1.CLASSIFICATION KINGDOM FUNGI
Carbon cycle
Carbon dioxide from the atmosphere
is absorbed by plants and used for photosynthesis. These plants serve as food
for herbivores, which are in turn eaten by carnivores.
When plants and animals die,
microorganisms cause decomposition and carbon dioxide is released into the
atmosphere.
The remains of plants and animals
after millions of years result in the formation of fossil fuels such as coal,
natural gas and oil. When these fuels are burnt, they release carbon dioxide
into the atmosphere.
Respiration of living things also
releases carbon dioxide into the atmosphere. The carbon dioxide is absorbed by
plants and then the cycle starts again.
The nitrogen cycle
Nitrogen cycle refers to a biochemical cycle in
the environment whereby nitrates in the soil are taken up by plant roots and
may pass along food chains into animals absorb it in this form. It must first
be converted into either nitrates or ammonium compound. Figure below shows the
nitrogen cycle
- Nitrogen-fixing bacteria in theroot nodules of legumes plant carry out fixation by converting atmospheric nitrogen to nitrates.
- Lightning converts atmospheric into nitrates. The nitrates get into and are later absorbed by plants. Plants use nitrogen compounds to produce plant proteins. Plants are eaten by animals. Animals use the nitrogen to produce animal proteins. When plants and animals die, decomposers such as bacteria and fungi feed on them. The decomposers release ammonia gas (NH3) which contains nitrogen. The ammonia is converted into nitrites and then nitrates by bacteria. Denitrifying bacteria release nitrogen from nitrates back into the atmosphere.
INTERACTION
AMONG LIVING ORGANISM
The relationship among organisms in
the environment can be explained in the form of predation, competition and
symbiosis.
PREDATION
– This happens when one organism captures, kills and feeds on another in order
to get nutrients. Example cats eat mice and sharks eat fishes.
COMPETITION
– This is a relationship where organisms both need the same limited environment
resources for survival. Examples lions and leopards both hunt antelope and
zebra. Hence lions and leopards are competitors. Organism from the same places
can also be competitors, Example cow competing for grass
SYMBIOSIS
– This is a relationship whereby there is a close association between
organisms. This association could take various forms, such as mutualism,
commensalism, Neutralism, synnecrosis, amensalism and parasitism.
MUTUALISM
– This is the relationship in which two organism benefit each other. Example:
The rhizobium bacteria in the root modules of legumes convert nitrogen into
nitrates for use by the plant. The bacteria get protection and nutrients from
the plants.
COMMENSALISM –
This is interaction that is beneficial to one organism and is neutral to the
other organism. Example when a bird builds a nest in a hole, in a tree.
NEUTRALISM –
This is the lack of interactions between two organisms. It get neither benefits
nor harm from each other. Example: Nile porch swimming in a lake.
SYNNECROSIS –
This relationship is detrimental to both organisms. Occur between two kind of
organism and each organism destroys other. It is usually short lived and rare
in nature.
AMENSALIMS
– This interaction is harmful to one species and neutral to the other organism.
Example: The black walnut tree which secretes jug lonea chemical that kills
some neighboring plants.
PARASITISM –
In this association one organism benefits while the others is harmed. Example:
Plasmodium that causes malaria in human beings.
FOOD CHAINS AND FOOD WEBS
Food chains and food webs show the
flow of nutrients and energy among organisms in the environment.
- Each organism in a food chain or food web represents a trophic level a food chain.
- Trophic level - is a position that organism occupies in food chain or food web on what eats it and what it eats
- Examples; producers like green plants, primary consumers like herbivores and secondary consumers like carnivores
PRODUCERS:
These are organisms that can manufacture their own food example: green plants
and photosynthesis bacteria, this is the first trophic level.
- Producers are eaten by primary consumers
- Primary consumers are mostly herbivores such as rabbits, cows, buffaloes, wild beasts, goat and sheep.
- Primary consumers form the second trophic level.
