Chapter 23Chapter 23

Environmental ScienceEnvironmental Science

23.1 Humans and the Environment23.1 Humans and the Environment

Environmental science is the study of Environmental science is the study of the relationships between humans the relationships between humans and the Earthand the Earth

Since all life is interconnected, Since all life is interconnected,

it is important to develop it is important to develop

ways to correct global ways to correct global

problems from humans problems from humans

A Global ConnectionA Global Connection

Warming and cooling air form loops Warming and cooling air form loops called convection cells in Earth’s called convection cells in Earth’s atmosphereatmosphere

Convection cells determine Convection cells determine

climate and create climate and create

oceanic circulation oceanic circulation

patternspatterns

Convection CellsConvection Cells

The sun’s rays heat air The sun’s rays heat air molecules near Earth’s molecules near Earth’s surfacesurface

The less dense, warm The less dense, warm molecules risemolecules rise

Eventually they cool Eventually they cool and sink back toward and sink back toward EarthEarth

UpwellingUpwelling

Cold water rises from the ocean Cold water rises from the ocean depths and carries nutrients upwarddepths and carries nutrients upward

More nutrients support more More nutrients support more plankton which leads to large plankton which leads to large populations of fishpopulations of fish

El NinoEl Nino

Occurs when the warm surface water Occurs when the warm surface water prevents upwelling from occurringprevents upwelling from occurring

Causes fish populations to decline Causes fish populations to decline (anchovy exports decrease)(anchovy exports decrease)

Declining OzoneDeclining Ozone

OO3 3 is a naturally is a naturally occurring gas that occurring gas that protects living protects living things from things from harmful UV raysharmful UV rays

CFC’s are ozone-CFC’s are ozone-destroying destroying chemicalschemicals

ChlorofluorocarbonsChlorofluorocarbons

Used as coolants in refrigerators and Used as coolants in refrigerators and air conditioners and as propellantsair conditioners and as propellants

Banned in 1992Banned in 1992

As long as we don’t use CFC’s, the As long as we don’t use CFC’s, the ozone layer will continue to recoverozone layer will continue to recover

Increasing COIncreasing CO22

Carbon dioxide is a byproduct of Carbon dioxide is a byproduct of cellular respiration and a component cellular respiration and a component of photosynthesisof photosynthesis

It is also released when fossil fuels It is also released when fossil fuels are burnedare burned

The Greenhouse EffectThe Greenhouse Effect

Greenhouse gases Greenhouse gases form a blanket around form a blanket around Earth and keep it at a Earth and keep it at a temperature suitable temperature suitable for lifefor life

When the layer gets When the layer gets thicker, it traps too thicker, it traps too much heat which much heat which causes global warmingcauses global warming

Evidence About Global WarmingEvidence About Global Warming

Ice-core samples show there is a Ice-core samples show there is a correlation between rising correlation between rising

temperatures and COtemperatures and CO2 2

concentrationsconcentrations

Global temperatures are expected to rise Global temperatures are expected to rise 2°C (4°F) within the next century2°C (4°F) within the next century

Can affect rainfall patterns, soil moisture, Can affect rainfall patterns, soil moisture, sea level, crop growth, biodiversity, sea level, crop growth, biodiversity, human diseases, etc.human diseases, etc.

Future Population GrowthFuture Population Growth

The U.N. estimates that human The U.N. estimates that human population will be at 12.5 billion by population will be at 12.5 billion by 20502050

This would result in more fossil fuels This would result in more fossil fuels being burned and higher global being burned and higher global temperaturestemperatures

23.2 The Biodiversity Crisis23.2 The Biodiversity Crisis

Biodiversity: the variety of organisms Biodiversity: the variety of organisms in a given areain a given area

Genetic diversity: the amount of Genetic diversity: the amount of genetic variation (the most important genetic variation (the most important measure of biodiversity)measure of biodiversity)

Measuring BiodiversityMeasuring Biodiversity

There are 3 million species that have There are 3 million species that have been been identifiedidentified on Earth on Earth

It is estimated that there are 10-30 It is estimated that there are 10-30 million speciesmillion species

Tropical rainforests have many Tropical rainforests have many undiscovered speciesundiscovered species

Earth’s BiodiversityEarth’s Biodiversity

ExtinctionExtinction

Extinction is forever!Extinction is forever!

