LSC S1:Diversity of Living Things

LSC S1:Diversity of Living Things,In this chapter, you should be able to:
a) know the processes that are characteristic of all living things and their importance.
b) know the parts and functions of typical animal and plant cells.
c) understand the levels of cellular organisation in multicellular organisms.
d) know the seven levels of taxonomy.
e) understand the two-word naming system of living organisms.
f) know the characteristics of organisms in different categories of living things.
g) analyse the uses and harmful effects of organisms in kingdom monera and fungi.
h) know the main characteristics of insects and understand their life cycles.
) appraise the useful and harmful aspects of some insects.

Key words
cell
taxonomy
life cycle
sensing
reproducing

Introduction
In this chapter, you will appreciate the diversity of plants, animals and microorganisms and the portance of organisms in life. This chapter will equip you with knowledge of some aspects that qualify organisms as living and the units that make up the organisms
known as cells which are found in both plants and animals. The various kingdoms of plants and animals and the significances of organisms in various kingdoms especially the common insects like houseflies, cockroaches, bees, mosquitoes and butterflies.
6.1: Characteristics of Living Things
Although there is a great variety of living things on earth, they have 7 similar characteristics which are common to all of them. In Activity 6.1 , you will learn about these characteristics of living things.
Activity 6.1: Discussing the characteristics of living things and their importance

What you need: notebooks, stylus, slate, and perkins brailler and braille papers.

What to do:
In small groups, discuss the pictures in Figure. 6.1.

2. Mention the characteristics of living things shown by each picture in Figure. 6.1.
3. What is the importance of each life process you have mentioned in (I) above?
4. Name one other characteristic of living things apart from those in (1). Explain how it is important.

2. How many life processes does a motorcycle ave .
3. How many life processes does a motorcycle share with a human being?
4. Is a motorcycle a living or a non-living? Give a reason for your answer.
   Hint: In your surroundings, which objects were once living but now are non-living?
   For a substance to be called a living organism it must possess all the 7 characteristics
   of living things. Non-living things do not possess all the characteristics of the living
   things. Living things can become non-living like animals when they die, trees when
   they are cut, and so on.
   6.2: Plant and Animal Cells
   Every organism is made up of structures called cells. The cell is the smallest unit
   with the basic properties of life. Some tiny organisms, such as bacteria and yeast,
   consist of only one cell. They are called unicellular organisms. Large plants and
   animals are called multicellular because they are made up of billions of cells.
   Human beings are made up of more than 75 trillion cells. In Activity 6.3 you will
   discover the basic structure of a cell.

From Activity 6.3, a cell has different parts that perform different functions. There are 2 main types of cells, that is, prokaryotic cells and eukaryotic cells. Eukaryotic cells are found in fungi, plant and animal cells while prokaryotic cells are the cells of primitive bacteria. The prokaryotic cells unlike eukaryotic cells do not have the nucleus or membrane bound organelles.
Mounting of a Cell
Mounting is the process of preparing a cell for viewing under the microscope. Mounting of cells on a slide is a very useful technique. It is needed when studying the structure of a cell under light microscope.
Why do we stain a cell using iodine or methylene blue? Cells are stained during mounting to make some of the features visible. Iodine is a useful stain when studying plant and animal cells. It causes the cell membrane and nucleus to appear more visible.
Methylene blue enables scientists to view the cell shape as well as the nucleus.

Activity 6.4: Mounting onion cells on a slide

What you need: Microscope slide, cover slip, knife, dissecting kit, microscope,
dropper, iodine solution and animation or a simulation showing how to mount onion cells, Notebooks, Stylus, Slate, and Perkins brailler and braille papers.

What to do

1. Cut onion cells into blocks of about lcm by lcm with a knife as shown in
   Figure. 6.4 (a).
2. Use forceps to peel a thin epidermis from the inner layer of the onion as
   shown in Figure. 6.4 (b).
3. Place a drop of iodine on the microscope slide as shown in Figure. 6.4 (c).
4. Place the thin epidermis directly in the drop of iodine on the slide as shown
   in Figure. 6.4 (d).
5. Gently lower the cover slide on top of the membrane.
   Wipe off the excess iodine using a tissue paper.
6. Place the slide on the microscope and view using the low power objective lens.

Task
I. Write or braille a well labeled drawing of the specimen..

