Chapter 2

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Chapter 2 8.1Principles of Ecology How
Organisms Obtain Energy

• Biology R/Biology
• Biology Academic
• Mrs. Fournier

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2.1 Organisms and Their Relationships

• Main idea The interactions of biotic and
  abiotic factors in a community or ecosystem form
  a tight web
• Objectives
• Describe the difference between abiotic and
  biotic factors
• Describe the levels of biological organisms
• Differentiate between an organisms habitat and
  its niche
• Review Vocabulary
• Species group of organisms that can interbreed
  and produce fertile offspring in nature

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Ecology

• The scientific discipline in which the
  relationships among living organisms and the
  interactions the organisms have with their
  environment are studied
• In 1866, Ernst Haeckel, German biologist, first
  introduced the study of ecology
• Ecologists are scientists who study ecology, they
  observe, experiment and model using a variety of
  tools and methods

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The Biosphere

• The proportion of Earth that supports life
• It extends several kilometers above the Earths
  surface into the atmosphere
• It extends several kilometers below the oceans
  surface.
• It includes areas such as the frozen polar
  regions, deserts, oceans, and rain forests

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Biotic factors

• The living factors in an organisms environment
• Example
• All living organisms in the environment
• All living organisms near the environment
• All migratory organisms
• The interactions among organisms are necessary
  for the health of all species in the same
  geographic location

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Abiotic factors

• The nonliving factors in an organisms
  environment
• Examples
• Temperature range - Air or water currents
• Sunlight - Soil type
• Rainfall - Nutrients available
• pH - Salt Concentration
• Organisms adapt to survive in the abiotic factors
  present in their natural environment.

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Levels of Organization

• The levels increase in complexity as the numbers
  and interactions between organisms increase.
• Organism
• Population
• Biological Community
• Ecosystem
• Biome
• Biosphere

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Organism, Population and Biological Communities

• The lowest level of organization is the
  individual organism
• Individual organisms of a single species that
  share the same geographic location at the same
  time make up a population
• A biological community is a group of interacting
  populations that occupy the same time.

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Ecosystems, Biomes and the Biosphere

• An Ecosystem is a biological community and all of
  the abiotic factors that affect it. Boundaries of
  an ecosystem are flexible and can change, and
  ecosystems might even overlap
• A Biome is a large group of ecosystems that share
  the same climate and have similar types of
  communities
• All the biomes on Earth combine to form the
  highest level of organization - the biosphere

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Ecosystems Interactions

• Interactions between organisms are important in
  an ecosystem.
• A community of organisms increases the chances
  for survival of any one species by using the
  available resources in different ways
• A habitat is an area where an organism lives
• A niche is the role or position that an organism
  has in its environment
• how it meets its needs for food, shelter and
  reproduction
• requirements for living space, temperature,
  moisture, or in terms of appropriate mating or
  reproduction conditions

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Community Interactions

• Interactions include competition for basic needs
  such as food, shelter, and mates, as well as
  relationships in which organisms depend on each
  other for survival
• Competition occurs when more than one organism
  uses a resource at the same time
• Predation is the act of one organism consuming
  another organism for food
• The organism that pursues another organism is the
  predator
• The organism that is pursued is the prey

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Symbiotic Relationships

• Some species survive due to the relationships
  they have developed with other species
• Symbiosis is the close relationship that exists
  when two or more species live together
• Mutualism
• Commensalism
• Parasitism

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Mutualism

• The relationship between two or more organisms
  that live closely together and benefit from one
  another
• Lichens on trees is an example of a mutualistic
  relationship between fungi and algae
• The close association of these two organisms
  provides two basic needs for the organisms food
  and shelter

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Commensalism

• Is a relationship in which one organism benefits
  and the other is neither helped or harmed.
• Examples
• Lichens and trees
• Clownfishes and sea anemones

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Parasitism

• A symbiotic relationship in which one organism
  benefits at the expense of another organism
• Examples
• External ticks or fleas
• Internal bacteria, tapeworms and roundworms

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2.2 Flow of Energy in an Ecosystem

