Ecology David Mellor, PhD Citizen Science Coordinator Virginia Master Naturalists
Alycia Crall Steven Gray Rebecca Jordan Greg Newman Cindy Hmelo-Silver
Collaborative Conservation Research Adaptive Land Management Discuss Where are we? Mental Models Share Who should know? CitSci.org Plan Where should we go? Evaluate Did we make it? Implement How will we get there?
Overview of Ecology Definition and Scope Energy and Food Webs Nutrient Cycles Population Dynamics Ecological Interactions Community Structure Ecosystem Services Human Impacts
Biosphere Scope of Biology Ecosystem Community Population Organism Organ System Organ Tissue Cell Organelle Molecules
Biosphere Scope of Ecology Ecosystem Community Population Organism Organ System Organ Tissue Cell Organelle Molecules
Scope of Ecology Biosphere Where life exists on Earth Ecosystem The group of interacting living communities and non-living factors in one area Community The group of interacting organisms in one area Population A group of organisms of one species Organism An individual living being
Scope of Ecology Biosphere Where life exists on Earth Ecosystem The group of interacting living communities and non-living factors in one area Community The group of interacting organisms in one area Population A group of organisms of one species Organism An individual living being
Scope of Ecology Biosphere Where life exists on Earth Ecosystem The group of interacting living communities and non-living factors in one area Community The group of interacting organisms in one area Population A group of organisms of one species Organism An individual living being
Scope of Ecology Biosphere Where life exists on Earth Ecosystem The group of interacting living communities and non-living factors in one area Community The group of interacting organisms in one area Population A group of organisms of one species Organism An individual living being
Scope of Ecology Biosphere Where life exists on Earth Ecosystem The group of interacting living communities and non-living factors in one area Community The group of interacting organisms in one area Population A group of organisms of one species Organism An individual living being
Worksheets Think about a nearby natural area and describe: 1) The ecosystem 2) The community 3) A few of the populations of organisms that live in that area Realizing that you do not know everything about that area, what steps would you take to learn more about it?
Energy and Food Webs
Energy and Food Webs Trophic levels are a classification of species based on their main source of nutrition Trophic levels: Primary producers Primary consumers Secondary consumers Tertiary consumers Decomposers Omnivores
Tertiary consumers Secondary consumers Primary consumers Primary Producers
Tertiary consumers Secondary consumers Primary consumers Omnivore Primary Producers
Primary Producers
Primary Consumers
Secondary Consumers
Tertiary Consumers
Decomposers
Omnivores
Photosynthesis H 2 O + CO 2 + energy C 6 H 12 O 6 + O 2 H 2 O + CO 2 + energy + O 2
This molecule can be used for: 1) Building block 2) Energy i. Growth* ii. Maintenance* iii. Metabolism* iv. Reproduction* * inefficient!
Respiration C 6 H 12 O 6 + O 2 H 2 O + CO 2 + energy + O 2 H 2 O + CO 2 + energy
Worksheet While thinking about energy and resource use, describe why eating lower on the food chain is more environmentally friendly. What new information surprised you most in the previous lecture? Why was this information new to you?
Nutrient Cycles The movement of nutrients through different environments on Earth Nutrients: Carbon Nitrogen Water Phosphorous Sulfur
Nutrient Cycles Nutrients move between different reservoirs. Reservoirs can be classified as: Accessible or inaccessible to living things Organic or inorganic materials 1) Accessible Organic 2) Accessible Inorganic 3) Inaccessible Organic 4) Inaccessible Inorganic
Nutrient Cycles Nutrients move between resevoirs through many different processes: Photosynthesis (moves carbon into plants) Respiration (moves carbon out of living organisms) Weathering (moves many nutrients out of rocks) Volcanism (moves carbon out of the Earth) Decomposition (move carbon out of recently living organisms back to atmosphere) Excretion (moves many nutrients out of living organisms)
Carbon Cycle Inorganic, Available Atmosphere Soil Water Photosynthesis Assimilation Respiration, Decomposition Organic, Available Living organisms Detritus Fossilization Weathering Rock formation Inorganic, Unavailable Rocks and minerals Organic, Unavailable Oil and Gas
Terrestrial Biosphere 550 Gigatons (living organisms) Carbon Cycle Respiration Atmosphere 720 Gigatons (CO2 and Methane) Photosynthesis Dissolve Detritus Earth s Interior 75,000,000 Gigatons (oil, gas, peat, limestone) Sedimentation Oceans 38,000 Gigatons (Calcium carbonate shells, carbonic acid)
Nitrogen Cycle
Water Cycle
Worksheet Describe ways in which natural nutrient cycles are being disrupted by human activities. What are the consequences of disrupting natural nutrient cycles?
Population Dynamics Limiting Factors Growth Rates Carrying Capacity Reproductive Strategies
Limiting Factors Saturation Optimum Response of Organism Response of Organism Environmental Factor Environmental Factor
Limiting Factors Worksheet Describe at least 10 environmental factors that could affect an organism. Describe at least 3 measurable responses of an organism.
