HUMAN IMPA

CT ON

ECOSYS

TEMS

CHAPTER 1

6

AKS Standards

11d - assess and explain human activities that influence and modify the

environment such as global warming, population growth, pesticide use, and

water/power consumption

HUMANS IN THE BIOSPHERE

• The human population is still growing, but the earth is not, and this places increasing demands on Earth’s air, water, land, and living things

• Understanding how humans interact with the biosphere is crucial to protecting these resources

• Industry & technology give humans a strong advantage in competing w/ other species for limited resources

• Human activity uses as much energy as all of Earth’s other multicellular species combined

• Hunting and gathering, agriculture, industry and urban development have significantly transformed the biosphere

• Human activities can change the flow of energy in an ecosystem and reduce the ability of ecosystems to recycle nutrients.

THE GREEN REVOLUTION

• The green revolution was introduced in the 1950’s by the government as an effort to greatly increase the yields of rice, wheat, and other crops Using highly productive varieties of certain crops Using monoculture – large fields cleared, plowed, and

planted with the same crops year after year Relied on pesticides, fertilizers, and large equipment to

support large growing areas Benefits: increased food production Problems: depletion of energy and water supplies, pest

species enabled to reproduce on a vast scale, pesticides can be potentially harmful, fertilizers can interfere with food webs and biogeochemical cycles

THE INDUSTRIAL REVOLUTION

• The era known as the Industrial Revolution was a period in which fundamental changes occurred in agriculture, textile and metal manufacture, transportation, economic policies and social structure (1760-1850). Dense human communitiesHuman waste productsReduction in habitatsPollutionOveruse of wildlife products

EARTH’S HUMAN POPULATION CONTINUES TO GROW

Our prediction of Earth’s human carrying capacity has changed over time.

Although we do not know of a fixed limit to the number of people that Earth can support, some limit must exist.

As humans have modified their environment through agriculture, transportation, medical advances, and sanitation, the carrying capacity of Earth has greatly increased.

http://www.classzone.com/cz/books/bio_07/resources/htmls/animated_biology/unit5/bio_ch16_0484_ab_humpop.html

THE GROWING HUMAN POPULATION EXERTS PRESSURE ON EARTH’S NATURAL RESOURCESRenewable Resources: those that replenish themselves quickly enough so that they

will not be used faster than they can be produced.• Examples include: oil & coal

Nonrenewable Resources: natural resources that are used more quickly than they can be formed.

• Examples include: wind energy, solar energy, and resource renewable through regrowth or reproduction (as long as they are not used faster than their regrowth)

EFFECTIVE MANAGEMENT OF EARTH’S RESOURCES WILL HELP MEET THE NEEDS OF THE

FUTUREEarth’s carrying capacity depends on how much land

is needed to support each person on Earth.

The amount of land necessary to produce and maintain enough food, water, shelter, energy, and waste is called an ecological footprint.

Individuals and populations vary in their use of resources and production of waste, and therefore in the size of their ecological footprint.

The average U.S. citizen’s ecological footprint covers an area larger than 24 football fields and is one of the largest in the world.

CRITICAL THINKING ACTIVITY: CONNECTING CONCEPTSThe progressive increase in Earth’s human carrying capacity

came from advances in technology. What density-independent and density-dependent limiting factors may prevent the human population from continued growth?

Disease, lack of food, limited water supplies (density-dependent)

Exhaustion of nonrenewable resources, medical and cultural practices (density-dependent)

AKS Standards

11d - assess and explain human activities that influence and modify the

environment such as global warming, population growth, pesticide use, and

water/power consumption

POLLUTANTS ACCUMULATE IN THE AIR

Pollution describes any undesirable factor, or pollutant, that is added to the air, water, or soil. The harmful effects of pollutants can be immediate or delayed, but these effects may add up over time and can disrupt the function of ecosystems.

Smog is a type of air pollution caused by the interaction of sunlight with pollutants produced by fossil fuel emissions.

ACID RAIN

The chemicals produced by the burning of fossil fuels become part of the ecosystem and can change the products of natural cycles.

For example, nitrogen oxides and sulfur oxides from fossil fuel emissions can lead to the formation of acid rain.

By decreasing pH levels in lakes and streams, acid rain threatens water supplies and species habitat.

Ecological Effects from Acid Rain in Lake SystemEcological Effects from Acid Rain in Lake System

• Changes begin to occur as soon as a lake starts to lose it natural bases or alkalinity.1. A large reduction in the number of plankton &

invertebrates. 2. The rate of decomposition of organic matter decreases3. Direct effects on fishes reproductive cycles.4. A calcium deficiency in fish leads to bone malformation.5. Fish can suffocate as their gills become clogged with

aluminum hydroxide.6. Songbirds are effected by eating insects contaminated

with toxic metals.

