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Environmental Health Environmental Health Chapter 3Chapter 3
Lesson 3.3 Lesson 3.3
Biodiversity and Environmental HealthBiodiversity and Environmental Health
PA Academic Standards for PA Academic Standards for Environment & EcologyEnvironment & Ecology
Standard 4.3.10.CStandard 4.3.10.C Explain biological diversity as an indicator of Explain biological diversity as an indicator of
a healthy environment.a healthy environment.• Explain species diversity.Explain species diversity.• Analyze the effects of species extinction on the Analyze the effects of species extinction on the
health of an ecosystem. health of an ecosystem.
Learning ObjectivesLearning Objectives
Students will define and explain biological Students will define and explain biological diversity.diversity.
Students will hypothesize the effects of species Students will hypothesize the effects of species extinction on health of an ecosystem extinction on health of an ecosystem
Biodiversity and Biodiversity and Environmental HealthEnvironmental Health
How can we use a measure of biodiversity to How can we use a measure of biodiversity to determine the health of an ecosystem?determine the health of an ecosystem?
Let’s see what Bill Nye, the Science Guy, has to say …
BiodiversityBiodiversity DefinitionDefinition: : variety of living organisms on earth
Biodiversity varies by Biodiversity varies by habitat The overall The overall health of an ecosystem is directly related to its of an ecosystem is directly related to its
biodiversitybiodiversity When in When in equilibrium, the number of species is balanced by , the number of species is balanced by
the resources in a systemthe resources in a system When ecosystems are When ecosystems are stressed, the organisms and , the organisms and
resources in a system are no longer in equilibriumresources in a system are no longer in equilibrium
BiodiversityBiodiversity
BiomonitoringBiomonitoring DefinitionDefinition: biological approach to monitoring an ecosystem’s : biological approach to monitoring an ecosystem’s
health. health. Using living organisms to gauge environmental health.
Ecosystem monitoring incorporates sampling & analyzing Ecosystem monitoring incorporates sampling & analyzing biological factorsbiological factors
Certain types of organisms occur within a Certain types of organisms occur within a limited range of of conditionsconditions
Example: ability to tolerate fluctuations in precipitation and Example: ability to tolerate fluctuations in precipitation and temperature in seasonal climatestemperature in seasonal climates
When conditions change, the When conditions change, the distribution and and number of of organisms in an affected site will also changeorganisms in an affected site will also change
These changes are the premise of biomonitoringThese changes are the premise of biomonitoring
BiomonitoringBiomonitoring How can we use biomonitoring in aquatic How can we use biomonitoring in aquatic
systems?systems?• Aquatic systems generally contain populations of
bottom-dwelling invertebrate species• If most systems have bottom-dwelling invertebrate
communities, then biomonitoring always works for a comparison of data within systems, as well as between unrelated systems
Benthic Macroinvertebrates
Why use bottom-dwelling invertebrates? They are present in nearly all aquatic
ecosystems Easy to collect and identify Limited mobility
Inability to avoid poor water quality conditions Sensitive to a wide range of environmental
conditions
Invertebrate Sampling ChartInvertebrate Sampling Chart
Bottom-dwelling Invertebrates: Bottom-dwelling Invertebrates: Field StudiesField Studies
Invertebrates are collected by nets and screening devices Invertebrates are collected by nets and screening devices using a variety of sampling techniquesusing a variety of sampling techniques
Identification of specimensIdentification of specimens Data collectionData collection
• The number and type of organisms is recordedThe number and type of organisms is recorded Data AnalysisData Analysis
• Charts have been developed to use a scoring table that Charts have been developed to use a scoring table that assigns a value to the level of tolerance an organism assigns a value to the level of tolerance an organism exhibitsexhibits
• The data is “scored” using these tablesThe data is “scored” using these tables ConclusionConclusion
• Data is reviewed, compared, repeated, and an overall tally Data is reviewed, compared, repeated, and an overall tally of indicators determines the overall health of the systemof indicators determines the overall health of the system
Humans and Species ExtinctionHumans and Species Extinction
