BIO 367 EXAM 4

Relative Edge Area

Affected by patch shape as well as size.

Satellite Photographs

Are useful for quantifying landscape changes.

What causes differences in species richness among communities?

Area Habitat Diversity Productivity Keystone species Disturbance

How is nitrogen fixation accomplished?

Bacteria of the genus Rhizobium

Ecosystem Energy Flow

Control of ecosystem energy flow depends upon organism influence. -Top-down control -Bottom-up control

Detrital

Dead organic matter.

Landscape Analysis

Depends on technology (satellite imagery). E.g. Vegetation types differ in absorption spectra. E.g. Thermal imaging Spectrophotometry measures reflectance of solar radiation from surfaces.

Autotrophs

Derive energy from inorganic sources.

Latitude

Diversity decreases with latitude.

Boundaries

Ecotones have higher diversity than habitats on either side.

What does carbon cycling occur in primarily?

Exchange between biomass and the atmosphere.

Atmospheric CO2 Concentrations

Have changed over time with changes in physical condition. Historical levels of atmospheric CO2 have been up to 20x higher than current levels. Evolution of terrestrial plants resulted in transfer of atmospheric CO2 to organic sediments.

Oligotrophic

Low nutrient content and low production

Viable Population

Must be large enough to withstand demographic and environmental fluctuations and avoid genetic problems.

Grazing

NPP at 1st trophic level.

Plants

Play an important role in retention of soil nutrients.

Keystone Species

Presence increases species richness

Food Chains

Provide general insight into ecosystem energetics, but not details about organism influences.

Edge Effects

Reduction of habitat quality for interior species while edge species become more abundant.

Evenness

Relative abundance of species. -Low values: mixture of abundant and less common species. -High values: all species similar in abundance.

Resistance

Resistance to change due to disturbance.

Productivity

Richness increases with energy availability.

Production Efficiency

The growth of new tissue from assimilated energy. Measured as the proportion of energy stored out of amount assimilated (production/assimilation). Varies with metabolic costs. -Endotherms -Ectotherms.

What should net ecosystem productivity be highest in?

A young forest.

Assimilation and Dissimilation

Assimilation through photosynthesis. Dissimilation through respiration.

What would the difference in species diversity between an adjacent forest and prairie be an example of?

Beta diversity

Exchange of CO2

Between atmosphere and aquatic environments.

Fat-Soluble Toxins

Biomagnify in food chains.

Pollution and Waste

Create many environmental problems. -Atmospheric -Chemical residues -Solid waste -Eutrophication

What is the main argument for conserving biodiversity hotspots?

They contain unusually high numbers of species.

Human Global Ecology

Humans have a dominant ecological influence: -Atmospheric. -Sediment transport and nutrient cycles. -Hydrologic -Biological Anthropocene.

keystone species

Increase diversity at lower trophic levels.

Habitat Diversity

Niche diversity increases with habitat space.

Sea Levels

Rise as glaciers recede.

Area

Species richness increases with sampling area.

Invasive Species

Can significantly impact native species.

Aquatic Systems

Described by their nutrient content and productivity.

Assimilation Energy

Energy from food that absorbed into the body - allocated to: -Maintenance: respired energy -Energy contained in waste: excreted energy -Growth and storage = production.

Grasslands

Grazer food chain (LCS) consumes 30-99% of NPP

Forests

Grazer food chain (usually <10% NPP consumed) because most plant biomass is woody. Decomposer chain dominant (35% or more of NPP).

Biomass Measures

Harvest (index of PP)

Global Temperatures

Have been progressively warming for the last 60 years.

Endotherms

Have high maintenance budgets and low production efficiencies (2%)

Exchange of matter and energy

Heterotrophs derive energy from organic sources.

Eutrophic

High nutrient content and production. -Cultural eutrophication.

Bottom-up Control

Higher trophic levels influenced mainly by amount of energy available at the bottom. Increased production results in greater productivity at al higher trophic levels.

Future Climate Change

Impacts of increasing global temperatures include: -Changes in timing of seasonal events. -Sea level rise -Regional climate changes. => Warmer and dryer, or cooler and wetter, depending on the areas. Increased frequency of severe weather events.

