FCAT Science Review

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FCAT Science Review

• Interdependence of Living Things
• Energy Flow in Ecosystems
• Cycling of Material in the Biosphere
• Interconnectedness of Earths Systems and the
  Quality of Life

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Predation

• Predator organisms that kill and eat other
  organisms
• Prey organism being eaten
• Prey gt Predators

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Symbiotic Relationships

• Symbiosis - occurs when one species lives in a
  close association with another species over a
  period of time
• Mutualism benefits both organisms
• Parasitism one organism lives on or in another
  organism (host), benefits the parasite, but harms
  the host
• Commensalism one organism benefits, the other
  is neither helped or harmed

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Mutualism
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Commensalism
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Parasitism
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Energy Flow in Ecosystems

• Most of the energy that flows through an
  ecosystem comes from the sun
• Energy is needed by living organisms for all of
  lifes functions (reproduction, growth, movement,
  etc.)
• Energy flow through the ecosystem is one-way
• Energy is lost as heat at every step in the food
  chain, which limits most food chains to 4 or 5
  links.

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Food Chains and Webs

• Most food chains begin with a photosynthetic
  autotroph (an organism that uses light to
  manufacture food). They are also known as
  producers because they produce the food that is
  used for the rest of the community.
• Plants, Algae, Phytoplankton
• Chemosynthetic bacteria do NOT use light to make
  food, but use the energy found in chemicals to
  make food.

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• heterotrophs (an organism that cannot make its
  own food). They are also known as consumers,
  because they must consume food for energy.
• Herbivore eats only plants, is also known as a
  primary (1?) consumer
• Carnivore eats only meat,
• could be a secondary (2?) consumer an organism
  that eats an herbivore
• could be a tertiary (3?) consumer an organism
  that eats a carnivore
• Omnivore eats both plants and animals, could
  act as a primary, secondary, or tertiary consumer
  in the food chain, depending on what the organism
  is currently eating.
• Scavenger feeds on the tissues of dead animals,
  could act as a primary, secondary, or tertiary
  consumer in the food chain, depending on what the
  organism is currently eating. Examples include
  vultures, ants, crows, hyenas.
• Decomposer feeds on wastes and dead matter from
  all levels of the food chain. The primary
  decomposers in ecosystems are bacteria and fungi.
  They break down decaying matter and return the
  nutrients to the ecosystem (soil or water) so the
  producers can use them again. For this reason
  they are important to the food chain as recyclers
  of nutrients.

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Ecological Pyramid

• Ecological pyramids can be used to show the
  amount of biomass, energy, or number of organisms
  in each trophic level.

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• Because the transfer of energy and matter is
  inefficient, only about 10 of what is on one
  level can be transferred to the level above it.
  This is called the 10 law.

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Cycling of Materials in the Biosphere

• The elements carbon (C), oxygen (O), hydrogen (H)
  and nitrogen (N) are essential to living things
  and their activities. In an ecosystem, these
  elements cycle between organisms and their
  environment in patterns called biogeochemical
  cycles.

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Water Cycle
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Carbon Cycle
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Nitrogen Cycle
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Ecosystems and Quality of Life

• Humans and the Water Cycle
• less than 3 of the water on the planet is fresh
  and drinkable
• pollution of the water supply trash, chemicals,
  sewage, toxic wastes, etc.
• deforestation reduces the amount of water that
  will transpire (evaporate across the leaf) into
  the atmosphere
• Humans and the carbon cycle
• cutting down forests less plants to take in CO2
• burning fossil fuels releases CO2 into the
  environment
• increased levels of CO2 may lead to changes in
  the climate because CO2 traps heats in the
  atmosphere (greenhouse effect leading to global
  warming)

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• Humans and the Nitrogen Cycle
• erosion and irrigation can wash nitrogen out of
  the soil
• sewage and fertilizer runoff can add excess
  nitrogen to rivers lakes and ponds where algae
  and plants grow out of control.
• growing the same crops repeatedly can deplete the
  nitrogen from the soil
• crop rotation with soybeans or other legumes can
  replace the nitrogen
• adding commercially produced fertilizer, but its
  expensive and uses lots of energy from fossil
  fuels to make