Chapter 18

Introduction to Introduction to EcologyEcology

Biology I Mrs. Schalles

ECOLOGY?ECOLOGY?

- comes from the GREEK Words: OIKOS (HOUSE where one lives) LOGOS (STUDY)

Ecology is the Study of the “House” in which We Live.

Ecology can be defined more specifically as:

• The Study of the Interactions between: –Living Organisms –Non-living Components of their

Environment.

Parts of the Environment:

• BioticBiotic-- Living Organisms

-Producers, Consumers, and Decomposer

• AbioticAbiotic- Non-living components -sunlight, temperature, humidity, water supply, soil type, mineral nutrients (Nitrogen, Phosphorous, Sulfur, etc)

InterdependeInterdependencence

- Effects of Interactions between organisms & their environment.

- Each organism Depends in some way on other living and nonliving things in its Environment.

Key theme of Ecology• No Organism is isolated- Everything is

interconnected

• Species interact with each other & with abiotic factors in the environment.

• Disturbances in one species can affect other species.

Example of Interdependence:

• See diagram on page 360 in textbook• Unexpected “chain reaction”• In a year when more acorns are produced-

eventually see humans with more lyme disease.

• Explain how this happens.

• Can you think of another example of how a change in your environment can indirectly affect living organisms?

Some examples of complex, Some examples of complex, controversial interactions are controversial interactions are not completely understood :not completely understood :

Because they involve: • dynamic ecosystems

• multiple governments • differing interpretations of data in

an area of ever-changing science.

Some Environmental Problems

1. Human Population Growth

2. Mass Extinction

3. What is Climate Change/Global Warming?

4. Pollution

5. Use of Resources/ Burning Fossil Fuels

6. Sustainability

Graph of Human Population Growth1. Human Population Growth

Growth-limiting factors

• the availability of food and water • invasion of parasites, pathogens or

disease • over-crowding (increasing competition

for food, water and space) • severe or sudden climatic changes • pollution of air, soil and water

1. Human Population Growth

2. Mass Extinction

• As human population has increased, many other species decline in number or become extinct.

• There have been at least 5 periods of mass extinction, could we be causing # 6?

What is the greenhouse effect?3. What is Climate Change/Global Warming?

Greenhouse Earth• The earth is naturally warmed by the

greenhouse effect.

• Without the greenhouse

effect the earth would be

too cold to maintain the

diversity of life that it

does now.

3. What is Climate Change/Global Warming?

Major Greenhouse gases Major Greenhouse gases and their sourcesand their sources

• H2O (water vapor) – evaporation, plant respiration.

• CO2 (Carbon dioxide)- burning fossil fuels, volcanic eruptions

• CH4 (Methane) -animal waste, fossil fuels, landfills, sewage, wetlands

• N2O (Nitrous Oxide) – deforestation, fossil fuels, microbe activities (in soil)

• CFCs (Chlorofluorocarbons)- aerosols, propellants, solvents, refrigerants

3. What is Climate Change/Global Warming?

Is Global Warming actually happening? • Many scientists say NO!Many scientists say NO!

• The Cooling World- Newsweek, April 28, 1975 – ( scientists warned in the 1970’s that the earth was dangerously cooling!

www.denisdutton.com/cooling_world.htm

• 1980’s-2006 Global Warming was the politically correct topic– See Al Gore & many Hollywood actors opinions.

• In 2007, hundreds of people died, not from global warming, but from cold weather hazards http://www.washingtontimes.com/article/20071219/COMMENTARY/10575140

• 2008 – Independent study commissioned by congress – Mr. Wegman& team from George Mason University concluded that the idea that

the planet is experiencing global warming "cannot be supported." http://www.washingtontimes.com/apps/pbcs.dll/article?AID=/20080314/COMMENTARY/702895001/home.html

3. What is Climate Change/Global Warming?

Concerns if there were global warming:

• Ecosystem interactions between predator & prey may change

• Change in breeding times

• Human health issues for increased mosquito population.

• Rising sea levels

• Coral Reefs

3. What is Climate Change/Global Warming?

If Ice caps were to melt- Rising sea levels would be a concern to islands like the Maldives.

3. What is Climate Change/Global Warming?

Coral reefs, the nurseries of many marine species, would be killed by higher temperatures, or by a

lack of sunlight as sea level rises.

