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Ecosystems: What Are They and How Do They Work?

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Title: Ecosystems: What Are They and How Do They Work?


1
Chapter 3
  • Ecosystems What Are They and How Do They Work?

2
THE NATURE OF ECOLOGY
  • Ecology is a study of connections in nature.
  • How organisms interact with one another and with
    their nonliving environment.

Figure 3-2
3
Organisms and Species
  • Organisms, the different forms of life on earth,
    can be classified into different species based on
    certain characteristics.

Figure 3-3
4
Classification of Life
  • Domain
  • Kingdom
  • Phylum
  • Class
  • Order
  • Family
  • Genus
  • Species

5
Connect Populations, Communities, and Ecosystems
  • Members of a species interact in groups called
    populations.
  • Populations of different species living and
    interacting in an area form a community.
  • A community interacting with its physical
    environment of matter and energy is an ecosystem.

6
Populations
  • A population is a group of interacting
    individuals of the same species occupying a
    specific area.
  • The space an individual or population normally
    occupies is its habitat.

Figure 3-4
7
Populations
  • Genetic diversity
  • In most natural populations individuals vary
    slightly in their genetic makeup.

Figure 3-5
8
Life on Earth is sustained by
  • Troposphere 78 Nitrogen and 21 Oxygen
  • Stratosphere GOOD ozone (O3)
  • Lithosphere nonrenewable resources and minerals

9
Life on earth is sustained by
  • Solar energy (low quality), the cycling of matter
    (fixed amount), and gravity (maintain atmosphere)
    sustain the earths life.
  • Can energy be recycled?

Figure 3-7
10
Solar Energy and the Earth
What does solar energy do that is important for
life on Earth?
11
Greenhouse Effect
  • solar radiation enters as visible light and
    degraded to infrared radiation
  • encounters the greenhouse gases in the
    troposphere.
  • The greenhouse gases absorb the IR waves and then
    emit more IR waves (even longer wavelengths)
  • this speeds up the air molecules (gain KE) and
    this heats the troposphere and earths surface.

12
What are ECOSYSTEM COMPONENTS?
  • Life exists on land systems called biomes and in
    freshwater and ocean aquatic life zones.

Figure 3-9
13
Nonliving and Living Components of Ecosystems
  • Ecosystems consist of nonliving (abiotic) and
    living (biotic) components.

Figure 3-10
14
Factors That Limit Population Growth
  • Range of Tolerance and Availability of matter and
    energy resources (limiting factors) can limit the
    number of organisms in a population.
  • Population controlsustainability

Figure 3-11
15
Biotic Factors in an Ecosystem
  • Most PRODUCERS capture sunlight to produce
    carbohydrates by photosynthesis
  • Autotrophs (plants, algae, phytoplankton,
    plant-like protists)

16
Photosynthesis A Closer Look
  • Chlorophyll molecules in the chloroplasts of
    plant cells absorb solar energy.
  • This initiates a complex series of chemical
    reactions in which carbon dioxide and water are
    converted to sugars and oxygen.

Figure 3-A
17
Producers cont.
  • Chemosynthesis
  • Some organisms such as deep ocean bacteria draw
    energy from hydrothermal vents and produce
    carbohydrates from hydrogen sulfide (H2S) gas .

18
Consumers Eating and Recycling to Survive
  • Consumers (heterotrophs) get their food by eating
    or breaking down all or parts of other organisms
    or their remains.
  • Herbivores
  • Primary consumers that eat producers
  • Carnivores
  • Primary consumers eat primary consumers
  • Third and higher level consumers carnivores that
    eat carnivores.
  • Omnivores
  • Feed on both plant and animals.

19
Decomposers and Detrivores-consumers TOO!
  • Decomposers Recycle nutrients in ecosystems.
  • Detrivores Insects or other scavengers that feed
    on wastes or dead bodies.

