All living things are thought to have evolved from bacteria, the first organisms that appeared on Earth.
Organisms are classified into five kingdoms: animals, plants, fungi, protists and bacteria.
All animals are consumers. The two major groups of animals are invertebrates (do not have a backbone) and vertebrates (do have a backbone).
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Plants can make their own food by photosynthesis.
Protists were the first organisms to evolve a nucleus. The majority of protists are unicellular and live in water.
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Fungi are decomposers. This means they help break down dead plant and animal material. Some can be eaten or used in making foods. Others are poisonous or cause disease.
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Bacteria are the most common organisms on Earth. All bacteria are unicellular and have no nucleus.
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Bacteria reproduce by binary fission. This means that their numbers double with every generation.
The BIGChallenge
Your task is to research four modern food preservation methods and four methods from the past.
Use your knowledge of the biological world to explain how each method stops microorganisms from spoiling food.
Your report on each should take the form of a poster with lots of images and no more than 100 words.
Go to your Portfolio to check what you have learned in this chapter.
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Bacteria play a very important role in cycling matter through the Earth. They are also used to make foods and antibiotics.
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Bacteria also cause some negative effects, including food spoilage and disease.
Viruses are usually not thought of as living things as they cannot reproduce by themselves. Viruses cause many diseases.
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Viruses are known as parasites because they live off or in another living thing.
Organisms that cause disease are called pathogens.
A vaccine is a treatment that protects the body from a particular disease. It is made from the pathogen that causes the disease.
