Introduction to Ecology PDF

An Introduction To Ecology  Ecological Levels of Organisation /Biome/Biotic Community /Species  Other factors that affect an Ecosystem ◼ The area where an ◼ A niche is the full range of organism lives is called its physical and biologi...

An Introduction To Ecology  Ecological Levels of Organisation /Biome/Biotic Community /Species  Other factors that affect an Ecosystem ◼ The area where an ◼ A niche is the full range of organism lives is called its physical and biological habitat. conditions in which an organism lives and the way in ◼ Habitats provide which the organism uses populations of wildlife with those conditions. It is an food, water, shelter and organisms’ occupation in its space. habitat  Producers ◼ Producers are autotrophic organisms that make their own food. ◼ Phototrophic organisms use photosynthesis and contain chlorophyll (Carbon Dioxide + Water + Sunlight =Sugar + Oxygen) ◼ Chemotrophic organisms use chemicals other than H20, such as H2S PRODUCERS!!!  Consumers Consumers are heterotrophic organisms that cannot make their own food. They must ingest (eat) other organisms. 1.Herbivores feed on vegetation (producers). 2. Carnivores feed on herbivores or on other carnivores. ❖ Secondary carnivores feed on herbivores, ❖ Tertiary consumers feed on other carnivores 3. Omnivores feed on both producers and consumers 4. Scavengers feed on dead or decaying organisms CONSUMERS!!! Scavengers feed on CARRION (dead or injured animal corpses) and dead plant biomass. Scavengers reduce the size of dead organic matter…Decomposers will finish the job! DECOMPOSERS are heterotrophs that recycle small, often microscopic bits of dead organic matter into inorganic nutrients availbe for plants to take up from the soil. Decomposers RECYCLE nutrients! BACTERIA and FUNGI are decomposers…most worms are plant scavengers!  Energy in the Ecosystem ◼ Energy from the sun enters and ecosystem when producers used the energy to make organic matter through photosynthesis. ◼ Glucose is the primary energy source (carbohydrate) produced by photosynthesis. ◼ Consumers take in this energy when they eat producers or other consumers.  Energy in the Ecosystem ◼ Plants absorb less than 1% of the sunlight that reaches them! ◼ However, photosynthetic organisms make about 170 billion metric tons of food each year! ◼ The energy captured by producers is used to make cells in both producers and consumers.  TROPHIC LEVELS  Trophic levels are the different feeding levels of organisms in an ecosystem. Producers are the first trophic level and consumers make up several more.  These relationships can be seen in an ecological pyramid.  Biomass: the total amount of organic matter present in a trophic level. The biomass in each trophic level is the amount of energy- in the form of food- available to the next trophic level. The Ten Percent Law  Most of the energy that enters through organisms in a trophic level does not become biomass. Only energy used to make biomass remains available to the next level.  When all of the energy losses are added together, only about 10% of the energy entering one trophic level forms biomass in the next trophic level. This is known as the 10 percent law.  MORE Ten Percent Law  The 10 percent law is the main reason that most food chains have five or less links. Because 90 percent of the food chain’s energy is lost at each level, the amount of available energy decreases quickly. 10 PERCENT LAW!!  Heat and Movement Consumed Digested Growth Not Digested Waste Not Consumed Decomposers The majority of energy is lost via heat and movement!  Ecological Pyramids  Relative amounts of energy are represented in an ecological pyramid: a diagram that shows the relative amounts of energy in different trophic levels in an ecosystem.  An ecological pyramid can show energy, biomass, or the number of organisms in a food web. Ecological Pyramid: Energy Shows the relative transfer of energy (joules) from one trophic level to the next. Ecological Pyramid: Biomass Shows the relative amounts of organic matter (gram) from one trophic level to the next. Ecological Pyramid: Number of Organisms Shows the relative number of organisms at each trophic level.  Food Chains A Food CHAIN is a series of organisms that transfer food between the trophic levels of an ecosystem using only one species at each level…a simple chain.  The arrows represent the flow of energy from one organism to the next.  The arrow points toward the organism doing the ‘eating’. Food Chains Food Chains Food Chains Food Chains  Food Webs Ecosystems are not as simple as shown and not often explained by a single food chain… Food WEBS more accurately show the network of food chains representing the feeding relationships among organisms in an ecosystem.  Most organisms feed on more than one type of organism at different trophic levels. RELATIONSHIPS IN THE ECOSYSTEM Effect of interaction on growth rate of : Name of Interaction Population/ Population/ Species A Species B Neutralism (is this really 0 0 interaction?) Commensalism (table scraps) 0 + Mutualism or synergism + + 0 - Ammensalism + - Parasitism, predation - - Competition RELATIONSHIPS IN THE ECOSYSTEM RELATIONSHIPS IN THE ECOSYSTEM RELATIONSHIPS IN THE ECOSYSTEM RELATIONSHIPS IN THE ECOSYSTEM RELATIONSHIPS IN THE ECOSYSTEM RELATIONSHIPS IN THE ECOSYSTEM RELATIONSHIPS IN THE ECOSYSTEM RELATIONSHIPS IN THE ECOSYSTEM RELATIONSHIPS IN THE ECOSYSTEM RELATIONSHIPS IN THE ECOSYSTEM RELATIONSHIPS IN THE ECOSYSTEM RELATIONSHIPS IN THE ECOSYSTEM RELATIONSHIPS IN THE ECOSYSTEM