ES Ecology. Abiotic Factors Nonliving factors in an environment Examples: –Air currents –Temperature –Moisture –Light –Soil Biotic Factors Biosphere –

ES Ecology

Abiotic Factors

• Nonliving factors in an environment• Examples:

– Air currents– Temperature– Moisture– Light– Soil

Biotic Factors• Biosphere – life-supporting layer of Earth• Biotic factors – all living organisms in a biosphere

• Ecology - Study of interactions between organisms and their environments. • Ecosystems are communities of organisms and their abiotic environment.

Air

Air purification

Climate control

Water

Water purification

Waste treatment

Nonrenewableminerals

iron, sand)

Natural gasOil

Soil

Soil renewal

Nonrenewableenergy

(fossil fuels)

Solarcapital

Land

Food production

Nutrientrecycling

Coal seam

Life(biodiversity)

Populationcontrol

Pestcontrol

Renewableenergy

(sun, wind,water flows)UV protection

(ozone layer)

Natural resourcesNatural services

NATURAL CAPITAL

Natural Capital = Natural Resources + Natural Services

Organization of Life

Organisms

Populations

Communities

Ecosystems

Biosphere

Levels of Ecological Organization

• Organisms are living things that can carry out life processes independently.

• Species are groups of organisms that are closely related and can mate to produce fertile offspring.

• Populations are groups of organisms of the same species that live in a specific geographical area and interbreed.

– An important characteristic of a population is that its members usually breed with one another rather than with members of other populations.

• Communities are groups of various species that live in the same habitat and interact with each other.

• Habitats are places where an organism usually lives.

– Every habitat has specific characteristics that the organisms that live there need to survive. If any of these factors change, the habitat changes.

Levels of Organization

Feeding Relationships

• Autotrophs• Heterotrophs

– Carnivores– Omnivores– Herbivores– Decomposers

Autotrophs vs. Heterotrophs

• Autotrophs fix their own energy from inorganic sources– Autotrophs are the producers in an ecosystem

• Heterotrophs depend upon energy and carbon fixed by some other organism

– They are consumers, detritivores, or decomposers• A mixotroph gets its energy from inorganic sources, but relies on inorganic sources of carbon

Food Web

Trophic Relationships

• Autotrophs• 1st level consumers (herbivores)• 2nd level consumers • 3rd level consumers• 4th level consumers (top predators)

•Ecosystems produce and process energy primarily through the production and exchange of carbohydrates which depends on the carbon cycle.

•Once energy is used, it is lost to the ecosystem through generation of heat

•Carbon is passed through the food chain through herbivory, predation, and decomposition, it is eventually lost to the atmosphere through decomposition in the form of CO2 and CH4 . It is then re-introduced into the ecosystem via photosynthesis.

•However, the amount of carbon present in a system is not only related to the amount of primary production, as well herbivory and predation (e.g., secondary production), it is also driven by the rates of decomposition by micro-organisms

•Atmospheric carbon is rarely limiting to plant growth

•When we look at other nutrients, a somewhat different picture emerges than with the energy cycle – e.g., phosphorous in a food chain within a small pond.

•Algae remove dissolved phosphorous from the water

•The phosphorous is then passed through different trophic levels through herbivory and predation.

•At each level there is some mortality, and then the phosphorous is passed to decomposers

•These organisms release phosphorous into the water where it is again taken up by primary producers and the whole cycle starts up again

Key Elements of Biogeochemical Cycles

Biogeochemical cycles

• Pathways tracing storage & exchange of chemical elements between living & nonliving systems via atmosphere, hydrosphere, lithosphere, & biosphere called biogeochemical cycles.

• Chemical reactions form basis of biogeochemical cycles and take place in the lithosphere, atmosphere, hydrosphere & biosphere.

• Chemical elements unavailable at right time or proper concentration can become limiting factors which restrict or prevent growth of individuals, population, or species.

• Have been greatly altered over time by earth's biota. • Essential to long-term maintenance of life on earth. • Can be altered by human activities; alterations have both +

& - consequences. We must recognize & balance.

Water cycle

• Evaporation• Transpiration• Precipitation• Runoff• Groundwater

Carbon cycle

• Combustion• Photosynthesis• Respiration• Decomposition• Fossil fuels

Carbon Cycle

  Carbon is foundation of all organic compounds, i.e. compounds containing C (& 1 C-H bond) & formed by living things.

Carbon cycle linked to biochemical cycles of C, O, & H

In gas phase, C stored in atmosphere primarily as CO2 & other organic & inorganic molecules.

CO2 exchanged between atmosphere & large bodies of water by diffusion.

• Plants remove C from atmosphere thru photosynthesis (Ps), light-dependent conversion of CO2 & water to organic sugars & free O2.