Rapid destruction of habitats is Rapid destruction of habitats is driving many species to extinction driving many species to extinction each dayeach day

More than half of all tropical More than half of all tropical rainforests have already been rainforests have already been destroyeddestroyed

Ways to Save BiodiversityWays to Save Biodiversity

Conservation strategies! Conservation strategies! (Ecotourism)(Ecotourism)

Debt-for-nature swapDebt-for-nature swap: richer : richer countries or private organizations countries or private organizations pay off some of the debts of a pay off some of the debts of a developing country in exchange for developing country in exchange for them not cutting down their them not cutting down their rainforestrainforest

The Importance of BiodiversityThe Importance of Biodiversity

Utilitarian Value: considers the economic Utilitarian Value: considers the economic benefits that biodiversity provides for benefits that biodiversity provides for humans (food, medicine, etc.)humans (food, medicine, etc.)

Nonutilitarian Value: All life-forms deserve Nonutilitarian Value: All life-forms deserve to exist (intrinsic value)to exist (intrinsic value)

Need for a “Declaration of Need for a “Declaration of Interdependence”Interdependence”

Conservation and Restoration BiologyConservation and Restoration Biology

Conservation biology: identify and Conservation biology: identify and maintain natural areas to preserve maintain natural areas to preserve biodiversitybiodiversity

Restoration biology: convert Restoration biology: convert damaged areas back into viable damaged areas back into viable habitatshabitats

Conserving Migratory BirdsConserving Migratory Birds

Migratory birds spend spring and Migratory birds spend spring and summer in Tundra and northern summer in Tundra and northern forests (abundant insects for food)forests (abundant insects for food)

In the Fall, they migrate to warmer In the Fall, they migrate to warmer climates where there will be enough climates where there will be enough food to last until their next breeding food to last until their next breeding season season

FlywaysFlyways

There are four major flyways in North There are four major flyways in North AmericaAmerica

Saving Critical HabitatSaving Critical Habitat

Wildlife refuges must be established along Wildlife refuges must be established along the flyways to allow birds a place to rest the flyways to allow birds a place to rest and eat during their long migrationsand eat during their long migrations

They also need protection in their They also need protection in their wintering groundswintering grounds

Conservation efforts need Conservation efforts need

to be international!to be international!

Magee MarshMagee Marsh

Reintroduction of the WolfReintroduction of the Wolf

The gray wolf is an endangered The gray wolf is an endangered species because they were killed by species because they were killed by peoplepeople

There has never been a documented There has never been a documented case of a human being attacked by a case of a human being attacked by a healthy wolf!healthy wolf!

They will occasionally kill livestockThey will occasionally kill livestock

Wolves in YellowstoneWolves in Yellowstone

Without wolves in Without wolves in the park, the elk the park, the elk population population explodedexploded

In 1995, 14 wolves In 1995, 14 wolves were releasedwere released

The Florida EvergladesThe Florida Everglades

Drainage canals Drainage canals were built to divert were built to divert water away from water away from the everglades so the everglades so people could use people could use the land for homesthe land for homes

More than 50% of More than 50% of the wetland was the wetland was destroyed destroyed

WetlandsWetlands

Wetlands are important habitats for Wetlands are important habitats for wildlifewildlife

They also purify drinking water and They also purify drinking water and help replenish groundwaterhelp replenish groundwater

Coastal wetlands prevent flooding Coastal wetlands prevent flooding and beach erosionand beach erosion

Everglades RestorationEverglades Restoration

Currently, a restoration plan is being Currently, a restoration plan is being implemented to remove some of the implemented to remove some of the drainage canalsdrainage canals

40,000 hectares (100,000 acres) will 40,000 hectares (100,000 acres) will be set aside for protectionbe set aside for protection

Melaleuca trees will be cut Melaleuca trees will be cut down (non-native species)down (non-native species)

Get Involved!Get Involved!

Learn about your local environmentLearn about your local environment

Get involved in your own community to Get involved in your own community to preserve local biodiversitypreserve local biodiversity

RecycleRecycle

Urban ecology: increasing biodiversity in Urban ecology: increasing biodiversity in heavily developed areasheavily developed areas