Instructions for printer-friendly copy.

x

x

x

x

x

x

    Ecology: The Study of Ecosystems

    Ecology (Greek oikos, "dwelling", logos, "study")
    is the study of

    • interactions of organisms with each other
    • interactions of organisms with their environment

    Ecology is the study of the various levels of ecosystems.

x

x

x

x

x

x

x

x

x

x


(click on pic for source)

    Why Study Ecology?
    What Does it Have to do with ME?

    Ecology provides information
    to better understand
    the world around us.

    This information can help us

    • improve/repair our environment
    • manage our natural resources
    • protect human health

x

x

x

x

x

x

x

x

x

x

x

x

x

    Environmental Reparation and Improvement

    The mid-20th century saw the rise of abnormal algal blooms
    in bays, rivers, streams, lakes, and other bodies of water.

    Ecological research in the 1960s pinpointed

    • the reason: excessive nitrogen and phosphorus in wastewater
    • the source: laundry detergent, fertilizer

    Wastewater is any water that has been affected by human use:

    • domestic
    • industrial
    • commercial
    • agricultural
    • surface runoff
    • stormwater
    • sewer inflow
    • sewer infiltration

x

x

x

x

x

x

x

x

x

x

x

x

x

    Algal Blooms

    High levels of N and P cause eutrophication.
    Ecosystem is disrupted as phytoplankton and cyanobacteria ("algae")
    reproduce very quickly with added N and P nutrients.

    Algal blooms

    • deplete aqueous oxygen
    • promote overgrowth of anaerobic bacteria
    • can produce dangerous toxins
    • magnify the effects of pollutants
    • threaten human and other animal health

x

x

x

x

x

x

x

x

x

x

x

    Taking Control

    Citizens in affected areas can take necessary steps to control
    • product content of nitrogen and phosphorus
    • effluent and runoff

    Many bodies of water have been restored to better condition.

    However, nutrient pollution is still a major environmental concern.

x

x

x

x

x

x


(click on pic for source)

    Biomedical: Disease Control

    Understanding the ecology of disease vectors allows more accurate, less toxic control.

    Aedes aegypti (Yellow Fever Mosquito)

    • prefers human host
    • effective vector of Zika, Dengue fever, chikungunya, and other disease agents
    • tropical, subtropical, temperate regions

    Aedes albopictus (Asian Tiger Mosquito)

    Climate change may allow these species to spread farther north,
    carrying diseases with them.

    It's easier to attack an enemy that you know is coming.

x

x

x

x

x

x

    Biomedical: Medicines

    Bioprospecting is searching for plant and animal species that could potentially provide useful compounds, including medicines.

    50% of top 10 U.S. prescription drugs come from animals, plants, fungi, or bacteria.
    75% of cancer medications are also of organismal origin.

    • paclitaxel (Taxol)
        produced by endophytic fungus in yew trees
    • captopril (first ACE inhibitor for blood pressure control)
      • derived from tropical viper venom
    • vincristine (treatment for Acute Lymphocytic Leukemia)
      • derived from the Madagascar Periwinkle (Vinca rosea)

    Tropical rainforest is destroyed at a rate of ~80,000 acres/day.
    Unknown numbers of species are destroyed along with them.
    Most of these extinctions occur without the species ever being known to science.

x

x

x

x

x

x

    Ecosystem Services: Human Benefits

    Ecosystem services are the benefits humans gain from healthy ecosystems.
    These can be grouped into four broad categories:
    • Provisioning
      • production of food
      • filtering of water
    • Regulating
      • control of climate
      • removal of waste
      • suppression of pathogens
    • Supporting
      • nutrient cycles
      • oxygen production
    • Cultural
      • recreational uses
      • aesthetic and spiritual benefits

    Ecosystems provide ~$150 trillion/year in services.
    This is more than twice as global GDP contribution to human wellbeing.

    Land use changes costs $4.3 - 20.2 trillion/year in lost ecosystem services.

x

x

x

x

x

x

    We Need Ecological Understanding

    Understanding how ecosystems work helps us develop
    effective public policy to manage environmental support systems:
    • watersheds
    • agricultural lands
    • wetlands
    • forests
    • urban and suburban areas

    Ecology helps us solve or prevent anthropogenic environmental problems.

