SCIENCE 20
UNIT D: Changes in Living
   Chapter 1: Biosphere of Life
  Chapter 2: Changing Populations
 Chapter 1: Biosphere of Life
1.0: Introduction
1.1: Abiotic factors
1.2: Biotic factors
1.3 The Web of Life
1.4 Conducting a Field Study
1.5 The Recycling of Matter
1.6 Biodiversity
Lesson 1.0: Introduction
               The Biosphere
• The biosphere is the area of the earth that
  supports life.
• It consists of the:
  – atmosphere or air
  – hydrosphere or water
  – lithosphere or land.
• “Ecology is the study of the biosphere.”
  – Study of the interactions of living
    organisms with one another and with their
    physical environment
                           Main interactions
                            in biosphere
                          •The sun is the primary
                          source of energy
                          •Producers change solar
                          energy into chemical energy.
•Consumers eat producers & other consumers.
•Decomposers break down the waste materials into
abiotic chemicals which can be used by plants.
•Waste energy is released as heat or thermal energy.
•Abiotic factors are non-living structures, while biotic
factors are living structures that interact in the
biosphere. The Habitat is all the biotic and abiotic
factors present in an area that encourage the
reproduction and survival of an organism.
The Organization of
Biosphere: Area that supports life
ie) Earth
Ecosystems: all the organisms &
interacting abiotic factors in an area
ie) Prairie grasslands
Communities: several populations
ie) deer and humans
Populations: Group of individuals
ie) herd of deer
Organisms: a single plant or animal
ie) deer
 How is the energy from
   the sun captured?
• Plants & algae capture energy
  from the sun during photosynthesis:
  6CO2(g)+6H2O(g)+solar chloroplast C6H12O6 (s)+6O2 (g)
• Plants make two vital components for life:
  oxygen and glucose or food.
• Since plants make their own food they are
  often called autotrophs or “self feeders”.
How is energy stored
in glucose released?
• Plants and animals release energy stored in
  glucose during cellular respiration:
 C6H12O6 (s)+6O2 (g) mitocondria6CO2(g)+6H2O(g)+Energy
• NOTE: The Cellular respiration reaction is
  the photosynthesis reaction backwards.
See What You Know
Lesson 1.1: Abiotic factors
    What are abiotic factors?
• Abiotic factors are the non-living components
  that influence and shape an ecosystem.
• They are classified into three general categories:
  climatic, physiographic and edaphic.
• They are vital to an ecosystem because they
  affect the type and number of organisms that live
          Five Climatic Factors:
• Light: The amount of light affects the rate of
  photosynthesis, which determines the amount and type of
  plants in the ecosystem.
• Temperature: The temperature range of an ecosystem sets
  limits to the type of organism that can survive. Life on earth
  exists between –60oC to + 60oC.
• Moisture: Water is necessary for life & influences the
  adaptations plants and animals have to survive. In low
  moisture areas, plants have waxy leaves and animals have
  skin to hold in the moisture.
• Wind: Wind affects the composition. Windy ecosystems
  will encounter soil movement & water loss due to
  evaporation & transpiration.
• Fire: Fire causes major changes to ecosystems and may be a
  necessary. Jack pine cones will only reproduce after a fire
  and fire beetles mate and lay eggs under the burned bark.
 Three Physiographic Factors:
• Latitude: As the latitude increases (towards north &
  south poles), temperatures decrease, greater variation in
  light occurs and diversity of species decreases.
• Altitude: At higher altitudes (higher up the mountain),
  temperature decrease, precipitation increases, wind
  increases and soil conditions worsen.
• Topography (physical features of the land): The
  physical features of land such as mountains, hills,
  flatlands and valleys can affect factors of an ecosystem
  such as precipitation. The Rocky Mountains creating dry
  warm Chinook winds are an example of a topographic
  factor affecting an ecosystem (look below).
        Two Edaphic Factors:
• Edaphic factors are factors related to the texture
  and chemical composition of the soil.
• FACTORS: Slope, organic content, age, particle
  size, ionic content and minerals present
• Edaphic factors determine what type of plant
  growth can be supported. 4 Typical Layers
                       •twigs and leaves.
                       •dead and decaying material.
                       •clay and minerals
                       •Bedrock & glacier deposits
Lesson 1.2: Biotic Factors
     What are biotic factors?
• Biotic factors are the “living” interactions
  between organisms in an ecosystem. There
  are three main biotic factors – symbiosis,
  predation, and competition.
               What is Symbiosis?
