ECOLOGY AND HUMAN IMPACT ON ECOSYSTEMS

Mrs. Woytowich Regents Biology

OBJECTIVESUpon completion of this unit students will be able to: 

1. List the abiotic factors in an environment.2. Differentiate the types of symbiotic relationships.3. Describe the feeding relationships in an ecosystem by using food web, food

chain and competition.4. Explain the flow of energy using energy pyramids, biomass and food webs.5. Describe the biogeochemical cycles (water, nitrogen, carbon and oxygen).6. Describe the conditions needed for s self-sustaining environment.7. Explain ecological succession. 8. Describe the major biomes’ climate, location and dominant organism type.9. Discuss the importance of human population control.10. Describe the problems that can arise from importing organisms. 11. Describe how human impact has damaged the environment.12. List the major types of pollution and how they damage the environment.13. Discuss biological methods of pest control. 14. Describe some of the efforts being made to control pollution.

KEY WORDS 1. abiotic

2. biomass

3. biotic

4. carrying capacity5. consumer6. decomposer

7.  nonrenewable resources

8. parasitism

   9. producer

10. recycling

  11. renewable resources

12. urbanization

I. INTRODUCTION•The earth is home to trillions of different organisms, all of which cannot survive alone. All organisms (including humans) must interact with both living and nonliving things that surround them.•Ecology is the study of how ORGANISMS INTERACT WITH THE LIVING AND NONLIVING THINGS THAT SURROUND THEM

II. LEVELS OF ORGANIZATION•The environment is organized into levels, from largest to smallest: BIOSPHERE BIOME ECOSYSTEM COMMUNITY POPULATION ORGANISM•The BIOSPHERE includes the part of the earth that supports life, and includes some space above and below the earth’s surface!•A BIOME is a group of ecosystems that have the same climate and similar dominant communities (for example, the taiga, desert, deciduous forest, etc.)•An ecosystem is otherwise known as AN ECOLOGICAL SYSTEM

•Ecosystems are made up of BIOTIC FACTORS and ABIOTIC FACTORS:

BIOTIC 

ABIOTIC

ALL LIVING THINGS THAT AFFECT AN ORGANISM; FOR EXAMPLE, BIRDS, FISH, FLOWERS

THE PHYSICAL AND CHEMICAL CHARACTERISTICS OF THE ENVIRONMENT; FOR EXAMPLE, WATER, SAND, AND CFC’s

•A COMMUNITY involves all interacting species of an area (for example, all of the organisms in Colonie)•A POPULATION includes all of the members of a single species that live in one place at one time (for example, all of the frogs in The Crossings Pond in 2005)•The simplest level of organization in ecology is the ORGANISM, an individual living thing.

http://www.cals.ncsu.edu/course/ent425/images/tutorials/ecology/trophic_levels/foodweb.gif

III. ENERGY FLOW•AUTOTROPH – ORGANISM THAT MAKES ITS OWN FOOD; SOURCE OF FOOD FOR HETEROTROPHS•HETEROTROPH – MUST OBTAIN THEIR FOOD FROM THE ENVIRONMENT; MUST CONSUME OTHER ORGANISMS•The main source for life on earth is SUNLIGHT, therefore the AUTOTROPHS, which make their own food using the sunlight and/or chemicals, are also known as PRODUCERS, because they not only produce their own food, but provide food to the HETEROTROPHS •You see, the heterotrophs EAT the autotrophs, and are therefore known NOT as producers (because they don’t produce food), but CONSUMERS

http://weedeco.msu.montana.edu/class/LRES443/Lectures/Lecture20/FoodWeb.JPG

•There are different types of heterotrophs:

HERBI-VORES

CARNI-VORES

OMNI-VORES

DETRI-VORES

DECOM-POSERS

ONLY EAT

PLANTS 

EAT ANIMALS

EAT PLANTS

AND ANIMALS

FEED ON REMAINS

AND DEAD

MATTER

BREAK DOWN

ORGANIC MATTER

http://www.alaska-in-pictures.com/data/media/4/eagle-scavenger_836.jpg http://www.geography4kids.com/files/art/land_chain4_240.jpg