Carbon Cycle

Involves both atmospheric and sedimentary reservoirs. Tied to energy flow. Cycling carbon is stored in organisms and detritus. Enters food chain from the atmosphere. Most carbon is tied up in sedimentary rock. -Mostly removed from the carbon cycle.

Habitat Fragmentation

Is a landscape process. Fragmentation involves the break up of large continuous habitats into small, isolated patches. -Usually involves anthropogenic causes. -Important threat to biodiversity.

Phosphorus

Is an important nutrient with a simple chemical cycle. Cycle is completely sedimentary except for dust. -Weathered bedrock source. Absorbed by plants as PO43- -Availability depends on soil pH. -Readily forms insoluble compounds. Readily precipitates out in aquatic systems to form sediments.

Food Chain Length

Is constrained by low efficiency of energy transfer. -Ingestion efficiency -Assimilation efficiency -Production efficiency

Can Human Populations Be Ecologically Sustainable?

It can be possible. Atmospheric CO2 levels and global temperature are directly related.

Landscape Approach

Large geographic scale. Components: Cover type: surface category of dominant vegetation. Patch: area that differs from its surroundings.

General Factors Influencing Species Diversity

Latitude Boundaries Geographic effects Area size

Nitrogen Mutualisms

Legumes enhance nitrogen availability through microbiological mutualisms. -Rhizobium bacteria live in specialized root nodules and fix atmospheric nitrogen directly into roots.

What would not be expected to influence species diversity patterns on a landscape scale?

Longitude.

Inbreeding Depression

Loss of reproductive potential due to inbreeding. Small populations are vulnerable. E.g. European Dunlins.

Ecological Efficiency

Low ecological efficiency limits food chain length. Only 5-20% (10% on average) of energy available at one trophic level is transferred to the next. Food chain lengths vary from 2-6 (3-4) trophic levels most common).

Human Population

Magnitude of human population impacts in environmentally pervasive.

Mercury Pollution

Mainly a result of fossil fuel combustion. Deposition increased 2-15 fold from around 1900 to recent times. Recent reductions in deposition rates are due to emission mitigation.

Modern Humans are Coincident with Very High Species Extinction Rates

Mass extinction events require a substantial proportion of living species to disappear rapidly. Sixth mass extinction will depend upon how many species are lost as human population increases. Modern extinction rate exceeds background extinction rate by 100-1000X, depending on how the estimate is calculated.

Biogeochemical Cycles

Movement of nutrients through ecosystems between food chains and abiotic reservoirs. Reservoirs are abiotic sources of chemical elements. Fluxes are the pathways by which chemical elements move between reservoirs and the food chain.

Allee Effects

Negative population growth at low densities.

Production in Aquatic Habitats

Strongly nutrient-limited. Have low levels of nitrogen and phosphorus. Have high levels of added nitrogen and phosphorus.

How much energy are humans harvesting?

Terrestrial ecosystems: estimated 35-40% of annual productivity. -Food (for us and animals) -Fiber Marine systems: total annual harvest has leveled off at 90 million tons after steep increases over the last 50 years.

Why have levels of atmospheric CO2 dropped significantly over the last 500 millions years?

The appearance of advanced plant communities which removed carbon from living biomass and transferred it to geologic organic sediments.

Why is secondary production of ectotherms higher than endotherms of comparable body size?

The maintenance costs of endothermy are much higher than they are for ectothermy.

Annual Primary Production

Varies among habitat types in both terrestrial and aquatic systems. Combinations of influential factors produce high variation in productivity among different ecosystems.

Edge-adapted Species

Become more abundant as habitats are increasingly fragmented.

IPAT Conceptual Model

CO2 emissions exemplify the IPAT concept.

Primary Production Estimation

Can be estimated by: -Biomass measures -Assimilation methods. Primary production = energy/area/time KJ per m2 per year. Can be estimated in small closed systems by measuring CO2 assimilation and production.

Species Diversity

Changes with spatial scale

Influence of Scale

Diversity increases with area size. Larger areas contain more species. Rarer species added as sampled area increases.

Which species would benefit from increasing fragmentation of the landscape?

Edge species

Egested Energy

Energy contained in indigestible portions of food.

