BIOLOGY IQ2  2.1-2.2 

 2.0   Living or Non-living?

In order to classify living things, taxonomists must first decide if they are living, or if they are non-living.

CLASSIFYING

The science of classifying organisms is called taxonomy. Scientists are called taxonomists. 

All modern classification systems are based on the Linnaean classification system. It was developed by Swedish botanist Carolus Linnaeus in the 1700s. He tried to classify all living things that were known at his time. He grouped together organisms that shared obvious physical (structural) traits, such as number of legs or shape of leaves... Linnaeus is known as the “father of taxonomy.” 

The Linnaean system of classification consists of a hierarchy of groupings, called taxa (singular, taxon). Taxa range from the kingdom to the species (see Figure below). The kingdom is the largest and most inclusive grouping. It consists of organisms that share just a few basic similarities. Examples are the plant and animal kingdoms. The species is the smallest and most exclusive grouping. It consists of organisms that are similar enough to produce fertile offspring together. Closely related species are grouped together in a genus.

https://bio.libretexts.org/Bookshelves/Introductory_and_General_Biology/Book%3A_Introductory_Biology_(CK-12)/05%3A_Evolution/5.01%3A_Linnaean_Classification#:~:text=The%20Linnaean%20system%20is%20based,inclusive%20taxon%20than%20the%20kingdom. 

Bacteria are microscopic, single-celled, prokaryotic (pro-carry-ot-ick) organisms found in environments that range from the soil to the ocean and inside the human gut.

Bacteria (singular: bacterium) are classified as prokaryotes because they are single-celled organisms with a simple internal structure that lacks a nucleus.

Sometimes bacteria lend us a helping hand, such as by curdling milk into yogurt or helping with our digestion. In other cases, bacteria are destructive, causing diseases like pneumonia and Staphylococcus aureus (Golden Staph).

There are three basic bacterial shapes: Cylindrical, capsule-shaped ones known as bacilli (singular: bacillus); round bacteria called cocci (singular: coccus),; and spiral bacteria, called spirilla (singular: spirillum). 

Adapted from https://www.livescience.com/51641-bacteria.html

Bacteria from different sources:

A sample of liquid soap spread onto nutrient agar and a swab from a bar of solid soap also spread onto nutrient agar. Soaps are not designed to kill microbes. They help to wash them off skin, better than water alone. Why do you think that the solid soap (kept by the sink and handled regularly) had more bacteria living on it than the liquid soap (kept in a dispenser, so not handled) which had none? 

Protists are single cell (unicellular) organisms. They are eukaryotes (you-carry-ots) because they have internal cell structure, but it is very simple.

The members of this group are not very alike, but they are in the group because they are one-cell organisms. 

Fungi (singular: fungus) are a kingdom of eukaryotes that are heterotrophs (other-feeding, they cannot make their own food) and have important roles in nutrient cycling in an ecosystem. Some fungi are single-cell (yeast), while others are multicellular. As eukaryotes, fungi cells have a membrane around their nucleus and their other organelles. Some fungi are responsible for diseases in humans eg fungal nail infection (#4), tinea (#5) and Candida (#6)