• Main idea Autotrophs capture energy, making it
  available for all members of a food web
• Objectives
• Describe the flow of energy through an ecosystem
• Identify the ultimate energy source for
  photosynthetic producers
• Describe food chains, food webs, and pyramid
  models
• Review Vocabulary
• Energy the ability to cause change energy
  cannot be created or destroyed, only transformed

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Energy in an Ecosystem

• One way to study the interactions of organisms
  within an ecosystem is to follow the energy that
  flows through an ecosystem
• Organisms differ in how they obtain energy, they
  are classified as autotrophs or heterotrophs
  based on how they obtain their energy in an
  ecosystem

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Autotrophs

• Is an organism that collects energy from sunlight
  or inorganic substances to produce food
• Green plants and other organisms that produce
  their own food are called primary producers
• They are the foundation of all ecosystems because
  they make energy available for all other
  organisms in an ecosystem

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Heterotrophs

• Is an organism that gets its energy requirements
  by consuming other organisms
• Heterotrophs are also called consumers
• Herbivore
• Carnivores
• Omnivores
• Detrivores
• Decomposers

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Heterotrophs

• If it eats only plants it is a herbivore
• Cow, rabbit or grasshopper
• If it preys on other heterotrophs it is a
  carnivore
• Wolves, lions, and lynxes
• If it eats both plants and animals it is a
  omnivores
• Bears, humans and mockingbirds
• Detrivores eat fragments of dead matter, return
  nutrients to the soil, air, and water where the
  nutrients can be reused by organisms
• Worms and many aquatic insects
• Decomposers break down dead organisms by
  releasing digestive enzymes
• Fungi and bacteria

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Models of Energy Flow

• Ecologists use food chains and food webs to model
  the energy flow through an ecosystem
• Each step in a food chain or food web is called a
  trophic level
• Autotrophs make up the first trophic level in all
  ecosystems
• Heterotrophs make up the remaining levels
• With the exception of the first trophic level,
  organisms at each trophic level get their energy
  from the trophic level before it

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Food Chains

• A simple model that shows how energy flows
  through an ecosystem
• Arrows represent the one-way energy flow which
  typically starts with autotrophs and moves to
  heterotrophs
• Each organism uses a portion of the energy it
  obtains from the organism it eats for cellular
  processes to build new cells and tissues
• The remaining energy is released into the
  surrounding environment and no longer is
  available to these organisms

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Food Webs

• This is a model that represents the many
  interconnected food chains and pathways in which
  energy flows through a group of organisms.
• Feeding relationships usually are more complex
  than a single food chain because most organisms
  feed on more than one species.
• Example Birds eat a variety of seeds, fruits
  and insects

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Ecological Pyramids

• Below is a diagram that shows the relative
  amounts of energy, biomass or numbers of
  organisms at each trophic level in an ecosystem

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Pyramid of Energy

• Each level represents the amount of energy that
  is available to that trophic level.
• With each step up, there is an energy loss of 90
  percent available energy decreases
• This energy is used by the organisms for cellular
  processes and energy is released to the
  environment as heat

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Pyramid of Biomass

• Biomass is the total mass of living matter at
  each trophic level
• In a pyramid of biomass, each level represents
  the amount of biomass consumed by the level above
  it
• The amount of biomass decreases at each trophic
  level

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Pyramid of Numbers

• Each level represents the number of individual
  organisms consumed by the level above it
  population size decreases
• The relative number of organisms at each trophic
  level also decreases because there is less energy
  available to support organisms

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2.3 Cycling of Matter

• Main idea Essential nutrients are cycled
  through biogeochemical processes
• Objectives
• Describe how nutrients move through the biotic
  and abiotic parts of an ecosystem
• Explain the importance of nutrients to living
  organisms
• Compare the biogeochemical cycles of nutrients
• Review Vocabulary
• Cycle a series of events that occur in a regular
  repeating pattern

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Cycles in the Biosphere

• Energy is transformed into usable forms to
  support the functions of an ecosystem
• A constant supply of usable energy for the
  biosphere is needed, but this is not true of
  matter
• The law of conservation of mass states that
  matter is not created or destroyed
• Natural processes cycle matter through the
  biosphere