•Energy flows through an ecosystem in one direction, from the sun or inorganic compounds to AUTOTROPHS to HETEROTROPHS•FOOD CHAINS show a series of steps in which organisms transfer energy by eating and being eaten:

A FOOD WEB shows the complex feeding relationships between several organisms, and are more intricate than food chains:

•Each step on a food chain or food web is called a TROPHIC LEVEL•Each consumer depends on the TROPHIC LEVEL below it for energy, and AUTOTROPHS are always on the first level•About 10% of the energy available within one trophic level is available to the next•A BIOMASS/ECOLOGICAL PYRAMID illustrates the amount of living organic matter at each trophic level. Since autotrophs make their own food and are PRODUCERS, they are the most numerous organisms, and are ALWAYS found at the BOTTOM of a biomass/ecological pyramid:

http://www.vtaide.com/png/foodweb/xfoodchains.gif

IV. RECYCLING AND REUSING MATERIALS•Unlike energy, MATTER is recycled within and between ecosystems.•The WATER, CARBON, NITROGEN, and PHOSPHATE cycles are ways that matter is recycled through ecosystems:

http://www.globalchange.umich.edu/globalchange1/current/lectures/kling/carbon_cycle/carbon_cycle.jpg

V. CLIMATE AND THE GREENHOUSE EFFECT

•Several environmental factors combine to produce weather and climate.•Weather – DAY TO DAY CONDITION OF EARTH’S ATMOSPHERE AT A CERTAIN TIME AND PLACE•Climate – AVERAGE YEAR TO YEAR CONDITIONS OF A PARTICULAR REGION•Greenhouse gases include CARBON DIOXIDE (CO2), METHANE,

WATER VAPOR, AND OTHER GASES•The greenhouse gases NATURALLY trap heat energy of sunlight inside the earth’s atmosphere to keep the earth habitable.•However, many scientists believe that due to human activities that increase the amounts of certain greenhouse gases, such as BURNING FOSSIL FUELS AND DEFORESTATION too much of the greenhouse gases is causing global warming. The carbon cycle cannot remove the CO2 fast enough!

Sunlight

Atmosphere

Some heat escapesinto space

Greenhousegases trapsome heat

VI. HABITAT vs. NICHE•An organism’s habitat is NOT the same as its niche.•For example, a bacteria’s habitat may be THE SOIL but its niche may be as a DECOMPOSER•You see, an organism’s niche is its ROLE, its occupation in a certain environment, if you will. An organism’s habitat is THE AREA WHERE AN ORGANISM LIVES or its ADDRESS•The biotic and abiotic factors determine an organism’s niche. A niche includes the type of FOOD IT EATS, how it OBTAINS THE FOOD, and which other organism eat the organism in question.•RULE: NO TWO SPECIES CAN SHARE THE SAME NICHE IN THE SAME HABITAT but different species can occupy niches that are very similar. For example, the warbler species.

Bay-Breasted WarblerFeeds in the middlepart of the tree

Cape May WarblerFeeds at the tips of branchesnear the top of the tree

Yellow-Rumped WarblerFeeds in the lower part of the tree andat the bases of the middle branches

VII. COMMUNITY INTERACTIONS

A.                   Competition•Competition occurs when ORGANISMS OF THE SAME OR DIFFERENT SPECIES ATTEMPT TO USE THE SAME RESOURCE AT THE SAME PLACE AND TIME•A resource refers to any necessity of life. Think of some of YOUR resources.•COMPETITIVE EXCLUSION PRINCIPLE - NO TWO SPECIES CAN OCCUPY THE SAME NICHE IN THE SAME HABITAT AT THE SAME TIME

http://www.kruger2canyons.com/images/antelopehist.jpg

B. Predation•Predation is when one organism CAPTURES AND FEEDS ON ANOTHER ORGANISM•The killer is the PREDATOR and the killed is the PREY

http://www.biologycorner.com/resources/harelynx.jpg

http://tiee.ecoed.net/vol/v4/experiments/insect_predation/img/dragonfly%5BHR%5D.jpg

A dragonfly consumes a plant-feeding stinkbug. The image illustrates prey capture ability and prey defenses, which are effective against some predators but not others. The photograph was taken by W. Wyatt Hoback in 2003 while in Manaus, Brazil.