Degree of Patchiness

Landscape patterns are determined by the heterogeneity. Local uniqueness: -Substrate (soil type) -Precipitation -Human activity Phase differences -Disturbance regimes -Variety of successional stages Dispersal capacity of organisms.

Minimum Viable Population (MVP)

Large enough to minimize extinction risk for considerable time. Estimated size to ensure 95% probability of persistence for 100 years. Analyses evaluate species characteristics and environmental factors to estimate extinction risk for different population sizes. Sizes vary from 500-5000 individuals.

What is the most frequent cause of species decline?

Loss of habitat.

Anaerobic Environments

Methane is dissimilated instead of CO2. 4CH3OH => 3CH4 + CO2 + 2H2O Methane production has increased with agricultural activity. -Livestock -Rice fields.

Detritus

Most important source of nutrients for plants. Nutrients are mainly made available to roots from decay of organic detritus. -Leaching of soluble substances. -Detritivore consumption of dead organic matter. -Breakdown of complex carbohydrates (especially lignin and cellulose) by fungi. -Release of phosphorus, nitrogen, and sulfur by bacteria.

Spatial Data

Multiple types of spatial data can be combined using Geographic Information Systems (GIS). Different types of information described as layers. Landscape-level questions can be addressed by analyzing relationships between layers. -Soil and vegetation type, etc.

What is the chemical reaction converting NO3 to N2 known as?

Nitrogen fixation

Most of the world's carbon is...

Present in geological sediments

Streams

Receive considerable energy from terrestrial systems (allochthonous input).

Renewable Energy

Renewable energy and energy conservation measures are becoming increasingly attractive. Wind farms, green architecture, solar power, etc. Energy conservation is economically beneficial.

Species-Area Relationship

S= species number A= area Z= slope (0.2-0.35)

Hydrologic Cycle

Simple, yet important physical process. Cycle of evaporation/transpiration/precipitation. Cycle driven by energy absorbed. Cycle of evaporation and precipitation repeats 26 times per year.

B Horizon

Soluble minerals leached from A horizon.

Species Richness

The number of species present

What is primary productivity of aquatic systems largely determined by?

The nutrients available to photosynthesis algae

What is a minimum viable population?

The population size needed to ensure a high probability of survival of the species against environmental and genetic threats for a lengthy specified time. Is estimated by computer models from biological information about the species.

What would be a statements that best describes the understanding of climate change?

There is a 95% consensus among climate scientists that human activity is causing an increase in global temperature.

The current rate of species extinction is estimated to exceed the background (natural) rate of extinction by at least:

100X

What percent of terrestrial primary productivity to humans harvest?

35-40%

Rate of Nutrient Cycling

Affected by climate. Rate of decomposition determines how rapidly nutrients are replenished in the soil. Rates vary with temperature and moisture. Fire also releases nutrients from detritus.

Length of Growing Season

Affects annual productivity.

Climate

Affects primary productivity. Temperature: rate of photosynthetic reactions. Water availability: photosynthesis is constrained by too much or too little water.

Pesticide residues exist in higher concentrations

At each level up the food chain because the residues accumulate in the bodies of animals resulting in each trophic level receiving a more concentrated dose of the pesticide in their diet.

Nitrogen Fixation

Atmospheric nitrogen (N2) is converted to NH3 by microbes (90%) or lightning (10%). -Ancient process -Bacteria and cyanobacteria that contain nitrogenase

What is the amount of energy passing between trophic levels?

5-20%

IPCC

97% certainty that global warming is caused by human activity.

What example would be the riskiest to consume in a mercury-contaminated lake?

A bass

Resiliency

Ability to recover from disturbance.

Secondary Production

Accumulation of energy in heterotroph biomass. Energy is ingested by heterotrophs follows a variety of paths: -Egested energy -Assimilation energy Production = Assimilated energy - Respired energy - Excreted energy

Availability of Light

Affects production. Light intensity varies: -Within habitats -Across seasons -With depth in aquatic systems

Nutrient Availability

Affects rate of primary production within a system. Nutrient levels influence plant growth independently of climate.

What is primary production in marine systems greatest in?

Along continental shelves

Habitat Area

Also affects population sizes, and viability. Reserves must be large enough to sustain viable populations.