• Vegetation, primarily trees, major storehouse for C in living tissue.

• C returned to atmosphere through respiration, process of oxidizing sugars to release E, CO2, & water, or by burning

• C enters rock cycle as organic material carried to wetlands & oceans & slowly incorporated into newly-forming rock.

Nitrogen Cycle

• Atmospheric nitrogen

• Runoff• Fertilizers• Decomposition• Nitrogen fixing• Synthesis of

amino acids

Nitrogen Cycle

N2made biological available to organisms thru N fixation, conversion of N to NH3, NO3, or amino acids (AA).

Lightning accounts for some N fixation, but living things account for bulk of conversion.

Higher plants & animals may live in symbiotic association w/N-fixing microbes or cyanobacteria, ↑ soil & tissue concentrations of fixed N.

Free-living soil bacteria help cycle NH3 & carry out denitrification, release of fixed N from soils & waters to atmosphere, thus completing N cycle.

Fixed N is important limiting nutrient in oceans & terrestrial ecosystems.

Thru heavy use of agricultural fertilizers (containing industrially-fixed N) & thru combustion of fossil fuels & other materials, humans have accelerated flux of N in various phases of cycle & ↑ pollution of water & air.

Phosphorous Cycle

Human Impact on the Phosphorous Cycle• Sewage treatment facilities and fertilizer also add large

amounts of phosphates to aquatic systems, causing eutrophication (overfertilization) of lakes.

• Leads to increased algae!

Rule of 10

• Only 10% of energy is transferred from one trophic level to the next.

• Example:– It takes 100 kgs of plant materials (producers) to

support 10 kgs of herbivores– It takes 10 kgs of herbivores to support 1 kg of 1st

level predator

Decomposition

Organicmatter inanimals

Organicmatter in

plants

Inorganicmatter in soil

Deadorganicmatter

Symbiosis

• A long-term interaction between two organisms where "long-term" is defined in generations for at least one of the organisms and the interaction is physically intimate.

• Often the symbiosis will consist of one organism, the symbiont, living either on or inside of the other organism (the host).

• Symbioses can be classified in terms of the location of symbiont as well as in terms of the impact of the symbiont on the host. There are parasitic, mutualistic, or commensal symbioses in which the host is either harmed, helped, or neither harmed nor helped by the symbiosis, respectively (the symbiont, on the other hand, usually is helped by the interaction).

Symbiosis – “living together”

Relationship Type

Species A Species B

Commensalism + 0

Mutualism + +

Parasitism + -

+ means the organism benefits0 means the organism neither benefits or is harmed- means the organism is harmed

Biomes

A Delicate Balance

Causes of Environmental Problems

• Population growth• Wasteful and unsustainable resource use• Poverty• Failure to include the harmful environmental costs of goods and services in their market prices• Insufficient knowledge of how nature works

Some Resources Are Not Renewable

• Nonrenewable resources Exist in fixed quantity in earth’s crust. Economically depleted when costs too much to obtain

what is left.– Energy resources– Metallic mineral resources– Nonmetallic mineral resources

Solutions:• Reuse• Recycle

Degradation of Normally Renewable Natural Resources and Services

Our Ecological Footprints Are Growing

• Ecological footprint:

- Biologically productive land and water needed to supply renewable resources and absorb waste for each individual.

- Humanity’s eco footprint: exceeds by about 39% the earth’s ecological capacity.

Natural Capital Use and Degradation

Cultural Changes Have Increased Our Ecological Footprints

• 12,000 years ago: hunters and gatherers

• Three major cultural events– Agricultural revolution– Industrial-medical revolution– Information-globalization revolution

We Are Out of Control

NATURAL CAPITAL DEGRADATION

Major Human Impacts on Terrestrial Ecosystems

Deserts Grasslands Forests Mountains

Large desert cities Conversion to cropland

Clearing for agriculture, livestock grazing, timber, and urban development

Agriculture

Soil destruction byoff-road vehicles

Timber extractionRelease of CO2 to atmosphere from burning grassland Conversion of

diverse forests to tree plantations

Hydroelectric dams and reservoirs

Mineral extraction

Soil salinization from irrigation Increasing tourism

Overgrazing by livestockDepletion of

groundwaterDamage from off-road vehicles

Urban air pollution

Increased ultraviolet radiation from ozone depletionLand disturbance

and pollution from mineral extraction

Oil production and off-road vehicles in arctic tundra

Pollution of forest streams

Soil damage from off-road vehicles

Studying Nature Reveals Four Scientific Principles of Sustainability

• Reliance on solar energy

• Biodiversity

• Population control

• Nutrient cycling

Solutions For Environmental or Sustainability Revolution