C. Symbiosis•Symbiosis means “LIVING TOGETHER”•There are three types of symbiotic relationships: 1. MUTUALISM – BOTH SPECIES BENEFIT For example, flowers depend on insects to pollinate them and certain insects need food…it’s a “win-win”!!

www.nearctica.com/ecology/pops/mutual.htm

2.             COMMENSALISM - ONE BENEFITS AND THE OTHER IS NEITHER HELPED NOR HARMED For example, barnacles attaching to whale skin. The barnacles benefit because they get food from the water moving past them, but the whale doesn’t really care either way, it doesn’t help or harm it!

http://www.learner.org/jnorth/images/graphics/u-z/gwhale_barnacles.jpghttp://www.mesa.edu.au/seaweek2004/images/whale01.jpg

3. PARASITISM – ONE BENEFITS WHILE THE OTHER IS HARMED Usually, the parasites do not kill their host, but just weaken it. For example, tapeworms living in the intestines of mammals. It benefits the tapeworm since it gets food, but can severely malnourish the host, plus its NASTY!!!! (Saturn cat story)

www.daviddarling.info/images/tapeworm.jpg http://instruction.cvhs.okstate.edu/JCFOX/HTDOCS/Disk1/Images/Img0059e.jpg

http://www.notsoboringlife.com/wp-content/uploads/2007/04/roundworms.jpg

http://scienceblogs.com/zooillogix/Hookworm.jpg

www.vcvikings.com

http://scienceblogs.com/zooillogix/Hookworm%20Foot.jpg

VIII. ECOLOGICAL SUCCESSION•Ecosystems are CONSTANTLY CHANGING in response to natural and human disturbances.

Biotic Factors

ECOSYSTEM

Abiotic Factors

•As an ecosystem changes, older inhabitants gradually die out and new organisms move in, causing further changes in the community (think of a fish tank)!•Ecological succession is the SERIES OF PREDICTABLE CHANGES THAT OCCURS IN A COMMUNITY OVER TIME•Succession generally happens SLOWLY (pond changing to a forest), but can happen FAST (clearing a forest).

http://www.earthhistory.org.uk/wp-content/modernecologicalsuccession.jpg

http://www.scienceclarified.com/images/uesc_10_img0552.jpg

IX. THE MAJOR BIOMES•Ecologists recognize at least TEN different biomes. Each of these biomes is defined by a set of abiotic factors (like climate) and has a characteristic ecological community.

Ten Major BiomesBiome Precipitation Temperature Soil Diversity Trees Grasses

Tropical Rain Forest high hot poor high dense sparse

Tropical Dry Forest variable mild rich moderate medium medium

Tropical Savanna variable mild clay moderate sparse dense

Desert low variable poor moderate sparse sparse

Temperate Grassland

moderate summer hot rich moderate absent dense

Temperate woodland and Shrubland

summer low, winter moderate

summer hot poor low medium medium

Temperate Forest moderate summer moderate, winter cold

rich high dense sparse

Northwestern Coniferous Forest

high summer mild, winter cold

rocky, acidic low dense sparse

Boreal Forest moderate summer mild, winter cool

poor, acidic moderate dense sparse

Tundra low summer mild, winter cold

poor low absent medium

X. POPULATION GROWTH

•Three important characteristics of a population are its GEOGRAPHIC DISTRIBUTIUON, DENSITY, AND GROWTH RATE•Geographic distribution – THE AREA INHABITED BY A POPULATION; RANGE•Density (aka population density) – NUMBER OF INDIVIDUALS PER UNIT AREA•Growth rate – HOW FAST/SLOW IT GROWS

•Three factors that affect population size are:o    # OF BIRTHSo    # OF DEATHSo    # OF INDIVIDUALS IMMIGRATING (ENTERING) AND EMIGRATING (LEAVING)

•Exponential growth occurs when the individuals in a population are REPRODUCING AT A CONSTANT RATE; under ideal conditions with unlimited resources, a population will grow exponentially.