Growth Rates dn (Ndt) = r = b - d The change in the number of organisms over time per organism equals the rate of growth of the population ( r ), which equals the number of births ( b ) minus deaths ( d ).
Carrying Capacity and Growth Curves Exponential growth leads to population crash if carrying capacity is overshot too quickly Population Size Carrying Capacity Stabilized population from S-shaped growth curve Time
Reproductive Strategies r Strategy Short maturation time Short lifespan Many offspring per reproductive event Usually one reproductive event per lifetime No parental care K Strategy Long maturation time Long lifespan Few offspring per reproductive event Usually many reproductive events per lifetime Extensive parental care
K Strategy
R Strategy
In Between
Population Dynamics Worksheet Why might different reproductive strategies be favored in different environmental conditions? Think about environments that have lots of change or disturbance occurring versus more stable environments.
Ecological Interactions
Interactions When two species interact, each can either benefit (+), be harmed (-), or have no effect (o)
Interactions +/+ Mutualism -/- Competition +/- Predation, parasitism +/o Commensalism -/o Amensalism o/o Neutral
Mutualism +/+
Competition -/- Species can compete for any resource: Food Space Limiting nutrients
Predation & Parasitism +/-
Commensalism +/o
Amensalism -/o
Indirect Interactions (trophic cascades) 2010 Nature Education
Species Interactions Worksheet How would you show, experimentally, that two species interact? In other words, how do we know that species X and species Y compete with each other?
Interaction Experiments
Responses to Predation Animals Aposematic Coloration Camouflage and Countershading Mimicry Plants Secondary Compounds Morphology Mutualisms Below-ground storage
Animal Coloration Aposematic: Warning Coloration Countershading Mimicry Camouflage
Plant Responses Morphological Secondary Compounds
Community Structure Species Diversity Keystone Species Disturbance Succession
Species Diversity Species Diversity Considers richness and abundance of species Species Richness The number of species in an ecosystem Relative Abundance The amount of a species in a given ecosystem (common to rare)
High Richness, Low Abundance
High Abundance, Low Richness
Keystone Species An organism whose role in the environment is critical. Hard to determine Species Dominance Role of organisms in an environment may not be directly related to the number of individuals e.g. Numerous understory trees may play less of a role than a few canopy species that determine light levels.
Disturbance and Stability Stability The tendency of a community to reach and maintain an equilibrium, or relatively constant condition, in the face of disturbance Community resilience The ability of a community to persist in the face of disturbance
Disturbance and Stability
Ecological Succession The change in community composition over time. Primary succession: creating a new ecosystem, such as after a volcanic eruption creates new land Secondary succession: community change in an existing habitat. Pioneer species: Early to inhabit a new community Seral stage: Each stage of the succession process, may last months to decades Climax community: A mature community that no longer exhibits change in species composition
Ecological Succession Time Annual weeds Perennial weeds and grasses Shrubs Young pine forest Mature hardwood forest
Intermediate Disturbance Hypothesis Biodiversity Frequency of Disturbance Events
Worksheet Why does a community change over time following a disturbance?
An ecosystem process that leads to a service from which humans benefit. Ecosystem Services
Ecosystem Services Process Services Benefits Nitrification Decomposition Pollination Photosynthesis Converting Ammonia or Nitrite to Nitrate or Atmospheric Nitrogen Using non-living organic matter for energy Growth of fruit or reproduction of useful plants Capturing carbon dioxide, creating sugars Clean Drinking Water Removing diseasespreading matter, Soil creation Fruit, nuts, timber, seeds Food production, Carbon capture, Breathable air
Worksheet Describe an ecosystem service not listed above that occurs in an natural area near your home.
Human Impacts and Threats Invasive Species Habitat Loss and Fragmentation Resource Overuse Loss of Biodiversity Climate Change
Invasive Species Typically, an organism that spreads outside of its natural habitat without the normal constraints of predators or other limiting factors that typically regulates its carrying capacity. Excludes many other species native to the specific environment. Excluded species no longer interact in the local ecosystem or provide ecosystem services
Photo: Craig Czarnecki, MI Sea Grant
Habitat Loss and Fragmentation
Habitat Loss and Fragmentation
Resource Overuse Overharvesting Overgrazing Any unsustainable natural resource extraction Tragedy of the Commons
Resource Overuse Impacts of Biodiversity Loss on Ocean Ecosystem Services (Worm et al., Science, 2006)
Loss of Biodiversity Genetic Biodiversity Variety of genes in a population Increases resilience to change and disease Ecological Biodiversity Variety of organisms in an ecosystem Increases resilience to change and disturbance Loss of ecosystem services
Climate Change Concentration of CO 2 increasing in atmosphere Resulting from combustion of fossil fuels and burning wood removed by deforestation Ecosystem Impacts Increased temperatures from global warming Shifts in species distribution or extinction
Greenhouse Gasses John Tyndall, 1863
Greenhouse Gasses water vapor carbon dioxide methane nitrous oxide ozone
Worksheet Besides loss of predators, what other missing factors could account for a species becoming invasive. What factors are blocking our ability to easily fix environmental problems?
Questions!