Nitrification

Ammonia oxidized to nitrate and nitrite.

Biodiversity

An inclusive measure of abundance. -Species and genetic diversity (ecotypic variation)

Landscape Ecology

Analysis of environmental patterns and their effects on ecological processes. Regions with variation in ecological factors and processes.

Landscape Patterns

Are affected by both abiotic and biotic factors.

Economically Valuable Species

Are most at a risk of being unsustainably harvested. K-selected species are particularly vulnerable. E.g. Sea turtles, Whales, etc.

Ocean Ecosystems

Are stressed. Excess nutrients in aquatic systems can lead to oxygen deficit through eutrophication. Dead zones in marine environments result form allochthonous nutrients. High decomposition rates result in hypoxic conditions of bottom waters.

Three Important Chemical Processes Involved in Carbon Cycling

Assimilation and dissimilation. Exchange of CO2 Precipitation

Ecosystem Energetics

Availability of energy in ecosystems is determined by autotrophic processes which derive energy from inorganic sources.

Ectotherms

Average 50% production efficiency. Can achieve high abundance because of high production efficiencies.

Nitrogen Cycles

Between atmospheric and sedimentary pools using four chemical processes: 1. Nitrogen fixation 2. Ammonification/mineralization 3. Nitrification 4. Denitrification

Ammonification/Mineralization

Breakdown of proteins to amino acids and then to ammonia.

Environmental Contaminants

Can accumulate to toxic levels in ecosystems. Include pesticides and common synthetic chemicals used in industry. -Chlorinated hydrocarbons (DDT, chlordane), PCB's. Widely dispersed and persistent in food chain. -Wind dispersed globally. -Long half lives -Fat solubility causes accumulation in animal bodies. Have effects a long way from their targets. -Arctic food chains adversely affected.

Photosynthetic Rate of Algae

Can be measured in small closed systems.

Anthropogenic Factors

Can causes habitat fragmentation. Fragmentation involves transformation of a continuous natural landscape into a series of disconnected patches within an altered habitat matrix. Species diversity and relative abundances change with fragmentation as patches: -Become smaller and more isolated. -Contain more edge habitat.

Habitat Changes

Caused by fragmentation favor some species and harm others. E.g. increased disturbance favors weedy species.

Actual Evapotranspiration (AET)

Combines water and temperature into a single metric.

Top-down Control

Community structure is determined by the highest trophic level. Consumers depress the trophic level on which they feed, indirectly increasing the next lower trophic level. Relative biomass of trophic levels alternate.

Size and Proximity of Islands

Compared to sources of immigrants influence diversity equilibria. Larger and closer islands should be more successfully colonized and retain more species than small, distant islands. Maximal diversity predicted for islands that are large and close to mainland source of immigrants.

Soils

Complex mixtures of parent material, organic matter, and organisms. Formation by physical (weathering) and biological (decomposition) processes. Layered in horizons.

What distinguishes conservation biology from ecology?

Conservation biology is a synthetic discipline involving an array of many different sciences while ecology is a distinct science. Conservation is a goal-oriented discipline that seeks to maintain biodiversity rather than answer basic scientific questions about biodiversity. Conservation is a recently discipline while ecology originated over 100 years ago.

Ecotones are Diverse

Contain some of the species pool from both adjacent habitats. Also contain "edge" or ecotone specialists. Ecotone contains 12 of 14 possible species, other areas contain maximum of 9.

How is the similarity of adaptations of cacti and African euphorb plants explained?

Convergent evolution and becoming adapted to similar environments.

Coral Reefs

Coral reefs and deep see environments are very diverse. E.g.: -Shallow coral reef. -Deep sea coral. -Deep sea hydrothermal vent.

Fresh Water

Critical limiting resource for human populations. Local demand for water doesn't match rainfall distribution. Current trends indicate water shortages and scarcities within 2-3 decades in many countries. Water conservation and cleansing measures essential for the future.

What ecosystem is decomposer food chain most important to?

Decomposer food chains dominate both forest and small stream ecosystems.

A Horizon

Decomposing biomass (humus), mineralization.