    It is unwise to take this knowledge for granted.

x

x

x

x

x

x

The Study of Ecosystems

    An ecosystem consists of
    • biotic components - the living organisms
    • abiotic components - non-living factors such as
      • light
      • temperature
      • water
      • nutrients
      • topography
      • etc.

x

x

x

x

x

x

    The Economy of Nature

    Darwin noted that the interactions of species in nature
    resembled humans doing business with one another.

    He called these interactions "The Economy of Nature".

    Ecological understanding is continually expanding.
    Ecological research is constantly yielding new discoveries.

x

x

x

x

x

x

x

x

x

x

    Ecology vs. Environmentalism

    Ecology is a natural science.
    • An ecologist employs hypothetico-deductive methods
      to address ecological questions scientifically.

    • An environmentalist is a person who advocates
      protection of the natural environment.

    Most ecologists are also environmentalists, but the two are not the same.

    One of the first environmentalists to apply ecological principles
    to modern awareness of our role in the biosphere was Rachel Carson,
    author of Silent Spring (1962), in which she documented the adverse environmental effects caused by indiscriminate use of pesticides.

x

x

x

x

x

x

    The Ecological Hierarchy

    Ecology can be studied from least inclusive to most inclusive levels.
    • organismal - study of the physiological, behavioral, and evolutionary mechanisms individual organisms use to meet environmental challenges

    • population - study of the factors that affect population growth and dynamics

    • community - study of how species interactions affect community structure and organization

    • ecosystem - study of the community and the abiotic components of its environment

    • landscape - study of the interactions between adjacent ecosystems

    • global - study of matter and energy exchange and species distributions across the biosphere

x

x

x

x

x

x

    Ecology: The Individual

    The individual is the most fundamental unit of ecology. An individual

    • acquires nutrients and energy
    • produces waste
    • is separated from the environment by a membrane boundary

    A group of genetically similar individuals capable of interbreeding
    to produce fertile, viable offspring comprises a biological species.

x

x

x

x

x

x

    Ecology: The Population

    A population is all the individuals of the same species living in a given area.

    Boundaries can be

    • natural (forest edges; shorelines, etc.)
    • artificial (country s; state lines, etc.)

    A population's

    • geographic range/distribution is the extent of land or water
      within which it lives.
    • abundance is the total number of individuals.
    • density is the number of individuals per unit area or volume.
    • composition is its makeup in terms of age, sex, or genotype.

x

x

x

x

x

x

    Ecology: The Community

    A community is all the populations of species living in a given area.

    Boundaries

    • may be fluid
    • may cover small or large areas

    Species interactions in a community are the manifestation of Darwin's "Economy of Nature".

x

x

x

x

x

x

x

x

    Ecology: The Ecosystem

    The ecosystem comprises the interactions of the community
    with abiotic factors in a given area.

    Biogeochemical cycles describe the movement of energy and matter
    between living and non-living components of the ecosystem:

    • Water Cycle
    • Carbon Cycle
    • Nitrogen Cycle
    • Phosphorus Cycle
    • etc.

    Ecosystem boundaries are often not distinct.

x

x

x

x

x

x

    Ecology: The Biosphere

    The biosphere comprises all of earth's ecosystems, considered collectively.

    Both proximate and distant ecosystems are connected by

    • wind movement
    • water movement
    • migration of organisms
    • energy exchanges

    The biosphere is the earth's thin outer layer of life
    and the abiotic components supporting it.

x

x

x

x

x

x

    Ecosystems and Thermodynamics

    First Law of Thermodynamics
    Energy can be transformed from one form to another,
    but can be neither created nor destroyed.

    Ecological systems

    • change energy into matter
    • change matter into energy.
    • gain and lose matter and energy to other systems
    • achieve a dynamic steady state when gains and losses are in equilibrium

x

x

x

x

x

x

    Ecology and Evolution are Interconnected

    Natural selection is driven by ecological interactions.

