Is the interdependence of organisms on one another and the physical environment
as nitrogen is traced from and back into the atmosphere
Although nitrogen is abundant in the atmosphere, most organisms are not able to
utilise it directly.
Meaning of cell physiology
The term physiology refers to the functions that occur in living organisms.
Cell physiology refers to the process through which substances move across the cell
Several physiological processes take place
General Principles of Classification
Classification is the science that puts organisms into distinct groups to make their
study easy and systematic.
Modern scientific classification is based on structure and functions.
Organisms with sim
Causative agent a bacterium Vibrio cholerae.
Transmission - It is spread through water and food contaminated by human faeces
containing the bacteria.
The bacteria produce a powerful toxin, enterotoxin, that causes inflammation o
Ecology is the study of organisms and their environment.
All organisms show interdependence on one another.
Organisms are affected by their environment, and they in turn affect the
Green plants manufacture food by photosy
Most animals move from place to place in search of food.
Major phyla are:
Effect of Pollution on Human Beings and other Organisms
This is the introduction of foreign material, poisonous compounds and excess
nutrients or energy to the environment in harmful proportions.
Any such substance is called a pollutan
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
Construction and Use of Dichotomous Keys
Biological keys are sets of statements that act as clues leading to the identification
of an organism.
By following the keys we can be able to place an organism in its group.
The most common key is the dichotomous
To examine Bryophyta
A mature moss plant is obtained.
The specimen is observed using a hand -lens.
A labelled drawing showing structures is made: rhizoids, set a capsule, gametophyte,
To examine Pteridophyta
A mature fern
Pyramid of Numbers
Refers to the number of organisms in each trophic level presented in a graphic form
and a pyramid shape is obtained.
The length of each bar is drawn proportional to the number of organisms
represented at that level.
This is because a he
Adaptations of Plants to Various Habitats
Organisms have developed structural features that enable them to live successfully
in their particular habitats.
Plants found beneath the canopies of trees are adapted to low light intensities by
having broad leav
Energy Flow in an Ecosystem
Most of the energy used in an ecosystem is derived from the sun.
Solar energy is trapped by photosynthetic plants.
It flows through different trophic levels .
At each level energy is lost as heat to space and also through respi
Classification is putting organisms into groups.
Classification is based on the study of external characteristics of organisms.
It involves detailed observation of structure and functions of organisms.
Organisms with similar