Chapter 55 - Ecosystem and Restoration Ecology

BIOL213

Nutrient cycling and Arctic foxes/birds relationship

Foxes preyed on sea birds which reduced production of nutrient rich guano; rich grassland turned to bare tundra

Hierarchy of ecological organization: community ecosystem etc.

Ecosystems include all the living organisms in an area and the abiotic factors with which they interact; community refers to the living organisms only

Describe the laws of physics that apply to ecosystems and how they apply.

1st law of thermodynamics: energy cannot be created or destroyed, only changed;

2nd law of thermodynamics: in an enclosed system, entropy increases; law of conservation of mass: mass cannot be created or destroyed; energy from the sun enters food bonds and nutrients cycle through ecosystems

Compare and contrast how energy and nutrients travel through an ecosystem.

Energy flows one-way from the sun to producers to consumers and is lost as heat; nutrients cycle within ecosystems and are reused; if outputs exceed inputs, nutrients limit production

Describe net primary productivity and how it is calculated.

Net Primary Production (Total primary production minus respiration of autotrophs)

NPP = GPP – Ra

Explain the NPP patterns of marine and terrestrial ecosystems and their limiting factors.

Marine NPP limited by nutrients and light; terrestrial NPP limited by temperature, precipitation, and nutrients; most productive ecosystems include wetlands and tropical rainforests

Interpret ecological pyramids

Trophic efficiency ≈10% limits food chain length; production decreases at higher trophic levels; ecological pyramids show energy, biomass, or individuals at each level

Identify the reservoirs of the major biogeochemical cycles.

Reservoirs include atmospheric nitrogen, marine sediments/rocks for phosphorus, water cycle reservoirs, carbon in sinks such as forests; reservoir means where large amounts of chemicals are found

Explain global warming, its causes, and its effects.

Caused by greenhouse gases (CO₂, methane, nitrous oxide, water vapor) that insulate Earth by absorbing radiation; effects include ↑ temperatures, ↑ drought, ↑ storms, ↑ sea level, melting ice caps, extinction, habitat destruction, disease outbreaks

Explain ocean acidification, its causes, and effects.

Increased CO₂ reacts with water creating acid; affects marine organisms that produce calcium structures

Explain eutrophication, its causes, and effects.

Eutrophication is the process where primary production increases as an ecosystem changes from nutrient-poor to nutrient-rich; creates hypoxic (little oxygen) and anoxic (no O₂) zones

Understand role of decomposers

Decomposers are heterotrophs that get their energy from detritus (nonliving organic matter) and recycle nutrients

Primary productivity of different ecosystems

Most productive ecosystems include salt marshes and wetlands; tropical rain forests have high productivity; deserts have low productivity

Limiting factors of primary productivity

Aquatic limiting factors: nutrients (N, P) and light; terrestrial limiting factors: temperature, precipitation, nutrients

Energy transfer between trophic levels

Trophic efficiency is the percentage of production transferred to the next level (often ~10%) which limits food chain length

Ecological footprint and meat consumption

Eating meat increases ecological footprint because energy transfer between trophic levels is inefficient, requiring far more plant biomass, land, and resources to produce animal-based food (Pearson Campbell Biology)

Chemotrophy mechanisms and food chains

Chemosynthesis uses H₂S: 18H₂S + 6CO₂ + 3O₂ → C₆H₁₂O₆ + 12H₂O + 18S; chemoautotrophs serve as primary producers in some ecosystems

Biogeochemical cycles what they are: C/N/S

Cycles include movement of carbon, nitrogen, sulfur; major factors: biological importance, forms available to life, reservoirs, and key processes driving movement

Purpose of restoration ecology

Initiate or speed up the recovery of land to its original state; restore degraded ecosystems such as wetlands, overgrazed land, and damaged habitats

Bioremediation examples

Use of organisms—mainly prokaryotes, fungi, or plants—to detoxify polluted ecosystems; example: bioremediation of uranium-contaminated groundwater at Oak Ridge Labs, TN