Microorganisms and decay | Year 7 Biology (Cambridge) PDF Download

Microorganisms: The Hidden Heroes of Earth

Microorganisms, or microbes, make up over 60% of all life on Earth. They are so small that we need a microscope to see them. Despite their size, they are crucial for our survival. Microbes help us breathe, grow food, and much more. There are estimated to be about two to three billion different species of microorganisms.

Let's explore the six main groups of microorganisms and their roles, both good and bad:

Protozoa

• Description: Protozoa are single-celled organisms usually found in water bodies and soil.
• Importance: They provide nutrients for other organisms and form the backbone of many food webs.
• Example: Protozoa play a crucial role in nutrient cycles by breaking down organic matter.

Fungi

• Description: Fungi include both visible forms like mushrooms and invisible forms like yeasts and molds.
• Uses:
  • Positive: Yeasts help in making bread rise and fermenting alcohol. Fungi are also essential in decomposing organic matter.
  • Negative: Some fungi can cause diseases such as yeast infections.
• Example: Yeast in bread-making and mold in cheese production.

Bacteria

• Description: Bacteria are single-celled organisms that can be found everywhere, from soil to human bodies.
• Uses:
  • Positive: Many bacteria are beneficial, aiding in digestion, boosting the immune system, and producing foods like cheese and yogurt. Some bacteria help in nitrogen fixation, making soils fertile.
  • Negative: Some bacteria can cause diseases.
• Examples:
  • Good Bacteria: Lactobacillus in yogurt, nitrogen-fixing bacteria in soil.
  • Harmful Bacteria: E. coli causing food poisoning.

Viruses

• Description: Viruses are tiny infectious agents that require a host to replicate.
• Impact:
  • Negative: Many viruses cause diseases like the flu and COVID-19.
  • Future Potential: Scientists are exploring how viruses might be used to kill harmful bacteria and create new treatments.
• Example: Common cold virus and its potential use in gene therapy.

Algae

• Description: Algae are photosynthetic organisms that live in water.
• Importance:
  • They produce oxygen and form the base of many food chains.
  • Algae-based ingredients are used in everyday products like ice cream, toothpaste, and cosmetics.
• Example: Spirulina in health supplements and algae in biofuel production.

Decomposition and Recycling

• Role of Microbes: Bacteria and fungi play a key role in decomposition, breaking down dead organisms and waste into simpler substances.
• Importance: This process recycles nutrients back into the soil, supporting plant growth and maintaining ecosystem balance.
• Example: Fungi decomposing fallen leaves and bacteria breaking down animal waste.

Microbes and Antibiotics

• Current Use: Many antibiotics come from soil bacteria.
• Future Potential: Researchers are investigating new ways to use microbes, including viruses, to develop powerful antibiotics to combat superbugs.
• Example: Penicillin from mold and potential use of bacteriophages (viruses that infect bacteria) to treat bacterial infections.

Fun Facts and Examples

• Smelly Armpits: The odor is caused by bacteria on the skin.
• Cheese and Yogurt: Made with the help of bacteria.
• Biogas Production: Bacteria are used in anaerobic digesters to create biogas as an alternative to fossil fuels.
• Antibiotic Crisis: New antibiotics are being developed from soil bacteria, and viruses are being explored as potential treatments for bacterial infections.

Conclusion

Microorganisms are vital to life on Earth. They help produce oxygen, decompose waste, and even create foods and medicines. While some can cause diseases, their overall impact is overwhelmingly positive. Understanding and harnessing the power of these tiny organisms can lead to significant advancements in health, agriculture, and environmental sustainability.