    Phenotype is a product of the interaction of genes and environmental influences.

    Organic evolution is the change in the genetic composition
    of populations over generations.

    Darwin's four tenets were inspired by his observations of ecological interactions.

x

x

x

x

x

x

x

    The Ecological Niche

    The sum of a species' use of the biotic and abiotic resources in its environment--as dictated by its evolutionary adaptations--is called that species' ecological niche.

    The ecological niche includes that species:

    • physical use of habitat
    • range of tolerance to physical extremes (heat, salinity, pH, etc.)
    • use of resources (food, space, etc.)
    • Circadian rhythm
    • reproductive strategies and natural history
    • interactions with biotic and abiotic environmental factors

    Everything a species is and does determines its ecological niche, which can be considered its ecological position relative to other species in the same ecosystem.

x

x

x

x

x

x

    Fundamental vs. Realized Niche

    The fundamental niche is the niche that a species potentially could occupy, given its physiology and natural history.

    Because of competition and other limitations, few species actually fill their fundamental niche.

    Instead, they occupy a subset of the fundamental niche, the realized niche.

x

x

x

x

x

x

MacArthur (1958) reported evolutionary divergence of five closely related warbler species that underwent adaptive radiation. Each species now uses a different part of their evergreen forest habitat for foraging.

    Competitive Exclusion

    The Competitive Exclusion Principle (Gause's Law):
    In a stable environment, two species cannot coexist
    if they occupy exactly the same ecological niche.

    Species competing for the same resources must
    evolutionarily adapt to exploit different resources.

    This leads to resource partitioning: dividing a common resource
    so that each competing species uses only a portion of that resource.

x

x

x

x

x

x

    Habitat vs. Niche

    An organism's habitat is the physical setting in which it lives.

    Habitats are usually distinguished by physical features,
    such as dominant plant life.

    • montane habitat
    • grassland habitat
    • stream habitat
    • desert habitat
    • forest habitat
    • etc.

    Habitat types overlap.
    Absolute distinctions between them rarely exist.

    Still, designating a species' habitat gives a good indication
    of the variety of conditions in which it must survive and thrive.

    • temperature
    • light levels
    • humidity
    • pressure
    • oxygen levels
    • salt concentrations
    • etc.

    Categorizing Species on the basis of Energy Source

  • A producer (autotroph) converts chemical energy into organic matter.

  • A consumer (heterotroph) obtains its energy from other organisms.
    • primary (1o) consumer feeds on producers
    • secondary (2o) consumer feeds on primary consumers
    • tertiary (3o) consumer feeds on secondary consumers
    • quaternary (4o) consumer feeds on tertiary consumers

  • A mixotroph can switch between autotrophy and heterotrophy

  • A scavenger consumes dead animals.

  • A detritivore breaks down dead organic matter (detritus)
    into smaller organic particles.

  • A decomposer breaks down organic detritus
    into inorganic elements that can be recycled by autotrophs.

x

x

x

x

x

x

Ecological Interactions Drive Coevolution

Interacting species coevolve in response to each other's activities.
Each type of interaction will yield a different type of coevolutionary result.

x

x

x

x

x

x

x


(Don't miss World Pangolin Day! Click on pic!)

    x

    Human Influence on Ecosystems

    Homo sapiens interacts--directly and indirectly--with more species than does any other animal species.

    In a few cases, non-human species have benefited from this interaction.
    Far more often, the impact of human interaction is negative.

    Most species that have existed on earth are now extinct.

    But the current rate of extinction qualifies as a mass extinction
    similar in scale to those that have occurred only a few times in earth's history.

x

x

x

x

x

x

x

    The Anthropocene Extinction

    The current extinction rate has been estimated at 24 - 150 species lost per day.
    This is 1,000 times higher than "normal" extinction rate.
    The current extinction rate is similar to that of previous mass extinctions.

    This extinction is anthropogenic, and being caused by

    And the most recent threat, anthropogenic climate change:

    Humanity will not be able to stop this process
    without clearly understanding how ecosystems work.