5. Tropic level- is each level in the food
chain.
Basal energy requirement (B.E.R)
-The amount of energy used by an
organism’s body just to keep alive,when
no food is being digested and no
muscular work is done.
6. Food web- a network of interrelated food
chains in a given area
7. BIOMAS PYRAMID
Pyramid of biomass is the graphic representation of biomass present per
unit area of different trophic levels, with producers at the base and top
carnivores at the tip".
The total amount of living or organic matter in an ecosystem at any time is
called 'Biomass'.
In a terrestrial ecosystem, the maximum biomass occurs in producers, and
there is progressive decrease in biomass from lower to higher trophic
levels. Thus, the pyramid of biomass in a terrestrial ecosystem is upright.
8. BIOLOGICAL MAGNIFICATION
Certain harmful substances, usually ones not found in nature but
introduced by man, may get into plants and/or animals. These poisonous
substances may not be broken down in the body or excreted easily,
efficiently and quickly. Instead, they accumulate in the tissues, and as the
living organism eats more, the concentration of these substances
increases and they pass from one trophic level to the next.
Since man is an omnivore and has access to all trophic levels for food, he
gets the toxic substances into his body in large amounts.
Secondary and tertiary consumers located on top of the food chain also
get the poison into their body, and accumulate in large concentrations.
9. Biological control
-is the deliberate use of one organism to regulate the population
size of a pest organism. There are three main branches of
biological control.
Classical biological control is the control of pests introduced from
another region through importing specialized natural enemies of
the pest from its native range. The aim is to establish a
sustained population of the natural enemies.
Conservation biological control aims to manipulate the
environment to favor natural enemies of the pest. topic.
Augmentation biological control occurs when the number of
biolotical control agents is supplemented. Inoculation is the
introduction of a small number of individuals of the biological
control agent, while inundation is the introduction of vast
numbers of individuals. This over all approach is common when
the biological control agent can not survive the entire year, or
can not achieve densities high enough to regulate the pest
population
11. Carbon and oxygen cycles
Carbon and oxygen are two elements that are essential to life. They
are naturally present in the atmosphere in the form of carbon dioxide and
gaseous oxygen. Due to their constant circulation between the soil, air,
and water--through processes such as photosynthesis and combustion--
living matter is constantly renewed. However, human activities can disturb
the balance of these cycles.
Photosynthesis – is the process used by plants containing
chloropyll to utilise sunlight,carbon dioxide and water to form sugar(as
glocuse) and oxygen.
six molecules of water plus six molecules of carbon dioxide produce
one molecule of sugar plus six molecules of oxygen-
12. Respiration is the process of releasing
energy from food. You could think of it as burning
the fuel, glucose.
Glucose is the key molecule. It is made by
plants in photosynthesis. In animals, although
lots of different molecules are absorbed after
digestion they are usually turned into glucose. In
animals glucose is especially important as two
organs can only use glucose as a fuel.