3. What is Climate Change/Global Warming?

• a volume that rapidly overflows local dumps.

Pollution Issues: An average person may produce a ton of refuse in a year

4. Pollution

Types of Hazardous Wastes

• Dyes, Cleaners, Solvents

• PCB’s (Polychlorinated biphenyls- from old electrical equipment)

• Plastics, Solvents, Lubricants, Sealants

• Toxic Heavy Metals ( Lead, Mercury, Cadmium, Zinc)

• Pesticides

• Radioactive Wastes

4. Pollution

-Over 85,000 synthetic chemicals are in use today, many now known to cause cancer & damage to the brain, nervous, reproductive & human hormonal systems.

-An estimated 3-4 million American Children live within one mile of at least one hazardous waste site. 

ToxicologyToxicology- The study of the harmful effects of toxins on organisms

Effects of Toxins on Health4. Pollution

Non- Renewable Energy

5. Use of Resources/ Burning Fossil Fuels

FUEL RESOURCESWhat is a sustainable energy source for the future???

Fossil Fuels- the remains of ancient organisms, changed

into coal, oil or natural gas. -central to modern lifestyle.

2 BIG Problems:(1) Supply is limited(2) Environmental Consequences

* March 2008- over 100$/barrel

Projected oil production:

http://www.almc.army.mil/alog/issues/JulAug99/MS406c2.jpg

5. Use of Resources/ Burning Fossil Fuels

Alternative Energy Sources(Renewable Energy)

• Nuclear Energy• Solar Energy• Wind Power• Biomass (methane, ethanol)• Hydroelectricity-water power• Geothermal Power- from inside the earth• Hydrogen Power- • Tidal Power- using water power for turbines• OTEC (Ocean Thermal Energy Conversion)

6. Sustainability

In Ecosystems- all things are connected

• To appreciate how an ecosystem works- think about other things depend on hundreds of individual parts.

• If one part is missing or breaks, the entire thing does not work.

BIOSPHEREBIOSPHERE

• The biosphere is the thin layer of the Earth’s crust with the atmosphere & ocean

layers that support LIFELIFE that includes: – All plant and animal life – The things that sustain life: air, soil and water. – It includes a variety of ecosystems that are

connected by natural cycles.

Biosphere- is composed of three parts:

• ATMOSPHEREATMOSPHERE – a light blanket of air enveloping the earth, with more than half its mass within 4 miles of the surface and 98% within 16 miles

• HYDROSPHEREHYDROSPHERE --- the surface and subsurface waters in oceans, rivers, lakes, glaciers, and groundwater,

• LITHOSPHERELITHOSPHERE --- the upper reaches of the earth's crust containing the soils that support plant life, the minerals that plants and animals require for life and the fossil fuels and ores that humans exploit.

Earth Age: About 4.5 Billion Years OldLocation: In the Solar System, on the outer edge of the Milky Way, about 28,000 light

years from the galactic center

Some Earth Facts:Some Earth Facts:

• Highest Point: 29,028 feet above sea level, Mount Everest, formed 60 million years ago, located on the border of Tibet &Nepal in the Himalayas (Asia).

• Lowest Point (on Land): 1,320 feet below sea level, Dead Sea, (middle east) It is so salty -- the saltiest on Earth -- that it is unable to support anytype of life.

• Deepest Point on Earth: 35,802 feet, Mariana Trench in the Pacific Ocean. The water pressure there is over eight tons per square inch.

• Surface Data: 70% covered by water, with the remaining 30% composed of the

77continental land massescontinental land masses..• Water Composition: • 97% salt water, 3% fresh water

– (about 2% Is glaciers/ice & only.3% of all water is usable).

• Air Composition:

• 78% nitrogen, • 21% oxygen, • 1% other content

Some Earth Facts:Some Earth Facts:

Hierarchical Levels of Organization-

EcologyEcology• Just like the hierarchy of levels of

organization in organisms, there are also levels of increasing complexity in the environment.

• Each level has unique properties that cannot be identified just by studying a lower level.

• Each level is influenced by the other levels.

Levels of Organization

• ORGANISM -Simplest Level of Organization (1 living thing)

• POPULATION- Includes all the members of the same species - that live in one place at a given time & make-up a breeding group.

