BIOLOGY PRACTICAL ACTIVITIES
- Ecology is best studied outdoors.
- Students identify a habitat within or near the school compound, e.g. a flower bed.
- The quadrat method is used.
- Observation and recording of the various animals as well as their feeding habits is done.
- Birds that feed on the plants or arthropods in the area studied are noted through observation of habitat at various times of the day.
- Food chains are constructed e.g green plants ~ caterpillar ~ lizard and many others involving all organisms in the area.
- The numbers of animals in 1 m2 is counted directly or estimated e.g small arthropods like black ants.
- The number of plants is easily counted and recorded and ratio of consumers to producers calculated.
- It will be noted that in terms of numbers where invertebrates are involved, there are very many consumers of one plant.
- Several other quadrats are established and studied and averages calculated.
Table of Contents
Adaptions to Habitat
- Specimen of hydrophytes e.g water lily is observed.
- Students should note the poorly developed root systems and broad leaves.
- Stomata distribution on leaf surface is studied through microscopy or by emersing a leaf in hot water and counting number of bubbles evolved.
- Ordinary plants e.g bean hibiscus and zebrina can be studied.
- Size of leaves is noted and stomata distribution studied.
- Specimen include Euphorbia, cactus and sisal which are easily available.
- The root system e.g in sisal is noted as shallow but extensive.
- It will be noted that sisal has fleshy leaves and stem while cactus and Euphorbia have fleshy stem but leaves are reduced to small hair-like structures.
Comparison of Root nodules from fertile and poor soils
- Are swellings on roots of leguminous plants.
- Soil fertility determines number of root nodules per plant.
- Bean plants are best used in this study.
- One plot can be manured while the other is not.
- Similar seeds are planted in the two plots.
- The plants are uprooted when fully mature (vegetatively) i.e any time after flowering and before drying.
- The number of nodules per plant is counted.
- An average for each plot is calculated.
- It is noted that the beans from fertile soil have more and large nodules than those grown in poor soils.
Estimation of Population using Sampling Methods
- The number of organisms both producers and the various consumers is recorded in each area studied e.g. using a quadrat.
- The total area of the habitat studied is measured.
- The average number of organisms per quadrat (1 m2) is calculated after establishing as many quadrats as are necessary to cover the area adequately.
- Total population of organisms is calculated from the area.
- Abiotic environment is studied within the area sampled.
- Air temperature soil surface temperature are taken and recorded.
- This is best done at different times of day, i.e., morning afternoon and evening.
- Any variations are noted.
- pH of the soil is measured using pH distilled water to make a solution.
- Litmus papers can be used to indicate if soil is acidic or alkaline, but pH paper or meter gives more precise pH values.
- Humidity is measured using anhydrous blue cobalt chloride paper which gives a mere indication of level of humidity.
- A windsock is used to give an indication of direction of wind.
- As all the abiotic factors are recorded observations are made to find the relationships between behaviour of organism and the environmental factors for example:
- The temperature affects the behaviour of animals.
- The direction of wind will affect growth of plants.
- The level of humidity determines the type, number and distribution of organisms in an area.