The very basics of microbial ecology

1
The very basics of microbial ecology

• What is the unique position of microbes in the
  environment?

2
I. Relationships among different organisms in an
ecosystem

• Microbes are found at all levels of interaction
• Most decomposers are microbes
• Decomposers convert waste material into forms
  that other organisms can use

3
II. Adaptation to high and low levels of nutrients

• Few nutrients (typically) in aqueous environments
  or in certain types of soil
• Successful organisms are very efficient in
  acquiring what they need
• Eutrophication- what happens when you get
  nutrients where theyre not supposed to be?

4
III. Competition and antagonism

• The organism that multiplies the fastest wins
• Some organisms produce substances that give them
  an advantage (antibiotics)

5
V. Adaptation to change
6
Habitats and their characteristics

• Aquatic- marine and fresh
• Wide variance in temperature, nutrients, access
  to light, solid supports
• Terrestrial
• Wet or dry, acidic or alkaline, little much
  organic material

7
Flow of energy and chemicals

• Energy sources sunlight or chemicals
• Energy continually enters the system much of it
  is wasted
• Chemicals are cycled through the environment (see
  part 30.4)
• Used as sources of energy and structure
• Microbes are required for cycling of carbon,
  sulfur, nitrogen, phosphorus and many other
  elements

8
Symbiotic relationships between microbes and
other organisms

• Mycorrhizae- fungi grow in symbiotic relationship
  with plants
• Nitrogen fixing bacteria- convert nitrogen gas
  into form that plants can use-associate with
  legumes

9
Summary

• Organisms do NOT exist in isolation in the
  natural environment
• Many different types of ecosystems are found on
  Earth the types of organisms vary in each
  ecosystem and are adapted to survive in that
  system
• If the system changes, organisms must adapt to
  that change in order to survive
• Microbes play unique and essential roles in each
  ecosystem
• Think of the body as an ecosystem