Experimental Evidence Supports Equilibrium Theory of Island Biogeography

Defaunation of four islands in Florida Keys. -Varying distances to mainland. Recolonization rate varied inversely with distance to source. Species diversity plateaued around pre-defaunation levels.

Crop Production

Depends on soil resources and fertility. Soil fertility has decline due to soil degradation and disruption of nutrient cycling. -Erosion -Loss of nutrients through harvest. Soil loss in U.S. is 4x the rate of soil production. Crop production declines 6% per inch of topsoil lost.

Chemosynthesis

Derives energy from oxidation of electron donors. Archaea and eubacteria.

Ecosystem Energy

Despite similar functions, ecosystems vary in the relative amount of energy distributed to different components.

Patch Characteristics

Determine landscape structure and affect organism interactions. Patches differ in area and perimeter. -Perimeter to area ratio indicates patch shape -High P/A ratio in complex or narrow patches. The distance between patches affects dispersal of organisms. -Isolation vs. connectivity. -Relative patch isolation determined by proximity.

Global Patterns of Primary Production

Differ strongly in terrestrial and marine systems. Global differences apparent in terrestrial environments due to climate. NPP in marine systems depends on nutrient availability. -Open ocean is very unproductive.

Tolerant of Disturbance

Diverse communities tend to be more stable. Stability increases with the number and complexity of trophic links. -Generally, more species = greater stability. Stability is indicated by: -Resistance -Resiliency

Area Size

Diversity increases with area.

Alpha Diversity (a)

Diversity of a single community in one location.

Beta Diversity (B)

Diversity of several communities in one location. -Difference in diversity between adjacent communities.

Assimilation Methods

EDDY analysis- uses sensors to measure uptake of CO2 in atmosphere. Remote sensing of chlorophyll - satellite measurement of reflected light. -Large scales.

Biogeochemical Cycle

Each cycle has 3 integrated elements: inputs, cycling, and outputs.

Multiple Food Chains

Each ecosystem has multiple food chains that differ in importance among systems. All are interconnected but function separately with different energy sources. Relative importance of each varies among systems.

Disturbance

Effect varies with frequency.

Heterotrophs

Energy captured in primary production is transferred to higher trophic levels by heterotrophs.

Secondary Production

Energy consumed by heterotrophs minus energy excreted and used in respiration.

Net (NPP)

Energy remaining after accounting for respiration.

Cultural Eutrophication

Enrichment of nutrients from anthropogenic sources.

Equilibrium Theory of Island Biogeography

Explains diversity through colonization and extinction processes. Colonization potential is high and extinction probability low when few species are present. The reverse is expected when species diversity is high. The maximum number of species (S) on the island should occur where extinction and colonization rates are equal. -S always smaller than mainland source pool (P).

Human Population Influences

Five major impacts: 1. Land transformation 2. Biogeochemistry 3. Changes in biotic communities. 4. Climate alterations. 5. Declining biodiversity. Population momentum and increased economic development ensure increased impacts in the future.

What is the main difference between patchy landscapes formed from natural disturbance and landscapes fragmented through human activity?

Fragmented landscapes are generally simpler in structure than natural landscapes. Fragmented landscapes usually have lower species richness than natural landscapes. Fragmented landscapes typically have greater contrast than natural landscapes.

Vertebrate Extinction Rates

Greatly elevated compared to background and are projected to worsen in the future.

Dead Zones

Have increased dramatically in the last 20 years. Dead zones have been documented in > 400 years. -425,000 km2 -Key stressor of marine systems.

Biomagnification of Mercury

In top predators is evident from museum samples.

What contributes to the extinction vulnerability of small populations?

Inbreeding depression, being more vulnerable to stochastic events. Allee effects.

Process of Fragmentation

Increases edge area. Edge areas are physically and climatically different from core areas.

Species Diversity

Increases with environmental productivity. E.g. certain animals have higher numbers within their populations, but have lower energy inputs into the environment.

Fragmentation

Influences conservation efforts. Bioreserve design must consider size and shape of protected areas. Large size minimizes edge and accommodates large species. Corridors allow dispersal.

Photosynthesis

Initially cyanobacteria, then algae, and plants. Fundamentally changed ecological systems.