Figure 3-13
20
Aerobic (with Oxygen) and Anaerobic Respiration
Getting Energy for Survival
  • breaking down carbohydrates and other organic
    compounds to obtain the energy
  • This is usually done through aerobic respiration.
  • The opposite of photosynthesis

21
Cont.
  • Anaerobic respiration or fermentation
  • Some decomposers get energy by breaking down
    glucose without oxygen.
  • The end products vary based on the chemical
    reaction
  • Methane gas
  • Ethyl alcohol
  • Acetic acid
  • Hydrogen sulfide

22
Two Secrets of Survival Energy Flow and Matter
Recycle
  • An ecosystem survives by a combination of energy
    flow and matter recycling.

Figure 3-14
23
Biodiversity maintains Ecosystems
  • We are losing biodiversity due to HIPPO
  • H for habitat destruction and
  • degradation-leading cause
  • I for invasive species- 2nd leading cause
  • P for pollution leading to global climate change.
  • P for human population growth that leads to
    resource consumption
  • O for overexploitation- overhunting and
    overconsumption
  • Who is Aldo Leopold?

24
ENERGY FLOW IN ECOSYSTEMS
  • Food chains and webs show how eaters, the eaten,
    and the decomposed are connected to one another
    in an ecosystem.
  • Energy flows in 1 Direction!

Figure 3-17
25
  • Interconnected food chains make up a complicated
    food web.
  • Which trophic level would there be more
    organisms, 1st or 4th? Why?

Figure 3-18
26
Energy Flow in an Ecosystem Losing Energy in
Food Chains and Webs
  • In accordance with the 2nd law of thermodynamics,
    there is a decrease in the amount of energy
    available to each succeeding organism in a food
    chain or web.

27
10 RULE in energy flow
  • Ecological efficiency percentage of useable
    energy transferred as biomass from one trophic
    level to the next.
  • Where does the energy go?

Figure 3-19
28
Due to the high need for producers to maintain
our growing population you must consider
  • Gross primary production (GPP)
  • Rate at which an ecosystems producers convert
    solar energy into chemical energy as biomass.

Figure 3-20
29
AND Net Primary Production (NPP)
  • NPP GPP R
  • Rate at which producers use photosynthesis to
    store energy minus the rate at which they use
    some of this energy through respiration (R).

Figure 3-21
30
Why does GPP and NPP matter?
  • As humans take up more land and degrade more
    forest ecosystems, we lower the earths possible
    GPP and NPP.
  • Estimates say that humans and domesticated
    animals take up 98 of earths biomass and
    wildlife only 2. OUT OF BALANCE!

31
  • What are natures three most productive and three
    least productive systems?

Figure 3-22
32
MATTER CYCLING IN ECOSYSTEMS
  • Nutrient Cycles Global Recycling
  • Global Cycles recycle nutrients through the
    earths air, land, water, and living organisms.
  • Nutrients are the elements and compounds that
    organisms need to live, grow, and reproduce.
  • Biogeochemical cycles move these substances
    through air, water, soil, rock and living
    organisms.

33
The Water Cycle
Figure 3-26
34
Water Unique Properties
  • There are strong forces of attraction between
    molecules of water.
  • Water exists as a liquid over a wide temperature
    range.
  • Liquid water changes temperature slowly.
  • It takes a large amount of energy for water to
    evaporate.
  • Liquid water can dissolve a variety of compounds.
  • Water expands when it freezes.

35
Effects of Human Activities on Water Cycle
  • We alter the water cycle by
  • Withdrawing large amounts of freshwater.
  • Clearing vegetation and eroding soils.
  • Polluting surface and underground water.
  • Contributing to climate change.

36
The Carbon CyclePart of Natures Thermostat
  • PS and CR recycle
  • Ocean stores (dissolved Carbon dioxide)
  • Shells of marine life store (Calcium carbonate)
  • Limestone stores
  • Fossil Fuels store until BURNED

Figure 3-27
37
Effects of Human Activities on Carbon Cycle
  • We alter the carbon cycle by adding excess CO2 to
    the atmosphere through
  • Burning fossil fuels.
  • Clearing vegetation faster than it is replaced.

