We live in a visible world of buildings, roads, people, trees, insects, animals, and cities. Yet what is invisible is more powerful and critical to all life. Invisible microbes, or microorganisms, by the trillions, are all around. We carry microbes on our hands, under our fingernails, eyelids, and bodies. We each have more than 100 trillion microbes on and in us right now! Microbes are Earth’s first life forms, appearing about 3.5 billion years ago. They began as anaerobic organisms before Earth had oxygen. These early microbes are similar to the purple and green bacteria of today. Photosynthetic bacteria took another million years to respond to the sun’s energy and synthesize into biological molecules. Cyanobacteria appeared another billion years later and began to oxygenate our atmosphere. Over the evolution of trillions of microbes, multicellular life forms appeared. Today around 60% of living and non-living organic material is full of microorganisms. Every ecological process on Earth encounters microbes directly or indirectly. Without microorganisms, life on Earth would not be possible!
Activity 1 – The Importance of Microbiology
Today we know that microbes represent the most significant number of living organisms on Earth. Microbes have evolved and adapted to almost every challenge in Earth’s environment. From boiling waters to freezing ice, microbes are resilient. They play a crucial role in nutrient recycling and are Earth’s largest reservoir of nitrogen and phosphorus reserves. They are critical to decomposition, decay, and digestion and are responsible for stopping diseases. They eat almost anything, including metals, acid, petroleum, and natural gas. Invisible yet mighty, they are essential building blocks of life. The study of microbes is called microbiology. When one thinks of the connectivity of life, microbes are one of the most critical domains. In the 17th century, a Dutch scientist created a single-lens microscope and was the first to observe bacteria and protozoa. Antonie Van Leeuwenhoek is considered the father of MicroBiology, but others since then have contributed to the study.
Make a timeline of key people and discoveries in the development of microbiology. Upload it to the gallery!
Activity 2 – Domains of Microbes
Scientists believe every living thing on Earth is either Prokaryote (without cell-bound organelles or Eukaryote (with membrane-bound organelles). They are our oldest relatives! Since the 1970’s scientists have classified all living forms into three domains - Bacteria, Archaea, and Eukarya. Eukarya all have cell nuclei and represent all living things-including plants, animals, humans, etc. Bacteria and Archaea do not have cell nuclei and are known as Prokaryotes. Investigators at the University of Illinois discovered two diverse groups of bacteria. This discovery resulted in the establishment of new terminology to identify the significant distinct groups of microbes—namely, the eubacteria (the traditional or “true” bacteria), the archaea (bacteria that diverged from other bacteria at an early stage of evolution and are distinct from the eubacteria), and the eukarya (the eukaryotes). Next, scientists explore the evolutionary relationships between various members of these three groups. Even traits characteristic of distinct taxonomic groups have unexpectedly appeared in other microbes. So, first, draw and label the Tree of life and the Three Domains. Then, upload it to the Gallery.
Activity 3 – Fantastic Fungi
Fungi are a kingdom of primarily microscopic organisms closely related to animals. They include unique spore-producing organisms such as mushrooms, yeast, truffles, and some molds. Watch the [Fabulous Fungi Trailer](. The fruiting bodies of fungi, such as mushrooms, can sprout from mycelium. Mycelium is a network of fungal threads or hyphae. Mycelia grow underground but also on decaying tree trunks. Mycelia decompose organic matter in the soil, making raw materials to continue living in the ecosystem. Over 90% of plants interact with fungi, insects, and other invertebrates. Today, fungi break down toxic substances and filter water. There are many edible mushrooms, but there are also many poisonous ones. Be sure to know the difference! Look at edible vs. poisonous fungi and think about the underground network every step you take in the woods. Watch the trailer of Fantastic Fungi.
Draw a diagram of trees and their connected mycelium. Add and label some pictures of edible mushrooms!
Activity 4 – Bacteria & Viruses
Bacteria are ancient, microscopic organisms found all over the Earth in the four living spheres- atmosphere, lithosphere, biosphere, and hydrosphere. Bacteria in our stomach aid healthy digestion and decomposes organic material breaking it down into the soil. Bacteria can survive without a host, but viruses cannot. The bacteria and viruses that make us sick are called pathogens. They spread throughout the air, through drinking water, food, and through contact with objects. (Washing your hands IS Important!) Today antibiotics treat bacteria, and vaccines treat viral infections. Watch the Smile and Learn video and list the similarities and differences between bacteria and viruses.
Activity 5 – Algae
Algae are found in freshwater, saltwater, and on land in tree trunks and other places. Algae, like plants, conduct photosynthesis but, unlike plants, do not have roots. Algae powered by the sun produces oxygen and biomass. They can be tiny, like diatoms or picoplankton, or as large as 60 meters in giant kelp fronds. Diatoms are unicellular eukaryotic microalgae responsible for 20% of global carbon fixation and 40% of marine primary productivity. Algae are significant contributors to climate change processes and form a substantial basis of the marine food web while producing oxygen. Ocean forms of algae are responsible for 60% of Earth’s oxygen. Algae is vital for our life on Earth and can be a form of food and energy.
Draw different diatoms and other forms of algae and label them.Upload them to the Gallery!
Activity 6 – Archaea
Archaea are prokaryotes whose members differ from the most prominent prokaryotes, bacteria. They have evolved to have certain physical, physiological, and genetic features. The archaea are aquatic or terrestrial. They come in diverse shapes like spheres, rods, and spirals. They can survive in extreme temperatures and hot or salty conditions. Some archaea require oxygen, whereas others produce methane. Some depend on sulfur for metabolism. The archaea can reproduce by several mechanisms, including binary fission, budding, and fragmentation. While the archaea share some features with bacteria, genetic studies have indicated that archaea are more closely related to eukaryotes (animals, plants, and fungi) than bacteria.
Activity 7 – Protists
Protists are any Eukaryote that is not a plant, animal, or fungi. They are everywhere- in the ocean’s depths, our stomachs, on land, etc.
Protists were the first microbes discovered, yet they are the microbes least understood. They are mostly invisible to the naked eye. They are single-celled or multicellular organisms. They are a large group of single-celled eukaryotes identified across the eukaryotic tree of life. Some species are close relatives of plants, animals, and fungi. Eukaryote microorganisms have nuclei and membrane-bound organelles that are evolving and that take up twice the global biomass of plants, animals, and fungi. Found in soil, other animals, salt, or freshwater, some produce their food (autotrophs), and some eat other things (heterotrophs). Protists contribute 50 % of the world’s oxygen. Their interactions and evolutions affect people, animals, plants, and fungi. They also play an essential part in the food chain.
Research and draw some protists and upload them to the gallery!.
- Bacteria And Viruses for Kids
- Fantastic Fungi
- Insect Parasitic Nemotodes
- Life on Earth, In Oceans, and Subsurfaces
- Microbiology Society Archaea & Tree of Life
- Microbiology What is Life?
- Studying Microbes
- The Invisable MicroWorld
- Video Fabulous Fungi Trailer
- Video Learn About Microorganisms
- Video Microorganisms
- Video Smile & Learn about Bacteria
- Video What are Bacteria?
- What are protists and why should I care?
- What is Micro-Biology?
- Tree Identification