Biomonitoring studies have shown that the health Biomonitoring studies have shown that the health of ecosystems statewide and nationally, have of ecosystems statewide and nationally, have improved since monitoring programs begansince monitoring programs began
Despite this accomplishment, ecologists estimate Despite this accomplishment, ecologists estimate that the current rate of extinction of species is that the current rate of extinction of species is 10,000 10,000 times faster than normal extinction ratestimes faster than normal extinction rates
Habitat lossHabitat loss is the most common reason for this is the most common reason for this increased rateincreased rate
Habitat AlternationsHabitat Alternations
Main causes of habitat destruction includeMain causes of habitat destruction include Sprawl Pollution Logging and mining Fire suppression
SprawlSprawl Problem: urban sprawl is the result of unplanned Problem: urban sprawl is the result of unplanned
development around urban areasdevelopment around urban areas Problem: major cause of habitat loss from the removal of Problem: major cause of habitat loss from the removal of
trees to clear properties, drainage and filling of wetlands, trees to clear properties, drainage and filling of wetlands, and increased amounts of impervious surfacesand increased amounts of impervious surfaces
Realistic Solution: Realistic Solution:
Smart DesignSmart Design
Smart Design BasicsSmart Design Basics Aims to reduce the amount of Aims to reduce the amount of sprawlsprawl and associated pollution and associated pollution Aims to increase the amount and affordability of mass Aims to increase the amount and affordability of mass transit transit
systemssystems Aims to provide alternatives to nonrenewable Aims to provide alternatives to nonrenewable fuel fuel
consumptionconsumption Aims to provide ecological ways of incorporated the needs of a Aims to provide ecological ways of incorporated the needs of a
growing population with the need for access to urban areasgrowing population with the need for access to urban areas
PollutionPollution Problem: results in the contamination of all forms of Problem: results in the contamination of all forms of
medium: air, water, and soilsmedium: air, water, and soils Problem: results in habitat Problem: results in habitat degradationdegradation and habitat and habitat lossloss Case Study: Case Study: DDTDDT in Pennsylvania in Pennsylvania
DDTDDT What is DDT?What is DDT? How is DDT linked to habitat loss and decreases in How is DDT linked to habitat loss and decreases in
overall habitat quality in Pennsylvania?overall habitat quality in Pennsylvania? What has been done to address the concerns What has been done to address the concerns
associated with the use of DDT in Pennsylvania?associated with the use of DDT in Pennsylvania?
DDT: DDT: DichlorodiphenyltrichloroethaneDichlorodiphenyltrichloroethane
What is it?What is it?• Chlorinated organic Chlorinated organic pesticide.pesticide.• Problem: Accumulates in Problem: Accumulates in fatfat..• Problem: Attacks Problem: Attacks nervousnervous system. system. • Problem: Affects Problem: Affects non-targetednon-targeted species species..
Uses of DDTUses of DDTHistoricalHistorical
• Agricultural productionAgricultural production• Limits crop lossesLimits crop losses
• ForestryForestry• Limits insect damageLimits insect damage
• Public healthPublic health• Malaria and Mosquito controlMalaria and Mosquito control
CurrentCurrent• Malaria control in “hot spots”Malaria control in “hot spots”
USDA 1947
Widespread Use of DDTWidespread Use of DDT
Current Status of DDTCurrent Status of DDT Banned in US in Banned in US in 19721972 Most other nations have banned DDTMost other nations have banned DDT
• ~19 countries still have exemption for its use~19 countries still have exemption for its use
Primarily used to control the spread of diseases by mosquitoes
Migration of DDT particleMigration of DDT particle
BioaccumulationBioaccumulation(Biological Magnification)(Biological Magnification)
DefinitionDefinition: : the accumulation of potentially harmful the accumulation of potentially harmful chemicals in organism higher in a food chainchemicals in organism higher in a food chain
DDT and Food websDDT and Food webs
Concept of Half-lifeConcept of Half-life
Half-life is the amount of time it takes for half of Half-life is the amount of time it takes for half of the chemical substance to degradethe chemical substance to degrade
The half life of DDT is 12-15 years. Let’s assume The half life of DDT is 12-15 years. Let’s assume that the half-life is a constant 15 years.that the half-life is a constant 15 years.
If we apply 100 pounds of DDT today, how much If we apply 100 pounds of DDT today, how much DDT will be left after 5 half-life's?DDT will be left after 5 half-life's?