•       Symbiosis describes close relationships between two or
        more species and a least one benefits. There are 3 types
        of symbiotic relationships
    –      Commensalism is a relationship where one organism benefits &
           the other is unaffected.
          •   Ie) cowbirds & bison – the bison stirs up insects for the cowbird.
          •   Ie) birds nesting in trees - the birds benefit and the tree is unaffected.
    –      Mutualism is a relationship where both organisms benefit.
          •   Ie) Prairie dogs aerate the soil and increase rich plant growth and the
              buffalo compacts the soil (better burrows) and keeps the plants short
              so the prairie dogs can see predators.
          •   Ie) Another example is the crab (provides protection) and the
              stinging anemone (provides larger feeding area).
    –      Parasitism is a relationship where one organism benefits and the
           other is harmed.
          •   Ie) Cowbirds lay their eggs in the yellow warbler nests
          •   Ie) The tapeworm benefits by eating the nutrients in the intestine,
              while the individual suffers weight loss/sickness.
                      What is predation and
•       Predation: relationships where the prey (organism eaten)
        becomes food for the predator (organism hunting).
    –      ie) Lynx & hare are an example of a predator-prey relationship
    –      ie) The Venus Fly Trap is a rare example of predation by a plant.
•       Occasionally, an intruder is introduced to a ecosystem
        where there are no predators.
    –      ie) Zebra Mussels or the West Nile Virus.
                                                  •The prey population is
                                                  larger to provide the
                                                  predator with a better
                                                  chance of survival.
                                                  • The delay is due to
                                                  time for reproduction.
         What is Competition?
•   Competition describes relationships
    where organisms compete for limited
    resources, territory or members of the
    opposite sex.
    –   Ie) Two mountain goats fighting for a female
    –   Ie) two coyotes fighting for food
    –   Ie) Grass & wildflowers (coneflower)
        compete for light, water & nutrients
Lesson 1.3: The Web of Life
          How does energy flow?
• Energy levels are called trophic levels
5th trophic level – decomposers (present after each level)
4th trophic level – 3rd order (tertiary) consumers
3rd trophic level – 2nd order (secondary) consumers
2nd trophic level – 1st order (primary) consumers
1st trophic level – autotrophs or producers
      How does energy flow?
• Energy levels are called trophic levels
  – can trap and change light energy to chemical
    energy; all other organisms depend on them.
  – Also called producers
  – Plants and algae are autotrophs
      How does energy flow?
  – feeds directly on a producer
  – are also called primary (first order)
    consumers, herbivores, or plant eaters.
  – A cow grazing on grass, a caterpillar browsing
    on leaves and a tadpole eating algae are
    examples of herbivores.
      How does energy flow?
• 3rd & 4th TROPHIC LEVEL: 2nd & 3rd
  – feeds directly on other consumers
  – are also called secondary & tertiary
    consumers, carnivores, or animal eaters.
  – A fox which eats a bird is an example of a
      How does energy flow?
  – feeds on the waste or dead material in the
    tropic level(s) below
  – Recycles the nutrients for producers
  – Bacteria & mushrooms are examples of
       What are food chains?
• Food chains are an oversimplified means of
  showing how the Sun's energy is passed
  from one organism to another. All food
  chains begin with a producer and have the
  following basic format:
       Energy flow
          What are food webs?
• A food web is
  several food
• It is organized
  with the trophic
  levels in rows &
  with arrows, like
  the one on the
       What are pyramids?
• Pyramids are triangles or horizontal bar
  graphs that illustrate energy loss, numbers
  of organisms involved or biomass.
• Three pyramids examined in this course
  – Energy pyramids
  – Number pyramids
  – Biomass pyramids
What are energy pyramids?
                • Energy pyramids
                  are organized by
                  the amount of
                  energy available
                  in each trophic
                • Rule: 90% of
                  energy is used
                  for life processes
                  or lost as heat;
                  10% of energy is
                  stored and
                  passed on to the
                  next consumer.
What are number pyramids?
                 • Number pyramids
                   are organized by
                   the number of
                   organisms present
                   in each trophic
                   level. Due to
                   energy used for
                   live processes, it
                   takes a great
                   number of
                   producers to
                   supply the energy
                   needs of a primary
What are biomass pyramids?
               • Biomass pyramids
                 are organized by
                 the mass of all the
                 organisms in that
                 trophic level.
               • Mass decreases as
                 energy flows up
                 the pyramid.
What is Biomagnification?
