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Bacteria – from http://www.biology4kids.com/files/micro_bacteria.html

Bacteria Basics – They are Alive!

Bacteria are the simplest, smallest of creatures that are considered alive.
Bacteria are everywhere. They are in the bread you eat, the soil that plants grow in, and even inside of you.

They are very simple cells that fall under the heading prokaryotic.
That word means they do not have an organized nucleus.
Bacteria are small single cells whose whole purpose in life is to replicate.

Okay. So we’ve told you they don’t have an organized nucleus. True.
They do have DNA. It is grouped in an area called the nucleoid.
They have cell membranes like other cells (e.g. a cell wall.)
Mind you, their cell wall is not like the one in a plant. It’s a special kind that bacteria have for protection.
They don’t have any organelles, just ribosomes. (These are all characteristics of prokaryotes if you remember.)

What Do Bacteria Look Like?

Very small. Very, very small. You might have seen pictures of some bacteria.
Spherical bacteria are in the shape of little spheres or balls. They usually form chains of cells like a row of circles.
Rod shaped bacteria are look like the E. coli living in your intestine. You can imagine a bunch of bacteria that look like hot dogs. They can make chains like a set of linked sausages.
Spiral shaped bacteria twist a little. Think about balloon animals for these shapes. It’s like a balloon animal in the shape of a corkscrew.



What Do Bacteria Do?

Some help plants absorb nitrogen (N2) from the atmosphere, into the soil.
Some cause diseases like botulism.
Some bacteria even live inside the stomachs of cows to help them break down cellulose.
Cows on their own can digest grass and plants about as well as we do.
They don’t get many nutrients out of the plants and can’t break down the cellulose.
With those super bacteria, the cellulose can be broken down into sugars and then release all of the energy they need.
(Imagine if scientists could develop bacteria to live inside of us that would break down plants. That would be something. We could eat grass and leaves!)


from the Virtual Museum of Bacteria (http://www.bacteriamuseum.org/)

Bacteria are everywhere, but their small size makes them invisible. Maybe you don’t even have a clear idea what bacteria are.

If you want to learn more about bacteria, this category is the best place to start. There are 6 exhibits in this category that are best read in the following order:

What are bacteria? That is explained here, and the links on this page provide further introductions in the subject. This exhibit is the best place to start. The links are all relatively easy to understand.

Not all microorganisms are bacteria. Those microorganisms that are not bacteria are briefly described here, but they will not further be covered in this museum.

What is bacteriology? The study of bacteria is explained here. Some of the many aspects that can be covered in bacteriology are touched upon.

In Applied bacteriology it is described how bacteria are applied in industry. There are more explorations than you might have thought about.

Bacteriophages are viruses that prey on bacteria. So bacteria can be ill, too.

Ok, after reading through all of this, you will have a better idea of what bacteria are. So here’s the last file, which is a bit of fun:Bacteria and our senses describes how we can see, taste, feel and hear bacteria. Or not.

Worksheets on bacteria (MS Word format) Archaea and Bacteria


First Detailed Microscopy Evidence of Bacteria at the Lower Size Limit of Life

Berkeley Lab research provides comprehensive description of ultra-small bacteria



Learning Standards

Massachusetts Science and Technology/Engineering Curriculum FrameworkLife

Science (Biology), Grades 6–8.
Classify organisms into the currently recognized kingdoms according to characteristics that they share. Be familiar with organisms from each kingdom.

Biology, High School
5.2 Describe species as reproductively distinct groups of organisms. Recognize that species are further classified into a hierarchical taxonomic system (kingdom, phylum, class, order, family, genus, species) based on morphological, behavioral, and molecular similarities.

Benchmarks for Science Literacy, American Association for the Advancement of Science

Students should begin to extend their attention from external anatomy to internal structures and functions. Patterns of development may be brought in to further illustrate similarities and differences among organisms. Also, they should move from their invented classification systems to those used in modern biology… A classification system is a framework created by scientists for describing the vast diversity of organisms, indicating the degree of relatedness between organisms, and framing research questions.

SAT Biology Subject Area Test

Evolution and diversity: Origin of life, evidence of evolution, patterns of evolution, natural selection, speciation, classification and diversity of organisms.

Teaching About Evolution and the Nature of Science, National Academy Press (1998)

Biological classifications are based on how organisms are related. Organisms are classified into a hierarchy of groups and subgroups based on similarities which reflect their evolutionary relationships. Species is the most fundamental unit of classification.



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