IUCN

International Union for the Conservation of Nature. Monitoring the conservation status of species. Species statuses are determined by: -Population trends -Population sizes -Threats

Abiotic Factors

Landforms Glacial and volcanic activity. Affect surface texture, elevation, slope.

Habitat Loss

Large cause of species declines. Habitats are progressively lost as the human population expands. 83% of terrestrial environments have been modified. 60% of ecosystems degraded or unsustainably used.

Why Should We Conserve Biodiversity?

Moral/ethical responsibility based on desirability of biodiversity. Economic benefit. -Natural resources have economic value. Preservation of ecosystem function (ecosystem services). Species as indicators of environmental quality.

Effective Population Size

Ne. The individuals that are actually breeding.

The energy available to consumers in trophic level 2 is best described by:

Net primary productivity.

Denitrification

Nitrates reduced to atmospheric nitrogen by bacteria (Pseudomonas) using NO as an oxygen source.

Species Diversity

Number of species found in a given location varies widely among habitats and geographic regions. Generally, diversity is high in the tropics and decreases with distance from the equator.

Niche Diversity

Number of species increases and ecological opportunities increase. E.g. Fish diversity in Mexican river increased from headwaters. Stream size influences environmental conditions. -Headwater: small stream size, few resource. -Mouth: more physical space, resources, and ecological opportunities.

Cultural Eutrophication

Nutrient pollution has significant ecological impacts. Nitrogen enrichment occurs from combustion, commercial fertilizers, nitrogen-fixing crops. Nitrogen fixed for the production of chemical fertilizers exceeds that of natural processes. Phosphorus - detergents, septic tanks, urban runoff. In the last 50 years, flux of N = . 2X, P = 3X

Trophic Cascade

Occur when changes in top predator densities affect lower trophic levels. Addition of a fourth trophic level results in a trophic cascade linking all of the trophic levels in a community.

Extinction Vortex

Occurs when factors that reduce population size reinforce each other to drive a small population to extinction.

Precipitation

Of carbonate sediments in marine systems. CO2 + H2O => H2CO3 => 2H+ + (CO3)2-

Species Occupying Communities

Often change along environmental gradients. Differences in responses of species to physical factors often results in zones of species' occurrence.

What would not be expected to influence primary productivity?

Oxygen availability

Insularization and Area Effects

Patches too small for some organisms. Disproportionate loss of specialists which are extinction-prone.

Geographic Effects

Peninsulas and islands tend to have lower diversity than other areas.

What is the only significant element cycle lacking an atmospheric reservoir?

Phosphorus.

Sources of Nutrients in Ecosystems

Physical Process: -Weathering of parent material. -Glacial deposition. -Atmospheric deposition. ==> Dust particles can contain nutrients and other chemicals. -Alluvial deposition. ==> Nutrient deposition in floodplains. Biological Processes: -Photosynthesis -Nitrogen Fixation -Migration of animals.

Intermediate Disturbance Hypothesis

Predicts high diversity with moderate disturbance. Species sensitivity to disturbance and competitive ability.

Biotic Factors

Presence/absence of important consumers. Keystone predators. Ecosystem engineers.

Climate Effects Across Ecosystem

Primary production varies predictably with climate effects across ecosystems. Productive ecosystems are warm and moist. -Tropical forest 1000-3500 g/m2/yr Least productive are cold and dry -Deserts and tundra: 100-250 g/m2/yr

Endangered Species Conservation

Problems often involve managing small populations which are unusually susceptible to extinctions. High vulnerability to: -Inbreeding, genetic drift. -Demographic stochasticity (random variation in demographics of the population). -Environmental stochasticity (weather and other density-independent events).

Ingestion Efficiency

Proportion of available energy consumed by organisms in next trophic level.

Sustained Inbreeding

Reduces genetic variation of populations. Is avoided in natural populations of plants and animals but may be unavoidable in captive situations or in small natural populations. Results in: -Loss of genetic variation. -Increased expression of recessive genes. Genetic diversity is lost rapidly in very small populations.

Crowding Effect

Reduction of population densities and loss of some species due to Crowding Effect. Fewer resources in smaller patches.