              • Biomagnification is also
                known as biological
              • Biomagnification occurs
                when a chemical
                increases in
                concentration as it
                moves up the food
                chain/web because the
                chemical becomes stored
                in the organisms tissues.
TOPIC 1.4: Field Study
     (See handout)
TOPIC 1.5: Recycling Matter
 What is the hydrologic cycle?
• The hydrologic (water) cycle is the movement of water
  between the hydrosphere, lithosphere and atmosphere.
  The energy that runs the water cycle comes from the sun.
           What are the steps of the
            hydrological cycle?
1. Evaporation (water turns into vapour) and transpiration
   (plants and animals releasing water vapour during cellular
   respiration) puts water vapour into the atmosphere.
2. The vapour condenses into clouds as the air rises & cools.
3. Precipitation (rain, snow, hail, dew or fog) returns water
   to the hydrosphere and lithosphere.
4. Run-off pools water into rivers, lakes and oceans so
   organisms can use it. Run-off also free minerals and
   nutrients that are needed by organisms.
5. Underground aquifers return the ground water from the
   lithosphere to the hydrosphere.
 What human activities affect the
         water cycle?
• Wildfires produce a waterproof layer and remove trees
  which increase run-off and erosion. Trees regulate
  temperature and moisture
• Potable water (water usable for human consumption) is
  an ever-increasing problem because of the lack of water
  in some areas and pollution in other areas (sewage,
  pesticides, acid rain, heavy metals, etc…)
• Aquifers provide water for people in areas where there is
  not very much surface water.
• Removal & overuse of too much water dries up lakes,
  rivers and aquifers.
• Changing climates also change the water cycle patterns.
      What is the carbon cycle?

• Carbon is the basic building block of all life on Earth.
  Carbon exists in the atmosphere as carbon dioxide(CO2)
  and exists as sediments (CaCO3) in the soil.
                                            • Contributors:
                                            volcanoes and
                                            and formation
                                            of minerals
        What is the oxygen cycle?
• The oxygen cycle recycles oxygen throughout the biosphere. Some of the
  oxygen is found as a gas (O2(g)) and is often called the global free oxygen
  supply. 21% of the atmosphere is free oxygen.
                                                            • Most of the
                                                            oxygen in the
                                                            biosphere is
                                                            combined with
                                                            other chemicals:
                                                            carbon dioxide
                                                            (CO2 (g)), water
                                                            (H2O (g)), calcium
                                                            (CaCO3) &
                                                            ozone(O3 (g)).
 What are the Contributors &
Depleters of atmospheric oxygen?
• CONTRIBUTORS: Photosynthesis,
  Weathering of Sediment & Ozone break-
• DEPLETERS: Cellular Respiration,
  Decomposition, Combustion, Ozone
  formation & Inorganic mineral formation
 What human activity affects the
   oxygen and carbon cycle?
• Wildfires, Burning wood and fossil fuels uses up free
  oxygen and increases the amount of carbon dioxide.
  Large amounts of carbon dioxide in the atmosphere traps
  heat, which affects climate and creates global warming.
• Deforestation, building on productive land and polluting
  the land & water reduces photosynthetic organisms,
  which also lowers the free oxygen supply.
• Using Chlorofluorocarbons (CFCs) in hairspray and cups
  reduces the amount of ozone (O3) in the upper
  atmosphere, which allow harmful UV rays through.
• Recycling materials allows humans to reduce the
  amount of energy (fossil fuels) and materials needed.
    What is the nitrogen cycle?
•   Note the four processes in the nitrogen cycle below –
    fixation, ammonification, nitrification, denitrification
    What is the nitrogen cycle?
•       Nitrogen is an important element for life. Nitrogen is the building
        block of amino acids, which are found in muscles, DNA and plant
        chlorophyll. Four processes cycle nitrogen through the ecosystem:
    –          Nitrogen fixation is a two-step process where rhibizom bacteria
               (attached to the roots of plants), lightning or the fertilizer industry
               changes nitrogen gas to ammonia (fertilizer).
           •       N2(g)  2 N(aq) + 3H2(g)  2NH3(g)
    –          Ammonification is another process where fungi and some bacteria
               decompose waste, producing ammonia from the nitrogen found in the
           •       CH2NH2COOH(s) + 3O2(g)  2NH3(g) + 4CO2(g) + 2H2O(l)
    –          Nitrification is the process where bacteria convert ammonia to nitrite
               and then to nitrate. (Some plants use the nitrate produced during
           •       2NH3(g) + 3O2(g)  H2O(g) + H+(aq) + NO2-(aq)
           •       NO2-(aq) + O2(g)  NO3-(aq)
    –          Denitrification is the process where bacteria change the nitrates back
               to nitrogen gas.