Figure 3-28
38
The Nitrogen Cycle Bacteria in Action
Figure 3-29
39
Explanation of the chart
  • 2 processes FIX atmospheric nitrogen into a
    usable form
  • Lightning
  • Nitrogen-fixing bacteria in soil
  • NITROGEN FIXATION
  • FIX N2?NH3 (ammonia)?NH4 (ammonium) that can be
    taken up by plants
  • NITRIFICATION
  • NH3 and NH4 is converted to nitrite,NO2- TOXIC
    TO PLANTS and then nitrate, NO3- GOOD FOR PLANTS
    AND ANIMALS WHO EAT PLANTS

40
Cont.
  • Plants and animals put nitrogen back into
    environment through wastes and when they die.
  • AMMONIFICATION is when decomposer bacteria
    convert this organic material from their death
    into simpler nitrogen-containing inorganic
    compounds like ammonia (NH3) and ammonium (NH4).
  • DENITRIFICATION is when specialized bacteria in
    wet areas convert ammonia and ammonium back into
    nitrogen gas and nitrous oxide gas (both GHGs).

41
Effects of Human Activities on the Nitrogen Cycle
  • We alter the nitrogen cycle by
  • Adding gases (NO, nitric oxide, from burning
    fuels) that contribute to acid rain.
  • Adding N2O, nitrous oxide to the atmosphere
    through fertilizers added to crops which can warm
    the atmosphere and deplete ozone.
  • Contaminating ground water from nitrate ions in
    inorganic fertilizers disrupting aquatic life.
  • Releasing nitrogen into the troposphere through
    deforestation.

42
The Phosphorous Cycle- doesnt enter AIR
Figure 3-31
43
Explanation of chart
  • Phosphorus is found as phosphate ions (PO43-) in
    rock and soil. As water runs over rocks the
    phosphates mix into the water and ends up in the
    ocean where it settles to the ocean floor.
  • Plants take phosphates directly from the soil or
    water and build macromolecules with it.
  • Animals take in plants and excrete extra
    phosphorus in urine.
  • Phosphorus is often a LIMITING FACTOR for plants
    because there is little in soil (unless added
    from fertilizer) and is only slightly soluble in
    water.

44
Effects of Human Activities on the Phosphorous
Cycle
  • We remove large amounts of phosphate from the
    earth to make fertilizer.
  • We reduce phosphorous in tropical soils by
    clearing forests.
  • We add excess phosphates to aquatic systems from
    runoff of animal wastes and fertilizers.

45
The Sulfur Cycle
Figure 3-32
46
Explanation of chart
  • Found as sulfate (SO42-)in rocks and minerals and
    salts buried deep under ocean sediments
  • Released from volcanoes as hydrogen gas (H2S)
    and sulfur dioxide (SO2)
  • Sulfate salts like ammonium sulfate are released
    by sea spray, dust storms, and forest fires
  • Plants absorb sulfate ions and incorporate them
    into their macromolecules
  • Marine bacteria produce dimethyl sulfide (DMS)
    which begins condensation thus can affect climate
  • DMS is converted to SO2 and SO3 and then to
    sulfuric acid (H2SO4) ACID RAIN

47
Effects of Human Activities on the Sulfur Cycle
  • We add sulfur dioxide to the atmosphere by
  • Burning coal and oil
  • Refining sulfur containing petroleum.
  • Convert sulfur-containing metallic ores into free
    metals such as copper, lead, and zinc releasing
    sulfur dioxide into the environment.

48
What is the Gaia Hypothesis?
49
Chapter 7
  • Community Ecology

50
What are important characteristics of a community?
  • Species diversity- the number of different
    species it contains (species richness) combined
    with the abundance of individuals within each of
    those species (species evenness)
  • Niche structure- of niches, differences in
    niches, and how individuals in different niches
    interact
  • Geographical location- closer to equator more
    diversity usually due to constant conditions near
    tropics

51
What are the types of species in a community?
  • Native species- normally live and thrive in a
    particular community
  • Nonnative species, invasive and alien species are
    introduced into a community.
  • NOT ALWAYS BAD (chickens, cattle) but CAN BE
    (African killer bee intended to help honey
    production increase)

