Page 134 - Biology Form Two

Table 6.1: Respiratory surfaces in various organisms
Organism Respiratory surface
Amoeba Cell membrane
Insects Tracheal system
FOR ONLINE READING ONLY
Spiders Book lung
Fish Gills
Plants Leaves, stems, and roots
Amphibians Skin, gills, lungs, and buccal cavity

Mammals Lungs
Birds Lungs
Reptiles Lungs
Earthworms Skin

Characteristics of respiratory surfaces Procedure
(i) They are thin in order to reduce 1. Collect various organisms from
the diffusion distance. the environment.
(ii) They are moist in order to dissolve Safety precautions
gases that diffuse in a solution Be careful when collecting organisms
form. since some are dangerous.

(iii) They are highly branched, folded,
or flattened in order to increase the 2. Observe the organs for gas exchange
surface area for gas exchange. in the collected organisms using a
(iv) They are surrounded by blood hand lens.
capillaries so that gases can be 3. Compare organs for gas exchange
taken to and from the cells easily. in different organisms.
(v) They are well ventilated so that 4. Record their similarities and
gases can pass through them differences in a tabular form.
easily.

Gas exchange in mammals
Activity 6.1: Examine sites of gas Task 6.2
exchange in various organisms
Search the library and internet sources
Materials for animations or simulations on the
Organisms from the environment such mechanism of gas exchange in mammals.
as insects, fish, a variety of leaves, Make observation and white short notes.
hand lens, notebook, and pencil

Student’s Book - Form Two
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05/10/2024 15:36:42
BIOLOGY FORM 2 NEW.indd 128
BIOLOGY FORM 2 NEW.indd 128 05/10/2024 15:36:42