MICRO-ORGANISMS IN THE ENVIRONMENT ABBOTTS COLLEGE

MAINTAING A BALANCE IN THE ENVIRONMENT Chapter 4 2  Most micro-organisms are harmless or extremely useful  Play a role in keeping eco-systems stable  They give the environment a better chance to survive changes or threats  The web of life heavily depends on these organisms with their huge biodiversity  Ensure environmental stability  Responsible for a wide range of vital functions in the environment  Most micro-organisms are harmless or extremely useful  Play a role in keeping eco-systems stable  They give the environment a better chance to survive changes or threats  The web of life heavily depends on these organisms with their huge biodiversity  Ensure environmental stability  Responsible for a wide range of vital functions in the environment PAGE 9

FUNCTIONS OF MICRO- ORGANISMS IN THE ENVIRONMENT 3  Plant-degraders  Micro-regulators of nutrients  Regeneration of oxygen  Nitrogen transformers  Biological control agents  Plant-degraders  Micro-regulators of nutrients  Regeneration of oxygen  Nitrogen transformers  Biological control agents PAGE 10

PLANT-DEGRADERS 4  Cellulose degrading fungi or bacteria clean up dead plants in the environment

MICRO-REGULATORS OF NUTRIENTS 5  Nutrients like carbon, nitrogen, phosphorus and sulphur are recycled in the environment  Saprotrophic bacteria and fungi are called microregulators because they break down the remaining organic matter from dead organisms into carbon dioxide and nutrients  Protozoan protists are micro- regulators in marine ecosystems  The nutrients eg nitrates and phosphates are absorbed by land plants and algae for growth  Nutrients like carbon, nitrogen, phosphorus and sulphur are recycled in the environment  Saprotrophic bacteria and fungi are called microregulators because they break down the remaining organic matter from dead organisms into carbon dioxide and nutrients  Protozoan protists are micro- regulators in marine ecosystems  The nutrients eg nitrates and phosphates are absorbed by land plants and algae for growth

REGENERATION OF OXYGEN 6  Micro-organisms play a vital role in keeping the level of oxygen at 21% in the atmosphere  Cyanobacteria (bacteria which can photosynthesise) and phytoplankton are vital oxygen generators  They replace about 50% of all used oxygen  Micro-organisms play a vital role in keeping the level of oxygen at 21% in the atmosphere  Cyanobacteria (bacteria which can photosynthesise) and phytoplankton are vital oxygen generators  They replace about 50% of all used oxygen

NITROGEN TRANSFORMERS 7  Nitrifying bacteria change nitrogen into a useable form ie nitrates PAGE 11

BIOLOGICAL CONTROL AGENTS 8  Micro-organisms can act as natural enemies of pests, pathogens and weeds eg fungus which destroys Port Jackson willow  This keeps the environment healthy and balanced  Micro-organisms can act as natural enemies of pests, pathogens and weeds eg fungus which destroys Port Jackson willow  This keeps the environment healthy and balanced

TO DO 9  TEXTBOOK PAGE 10 LEARNING ACTIVITY 7: KEEPING ENVIRONMENT BALANCED  TEXTBOOK PAGE 10 LEARNING ACTIVITY 7: KEEPING ENVIRONMENT BALANCED

ROLE OF MICRO-ORGANISMS IN SYMBIOTIC RELATIONSHIPS 10 PAGE 11

Escherichia coli and humans 11 Chapter 4

12 Figure 1: Location of normal microbial flora bacterial cells in the human flora

Escherichia coli and humans 13  In this mutualistic relationship:  Bacteria benefit by obtaining glucose and other nutrients from the undigested food remains in the colon  Humans benefit by gaining Vitamin K needed in the process of blood clotting  And protection against the growth of pathogenic bacteria within the gut  In this mutualistic relationship:  Bacteria benefit by obtaining glucose and other nutrients from the undigested food remains in the colon  Humans benefit by gaining Vitamin K needed in the process of blood clotting  And protection against the growth of pathogenic bacteria within the gut

Nitrogen-fixing bacteria and plants 14 Chapter 4 Rhizobium leguminosarum nitrogen fixing bacteria. Nodules formed where Rhizobium bacteria infected soybean roots PAGE 11

Nitrogen-fixing bacteria and plants 15 Rhizobium leguminosarum

MYCORRHIZAL FUNGI AND PLANT ROOTS 70 – 80% of all plants have mycorrhizae The fungi send out hyphae to increase surface area of the plant roots The fungi send out hyphae to increase surface area of the plant roots PAGE 12

TO DO 17  TEXTBOOK PAGE 12 LEARNING ACTIVITY 8: MUTUALISM  TEXTBOOK PAGE 12 LEARNING ACTIVITY 8: MUTUALISM

18  THE END