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I. INTRODUCTION

This article provides an introduction to ecology, the study of how organisms interact with the living and nonliving things in their surroundings. It discusses the levels of organization in the environment, energy flow, recycling of materials, the greenhouse effect, and the difference between habitat and niche.

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I. INTRODUCTION

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  1. 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

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

  3. 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

  4. 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

  5. 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 • There are different types of heterotrophs: http://www.alaska-in-pictures.com/data/media/4/eagle-scavenger_836.jpg http://www.geography4kids.com/files/art/land_chain4_240.jpg

  6. 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:

  7. 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

  8. 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:

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

  10. 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!

  11. Sunlight Some heat escapes into space Greenhouse gases trap some heat Atmosphere

  12. 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.

  13. Cape May Warbler Feeds at the tips of branches near the top of the tree Bay-Breasted Warbler Feeds in the middle part of the tree Yellow-Rumped Warbler Feeds in the lower part of the tree and at the bases of the middle branches

  14. 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

  15. B. Predation • Predation is when one organism CAPTURES AND FEEDS ON ANOTHER ORGANISM • The killer is the PREDATORand the killed is the PREY http://www.biologycorner.com/resources/harelynx.jpg

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

  17. 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

  18. 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.jpg http://www.mesa.edu.au/seaweek2004/images/whale01.jpg

  19. 3. PARASITISM – ONE BENEFITS WHILE THE OTHER IS HARMEDUsually, 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

  20. www.vcvikings.com http://www.notsoboringlife.com/wp-content/uploads/2007/04/roundworms.jpg http://scienceblogs.com/zooillogix/Hookworm.jpg http://scienceblogs.com/zooillogix/Hookworm%20Foot.jpg

  21. VIII. ECOLOGICAL SUCCESSION • Ecosystems are CONSTANTLY CHANGING in response to natural and human disturbances. Abiotic Factors Biotic Factors ECOSYSTEM

  22. 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

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

  24. 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.

  25. 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 BIRTHS • o# OF DEATHS • o# OF INDIVIDUALS IMMIGRATING (ENTERING) • AND EMIGRATING (LEAVING)

  26. 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 Peak population size Rapid decline Steady population size Steady population size

  27. 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)

  28. Logistic growth Exponential growth S-shaped curve Limits on growth J-shaped curve No limits on growth Unlimited resources Constant growth rate Falling growth rate CONCEPT MAP ON POPULATION GROWTH: Population Growth can be characterized by represented by characterized by represented by which cause a

  29. 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.

  30. 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 USEis 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.

  31. BIODIVERSITYis 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: • oALTERING HABITATS • oHUNTING SPECIES TO EXTINCTION • oINTRODUCING TOXIC COMPUNDS INTO FOOD • WEBS INTRODUCING FOREIGN SPECIES INTO • ENVIRONMENTS http://www2.warwick.ac.uk/about/environment/faqs/biodiversity.jpg

  32. 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

  33. GLOBAL WARMING - INCREASED GREENHOUSE GASS IN THE ATMOSPHERE IS TRAPPING HEAT AND THUS INCREASING EARTH’S TEMP. naturematters.wordpress.com/2006/11/

  34. Industrial growth Urban development Hunting and gathering Agriculture Green revolution Extinctions of large animals Increased pollution High standard of living Monoculture use Food supply Pesticide use CONCEPT MAP ON HUMAN ACTIVITIES: Human Activities that have changed the biosphere include may have once caused often relies on the methods of the have resulted in which increased

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