LESSON 9: Living Beings: Micro-Organisms

LESSON 9: LIVING BEINGS: MICRO-ORGANISMS Classification of Life

Pg. 156 – Categories of Classification

- Two individuals belong to the same species when they can reproduce with each other and have fertile descendants.

Pg. 157 – How are species named?

Pg. 158 – The Five Kingdoms

- Criteria to include a living being in a kingdom.

Pg. 160 – What are bacteria like?

- Types of Bacteria (singular: bacterium, plural: bacteria)

Pg. 161 – The Protozoa (singular: protozoan, plural: protozoa)

- Classes of Protozoa, Algae (singular: alga, plural: algae)

Pg. 162 – Classification of Algae

- The Importance of Algae

Pg. 165 – General Characteristics and Types of Fungi (singular: fungus, plural: fungi)

Activities

1) What is the natural system of classification of living beings based on? And the artificial system? Which would you use to classify all living beings? Explain your answers.

3) What are taxonomic categories?

4) How many subdivisions does a kingdom have? What are they?

5) How is a type different from a species?

6) When do we say that two individuals belong to the same species?

8) What is binomial nomenclature? Who created this system?

10) In what kingdom would you include an autotrophic, unicellular organism, whose nucleus is surrounded by a membrane? What type of living being could it be? Would it have tissues? 14) In what forms can bacteria be found? What are the characteristics of protozoa?

18) Is it correct to say that only green algae possess chlorophyll?

19) What importance do algae have in the marine environment?

20) Why do algae need light?

21) What does it mean when we say that fungi are heterotrophic?

24) Is a mushroom the same as a fungus? Why?

Clear Ideas

 The classification of living beings allows us to arrange them and to determine the principal characteristics that define them.

 At present we use a system of natural classification based on evolution, that is to say, on the relationships that exist between living beings.

 The artificial system, on the contrary, is based on the observation of external characteristics.

 Organisms are classified in hierarchic groups that are arranged from kingdoms, the largest groups, down to species, the smallest. Every group constitutes a taxonomic category.

 Species is the set of individuals with similar characteristics that can reproduce with each other and have fertile descendants.

 Can von Linnaeus established the system of binomial nomenclature, which we use to name living beings with two Latin words: the first coincides with the name of the genus and the second word describes some characteristic of the species to which they belong.

 Living beings are classified into five kingdoms: Monera, Protistia, Fungi, Plants, and Animals.

 All microscopic beings belong to one of the following kingdoms: Monera, Protista, or Fungi.

 Bacteria are unicellular, prokaryotic, autotrophic or heterotrophic organisms that can live in any environment. The majority of bacteria are beneficial.

 The Protista Kingdom includes living beings that are very different from one another; they can be unicellular or multi-cellular, autotrophic or heterotrophic, and composed of eukaryotic cells. Protozoa and algae are found in this kingdom.  Protozoa are heterotrophic unicellular organisms, some of which are parasites, which live in aquatic environments.

 Algae are autotrophic, unicellular or multi-cellular organisms that do not have tissues.

 Fungi are heterotrophic, eukaryotic organisms. They can be unicellular or multi-cellular, and in this case they are grouped in filamentous cells that are called hyphae.

 The microbes that provoke infectious diseases are called pathogenic agents. All the diseases that they cause are contagious.