 What human activities affect the
        nitrogen cycle?
• Wide scale cultivation of legumes (plants that fix
  nitrogen) and industrial fixation of nitrogen to
  produce fertilizers have started to deplete the
  amount of nitrogen in the atmosphere.
• Over fertilization has resulted in excess nitrogen
  and phosphorus running into rivers and lakes.
  This has resulted in increase growth of algae and
  plants. When the algae and plants die,
  decomposers use up the valuable oxygen in the
  water, killing fish and other oxygen-dependent
  How are the biochemical cycles
• Oxygen is found in all the cycles.
• Reforestation will increase the amount of
  nitrogen used in the soil (nitrification) and
  increase the amount of oxygen released into the
  atmosphere, but it will decrease the amount of
  carbon dioxide & water in the atmosphere.
• Preserving wetlands would increase
  ammonification and photosynthesis, increasing
  the amount of nitrogen and oxygen available for
  the ecosystem.
TOPIC 1.6: Biodiversity
       What is Biodiversity?
• Biodiversity is the variety of ecosystems,
  species and genes in an area. Boreal forests
  and rain forests have more biodiversity.
What is the connection between
the caribou and food packaging?
• The woodland caribou need a forest that is older
  than 80 years to grow enough tree lichen, their
  main winter food.
• Food packaging comes from oil and natural gas.
  Oil and natural gas companies cut down the trees
  in the north for exploration and removal.
• This tree removal has contributed to making the
  caribou a endangered species (may soon no
  longer exist) and decreasing the biodiversity.
What are the categories of species risk?
  What affects biodiversity and
      endangers species?
1. Habitat Fragmentation
2. Habitat destruction
3. Clash between ecological systems and
   economic systems
What is Habitat Fragmentation?
• Habitat fragmentation is the change of a
  complete habitat into patches separated by
  non-habitat areas. This is caused by
  building houses, farms and seismic lines
  What is Habitat Destruction?
• Habitat destruction is the permanent
  alteration of vital characteristics in an
  organism’s habitat. Ie) trees in the forest
What is the difference between the
ecological and economic systems?
     Chapter 2: Populations
2.1 Primary Succession
2.2 Secondary Succession
2.3 Populations
2.4 Adaptations
2.5 Evolutionary Theory
  TOPIC 2.1: Primary Succession
TOPIC 2.2: Secondary Succession
            What is succession?
The natural change in the types & numbers of species in a
   community is called ecological succession.
1. First a pioneer community (first community), like
   bacteria or lichen invades the ecosystem. Chemicals from
   the lichens and bacteria, along with weathering break
   down rocks into fertile soil.
2. Eventually plants species, like mosses and grass start to
   grow in the soil.
3. Next herbs and flowers invade the grass community.
4. Shrubs begin to grow and out-compete the herbs and
5. Eventually trees like poplars and spruce trees begin to
   grow. This dominant, stable species is called the climax
What are the two types of
• Primary succession starts in an
  ecosystem where no life has existed
  before, such as new lakes,
  volcanoes, deltas and sand dunes.
• Secondary succession occurs in an
  ecosystem that has been disturbed
  by fire, floods or human activities
  and is more common & quicker than
  primary succession.
 TOPIC 2.3: Populations

Def: Number of individuals living in
          a given area
    What is happening to the human
    and some organism population?
• Human and many microscopic populations
  rapidly increasing by constantly doubling
  (time it takes is called the doubling time); this
  growth is called exponential growth and it
  produces an exponential (J) curve (below).
   What are the 4 factors affecting
• Populations increase because of 1) births
  & 2) immigration (movement in).
• Populations decrease because of 3) deaths
  & 4) emigration (movement out).
• Closed populations are only affected by
  births and deaths. Ie) zoo
• Open populations are affected by all 4. ie)
  National parks
What causes population explosions,
           & crashes?
• Populations explode (increase rapidly)
  when there is plenty of food &/or no
• Populations crash (decrease rapidly) when
  there is little food &/or several predators
 What is carrying capacity & a S-curve?
• Carrying capacity is the maximum number of
  individuals that a given ecosystem can sustain.
• S-curve is the shape of a population graph
  limited by disease, competition and famine

                                 • The human
                                 population has
                                 not reached
                                 it’s carrying
TOPIC 2.4 Adaptations
  Why does variation exist?