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Matter/Nutrients

• Matter
• Anything that takes up space and has mass
• Provides the nutrients needed for organisms to
  function
• Nutrients
• A chemical substance that an organism must obtain
  from its environment to sustain life and undergo
  life processes
• The bodies of all organisms are built from water
  and nutrients such as carbon, nitrogen, and
  phosphorous

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Biogeochemical Cycle

• The cycling of nutrients in the biosphere
  involves both matter in living organisms and
  physical processes found in the environment
• The exchange of matter through the biosphere is
  called biogeochemical cycle
• These cycles involve living organisms (bio),
• Geological processes (geo), and chemical
  processes (chemical).

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The Water Cycle

• Evaporation -
• Water is constantly evaporating from bodies of
  water
• Energy from the Sun heats the liquid water,
  forming the gaseous form of water called water
  vapor
• The water vapor rises and begins to cool in the
  atmosphere
• Clouds form when the cooling water vapor
  condenses into droplets around dust particles in
  the atmosphere

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The Water Cycle

• Precipitation
• Water falls from the clouds as precipitation
• Precipitation transfers water from the atmosphere
  to Earths surface
• Precipitation can be in the form of rain, snow,
  sleet or hail
• Precipitation is absorbed by the soil
• Percolation of water in soil is transferred into
  groundwater

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The Water Cycle

• Groundwater and runoff from land surfaces flow to
  oceans and other bodies of water and undergo the
  process of evaporation
• Water also evaporates from other sources of
  moisture, such as water in the soil
• Over land, approximately 90 of the water
  evaporates, 10 from the surface of plants
  through a process called transpiration

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The Water Cycle

• Because oceans cover ¾ of Earths surface, most
  of the precipitation falls directly into the
  ocean.
• Only about 2 of all the freshwater on Earth is
  held in any type of reservoir, such as an ice
  cap, glacier, aquifer, or lake.
• The remaining water on Earth circulates through
  the water cycle

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The Carbon and Oxygen Cycles
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The Carbon and Oxygen Cycles

• Carbon and oxygen often make up molecules
  essential for life
• During a process called photosynthesis, green
  plants and algae convert carbon dioxide and water
  into carbohydrates and release oxygen back into
  the air
• These carbohydrates are used as a source of
  energy for all organisms in the food web
• Carbon dioxide is recycled when autotrophs and
  heterorophs release it back into the air during
  cellular respiration

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The Carbon and Oxygen Cycles

• Carbon and oxygen recycle relatively quickly
  through living organisms
• Carbon enters a long-term cycle when organic
  matter is buried underground and converted to
  peat, coal, oil, or gas deposits
• The carbon might remain as fossil fuels for
  millions of years
• Carbon is released from fossil fuels when they
  are burned, which adds carbon dioxide to the
  atmosphere

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The Carbon and Oxygen Cycles

• Carbon and oxygen can enter a long-term cycle in
  the form of calcium carbonate, too.
• Calcium carbonate is found in the shells of
  plankton and animals such as coral, clams, and
  oysters
• These organisms fall to the bottom of the ocean
  floor, creating vast deposits of limestone rock
• Carbon and oxygen remain trapped in these
  deposits until erosion processes cause calcium
  and carbon to become part of the short-term cycle

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The Nitrogen Cycle
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The Nitrogen Cycle

• Nitrogen is an element that organisms need in
  order to produce proteins
• Plants and animals cannot use nitrogen directly
  from the atmosphere
• Nitrogen gas is captured from the air by species
  of bacteria that live in water, the soil, or grow
  on roots of some plants

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The Nitrogen Cycle

• The process of capture and conversion of nitrogen
  into a form that is useable by plants is called
  nitrogen fixation
• Some nitrogen also is fixed during electrical
  storms when the energy from lightening bolts
  changes nitrogen gas to nitrates.
• Nitrogen also is added to soil when chemical
  fertilizers are applied to lawns, crops, or other
  areas

