DOMAINS OF LIFE Domains A New Taxa 1996

DOMAINS OF LIFE

Domains: A New Taxa � 1996: Proposed by Carl Woese and George Fox

Domains

THE PROKARYOTES

Prokaryotes � Single-celled organisms that lack membranebound organelles

Prokaryotes � Smallest living organisms � Found living everywhere on Earth � Some are: � heterotrophs, � autotrophs, � chemotrophs

Roles of Prokaryotes � Pathogens: � Decomposers:

Roles of Prokaryotes

Roles of Prokaryotes � Live in the intestines of animals � Mutualistic � How � relationship: do both organisms benefit? Live in soil and “fix” nitrogen � What type of relationship is this?

Roles of Prokaryotes

Roles of prokaryotes � Used in food production � Most recently, bacteria have been utilized for their ability to produce chemicals

Kingdoms of Prokaryotes � Split into: � Eubacteria � Archaea (true bacteria) (ancient organisms)

Eubacteria • Capsule: • Cell wall: • Peptidoglycan • Historically, bacteria were classified based on whether their cell wall turned color when the bacteria was stained in the Gram staining protocol

Eubacteria • Chromosome: • Nucleoid region: • Plasmid: • Flagellum and Pili:

Eubacterial shapes

Eubacterial Metabolism � Aerobes: � Anaerobes:

Eubacterial Metabolism � Obligate vs. Facultative

Types of Eubacteria � The autotrophs: �Know table on page 48 of textbook

Types of Eubacteria � The autotrophs: � Purple bacteria (proteobacteria)

Types of Eubacteria � The autotrophs: � Green bacteria

Types of Eubacteria � The autotrophs: � Blue-green algae (cyanobacteria)

Types of Eubacteria � The heterotrophs � Gram-positive bacteria

Types of Eubacteria � The heterotrophs � Spirochetes

Types of Eubacteria � The heterotrophs � Chlamydias

Cell Division � Cells divide by binary fission � During binary fission, describe what happens to the cell and what happens to the DNA?

Cell Division � Cells divide by binary fission � Mutations? What are they?

Increasing Genetic Diversity � Conjugation: � Transformation: � Role of these?

ARCHAEA Extremophiles

Types of Archaea � Methanogens

Types of Archaea � Halophiles

Types of Archaea � Thermophiles

Types of Archaea � Psychrophiles

Homework � To be completed for Monday, Oct 14. � 1) Believe it or not, pathogens are a required part of a healthy ecosystem. What role(s) do pathogens play in the environment? � 2) List out 5 -10 other roles that prokaryotes play in the environment. � Textbook: Read pages 44 -53. Do problems 6 -10 on page 53.