• Variation exists because the genes in DNA
  (genetic blueprint or code) can mutate.
• Mutations are changes in instructions
  from a gene.
• Mutations that aid an organism are passed
  on to their offspring.
• The greater the genetic variation, the better
  a population can respond to environmental
  How do populations change?
• Very gradual changes
  in populations is called

• Sudden changes in
  populations is called
      What are adaptations?
• Inherited traits that increase an organism’s chance
  for survival are called adaptations. There are
  three types of adaptations:
   – Structural: a physical adaptation that helps them
     survive or reproduce. E.g) Fur is an example of an
     adaptation for animals living is cold regions.
   – Physiological: an adaptation that helps an organism
     with a biological process. E.g.) Colored pigments help
     flowers attract pollinators.
   – Behavioral: an action that helps an organism survive
     or reproduce. E.g.) A mating dances to ensure
     reproduction is an example.
TOPIC 2.5: Evolutionary Theory
After observations on the Galapagos Islands,
Darwin published On the Origin of Species in 1859.
           Galapagos Finches
• Selection
  pressures are
  conditions such
  as food &
  habitat, which
  result in new
    What is Darwin’s Theory of
       Natural Selection?
Charles Darwin, from his travels, made 3 observations:
   1. Organisms produce more offspring than can survive.
   2. Variation exists among individuals of a species.
   3. Organisms compete with each other for limited resources.
• From these observations, Darwin proposed the
  theory of natural selection – organisms best suited
  for their environment survive, reproduce and pass
  on these traits.
   – Eg) Peppered Moth: when coal was burned the black
     moth was more common; when coal burning stopped, the
     gray moth became more common
What is the theory of Evolution?
• Darwin suggested that natural selection could also create
  a new species called speciation.
• Theory of Macro Evolution is an explanation of how
  many slow changes over time created by natural selection
  eventually resulted in the creation of a new species.
• Theory of Micro Evolution is an explanation of how
  many small changes over time created by natural
  selection result in changes within a species.
• The reproductive success of an organism is now called its
  Darwinian fitness.
• Evolution is also called the survival of the fittest.
       What are the essential
requirements for Natural selection?
1. There must be a genetic basis for variation
2. The new trait must increase the rate of
   survival and/or rate of reproduction.
3. The environment and/or catastrophes play
   an important role
What role did Alferd Wallace &
 Jean-Baptiste Lamarck have?
• Wallace came to similar conclusions as
• Lamarck proposed that organisms change
  during their lives to meet the challenges of
  their environment. Eg) giraffe necks
  became long due to stretching for higher
  leaves. The stretched neck trait was
  passed on.
• Both Wallace and Lamarck started people
  thinking about how and why organisms
     What evidence is there for
1. Fossils provide a history of the past.
2. Embryology: species that are related have
   embryos (babies) that are very similar.
    What evidence is there for
3. Comparative Anatomy shows that species
   that are related have structures that are
   similar. Homologous structures have
  similar origin but different uses. Ie)
  human arm, whale flipper & bat wing
     What evidence is there for
4. Vestigial structures (structures with
   no use) suggest that through
   adaptation the use of these structures
   has been lost
5. Biochemistry indicates the species
   that are related have similar
   chemical make-up. Ie) the DNA of
   cats and dogs is almost the same.
6. Biogeography – organisms
   separated by geography have
   similar characteristics suggests they
   may have had a common ancestor
What are some other theories?
• Punctuate Equilibrium and Creation are
  two other theories that describe how
  speciation occurred.
  – Punctuate Equilibrium states that very sudden
    changes in the environment forced organisms
    to adapt very quickly.
  – Creation states that a higher being created the
    species with similarities to each other.
Evidences that support Creation
1. Very complex design –statistical
   impossible that if evolved randomly
  –   Cells have thousands of complex functions
2. Lack of transitional fossils
3. Signs of devolution:
  –   Increase in number of disorders
  –   Lose of species and diversity
  –   Decreasing magnetic field strength
 Evidences that support Creation
4.       Supports the 2nd Law of Thermodynamics: the universe
         is going from a state of order to a state of disorder
5.       Redshift and “Hubbles Law” states that the universe is
         expanding; therefore the universe had a beginning.

4.       DNA or the genetic code is complex indicating
         intelligent design.
     –      The information stored on the DNA of one bacteria could fill
            all the books in one of the largest libraries of the world.

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