Course General Physiology 1 PDF
1.Introduction:
This chapter describes what botany is and why you will enjoy studying it. You’ll learn about the importance of plants, the lore of plants, and the concepts that unify the study of plants. This is why the entire course is titled the biology of plants, and it is only natural that you will study the biology of plants by talking about Botany which is the study of plants. You will also be introduced to the scientific method which will lead you to knowledge of the process of scientific research and how we came about most of the scientific knowledge we have. The unit will end with a study of the way Botanists view (see) life.
2.Objectives:
At the end of this unit, you should be able to:
• state at least six uses of plants that establishes our dependence on them
• list the products that are obtained from plant
• state the role that plants have played in the history of mankind
• describe the scientific method list and discuss the five unifying themes in botany
• explain four uses of biotechnology
• give at least three reasons why we study Botany.
3.Main Content:
3.1.Plants and Life:
Let us open this section by examining what we had as our meals today. It is possible that you have had either breakfast, lunch or dinner or may be you have had the three meals today. Think back on the components of the meals. You will notice that our meal was more than 80% plant. This is a good introduction to our relationship with plants or put in another way, the relationship of plants and life.
For many centuries, humans have relied on plants for survival and pleasure. Asian civilizations were based on rice, middle Eastern civilizations were based on wheat and barley and American civilizations was based on corn. In Nigeria, before the advent of oil, our economy was based on palm tree (east) and groundnut (north) so we can rightly say that the Nigerian economy was also plant dependent.
Out dependence on plants is an ongoing affair. Almost everything we do is influenced directly or indirectly by plants. We use plants to make clothes, strings, ropes, furniture, medicines explosives and musical equipments among others. Yet there are so many other uses of plants. Let us look at some examples.
Green plants and algae generate the oxygen and sugars that sustain life on earth.
• Plants supply our food and many of our drinks. For example, about 95% of our food comes from only twenty species of plants. Tea and coffee, the world’s two most popular beverages are made from plants.
• Extracts from plants and plant like organisms are used to make paints, waxes, dyes, spices and drugs such as cocaine, aspirin quinine and antibiotics.
• We use flowers for decorations, perfumes and as a means of expressing our feelings.
• On the negative side, plants clog our rivers, damage our crops, cause allergies, and poison us. (I am sure you can recall incidences of people who died after a meal prepared with poisonous mushrooms, or improperly processed cassava); many children are poisoned each year from eating poisonous plants.
Plants dominate our lives and economy and we can rightly conclude that plants affect virtually everything we do.
The various needs and uses we have of plant have given rise to Botany, which is the scientific study of plants.
3.1.1.What is a Plant?
You may be one of those who have never given a though to the above question. You will not be alone in this because most of us think that we have a fairly good idea of what a plant is – quiet green organism that we eat, use for decoration, cut down when we please and plant as shades. Our notion is correct if it fits into the above, but that is not all that a plant is. It is difficult to come up with a complete definition for the word plant. The nature of plants is so varied that it will be difficult to hold unto a trait and say that it is common to all plants. For example, not all plants are green. There are plants that consume animals. Some plants do not look like or act as plants and yet they are plants. Plants have also being considered an uninteresting.
Some Plants and their Characteristics
Giant sequoia (sequoidendron gigantum) and its taller but slimmer relative, the coastal red word (sequoia sempervirens) are the world’s tallest plants. A twenty-year old tree is often more than 15 metres (50 feet) high.
• The General Sherman tree in California weighs 1,400 tons that is as much as 20 million boxes of toothpicks, 200 elephants or 10 blue whales. (The whales are the largest representative of the animal kingdom). Interestingly, these giant trees are supported by roots that seldom go deeper than 1.8 metres (6 feet) into the soil (Ask yourself, if their roots are that shallow, how come the first major wind doesn’t blow them down – that is an interesting aspect of plant life).
• The oldest giant sequoia are about 3,200 years old, meaning that the trees that grow today were already 200 years old when kind David ruled the Israelites. (How come they were not destroyed when that civilization and subsequent ones were wiped out).
• Cherry tree has been used for many purposes, cherry black has been used to make a tea to ease the pains of childbirth and to cure coughs, colds and dysentery.
• Plants are used to produce the tons and tons of newsprints read in this and other countries.
• Sweet potatoes were once considered strong aphrodisiacs.
• Spinach contains little that is nutritious (expect vitamin A), Cartoons and parents try to convince their children otherwise.
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