52
  • Indicator species- serve as early warnings of
    damage to a community
  • Example trout for water quality because they
    need clean water with lots of dissolved oxygen
  • Ex. Birds and butterflies greatly affected by
    habitat loss and chemical exposure
  • Ex. Amphibians GOOD INDICATOR SPECIES

53
Why are Amphibians Vanishing?
  • Because they live part of life in water and part
    on land so tell about water, soil, and air
    quality.
  • Affected by pollution (pesticides), habitat
    loss, drought, increase UV light, climate change,
    overhunting

Figure 7-3
54
  • Keystone species- a species that greatly affects
    other species in the community.
  • Ex. Pollinators like bees and butterflies
  • Ex. Top predators like wolves, lions, alligators,
    some sharks
  • Foundation species- play a major role in shaping
    communities by creating and enhancing their
    habitats in ways that benefit other species.
  • Ex. Elephants that push over trees and allow
    smaller grasses to grow that allow grazers like
    antelope to eat.
  • Ex. Bats and birds that move seeds around by
    eating and dropping them in feces to re-grow a
    forest that has been depleted.

55
What types of interactions do species have?
  • Interspecific competition- ability of one species
    to become more efficient in acquiring resources
    than another. POPULATION SIZE CONTROL
  • 1. Resource partitioning- adaptations evolved
    that reduce competition that allow species to
    share resources by evolving specialized traits.
  • Example hawks feed during day, owls at night
  • Ex. Lions take larger prey, leopards take smaller

56
Resource Partitioning
  • Each species minimizes competition with the
    others for food by spending at least half its
    feeding time in a distinct portion of the spruce
    tree and by consuming somewhat different insect
    species.

Figure 7-7
57
Niche Specialization
  • Niches become separated to avoid competition for
    resources.

Figure 7-6
58
Interactions of species cont.
  • Predation- predators feed on prey. POPULATION
    CONTROL AND NATURAL SELECTION (makes population
    stronger)
  • Ex. Lions feed on zebras predator-prey
    relationship
  • Parasitism- parasite benefits by living in or on
    the host who is harmed. POPULATION CONTROL
  • Tapeworms, ticks, fleas, mistletoe, cowbirds
  • Mutualism- both species benefit
  • Honeybees, caterpillars, butterflies pollinate
    flowers and feed on nectar
  • Clownfish and sea anemone
  • Fungus with plant roots that makes Mycorrhizae.
    Fungus feeds on plant roots but plant has more
    roots for water uptake.
  • Commensalism- benefits one species but has little
    to no effect on the other.
  • Birds and trees- birds have habitat
  • Orchids that grow on trees in tropics get more
    light and stable place to grow but dont affect
    tree.

59
PREDATION
  • Some prey escape their predators or have outer
    protection, some are camouflaged, and some use
    chemicals to repel predators.

Figure 7-8
60
Mutualism Win-Win Relationship
  • Two species can interact in ways that benefit
    both of them.

Figure 7-9
61
Commensalism Using without Harming
  • Some species interact in a way that helps one
    species but has little or no effect on the other.

Figure 7-10
62
Ecological succession the gradual change in
species composition of a given area
  • Primary succession the gradual establishment of
    biotic communities in lifeless areas where there
    is no soil or sediment.
  • No soil present, exposed rock, lava, concrete
  • Lichens or mosses attach to rock and break them
    down by releasing acids, and catch soil particles
    floating in wind (millions of years to produce
    fertile soil)

63
  • Secondary succession series of communities
    develop in places containing soil or sediment.
  • Begins in an area where the community has been
    disturbed or destroyed (forests burned, farm
    abandoned, heavily polluted streams

64
How do living systems maintain stability?
  • Adaptations in response to changing environments
    (not within an individuals lifetime but over
    generations)
  • Persistence- ability of a living system to resist
    being disturbed
  • Constancy- ability of a living system to keep its
    numbers within the limits imposed by natural
    resources
  • Resilience- ability of living system to bounce
    back and repair damage after a disturbance that
    it not too drastic
  • Diversity

65
Function within the 4 scientific principles of
sustainability
  • Depend on solar energy
  • Participate in chemical cycling
  • Have a diversity of types and species
  • Populations are controlled by interactions among
    their species
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