6.3 How does a tropical rainforest ecosystem · Energy flow in a tropical rainforest ecosystem...

© Oxford University Press 2009 Quit

Part 6 Disappearing green canopy―Who should pay for the massive deforestation in rainforest regions?

6.3 How does a tropical

rainforest ecosystem

function?



What is an ecosystem? What are the components of an ecosystem?

Ecosystem

Abiotic

components

Biotic

components

Environment

Plants

Animals



What are the biotic components in a

tropical rainforest ecosystem?

Microscopic organisms

Animals

Plants

Biotic

components refer

to living things.

Decomposers

Producers

Consumers They may be

classified into

different trophic

(feeding) categories.





1 Producers Producers are green plants. They can produce their own food by ______________. photosynthesis

Carbon

dioxide

Sunlight Chlorophyll

Food

Water

Oxygen

at the presence of





2 Consumers

Consumers are animals. They cannot

produce their own food.

Primary consumers:

feed directly on

producers

Secondary

consumers: feed on

primary consumers

Tertiary

consumers: feed

on secondary

consumers





2 Consumers

We can classify the

consumers by their

diet.

A crocodile eats animals. It is

a _________. carnivore

A rabbit eats plants only.

It is a _________. herbivore

Humans eat both plants

and animals. They are

__________. omnivores





2 Consumers

Producers and consumers make up a food chain.

Rainforest tree

(Producer)

Grasshopper

(Primary consumer)

Lizard

(Secondary consumer)

A food chain usually starts with a producer and ends with a secondary consumer or tertiary consumer.





2 Consumers

In a tropical rainforest, individual food chains are interlocked at various levels to form a food web.





3 Decomposers

Fungi are an example of decomposers

Decomposers such as fungi and bacteria break down dead plant and animal tissues.

They secrete _________ to break down dead organic materials into inorganic matter. Plants can absorb them easily.

enzymes



What are the abiotic components in a

tropical rainforest ecosystem? Abiotic components refer to the non-living things.

They are found in:

Atmosphere

Air

Precipitation

Solar radiation

Hydrosphere

Water at the

earth’s

surface

Underground

water

Lithosphere

Soil

Rocks



Can you categorize the

following abiotic

components and state

their importance to

plants and animals?

What are the abiotic components in a


Abiotic components

Atmosphere

carbon dioxide

weathered rocks

rivers and lakes

oxygen

ground water

organic materials from soil rainfall solar radiation

carbon dioxide

An input of photosynthesis

of plants.

They provide nutrients to

plants.

rainfall

It provides water for the

photosynthesis of plants.

They provide drinking water

and living habitats for

animals.

oxygen An input of the respiration of

living organisms. solar radiation An input of the

photosynthesis of plants.

It provides moisture in the soil

for the plants. They provide nutrients for plants.

Hydrosphere Lithosphere

weathered rocks rivers and lakes

ground water organic materials from soil



How are biotic and abiotic components

linked in a tropical rainforest ecosystem?

Biotic and abiotic components are closely linked by:

Energy flow

Nutrient cycling



Why is a tropical rainforest a fragile

ecosystem?

As mentioned before, most nutrients in the tropical rainforest are stored in the biomass. That means a high proportion of the energy and nutrient is stored above ground. This biomass is vulnerable to various disturbances, such as fires or deforestation.

(Credit: K. Wothe/Blickwinkel)




ecosystem?

As the rainforests support the wildlife there, destroying the rainforest will cause the rainforest ecosystem to collapse.

(Credit: Joerg Boethling/Still

Pictures)



The biomass stores most of

the nutrients in a rainforest.

Removal of trees caused by a

sudden change in climate or

external agents

Loss of stored nutrients

No supply of nutrients to the soil

created through decomposition

Soil depletion No regrowth of

trees

Collapse of the

ecosystem

Animals die


ecosystem?



Energy flow in a tropical rainforest

ecosystem

Energy flow is the transfer of energy through various living organisms along the food web. There are five trophic levels in a tropical rainforest ecosystem.

Input

of

solar

energy

T1

Producers

T2

Primary

consumers

T3

Secondary

consumers

T4

Tertiary

consumers

T5 Decomposers

The sun is the primary source of energy that maintains the ecosystem. Energy is passed along the food chain or food web.




ecosystem

Input

of

solar

energy

T1

Producers

T2

Primary

consumers

T3

Secondary

consumers

T4

Tertiary

consumers

T5 Decomposers

Producers carry out photosynthesis with the input of solar energy.

Net input of

energy at each

tropic level

Energy loss through

transpiration or

respiration

Heat loss

through

respiration

Energy loss

through decay and

decomposition

Some energy is lost during the transpiration, respiration and decomposition.




ecosystem

Input

of

solar

energy

T1

Producers

T2

Primary

consumers

T3

Secondary

consumers

T4

Tertiary

consumers

T5 Decomposers

Net input of

energy at each

tropic level

Energy loss through

transpiration or

respiration

Heat loss

through

respiration

Energy loss

through decay and

decomposition

When primary consumers eat the producers as food, energy is transferred to them. Since primary consumers cannot fully digest the producers, the remains of the producers are being processed by decomposers.

Energy not

being used




ecosystem

Input

of

solar

energy

T1

Producers

T2

Primary

consumers

T3

Secondary

consumers

T4

Tertiary

consumers

T5 Decomposers

Net input of

energy at each

tropic level

Energy loss through

transpiration or

respiration

Heat loss

through

respiration

Energy loss

through decay and

decomposition

Energy not

being used

The energy flow carries on at different tropic levels.

Energy not

being used

Energy not

being used

The energy flow carries on at different tropic levels. The higher the tropic level (except decomposers), the ( less / more ) the energy remains.



Trophic pyramid

A trophic pyramid shows the amount of organic matter of the living organisms in an area.

As the trophic level increases, the amount of organic matter of each tropic level ( decreases / increases ).



Nutrient cycle refers to the circulation of nutrients from the environment to organisms and back to the environment.

Environment Organisms

Nutrients are circulated among three stores

Biomass

Litter

Soil

Nutrient cycling in a tropical rainforest

ecosystem




ecosystem

A Biomass Biomass refers to the total weight of living organisms, i.e. plants and animals, of an area.

Biomass

Nutrients are stored in plants and animals.

Plants consume nutrients from the soil and sun’s energy to produce their own tissues through photosynthesis.

When animals eat plants, they take up the nutrients and convert plant tissues to their own tissues.

Uptake

by

plants

Soil

Amount of nutrients

transferred




ecosystem

B Litter Amount of nutrients

transferred

Biomass Litter

Dead plants tissues, dead animals and animal wastes accumulate on the ground to form a layer of litter.

Littering

The falling rain dissolves minerals, e.g. nitrogen and carbon in the air, and add the nutrients to the litter.

Some of the nutrients may be washed away by run-off.




ecosystem

C Soil Amount of nutrients

transferred

Litter Soil

When litter is decomposed, the nutrients are broken down into inorganic form and stored in the soil.

Nutrients decomposed

from litter

Weathering of rocks contributes nutrients to the soil.

Input from weathered rock

Nutrients of soil may lose through leaching.




ecosystem

Biomass

Soil

Litter Litter is quickly decomposed

Heavy rain causes strong

leaching

Quick uptake by plants

Most nutrients are stored in

the dense vegetation

Much input from rainfall

In tropical rainforests, the nutrient store of biomass is huge, but the stores in soil and litter are small.

Amount of nutrients

transferred

6.3 How does a tropical rainforest ecosystem · Energy flow in a tropical rainforest ecosystem...

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