Niche Specialization

Reflected by morphological variety. E.g. difference between fruit bats and insectivorous bats. -Ear-forearm ratio is related to the type of prey the bat can locate. -Digit length ratio is related to wing shape, maneuverability, and prey capture efficiency.

Gamma Diversity (y)

Regional diversity. -Across all habitats in a region.

Diversity and Abundance Trade-Off

Relative abundance declines as more species occupy a given space. Lower diversity means less competitions. -Niche breadth inversely related to diversity. -As the size of the regional species pool increases, average species abundances and numbers of habitats occupied by species in local communities decreases while local species richness increases.

Environmental Impact

Relative impact of human populations varies with affluences. IPAT equation relates population size, technology, and lifestyle to environmental impact: Environmental Impact = (population size) X (per capita influence) X (technology to achieve a given level of affluence) Generally useful but does not reflect threshold effects or synergistic relationships.

How is diversity quantified?

Shannon/Weaver diversity index (H) incorporates both richness and evenness.

Primary Production

Solar energy converted to organic molecules by photosynthesis. Measured as the amount of energy produced per unit of area/unit of time (Kcal/m2/year). NPP=GPP - Respiration

Sampling to Estimate Diversity

Species detection: Species sampling curves relate diversity to sample effort. Problem: species differ in detectability so rare species, or those with variable encounter rates, are easily overlooked. IN many communities, most species are moderately abundant.

Habitat Complexity

Species diversity tends to increases with habitat complexity. Complex habitats have more "ecological space" (i.e. more potential niche opportunities). E.g. Tropical forests are vertically layered, supporting high diversity. E.g. Salt marshes are structurally simple and have low diversity.

What is Conservation Biology?

Synthetic science composed of ecology, genetics, management fields. Synergy important. Originated as a response to observed species declines and extinctions. Relatively new: formally described in late 70's. Goal-oriented purpose of long-term preservation of biodiversity.

Assimilation Efficiency

The amount of ingested food that is digested and absorbed. -Diet-dependent (30% for herbivores, 60-90% for carnivores)

What does the Ecological footprint compare?

The relative resource consumption of individuals in different countries.

Conservation Biology

The science of scarcity and diversity. Conservation is the scientific study of the nature and of Earth's biodiversity with the aim of protecting species, their habitats, and ecosystems from excessive rates of extinction and the erosion of biotic interactions. It is an interdisciplinary subject drawing on natural and social sciences, and the practice of natural resource management.

An extinction vortex describes the elevated extinction risk of small populations from..

The tendency for inbreeding and loss of genetic variation, genetic drift, random fluctuations in population size to have a reinforcing effect to make the population smaller and less well adapted to its environment.

What ecosystem has the highest rate of nutrient cycling?

Tropical rain forest.

How is species diversity measured?

Two components: -Species richness -Evenness Biodiversity is an inclusive measure of abundance. E.g. Two communities with identical richness but different evenness patterns.

Residence Times of Carbon

Varies among cycle compartments. Atmospheric CO2 residence time is only about 5 years. Average residence time in food chain is 31 years. Carbon sediments have lengthy residence times. -Released to atmosphere through volcanic activity and fossil fuel combustion.

Decomposition Rates

Vary with chemical makeup of detritus. Variation in leaf decomposition rates is explained by difference in lignin content. Lignin inhibits decomposition. Nutrient availability affects decomposer activity.

Water Consumption

Water is consumed unsustainably. "Hidden" water in everyday life. Gallons of water needed to produce one lb of: - Beef - 1,857 - Pork - 756 - Chicken - 469 -One of pair of blue jeans - 2,900

C Horizon

Weathered bedrock.

What could be used to estimate primary productivity in an ecosystem?

Weighing biomass of plants harvested from a known area, measuring carbon intake by leaves and extrapolating to a larger area, measuring changes in oxygen production by algae within a closed system.

What characteristics accurately describe a species that has a high potential to become invasive if transported to a new habitat?

Wide tolerance for environmental conditions (temperature, moisture, etc.)

Mesopredator Release

a top-down effect on community structure. E.g. Blacktip shark is an apex predator that consumes little skates, which are mesopredators. Little Skates consumed bay scallops.

Gross (GPP)

total sunlight converted to stored energy by photosynthesis