Lesson Notes By Weeks and Term - Senior Secondary 2

TERM – 2^ND TERM

WEEK EIGHT

Class: Senior Secondary School 2

Age: 16 years

Duration: 40 minutes of 5 periods each

Date:

Subject: Biology

Topic: POLLINATION IN PLANTS

SPECIFIC OBJECTIVES: At the end of the lesson, pupils should be able to

1. Define pollination
2. Identify and discuss the types of flowers
3. Identify the features of self pollination and cross pollination
4. Identify the agents of pollination

INSTRUCTIONAL TECHNIQUES: Identification, explanation, questions and answers, demonstration, videos from source

INSTRUCTIONAL MATERIALS: Videos, loud speaker, textbook, pictures

INSTRUCTIONAL PROCEDURES

PERIOD 1-2

PRESENTATION	TEACHER’S ACTIVITY	STUDENT’S ACTIVITY
STEP 1 INTRODUCTION	The teacher introduces pollination and explain the two types of pollination	Students pay attention
STEP 2 EXPLANATION	Teacher discusses the features of self pollination and cross pollination of plants	Students pay attention and participate
STEP 3 DEMONSTRATIO N	Teacher identify and explain the agents of pollination. Teacher to ask students to relate the position of stigma and stamens to the type of pollination students also to examine the nature of the pollen grain.	Students pay attention and participate
STEP 4 NOTE TAKING	The teacher writes a summarized note on the board	The students copy the note in their books

 

NOTE

POLLINATION IN PLANT

Pollination is the transfer of pollen grains from the male reproductive part (anther) to the female reproductive part (stigma) of a flower, leading to fertilization. There are two main types of pollination:

1. Self-Pollination: In self-pollination, pollen from the same flower or a different flower on the same plant reaches the stigma. Self-pollination is sub divided into two:

     - Autogamy: Pollen from the same flower fertilizes the ovules.

     - Geitonogamy: Pollen from a different flower on the same plant fertilizes the ovules.

2. Cross-Pollination: Here, pollen is transferred from the flower of one plant to the stigma of a flower on another plant. Cross pollination is also sub divided into two:

     - Allogamy: Cross-pollination between two different plants of the same species.

     - Xenogamy: Cross-pollination between two different plants of different species.

Features of Self-Pollinated Flowers

1. Structural Adaptations: Anthers and stigmas are in close proximity, facilitating easy transfer of pollen.
2. Mechanisms to Prevent Cross-Pollination: Presence of specialized structures to promote self-pollination (e.g., cleistogamous flowers that do not open).
3. Consistency in Traits: Offspring generally show little genetic variation from the parent plant.

Features of Cross-Pollinated Flowers

1. Structural Adaptations: Larger, colorful flowers with prominent petals to attract pollinators. Also, the anthers and stigmas are often positioned to avoid self-pollination.
2. Mechanisms to Ensure Cross-Pollination: Dioecious plants have separate male and female individuals. While others exhibit self-incompatibility mechanisms to prevent fertilization by own pollen.
3. Genetic Variation: Offspring exhibit greater genetic diversity due to the mixing of genetic material from different plants.

Agents of Pollination

1. Wind: Pollinate plants that have inconspicuous, small flowers with abundant, lightweight pollen. Examples include, Grasses, many trees (e.g., pine, oak).
2. Water: Pollen of plants to be pollinated are buoyant and adapted for transport in water. Examples include, Water lilies, eelgrass.
3. Insects: Plants often have brightly colored, fragrant flowers with nectar as a reward. Examples of insects include, Bees, butterflies, moths.
4. Animals (other than insects): Plants pollinated may have specific adaptations for attracting particular animals. Examples are, Birds (e.g., hummingbirds), bats.

EVALUATION: 1. What pollination?

2. Discuss the two types of pollination
3. Identify three agents of pollination.

CLASSWORK: As in evaluation

CONCLUSION: The teacher commends the students positively