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The Nitrogen Cycle

• Nitrogen enters the food web when plants absorb
  nitrogen compounds from the soil and convert them
  into proteins
• Consumers get nitrogen by eating plants or
  animals that contain nitrogen
• They reuse the nitrogen and make their own
  proteins
• Because the supply of nitrogen in a food web is
  dependent upon the amount of nitrogen that is
  fixed, nitrogen often is a factor that limits the
  growth of producers

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The Nitrogen Cycle

• Nitrogen is returned to the soil in several ways
• When an animal urinates, nitrogen returns to the
  water or soil and is reused by plants
• When organisms die, nitrogen returns to the soil
  when decomposers break down the dead organisms
  into the nitrogen compound ammonia.
• Organisms in the soil convert ammonia into
  nitrogen compounds that can be used by plants
• In a process called dentrification, some soil
  bacteria convert fixed nitrogen compounds back
  into nitrogen gas, which returns it to the
  atmosphere

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The Phosphorous Cycle
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The Phosphorous Cycle

• Phosphorus is an element that is essential for
  the growth and development of organisms
• It is found in various compounds of cells
• The phosphorous cycle, like the carbon and oxygen
  cycles consists of short-term and long-term
  cycles

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The Phosphorus Cycle

• Short-term cycle
• Phosphorus is cycled from the soil to producers
  and then from producers to consumers
• When organisms die or produce waste products,
  decomposers return the phosphorus to the soil
  where it can be used again
• Long-term cycle
• Weathering or erosion of rocks that contain
  phosphorus slowly adds phosphorus to the cycle
• Phosphorus, in the form of phosphates, may be
  present only in small amounts in soil and water
• Phosphorus often is a factor that limits the
  growth of producers

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Section 8.1 How Organisms Obtain Energy

• Main idea All living organisms use energy to
  carry out all biological processes
• Objectives
• Summarize the two laws of thermodynamics
• Compare and contrast autotrophs and heterotrophs
• Describe how ATP works in a cell

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Transformation of Energy

• All cellular activities require energy the
  ability to do work
• Thermodynamics is the study of the flow and
  transformation of energy in the universe

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Laws of Thermodynamics

• The 1st Law Law of conservation of energy
  Energy can be converted from one form to another,
  but it cannot be created nor destroyed
• The 2nd Law Energy that is lost is generally
  converted to thermal energy entropy increases
• Entropy measure of disorder or unusable energy,
  in a system.

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Autotrophs Heterotrophs

• Autotrophs organisms that make their own food
• Chemoautotrophs uses chemicals as a source of
  energy
• Photoautotrophs convert light energy from the
  Sun into chemical energy
• Heterotrophs organisms that need to ingest food
  to obtain energy

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Metabolism

• All of the chemical reactions in a cell are
  referred to as the cells metabolism
• Metabolic pathway is a series of chemical
  reactions in which the product of one reaction is
  the substrate for the next reaction
• Catabolic pathways releases energy by breaking
  down larger molecules into smaller ones
• Anabolic pathways uses the energy released by
  catabolic pathways to build larger molecules from
  smaller molecules
• The continual flow of energy within an organism
  is the result of the relationship of catabolic
  and anabolic pathways

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Photosynthesis

• Photosynthesis is the anabolic pathway in which
  light energy from the Sun is converted to
  chemical energy for use by the cell
• 6CO2 6H2O ? C6H12O6 6O2

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Cellular Respiration

• Cellular Respiration is the catabolic pathway in
  which organic molecules are broken down to
  release energy for use by the cells
• C6H12O6 6O2 ? 6CO2 6H2O ATP

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Photosynthesis Cellular Respiration Form a Cycle
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ATP The Unit of Cellular Energy

• Adenosine Triphosphate (ATP) is the most
  important biological molecule that provides
  chemical energy
• ATP is made of an adenine base, a ribose sugar,
  and three phosphate groups
• ATP releases energy when the bond between the
  second and third phosphate groups is broken,
  forming adenosine diphosphate (ADP) and a free
  phosphate group
• Energy is stored in the phosphate bond formed
  when ADP receives a phosphate group and becomes
  ATP

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ATP The Unit of Cellular Energy