RELEVANCE OF BIOLOGY TO AGRICULTURE

 Relevance of biology to agriculture 

MAIN AIM: To help the learners understand Relevance of biology to agriculture 

SUSIDIARY AIM: By the of the lesson, learner should be able to;

1. Mention the major groups of classification of plants
2. Explain botanical classification
3. Explain agricultural classification
4. Explain classification base on life cycle.

PERSONAL AIM: To keep strictly to time allotted to each stage of the lesson

PREVIOUS KNOWLEDGE: The learners know about agriculture from their previous lesson 

TEACHING AIDS: Research work from the internet, pictures 

PROCEDURE: The teacher presents the lesson with the following steps 

STEP ONE: CLASSIFICATION OF PLANTS

Plants are classified based on the following criteria:-

1. Botanical classification
2. Agricultural classification
3. Life cycle.

STEP TWO: BOTANICAL CLASSIFICATION

This classification is mainly based on structure, functional and evolutionary trends. Based on this classification the plant kingdom is divided into 4 major groups;

a. Thallophyta (the algae and fungi)

Algae: Are simple plants without roots, stem and leaves. They have chlorophyll and are mainly aquatic with few living on damp soil and shady places e. g. Spirogyra, Anabaena.

Fungi: Are non-green plants. Are also simple multicellular plants with body not differentiated into root, stem and leaves. Their vegetative body is collectively known as mycelium. Examples include Mucor, Rhizopus, yeast and Fusarium.

b. Bryophyta (Liverwort and Mosses): They do not have vascular tissues (xylem and phloem) but are multicellular organisms. They have chlorophyll, are terrestrial but live in moist environment. They lack true roots, stem and leaves. Examples; Marchantia species (liverworts), Funaria hygrometrica (Mosses).

c. Pteridophyta (ferns): Body differentiated into true roots, stem and leaves, with well- developed vascular bundles (xylem and phloem). They lack flowers. Dispersal is by means of spores. Are mainly terrestrial with few aquatic members. Examples: Dryopteris, Cyclosorus, Azolla.

d. Spermatophyta (the seed bearing plants): Are divided into two:-Gymnosperms and Angiosperms.

Gymnosperms: Are non-flowering large plant with well-developed vascular bundles with true roots, stem and leaves. Leaves are green in colour, small, scaly and needlelike. They are terrestrial. Examples include whistling pine and Cycas.

Angiosperms (flowering plants): They possess true flowers for sexual reproduction. Well-developed roots, stem and leaves are present. They possess well-developed vascular bundles. They produce seeds and fruits after fertilization. Angiosperms are terrestrial but few are aquatic e. g. oil palm tree, goat weed, mango tree, maize plant etc.

STEP THREE: AGRICULTURAL CLASSIFICATION

In this case, plants are classified according to the main food substance/products existing in them.

Legumes: Are rich in protein and have noodles or swellings in their roots; and are capable of converting atmospheric nitrogen to nitrates which they absorb e.g cowpea, soya beans, groundnuts, pigeon pea (Cajanus cajan).

Cereals: They are grain crops grown mainly for their seeds which are very rich in carbohydrates e. g. rice, maize, guinea corn, millet, barley, oats, etc.

Roots and tubers: These crops store food in their roots and stems in form of tubers. They are rich in carbohydrates e.g. yam, cassava, Irish potatoes, carrot, etc..

Vegetables: Are crops whose leave and fruits are usually vegetables. They supply the body with vitamins and minerals e.g. tomatoes, onion, fluted pumpkin, okra, green (Amaranthus spp.), lettuce, cabbage, etc.

Fruits: These crops are grown for their fruits which are rich sources of vitamins (especially A and C), minerals and sugars e.g. orange, mango, guava, pineapple, banana, cashew, etc.

Beverage crops: These crops are grown for use as beverage drinks or a sort of refreshment. They supply mineral to the body e. g cocoa, coffee, tea etc.

Latex crops: Are grown because they produce milky fluid known as latex. This latex is used in the industries for making of tyres, tubes and plates. An example of latex crop is rubber.

Oil crops: The seeds and fruits of the crop are rich in oils and fats e. g. oil palm, groundnut, coconut, etc.

Fibre crops: They supply ropes and thread for textile industries e.g. cotton and jute.

Spice crops: Are used in flavoring foods e. g. pepper, ginger, onion, thyme, etc.

Stimulants and drugs: These crops produce substances used as stimulants for medical purposes e. g. cocaine plants, kola, lime, quinine.

Forage crops: Are grasses and legumes grown for animal feed e. g. guinea grass, elephant grass, etc.

Nuts: These are crops whose fruits consist of hard-shells that enclose the fleshy parts which are edible. Examples include coconut, cashew and oil palm.

STEP FOUR: CLASSIFICATION OF PLANTS ACCORDING TO LIFE CYCLE

Plants are classified into three (3) major groups according to the life span or lifecycle. This classification applies mainly to flowering plants.

Annual crops: These are crops which complete their life cycle in one year. They include maize, yam, groundnut, rice, beans, etc.

Biennial crops: these crops complete their life cycle in two years, in the first year, they grow and store food and then use the food in the second year to produce flowers, seeds and fruits, before they die. Examples include cassava, pepper, plantain, onion, ginger, etc.

Perennial crops: These include crops that take three or more years to complete their life cycle. Examples include tree crops like rubber, cocoa, mango, oil palm, orange; and herbaceous crops like ginger and onion.

Evaluation

1. Mention the major groups of classification of plants
2. Explain botanical classification
3. Explain agricultural classification
4. Explain classification base on life cycle.

Assignment

Mention the major groups of classification of plants

Explain botanical classification