Subject:-Biology

Class:- SS2

Topic:- Strata In the Forest

Duration:- 40 minutes

Date:- 2nd May, 2020

Behavioural Objects:-

At the end the lesson students should be able to:-
1. List and define the different strata in the forest; and
2. List at least three(3) plants in a forest habitat and their Adaptive features.

Instructional Material(s):-

A chart showing picture of different plants in the forest.

Introduction:-

Presentation:-

Step 1:- Strata In The Forest.

The rain forest vegetation had plants which are naturally arranged in layers, strata or storeys. There are about five storeys in the forest. These are:-
1. The upper Layer:-
The upper layer or storeys is made up of tall trees of over 40 metres tall. These trees are called emergents. The crown of the emergents do not normally touch each other. Examples of plants in this category are Iroko, Obeche, Mahogany, African walnut, Ebony etc.

2. The middle Layer:-
The second layer in the rain forest is made up of tall trees of about 16-40 metres tall. Their crown touches each other, thereby forming a continuous canopy just below the emergents.

3. The lower Layer:-
This is the third layer which is made up of small trees, less than 26m tall. They also form a continuous canopy below the mid storey.

4. The shrub layer:-
This layer is made up of small trees, 1-5 metres in height. These are essentially small trees collectively referred to as shrubs.

5. Ground layer or forest floor:-
This contains wet and shade loving plants hardly receive sunlight due to canopies formed by bigger plants. Most plants are bryophytes and they include mosses, liverwort, lichens and thin leaved ferns.

Step 2:- Distribution of Plants in a Forest Habitat.

Varieties of plants exist in the forest. Popular examples of Forest trees include African walnut, Mahogany(Khaya ivorensis), teak(Tectonia grandis), Opepe(Sarcocephalus), Obeche(Triplochiton), Iroko(Chlorophora), Oil Palm(Elaeis guineenis), Ferns, Orchids, lianas, Mosses, Lichens, Liverworts, Fungi and Mistletoe.

Adaptive features of plants in a Forest habitat.

1. Iroko and Mahogany:-
These plants have strong tap root system and buttress roots which aid anchorage and support for the weight of the plants.

2. African Walnut:-
Thses plants have broad leaves which aid transpiration and photosynthesis.

3. Obeche:-
These plants have tap root system and large buttresses roots for support as well, also it has broad leaves to aid photosynthesis activities.

4. Mistletoe:-
These are complete plant parasites capable of developing root system that can penetrate the stem of a plant and feed directly from manufactured food by placing their roots on the phloem vessels of the host plants.

5. Orchid:-
These are epiphytes which have mechanism for storing water and absorbing moisture from air while growing on tree branches.

Evaluation:-

The teacher ask the students questions to ascertain the level of their understanding:-
1. List and define the different strata in the forest; and
2. List at least three(3) plants in a forest habitat and their Adaptive features.

Homework:-

1. The third strata in the rain forest is called----------?
2. The collection of shrubs is called --------?
3. The plant that feed directly from the manufactured food by placing their roots on the phloem vessels of the host plant is called----------?
4. Draw a Mistletoe.

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glotokens

Your biology teacher.