Half-life of DDTHalf-life of DDT
One Half-LifeOne Half-Life
(15 years)(15 years)
Two Half-LivesTwo Half-Lives
(30 years)(30 years)
Three Half-LivesThree Half-Lives
(45 years)(45 years)
Four Half-LivesFour Half-Lives
(60 years)(60 years)
Five Half-LivesFive Half-Lives
(75 years)(75 years)
50% degraded50% degraded
50 lbs.50 lbs.
75% degraded75% degraded
25 lbs.25 lbs.
88% degraded88% degraded
12 lbs.12 lbs.
94% degraded94% degraded
6 lbs.6 lbs.
97% degraded97% degraded
3 lbs.3 lbs.
Weighing in on DDT use…Weighing in on DDT use…
ProPro• Toxic to wide range of Toxic to wide range of
insect pests insect pests • Appeared to have low Appeared to have low
toxicity to mammals toxicity to mammals and birdsand birds
• Persistent - does not Persistent - does not have to be reappliedhave to be reapplied
• Insoluble - doesn’t get Insoluble - doesn’t get washed off by rainswashed off by rains
• Inexpensive and easy to Inexpensive and easy to applyapply
ConCon• Toxic to a wide range Toxic to a wide range
of insect pestsof insect pests• Toxic to mammals and Toxic to mammals and
birds even in very low birds even in very low concentrationsconcentrations
• Persistent – does not Persistent – does not have to be reappliedhave to be reapplied
• Insoluble – doesn’t get Insoluble – doesn’t get washed off by washed off by precipitationprecipitation
Silent SpringSilent Spring When?When?
• 19621962 Who?Who?
• Rachel CarsonRachel Carson• Biologist and Biologist and
naturalistnaturalist• Noticed a “silent Noticed a “silent
spring”spring” What?What?
• Silent SpringSilent Spring; response ; response to massive use of to massive use of pesticides and pesticides and subsequent wildlife subsequent wildlife mortalitymortality
DDT Affects Non-Target DDT Affects Non-Target SpeciesSpecies
Reproductive failure in birdsReproductive failure in birds• Thinning of eggshells.Thinning of eggshells.• Modification of parental behavior.Modification of parental behavior.• High mortality of embryos and fledglings.High mortality of embryos and fledglings.
Pennsylvania Example: Pennsylvania Example: Peregrine Falcon PopulationsPeregrine Falcon Populations
Rosalie Edge – Hawk Mountain
Value of Raptors
What do we know about What do we know about Latin America?Latin America?
Latin America: Latin America: The DDT ConnectionThe DDT Connection
Falcons and other migratory birds can travel as Falcons and other migratory birds can travel as far as Latin America during period of migrationfar as Latin America during period of migration
Latin America still uses DDT as a means of Latin America still uses DDT as a means of mosquito and pest controlmosquito and pest control
Falcons traveling to these regions are coming in Falcons traveling to these regions are coming in contact with DDT; exposure to DDT occurs while contact with DDT; exposure to DDT occurs while falcons are in Latin Americafalcons are in Latin America
Logging and Mining: ProblemsLogging and Mining: Problems
Logging and mining have destroyed many habitats Logging and mining have destroyed many habitats statewidestatewide
Timber extraction increases erosion and sediments in Timber extraction increases erosion and sediments in waterwayswaterways
Acid mine drainage acidifies waterwaysAcid mine drainage acidifies waterways
Logging and Mining: Logging and Mining: Realistic SolutionsRealistic Solutions
Minimize and prevent further destructionMinimize and prevent further destruction Create and enforce regulations that oversee land Create and enforce regulations that oversee land
use for these practicesuse for these practices Restore and replace destroyed habitats for wildlife Restore and replace destroyed habitats for wildlife
and recreational useand recreational use
RECLAMATION
Fire Suppression: Fire Suppression: ProblemsProblems Interrupts natural processes of ecological successionInterrupts natural processes of ecological succession Disturbs the cycles of organisms which depend on periodic Disturbs the cycles of organisms which depend on periodic
firesfires Native plants vulnerable to competitors better adapted to Native plants vulnerable to competitors better adapted to
survive firessurvive fires
What we want... What we have.
Fire Suppression: Realistic Solution
Allow controlled fires to prepare land for ecological succession to occurAllow controlled fires to prepare land for ecological succession to occur