2. What are the functions of the parts you have listed?
3. Which parts are unique to only the plant cell?
   Wash your hands after performing the experiment
   Hint: Did you know that plant and animal cells have some similarities and differences?
   In activity 6.5, you will explore the differences between a plant and an animal cell.
   Activity 6.5: Comparing a plant and an animal cell
   What you need: Toothpick, microscope slide, cover slip, dissecting kit, microscope,
   dropper, iodine solution and a simulation or animation showing how to mount an
   animal cell, notebooks, stylus, slate, and perkins brailler and braille papers.
   Be gentle when scrubbing the inside of your cheek. Wash your hands after performing the experiment.
   What to do
4. Gently scrub the inside of your cheek with a toothpick as shown in Figure. 6.5 (a).
5. Smear the collected fluid onto the slide Figure. 6.5(b).
6. Apply the cover slip Figure. 6.5(c) and add a drop of diluted methylene blue stain to the slide Figure. 6.5 (d).

4. Wipe the excess stain Figure. 6.5(e).
5. View the slide at low and high power.

6. Mounting of cheek cells on a slide
7. Compare an onion cell (Activity 6.4) and a cheek cell.
8. Present your findings to the rest of the class.
   Plant and animal cells have similar basic features common to both of them. However, they also have different structures due to the different functions they perform. It is important to note that not all the similarities and differences can be seen under a light microscope.
   Project work
   Activity 6.6: Making a model of a cell
   What you need: Plasticine of different colours, card board or super glue, beads
   or clay and paint,notebooks, stylus, slate, and perkins brailler and braille papers.
   What to do
   Using locally available materials in your area to make a model of a cell. Your model must clearly show the cytoplasm, nucleus, cell membrane, (vacuole and chloroplast in case of a plant cell).

6.3: Levels of Cellular Organization of Multicellular Organisms
Multicellular organisms have complex bodies that contain many functional parts. For efficient functioning, these parts are organised into different levels of complexity or cellular organisation. They range from the basic unit of living things to the whole organism. In activity 6.7, you will discover the levels of
cellular organisation in a multicellular organism.
Activity 6.7: Discussing the levels of cellular organisation of multicellular organisms
What you need: notebook, stylus, slate, perkins brailler, and braille papers What to do: The following levels of competition exists in a sports league: National, interclass, district, sub-county and regional.

In groups:

1. Arrange those levels of a sports league from the lowest level to the highest.

Using the same knowledge arrange the pictures in Figure. 6.6 following levels
2. of cell organisation from the lowest to the highest.
3.Give an explanation for your arrangement in (2) above.
4. Compose a mnemonic or a song to help you remember the levels of cellular organization.
5. Write or braille you findings.
hint there are levels of organisation in multicellular organisms: the smallest, basic and functional unit of life.
Cell –
Tissue – group of cells which perform a specific function.
Organ – a group of tissues which perform a particular function.
Organ system – a group of organs which work together to perform a specific task.
The organ systems collectively form an organism.

What you need: notebook, stylus, slate, perkins brailler, braille papers, dictionary internet connection and science textbooks
What to do: In groups:

1. Look up for the meaning of the word taxonomy.
2. Draw or describe a pyramid representation of the taxonomic hierarchy.
3. Write or braille your findings.
4. Present your work to the class.
   Hint

• The taxonomic hierarchy consists of seven levels.
• You can easily remember the taxonomic hierarchy with this sentence: King
  Paul Came Over For Great Sausages.
  The highest level is the kingdom and the smallest or the lowest level is
  the species.
  Biological classification is a way scientists categorise and organise all forms of life. It can help to distinguish how similar or different living organisms are to each other.
• 6.5: Writing Scientific Names
  Common names vary among languages and even among regions within Uganda. Furthermore, different species may share a single common name. This led to a need for a system of giving names to organisms. In activity 6.9, you will practice how to give scientific names to living organisms following a set of international rules.

Activity 6.9: Using the two-naming system of living organisms What you need: notebooks, stylus, slate, and perkins brailler, braille papers and

What to do: In groups, study Figure. 6.8 and:
1. What are the names of the organisms in the pictures in your local language?

2. Basing on the rules in the hint, write the scientific name of each of the organisms shown in Figure. 6.8.
3. Write your findings on a manila paper/ news prints.
4. Present your work to the class.