THE GREENHOUSE EFFECT

GLOBAL WARMING

ANIMATED BIOLOGY: GREENHOUSE WARMING

http://www.classzone.com/cz/books/bio_07/resources/htmls/animated_biology/unit5/bio_ch16_0491_ab_co2fx.html

AKS Standards

11d - assess and explain human activities that influence and modify the

environment such as global warming, population growth, pesticide use, and

water/power consumption

WATER POLLUTION AFFECTS ECOSYSTEMS

Algae are microscopic plants that are usually aquatic, unicellular, and lack true stems, roots, and leaves. Algal blooms occur in both marine and freshwater environments when an algal species outcompetes other species and reproduces rapidly.

An algal bloom can still kill fish and other aquatic life by decreasing sunlight available to the water and by using up all of the available oxygen in the water.

Blooms can be caused by several factors. An increase in nutrients can cause algae growth and reproduction to increase dramatically into a bloom just as fertilizing a lawn makes the grass grow faster.

BIOMAGNIFICATION CAUSES ACCUMULATION OF TOXINS IN THE

FOOD CHAIN

In biomagnification, there is a tendency for pollutants to concentrate as they move from one link in a food chain to another…top level carnivores suffer the most harmful effects of biomagnification.

Know and be able to explain how biomagnification of DDT affected the health of large birds of prey.

INTERACTIVE REVIEW: WATER QUALITY

http://www.classzone.com/cz/books/bio_07/resources/htmls/interactive_review/bio_intrev.html

Complete this interactive review using your virtual

textbook at home. Concept maps are an

excellent way to organize your thoughts and review

material!

AKS Standards

11d - assess and explain human activities that influence and modify the

environment such as global warming, population growth, pesticide use, and

water/power consumption

PRESERVING BIODIVERSITY IS IMPORTANT TO THE FUTURE OF THE

BIOSPHEREBiodiversity is the sum total of the genetically based variety of all

organisms in the biosphere Biologists have identified ~1.5 million species and estimate

that there are millions more. Biodiversity is one of the Earth’s greatest natural resources –

food, industrial products, medicines!!!!

Ecosystem diversity includes the variety of habitats, communities, and ecological processes in the living world

Species diversity is the number of different species in the biosphere

Genetic diversity is the sum total of all the different forms of genetic information carried by all organisms living on Earth today

LOSS OF HABITAT ELIMINATES SPECIES

Development often splits ecosystems into pieces (habitat fragmentation). This results in remaining pieces of habitat becoming biological “islands”. Fewer species can survive here and they are more vulnerable to further disturbances or climate changes.

INTRODUCED SPECIES CAN DISRUPT STABLE RELATIONSHIPS IN AN

ECOSYSTEM One of the largest threats to

biodiversity is the accidental or intentional introduction of new plants and animals to areas around the world by humans.

These can often become invasive species (a new species able to reproduce rapidly because their new habitat lacks the natural population controls they face in their old habitat). Cane Toads in Australia Kudzu in America African Bees in South America Burmese Python in Florida

Everglades

CONSERVING BIODIVERSITY

Conservation describes the wise management of natural resources

Today, conservation efforts focus on protecting entire ecosystems as well as single species

Most often, the need to protect biodiversity is greatest in countries that are least able to do so (these are known as “hot spots”) – immediate danger of extinction of species as a result of human activity Example: rainforests are found in developing countries

BIOLOGICAL HOT SPOTS

In an effort to locate problem areas and set up a list of conservation priorities, conservation biologists identify “hot spots”…places where significant numbers of habitats and species are in immediate danger of extinction as a result of human activity.

WEBQUEST: INVASIVE SPECIES

http://www.classzone.com/cz/ot/bio_webquest/16/intro.jsp

DATA ANALYSIS ONLINEhttp://www.classzone.com/cz/books/bio_07/resources/

applications/data_analysis/ch16_frog_recovery/index.html

AKS Standards

11d - assess and explain human activities that influence and modify the

environment such as global warming, population growth, pesticide use, and

water/power consumption

SUSTAINABLE DEVELOPMENT MANAGES RESOURCES FOR PRESENT AND FUTURE

GENERATIONS• Sustainable use is a way of using natural resources at a rate that

does not deplete them• Land resources• Forest resources• Ocean resources• Air resources• Water resources

• A sustainable system operates without causing long-term harm to the ecological resources on which it depends

• Example: alternative methods of pest control that do not involve harmful chemicals

CRITICAL THINKING ACTIVITY: INTERPRETING VISUALS

ANIMATED BIOLOGY: HUMAN EFFECTS ON A FOOD WEB

http://www.classzone.com/cz/books/bio_07/resources/htmls/animated_biology/unit5/bio_ch16_0507_ab_foodwbfx.html