Learn that bacteria outweigh plants and animals

Time needed: 10-12 minutes Difficulty: Beginner Category: Science

About this idea

Discover the shocking fact that the total weight of all bacteria on Earth exceeds that of all plants and animals combined! This quick microbiology lesson reveals how microbes make up most of our planet's biomass and why they're the true rulers of Earth.

#microbiology#biology#bacteria#biomass#ecology

On this page

How to get started

STEP 1
the numbers (3 minutes)
  1. Total Earth biomass:
  2. - Bacteria: ~70-90 billion tons (largest!)
  3. - Plants: ~450 billion tons
  4. - Animals: ~2 billion tons
  5. Wait - plants are more?
  6. But most plant mass is dead wood
  7. Living plant tissue: ~200 billion tons
  8. Living bacteria: ~70-90 billion tons
  9. Bacteria make up ~13% of ALL living biomass
  10. More than all animals combined!
STEP 2
where they live (4 minutes)
  1. Everywhere:
  2. - Soil (trillions per gram)
  3. - Ocean (most of ocean biomass)
  4. - Inside other organisms (your gut, plants, animals)
  5. - Deep underground (subsurface biosphere)
  6. - Extreme environments (hot springs, ice, deep sea)
  7. Most are in:
  8. - Ocean (marine bacteria)
  9. - Soil (terrestrial bacteria)
  10. - Deep subsurface (underground)
STEP 3
why SO many? (3 minutes)
  1. Tiny but numerous:
  2. - Single bacterium: ~1 picogram (trillionth of gram)
  3. - But there are quintillions of them!
  4. - Reproduce rapidly (some every 20 minutes)
  5. - Adapt to any environment
  6. - Been around 3.5+ billion years
  7. - Found life in every tested environment
STEP 4
IMPLICATIONS (2 minutes)
  1. Bacteria run the planet:
  2. - Cycle nutrients
  3. - Produce oxygen (cyanobacteria)
  4. - Decompose dead matter
  5. - Fix nitrogen for plants
  6. - Regulate climate
  7. We're living in the 'Age of Bacteria'
  8. Humans are recent additions
  9. Bacteria will outlast us

What you’ll need

Recommended resources

Tutorials & Learning

  • Earth Biomass Study
    Scientific research
  • Bacteria: Rulers of Earth
    Documentary clip

Communities

  • r/microbiology
    Microbiology discussion
  • r/ecology
    Ecology discussion

Progress milestones

Track your progress with these key achievements:

1
5 minutes
Understand bacteria's dominance
2
8 minutes
Learn where they live
3
12 minutes
Grasp their planetary importance

Common challenges

Every beginner faces obstacles. Here's how to overcome them:

Plants seem bigger, so how are bacteria more?
Solution: Most plant mass is dead wood (not living). When you count only living tissue, bacteria make up a huge portion. Also, bacteria are everywhere - in soil, water, inside organisms - so their total mass is enormous despite being tiny.

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