The Microbial World

Chapter 5http://www.youtube.com/watch?v

=1TmHlcMDIOQ

Microorganisms

• All three domains have microogranism representation

• What are those three domains?

• Without microorganisms there would be no life on earth.

Domain: Bacteria

Domain: Archaea

Domain: Eukaryota

Primary producers

• Microorganisms are the most important primary producers

• Directly or indirectly feed most marine animals

Prokaryotes

• Small• Structurally simple• Oldest life forms on earth– Carry out nearly all the chemical processes more

complex organisms do• Some unique processes to prokaryotes

• Most chemical processes evolved first in prokaryotes

Prokaryote Structure

• Cell wall• Lack a nucleus• Lack membrane bound organelles• Differ from Eukaryotes in – Shape of DNA – circular shape– Size of ribosomes

Prokaryote

Two Prokaryotic Domains • Bacteria • Archaea

• Even these two prokaryotic domains have important differences

• Bacteria and Archaea are as different from each other as they are from humans! Woah!

• • Discovery ed

Bacteria

• Structurally simple• Classified as prokaryotes • Evolved a range of metabolic abilities• Abundant in all parts of the ocean• Shapes– Spheres, rods, sprials, rings-Ridged cell wall with slimy covering (attach to

surfaces)

Size of bacteria

• Smaller than unicellular eukaryotes. • Exception- bacteria found in sediment off

southwest Africa- large enough to be seen with the naked eye

Where do they live

• Can grow to extremely high numbers in favorable conditions– Detritus (particles of dead organic matter)

• Decay bacteria – break down waste products and dead organic matter– Releases nutrients into the environment

Why are they important

• As we know bacteria are very abundant – Marine environment offers some new discoveries

• Make up large part of the organic material that feeds bottom-dwellers

• Important in dredging oil and other toxic pollutants

• Bad side- spoil fish and shellfish catches

• http://www.youtube.com/watch?v=mYG5vmad1mk

Cyanobacteria

• Blue-green algae• Photosynthetic– Pigments chlorophyll – Phycocyanin (Blue)– Phycoerythrin (Red)

• Visible color depends on the relative amounts of the two pigments

Cyanobacteria

• Where among the first photosynthetic organisms on earth. – Accumulation of oxygen in our atmosphere

• Stromatolites- Massive calcareous mounds formed by cyanobacteria.– Date back to 3 million years – http://www.youtube.com/watch?v=uzwvjOSS2Pc

Cyanobacteria

• Endolithic- burrow into calcareous rocks and coral skeletons

• Red tides- caused by a planktonic form that blooms– Some can cause skin rashes on divers and

swimmers• Epiphytes- on algae and plants• Endophytes- live inside algae

Bathroom Break

•

Archaea

• Some times called archaebacteria• Simple• Primitive life• Important role in the early evolution of life

Structure

• Small• Spherical, spiral, rod shaped• Despite being prokaryotic, there is evidence

that archaea are more closely related to eukaryotes than bacteria

Where do they live?

• Some groups were discovered recently • Extreme environments– Hot sulfur springs, saline lakes, highly acidic or alkaline

environments– Extremophiles “lovers of extreme environments”

• Also found in extreme marine environments• They are not restricted to extreme environments– Common in the water column and other marine

environments– http://www.youtube.com/watch?v=D69hGvCsWgA

Exit Ticket

• 1)Blue green algae are known as• a) Archaea b) Extremophiles c) Cyanobacteria d) Cilliates

• 2) Which of the following is not a domain a) Archaea b) Bacteria c) Eukaryota d) Fungi

• 3) Bacteria and Archaea are very closely related • a) True b) False

• 4) Stramenopiles are made up of• a)Cyanobacteria b) Diatoms c) Dinoflagellates d) Amebas

• 5) Bacteria are prokaryotes • a) True b) False