Exponential growth

Steady population size

Steady population size

Rapid decline

Peak population size

•As resources become less available, the growth of a population SLOWS OR STOPS•The largest number of individuals that an environment can support is called CARRYING CAPACITY of that environment.

Carrying capacity

Time (hours)

CONCEPT MAP ON POPULATION GROWTH:

PopulationGrowth

can be

represented bycharacterized by characterized by represented by

which cause a

Exponentialgrowth

Logisticgrowth

Fallinggrowth rate

S-shapedcurve

Limits ongrowth

No limits on growth

J-shapedcurve

Constantgrowth rate

Unlimitedresources

XI. LIMITING FACTORS

•A factor that causes a population’s growth to decrease is called a LIMITING FACTOR•Examples of limiting factors include: HUMAN DISTURBANCES, DISEASE, PREDATION, AMOUNT OF LIGHT/WATER, COMPETITION•Limiting factors that depend on population size are called DENSITY-DEPENDENT LIMITING FACTORS and include parasitism, disease, competition, and predation.•Limiting factors that do not depend on population size, since they will affect all populations in similar ways, regardless of their size, are called DENSITY-INDEPENDENT LIMITING FACTORS and include natural disasters, seasonal changes, and human disturbances.

XII. THE EFFECT OF HUMANS ON THE BIOSPHERE•Among the human activities that have transformed the biosphere are HUNTING/GATHERING, AGRICULTURE, INDUSTRY, AND URBAN DEVELOPMENT•Environmental resources are classified as being RENEWABLE OR NONRENEWABLE

o RENEWABLE – CAN REGENERATE AND ARE REPLACEABLE; TREE, FRESH WATER O NONRENEWABLE – CANNOT BE REPLENISHED NATURALLY; OIL, GAS, OTHER FOSSIL FUELS•SUSTAINABLE USE is a way of using natural resources without depleting them.•Human activities affect the SUPPLY AND QUALITY OF RENEWABLE RESOURCES, such as land, forests, air and water.

•BIODIVERSITY is one of the Earth’s greatest natural resources.•Species of many kinds have provided us with FOODS, INDUSTRIAL PRODUCTS, MEDICINES•Human activity can reduce biodiversity by:

o    ALTERING HABITATSo    HUNTING SPECIES TO EXTINCTIONo    INTRODUCING TOXIC COMPUNDS INTO FOOD

WEBS INTRODUCING FOREIGN SPECIES INTOENVIRONMENTS

http://www2.warwick.ac.uk/about/environment/faqs/biodiversity.jpg

OZONE DEPLETION – OZONE LAYER THAT PROTECTS US FROM HARMFUL UV RAYS IS BEING DEPLETED, WHICH INCREASES THE RISK FOR SKIN CANCER, EYE DAMAGE, ETC.

Ozone absorbs 99% of the harmful ultraviolet (UV) radiation; Most of the harmful UV radiation will penetrate the atmosphere

http://js082.k12.sd.us/My_Classes/Physical_Science/Phys_Sci_ch_7/ozone_3.jpg&imgrefurl=http://js082.k12.sd.us/My_Classes/Physical_Science/Phys_Sci_ch_7/ozone_layer_depletion.htm&h=289&w=288&sz=14&hl=en&start=2&sig2=GuPYrwgVnTwRtUn7S4p6Xw&tbnid=Jcf6inn5WEv__M:&tbnh=115&tbnw=115&ei=qRZESMHbFpXWesTM0LoE&prev=/images%3Fq%3Dozone%2Bdepletion%26gbv%3D2%26hl%3Den%26client%3Dfirefox-a%26rls%3Dorg.mozilla:en-US:official%26sa%3DG

GLOBAL WARMING - INCREASED GREENHOUSE GASS IN THE ATMOSPHERE IS TRAPPING HEAT AND THUS INCREASING EARTH’S TEMP.

naturematters.wordpress.com/2006/11/

CONCEPT MAP ON HUMAN ACTIVITIES:

HumanActivities

that have changed the biosphere include

may have once caused often relies on the methods of thehave resulted in

which increased

Food supply Pesticide use Monocultureuse

Hunting andgathering Agriculture

Industrial growth

Urbandevelopment

Extinctions oflarge animals

Greenrevolution

High standardof living

Increasedpollution