Notes: Energy in Ecosystems, Different Ecosystems and Environmental Succession

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Notes Energy in Ecosystems, Different Ecosystems
and Environmental Succession

• Sci.7.12B, Sci.7.8B and Sci.7.12D

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What is an Ecosystem?

• An ecosystem is composed of all the living and
  nonliving things that interact in a particular
  area.
• All the living things within an ecosystem are
  called biotic factors. Organisms in an ecosystem
  interact with one another. They also interact
  with nonliving things. Plants, bacteria and
  animals are biotic factors.
• The nonliving things within an ecosystem are
  called abiotic factors. Soil, temperature,
  water, oxygen level, carbon dioxide level,
  nitrogen level are abiotic factors.

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Parts of an Ecosystem.

• Every organism gets the resources it needs from
  their surroundings. Organisms live in specific
  environments that provides the things the
  organisms needs-this is called a habitat.
• An ecosystem will have several habitats. A
  species is a group of similar organisms and will
  live in a specific habitat.
• All organisms have a role to play within the
  ecosystem-this is its niche. An organisms niche
  includes such things as the type of food it
  eats, how it obtains this food, and the physical
  conditions that it needs to survive and
  reproduce.

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Energy in Ecosystems.

• An organisms energy role is determined by how it
  obtains energy (food) and how it interacts with
  the other living things in its ecosystem.
• An organisms energy role in an ecosystem may be
  that of a producer, primary consumer, secondary
  consumer, tertiary consumer or decomposer.
• Energy first enters most ecosystems from the sun.

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Producers

• Plants, some bacteria and algae (in aquatic
  environments) capture radiant energy from the
  sun. They capture the energy from sunlight and
  use carbon dioxide to create chemical energy in
  the form of glucose . Oxygen is also formed as a
  by-product.
• Organisms that carry out photosynthesis are
  called autotrophs. They are considered producers
  because they produce their own energy.
• Producers pass the energy from the sun along in
  the form of glucose to organisms which eat them.

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The 3 types of consumers.

• Organisms that cannot make their own energy are
  called heterotrophs. Heterotrophs get their
  energy from producers.
• Consumers that eat only plants are called
  herbivores. Primary consumers are herbivores
  because they are the first to get the energy that
  plants captured from the sun.
• Consumers that eat only animals are called
  carnivores. Secondary consumers can be carnivores
  because they will eat the animals which have
  eaten the plants, which captured the energy from
  the sun.
• Consumers which eat secondary consumers are
  called tertiary consumers. Scavengers can be
  tertiary consumers because they are carnivores
  that feed on the bodies of dead organisms.

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Decomposer

• As the organisms in the ecosystem continue to
  take water, minerals and other raw materials from
  their surroundings-these materials begin to run
  out. When these materials run out new organisms
  will not grow.
• Organisms create waste and eventually die.
• Organisms that break down wastes and dead
  organisms and return the raw materials to the
  environment are called decomposers. Two major
  groups of decomposers are bacteria and fungi
  (molds mushrooms).
• Energy form the sun is transformed into chemical
  energy by producers. Consumers eat producers and
  pass that energy along from organism to organism
  until they die off where decomposers release that
  energy back into the environment. All along the
  amount of energy available to each energy level
  decreases.

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Food Chains Food Webs

• A food chain is a series of events in which one
  organism eats another and obtains energy. The
  first organism in a food chain is always a
  producer. The second organism is a primary
  consumer.
• A food web consists of many overlapping food
  chains in an ecosystem.

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Energy Pyramid

• When an organism eats food, it obtains energy.
  The organism uses some of this energy to move,
  grow, reproduce and carry out life processes.
  This means that only some of the energy will be
  available to the next organism in the food web.
• A diagram called an energy pyramid shows the
  amount of energy that moves from one energy level
  to another.
• Most of the energy in an ecosystem is available
  at the producer level. At each subsequent level
  there is less available energy. Only about 10 of
  the energy contained in one energy level of a
  food web is transferred to the next energy level.

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Biomes

• A biome is a group of ecosystems with similar
  characteristics
• Different biomes will have different environments
  which will support different types of organisms.

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• A community is all the different organisms that
  live together in an area. A community in an
  ecosystem is in equilibrium, or a state of
  balance, when the numbers and species of
  organisms in it do not change suddenly.
• Fires, floods, volcanoes and hurricanes can
  disrupt the equilibrium of a community by
  changing it drastically in a short period of
  time.

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Ecological Succession

• Communities sometimes change even without
  disasters.
• Succession occurs when populations in a community
  change due to events in the environment. These
  changes may be sudden or they may happen very
  slowly
• There are two main types of succession primary
  and secondary

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Primary Succession

• Primary succession is the series of changes that
  occur in an area where no ecosystem previously
  existed-like a newly formed volcanic island or a
  bare rock.
• The first species to populate this brand new area
  are called pioneer species.
• Pioneer species are often lichens and mosses
  carried to the area by wind or water. Mosses and
  lichens can grow on bare rocks with little to no
  soil. As they grow they help break up the rock.
  When the mosses and lichens die they enrich the
  thin layer of soil with their nutrients.

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Primary Succession

• Lichen are a mixture of fungi and algae that have
  grown together.
• Moss are a lot smaller than other plants and do
  not have true leaves or roots.
• Overtime plant seeds land in the new soil and
  begin to grow. The type of plants that grows
  depends on the biome.
• Eventually primary succession may lead to a
  community of organisms in equilibrium, which does
  not change drastically unless the ecosystem is
  disturbed. Reaching equilibrium can take
  centuries.

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Secondary Succession

• Secondary succession is the series of changes
  that occur after a disturbance in an existing
  ecosystem.
• Natural disturbances that have this effect
  include fires, hurricanes, and tornadoes. Human
  activities such as farming, logging, or mining
  may also disturb an ecosystem.
• Unlike primary succession, secondary succession
  occurs in a place where an ecosystem has
  previously existed. Secondary succession restores
  the ecosystem to a state in which equilibrium can
  be maintained. However the ecosystem may not be
  exactly as it was before the disturbance.
• Secondary succession occurs somewhat more rapidly
  than primary succession.

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