ECOSYSTEMS
ecosystem
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flora
fauna
non-living environment
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living environment
biomes
is a natural system, in which the life cycles of its parts are closely lined to each
other
plants
animals
water – in the form of rain or water in the soil
air – provides oxygen and carbon dioxide
solar energy – primary source of energy, heat and light
rocks – provide nutrients (permeable/impermeable)
soils – vary in depth, acidity, nutrients and fertility
plants, animals, insets and micro-organisms – harmony
people – disharmony
the world's major communities, classified according to the predominant vegetation
and characterized by adaptations of organisms to that particular environment
main source of energy is sunlight
sunlight is absorbed by green plants and converted through photosynthesis
energy passes through the ecosystem in the food chain
it´s an open system
plants/algae use carbon dioxide and water to make carbohydrates (energy) through
the photosynthesis process
photosynthesis
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food chain
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energy moves around within an ecosystem, from factor to factor, as producers and
consumers are eaten and this flow of energy is what we call the food chain.
recycling of nutrients
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some nutrients are part of a closed system
plants take up nutrients from the soil
they are returned back through dead bodies of animals
micro – water droplet
meso – freshwater pond, sand-dunes
global – tropical rainforest, coniferous forest
flow of energy
levels of ecosystems
ECOSYSTEMS
An ecosystem is an environment containing a community of interdependent plants and animals. It is all the animals and
plants in a particular area, and the way in which they are related to each other and to their environment. Food chains link
animals to the plants/animals they eat and the animals that eat them.
Communities
Ecosystems are made up of both non-living (abiotic) and living (biotic) factors.
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Abiotic factors are the elements of an ecosystem that are non-living. Nevertheless, they still have an affect on the
ecosystem. Water, temperature, relief, soil type, fire, and nutrients are all examples of abiotic factors.
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Biotic factors are the living elements of an ecosystem, i.e. plants and animals. All biotic factors require energy to
survive. These living organisms form a community within an ecosystem.
Biotic and abiotic factors are interrelated. If one factor is changed or removed, it impacts the availability of other resources
within the system.
Biotic and abiotic factors combine to create a system or more precisely, an ecosystem. An ecosystem is a community of
living and nonliving things considered as a unit. If a single factor is changed, perhaps by pollution or natural phenomenon,
the whole system could be altered
The community within an ecosystem is linked together by food chains. Biotic factors become linked in a food chain when
they eat one another. The start or bottom of a food chain is made up of producers, such as plants and algae. Producers are at
the start, or the bottom, of the food chain because they do not eat other biotic factors to get the energy they need to survive.
Instead of taking energy from food, producers get energy by converting it from carbon dioxide and water using sunlight. This
process is called photosynthesis.
Photosynthesis explains how energy from the sun is captured by green plants and used to make food. Most of this energy is
used to carry on the plant's life activities. The rest of the energy is passed on as food to the next level of the food chain.
Grass is a producer and gains its energy from photosynthesis
Other biotic factors in the food chain survive by eating the producers. This gives them the energy that the producers
obtained through photosynthesis. These biotic factors are called consumers because they eat other organisms to get their
energy, rather than taking it direct from sunlight. Biotic factors that eat consumers are also consumers and they are often
called carnivores. There are four types of consumer:
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Herbivores are organisms that eat plant matter (producers) to gain energy.
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Carnivores are organisms that eat meat to gain energy
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Omnivores are organisms that eat both plant (producer) and animal (consumer) matter to gain energy.
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Decomposers are organisms that feed on the remains of dead plant and animal matter. They help to speed up the
process of decay. They also assist in recycling nutrients back to producers in nutrient cycles.
Energy moves around within an ecosystem, from factor to factor, as producers and consumers are eaten. The flow of energy
in this way is what we call the food chain.
Biomes are defined as "the world's major communities, classified according to the predominant vegetation and characterized
by adaptations of organisms to that particular environment" The importance of biomes cannot be overestimated. Biomes have
changed and moved many times during the history of life on Earth. More recently, human activities have drastically altered
these communities. Thus, conservation and preservation of biomes should be a major concern to all.
FLOWS AND CYCLES
As well as the flow of energy through a food chain, other flows and cycles can be found within ecosystems. Ecosystems have
water cycles and nutrient cycles. So when an animal eats another animal or a plant it not only obtains that organism's
energy, but its water and nutrients as well. Different nutrients are passed around an ecosystem as organisms consume other
biotic and abiotic factors. Two important nutrients are carbon and nitrogen.
The carbon cycle
The carbon cycle describes how carbon circulates around an ecosystem. Carbon will change form. Sometimes it is an element
and sometimes a compound. Carbon is passed between living organisms and between non-living and living systems. There
are many different elements to the carbon cycle.
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Producers, eg plants/algae use carbon dioxide and water to make carbohydrates (energy) through the photosynthesis
process.
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Animals can not photosynthesise. When animals consume the producers they use the carbohydrates to provide the
energy for reproduction, growth and daily living. This process of creating energy is called respiration. It requires oxygen and
carbohydrates and produces as a by-product carbon dioxide (CO2) and water (H2O). The CO2 is exhaled by animals back
into the atmosphere where the carbon cycle begins again.
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When organisms die, they decompose. This releases nutrients into the soil, but carbon remains stored in the remains
of the animals. It can remain stored for a very long time and can be still be used to provide energy - eg coal, oil.
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When this energy is released by humans through burning (eg oil) in industrial processes, carbon gasses, such as
carbon dioxide are released into the atmosphere.
Water cycle
The water cycle describes how water moves from the ocean, to the atmosphere (evaporation), to land (rain) and back to the
ocean (rivers). On the way the water will be intercepted by plants and animals, both of which need water to survive.
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plants need water for photosynthesis
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animals use water to remove toxins and stay cool (sweat)
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both plants and animals give off water as a by-product of respiration
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animals drink water but can also obtain water by consuming plants and animals that have stored water