Microbes

1. Microbes Helpful or Harmful?

2. Microbes Defined • A Microbe: • Is a very tiny form of life • Includes: • Viruses • Bacteria • Fungi • Protozoans • Is best seen under the microscope

3. Misconceptions • As you already know, every organism in an ecosystem serves a function, even those we are afraid of. • When most people think of microbes, they tend to think only of the more harmful disease causing microbes such as viruses and bacteria. • However, harmful microbes are not all that exist. • A number of the microbes that are found on Earth are actually highly beneficial to humans.

4. Helpful & Harmful Microbes

5. Microbes in the Environment • In addition to the small scale ways in which microbes affect humans, there are also much larger scale instances in which microbes affect the balance of entire ecosystems. • Two such instances include: • Microbes and Food • Microbes and Disease

6. Microbes and Recycling • As you are already aware, all nutrients in the environment must be recycled. • This recycling process takes place when upper level organisms consume lower level organisms in a food chain, better known as the cycling of matter. • However, upper level organisms consuming other lower level organisms alone, does not complete this cycle. • Instead, smaller, more discrete organisms are needed to complete the necessary decomposition process.

7. Microbes and Food • These essential organisms are microbes, such as fungi, and bacteria. • In a food chain, once an organism is consumed, the nutrients in its body are returned to the soil via its remains, as well as through the expulsion of waste from the consumer. • However, when these remains and waste are deposited on the soil, they require additional assistance to be broken down into basic nutrients so they can then seep into the soil and serve as food for plant life. • It is at this point that microbes step in.

8. Microbes and Food Cont’d • Microbes such as bacteria and fungus feed off the remains and wastes, breaking them down into small molecules which are then able to sink into the soil and in turn, be absorbed by the plant life, to start the matter cycle over again. • If these microbes did not exist however, the entire ecosystem would collapse, as the remains of organisms would simply stay as wastes on the surface of the soil rather than become nutrients within it. • Gradually plants, starved of nutrients, would die, leaving herbivores with no food and therefore causing the total collapse of the food chain.

9. Scavenger 4th Trophic Level Tertiary Consumers ( Top Carnivores) 2nd Trophic Level Primary Consumers (Herbivores) 3rd Trophic Level Secondary Consumers (Carnivores) 1st Trophic Level Producers (Plants) Radiant Energy Decomposers

10. Microbes and Disease • Imagine what would happen if all organisms in an ecosystem were completely healthy and never died… • What would happen to the ecosystem?

11. Microbes and Disease Cont’d • What occurs is overcrowding and eventual collapse of the entire ecosystem. • This is where microbes step in. • When microbes cause disease among populations of organisms, it is a means of regulating population. • This regulation prevents overpopulation of an area and the eventual collapse of the entire ecosystem.

12. Microbes and Disease Cont’d • For example: • If deer in Cape Breton never died, they would eventually overpopulate the area and run out of resources to survive (food, shelter, etc.), thus all of them would be wiped out. • If however, some of them became infected by a microbial disease and died, their population would be reduced and allow all of the deer that remained, the opportunity to obtain the resources necessary for survival.

13. In Conclusion • Microbes are both Helpful and Harmful! • They are a necessary “evil” of an ecosystem.