen

2. Eubacteria “true” bacteria microscopic ex cyanobacteria (blue-green algae) on earth for over 3 billion years able to carry out photosynthesis (produces oxygen) oxygen conc of atmosphere increased allowing oxygen breathers (animals) to survive

Uses of Eubacteria digestion in intestines yoghurt/cheese production fermentation (wine, beer, pickling…) wastewater/oil spill/toxic spill treatment BiologySource decomposers

Dangerous Eubacteria cause health problems: strep throat food poisoning (E. coli and salmonella)

Structure & Function of Bacteria microscopic smallest living cells classified according to: 1. cell shape 2. cell wall structure 3. motility (way of moving)

1. Cell Shape 3 basic cell shapes spherical – “cocci” rod-shaped – “ bacilli” spiral – “spirochetes”

prefixes are added to show living arrangement of bacteria strepto – chain stphlyo - cluster

CAN YOU NAME IT??? staphylococcus diplococcus streptococcus

2. Cell Wall Structure 2 kinds of cell walls, appear different when stained with Gram stain peptidoglycan – thick coat of sugars, makes wall strong & rigid (Gram postive) less peptidoglycan (Gram negative)

Movement various methods: most mobile bacteria use flagella (whip- like tail) others secrete mucous can glide on

Typical Bacteria

How Bacteria Reproduce 1. Asexual - Binary Fission 1 original cell splits into 2 can occur in 20 minutes for many bacteria species. In 12 hours, 1 bacterium can divide to form a colony of 68 billion cells. overcrowding, waste, and food availability do not allow populations to grow this large. produces colonies of bacteria that are genetically identical.

2. Types of Sexual Reproduction 1. Transformation: bacteria pick up stray DNA from their surroundings. 2. Conjugation: two bacterial cells join (= conjugate) to exchange genetic material (plasmids, separate from main DNA)

3. Transduction: viruses that infect bacteria transmit genetic material from another source Endospores form when environmental conditions make normal functions too difficult.

Viruses: Structure and Function Viruses not considered to be living organisms. ◦ have DNA and RNA, and can adapt to change. ◦ made of proteins and nucleic acids, not cells. ◦ must use a host cell to reproduce. See page 29

structure of virus allows it to enter host cell and reproduce ◦ many shapes and sizes. ◦ usually classified by the type of cell they infect. ◦ protein coat is like the key to a specific cell membrane, e.g., HIV only infects T cells of the immune system. ◦ Sometimes, (avian flu virus) protein coat is a master key. ◦ Bacteriophages enter and infect bacteria, used in biotechnology and gene therapy.