• Rules for writing scientific names
  Hint.
  i) Scientific names are made up of two parts. When written by hand, the
  two names must be underlined using separate lines; when they are
  printed, they must be in italics.
  ii) The first part is the name of the genus the organism belongs to. It starts
  with a capital letter.
  iii) The second part is the name of the species the organism belongs to.
  It starts with a small letter.
  Every recognised species on earth is given a two-part scientific name. This system is called binomial nomenclature.’ These names are important because they allow people throughout the world to communicate unambiguously about living organisms. The scientific name has several advantages over using the common names.
  These include:

1. To organise and classify organisms easily – the organisms can be easily categorised, this really helps making it easier to understand the characteristics of a specific organism.
2. Clarity and precision – the scientific names given are unique with each animal having only one scientific name. This helps avoid confusion created by common names.
3. Universal recognition – scientific names are standardised and accepted universally.
4. Inter specific relationship – binomial terms help scientists to understand the similarities and differences between different species belonging to the same genera and this is useful in establishing a relationship among the species.

6.6: Characteristics of Organisms in Different Categories of Living Things
As you have discovered, organisms are categorized into larger taxonomic groups called Kingdoms. We have five kingdoms (broad categories of organisms) namely Kingdom Monera, Protoctista/Protista, Fungi, Plantae and Animalia
We also have another category of organisms that does not fall in the above 5 kingdoms called viruses. In this activity 6.10 you will find out the characteristics of organisms in these Kingdoms.

Activity 6.10: Discussing the characteristics of organisms of different categories of living things
What you need: notebooks, stylus, slate, and perkins brailler and braille paper

What to do: In groups, discuss and do the task:

1. From which kingdom does each organism in Figure. 6.9 belong?
2. What are the characteristics of the organisms in kingdoms you have identified in (2) above?
3. Present your work in class and hand in group reports to the teacher.
4. 6.7: Economic importance of organisms of kingdom
   Monera and Fungi
   Bigger isn’t always better! Today, you are going to discover how some micro- organisms on Earth contribute to the global economic success. By doing Activity 6.11 , you will discover the economic importance of bacteria and fungi in our everyday lives. These micro-organisms are incredibly diverse and living in all environments on Earth. But don’t be deceived by their size, bacteria and fungi
   are incredibly important in the lives of other living organisms.

Activity 6.11: Discussing economic importance of organisms of kingdom Monera and Fungi
What you need: notebooks, stylus, slate, and perkins brailler and braille papers

6.8: Main Characteristics of Insects and their Life Cycles Main Characteristics of Insects
There is a great variety of insects in the world. These insects are adapted to live in almost all habitats from arid areas, to tropical areas and even in cold habitats. They are successful on earth because they excrete uric acid; they have wings for flight among others. With all this variety the insects have basic similar characterises that are common to all of them. In activity 6.12, you will identify the main characteristics of all insects.

Activity 6.12: Identifying the main characteristics of insects What you need: Notebooks, Stylus, Slate, and Perkins brailler and braille papers.

What to do:
In small groups, discuss the picture in Figure 6.11 and do the task.

1. Which features can you use to identify the insects in Figure 6.11?
2. State the characteristics that are common to the insects you have identified in Figure. 6.11 that make them to be classified as a) Arthropods b) Insects.
3. Present your findings to the rest of the class.

Life Cycles of Insects
The life cycle of insects is as interesting as you might think. They undergo courtship they mate, and some care for their developing young ones, in activity 6.13, you will discuss the life cycles of some common insects.
Activity 6.13: Discussing life cycles of insects
What you need: notebooks, stylus, slate, perkins brailler, television, dvd reader, CD or radio.
Watch or listen to the simulations or animations of life cycles of different insects.
What to do: In groups, study and discuss the life cycles of insects in Figure. 6.12.

1. Write or braille a summary of the life cycles.
2. Describe how you can classify the life cycle of the insects.
3. Present your work in class.
6.9: Useful and Harmful Aspects of Insects
Some insects like locusts and the fall army worm tend to be destructive, yet some insects are actually very useful.

In Activity 6.14, you will discuss the useful and harmful aspects of insects.
Activity 6.14: Discussing useful and harmful aspects of insects
What you need: notebooks, stylus, slate, perkins brailler, cockroaches and mosquitoes
What to do:

1. Form small groups, and discuss about the following insects: bees, cockroaches, mosquitoes, butterflies and houseflies.
2. Write or braille:
   a) The economic importance of each insect.
   b) The harmful effects of the insects.
   c) The possible ways of preventing the harmful effects of each insect.
3. Identify other useful insects apart from those mentioned in this Activity.