• COMMUNITY- Includes all the interacting populations in one area.

• ECOSYSTEM- Includes all the living (biotic) & non-living (abiotic) factors in the environment.

• BIOSPHERE- Thin layer of life around the earth.

Levels of Organization

• Examples of populations:

All the bacteria of one All the gorillas of 1kind on this agar plate species on this mountain

Example of community: All the organisms livingTogether in this pond

A Changing Environment

• Abiotic Factors Abiotic Factors do not remaindo not remain constant constant• Organisms are able to survive in a range of

conditions. • Most individuals can survive average conditions

Tolerance CurveTolerance Curve• A graph showing performance vs. values for

a specific variable such as temperature for a species. (See page 364 textbook)

Example: Some bacteria can survive boiling water, some plants can survive arctic cold. But- Most organisms can not survive BOTH extremes.

AcclimationAcclimation• Some organisms can adjust their

tolerance to abiotic factors.– Examples- YOU adapting to less oxygen in higher altitudes

– Goldfish, adapting to new water temperature

• Conformers- organisms that do not regulate their internal conditions– Examples- Lizards, cold blooded organisms

• Regulators- Organisms that use energy to control some of their internal conditions to optimum range in a variety of conditions.

Escape from unsuitable conditions

Ways organisms cope with changes:

• Dormancy

• Hibernation

• Estivating

• Migration

• Encysting

An Organism’s Relationship to the Environment

Niche- The way of life of an organism

-the status of an organism in its environment & community (affecting its survival as a species).

-a position particularly well suited to the organism that occupies it.

- An organism’s “PROFESSION”

- Includes both biotic and abiotic factors

The Niche includes:

• the range of conditions that the species can tolerate,

• the methods by which it obtains needed resources,

• the number of offspring it has, • its time of reproduction • and all its other interaction with its

environment.

Earthworm Niche

Generalists & Specialist Niches

GENERALIST are species with Broad Niches; they can tolerate a range of conditions and use a variety of resources.

example: opossum- eats a lot of different things

SPECIALIST. Species that have narrow Niches, such as the koala, who only eats 1 kind of leaf.

Energy Transfer: from producers to consumers

• Producers- are Autotrophs that manufacture their own food. (grass, plants, phytoplankton)

• Creates BiomassBiomass(all the organic material in an ecosystem)

• Biomass is the stored energy-stored energy- the foodfood for the rest of the organisms

• Consumers-

have to eat

something

(deer, bear)

http://www.ftexploring.com/ftimages2/dr_br1.gif

Net Productivity

• Measuring Productivity–Gross primary productivityGross primary productivity is the rate at

which producers in an ecosystem capture the energy of sunlight & organic compounds.

– The rate at which biomass accumulates is called

net primary productivity.net primary productivity.

– different BIOMES (Places w/ a distinct climate like the tropical rain forest or the desert) produce different amounts of biomass.

Food Chains and Food Webs

– A single pathway of energy transfer is a food chain.food chain.

– A network showing all paths of energy transfer is a food web.food web.

-Trophic level- -Trophic level- an organism’s relative position in the sequence of energy transfer in a food chain or web (who eats what)

• Producers …………………… very many in #• Primary Consumers …………….many• Secondary Consumers …………..fewer• Tertiary Consumers…………fewest # organisms

Food Chain & Food web in an Antarctic Ecosystem

Energy Transfer

– Ecosystems contain only a few trophic levelstrophic levels

because there is a low rate of energy transfer between each level.

Trophic levels

10s

100s

1000s

millions

Biochemical cycles:Biochemical cycles:• Matter must be recycled & reused.

• Water -evaporation, transpiration,& precipitation

• Carbon- photosynthesis, cellular respiration, role of autotrophs, consumers, decomposers

• Nitrogen-note role of Nitrogen-fixing bacteria & plants

• Calcium & Phosphorous- moves from rocks to soil to organisms to the oceans.

Your Assignments:• Draw each of the 4 cycles.• Label all parts of each drawing (40

points)

• Questions: Write in complete & legible sentences or I will not grade them:

• Answer 8 questions in sect. 4 (p 374)• Chapter review questions # 7-20 on page

376 ( 20 points)

Water cycle Carbon cycle

Nitrogen cycle