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Ecology Ch 3, 4, 5, 6 Organization of Life Molecules – carbohydrates, nucleic acids, proteins, lipids, water, and other molecules necessary for life Cells – basic building block of life. Tissues – similar cells with similar functions grouped together. Organs and Organ systems – Tissues that form a specific function for the organism. Organization of Life - Ecology Individual – one organism Population – one species in a defined area Community – all biotic factors in a defined area Ecosystem – all biotic and abiotic factors in a defined area Biosphere – all biomes and ecosystems (EARTH) Ecosystem Structure An ecosystem is based on energy and nutrients available. One way flow. Inputs: sun, dissolved minerals Outputs: heat, loss of minerals Order of feeding relationships: trophic levels. Some organisms are in one specific level, others can be multilevel. Ecosystem Structure Main Energy Source: Sunlight 1) Primary Producers (Autotrophs): Photosynthesizing Organisms convert radiant energy to chemical energy. CO2 + H2O C6H12O6 + O2 Ecosystem Structure 1)Primary Producers: Chemiosynthesis – a process of generating organic molecules from inorganic substances (Nitrogen and Sulfur compounds) Few bacteria: nitrogen fixing bacteria and archaebacteria Ecosystem Structure 2) First Level Consumers (heterotrophs): herbivores – animals that eat plants (gophers, squirrels) parasites – insects that harm plants (grubs) detrivores – animals that eat decaying organic matter. (earthworms) ! decomposers – fungi and bacteria that eat on dead material All feed on producers Ecosystem Structure 3) Second Level Consumers (heterotrophs): Carnivores – Omnivores – Parasites – Detritivores – Decomposers – All feed on first level consumers! Ecosystem Structure 4) Third Level Consumers (heterotrophs): Carnivores – Omnivores – Parasites – Detritivores – Decomposers – All feed on Second Level Consumers! Ecosystem Structure 5) Fourth Level Consumers (heterotrophs): Top Carnivores – Parasites – Detritivores Decomposers – All feed on Third Level Consumers! Food Web VS. Food Chain? Food Chain – A straight sequence from producer to 4th level consumer. Food Web – several food chains cross – connecting with each other. Energy Flow Energy flows from producers to top level carnivores. Energy transfer is never 100%. Some is lost as heat. Ecosystems will never be more than 4 or 5 trophic levels. Energy transfers are only one way. Warm – Up 1. Give an example of an organism in each trophic level: 1. 2. 3. Primary producer, primary consumer, secondary, tertiary, and quartinary consumers Explain how decomposers, detrivores, and parasites fit into the ecosystem. What is the primary source of energy and is it cyclic or one-way flow? Ecological Pyramids Biomass – depicts the mass of organisms at each trophic level for an ecosystem. Can be an upside down in an aquatic ecosystem due to primary producers having less biomass (algae or phytoplankton) Ecological Pyramids Energy – shows how energy changes from each trophic level. Only 10% of energy will be transferred. The rest is lost as heat. Always a traditional pyramid shape. Numbers – shows how many organisms are at each level. Will not always be a traditional pyramid shape. Energy Pyramid Biomass Pyramid Numbers Biogeochemical Cycles Biogeochemical Cycles Water Cycle Carbon Cycle Nitrogen Cycle Sedimentary Cycles Success of an Ecosystem Primary Productivity Limiting Nutrients Example: Nitrogen – cause algal blooms Community Interactions and The Biosphere Ecosystem Biotic Factors – all living organisms in an ecosystem. Abiotic Factors – all nonliving substances in an ecosystem These determine survival and growth of an organism and the productivity of the ecosystem. Warm-UP Describe a commenalistic, parasitic, and mutualistic relationship Habitat – place where an organism lives. Several organisms may have the same habitat. Niche – activities, relationships, and resources needed for survival and reproduction. EX: temperature needed, pH levels, place in the food web, competition, time of the year it reproduces, time of the year it hibernates or migrates, and any other characteristic for the survival of the organism. Competition When organisms of the same or different species attempt to use the same ecological resource. Adaptations occur to help organisms compete in the same ecosystem. Ex: Resource Partitioning. Can suppress growth of populations. Competitive Exclusion Principle No two species can occupy the same niche in the same habitat at the same time. Interactions Commensalism – one species benefit, the other neither helped or harmed. Mutualism – both species benefit Parasitism – one species benefit, the other is harmed. Interactions Predator / Prey: one consumer hunts another May control population size of prey. Unique defense adaptations of prey. Unique adaptations of predators.Horned Toad (Short-Horned Lizard) -- Animal Videos -- National Geographic Succession Ecosystems change in response to natural and human disturbances. Ecosystems begin with pioneer species: colonizers of vacant habitats, high dispersal rates, grow fast, and have high reproduction rates. Ex: Lichens Stronger competitor species come to replace pioneer species. Succession Primary Succession – pioneer species inhabit a barren habitat. Ex: new volcanic island, new land after glacier retreat. Pioneer species break rock, release nutrients to make way for grasses and flowering plants. Soon more species of seeds arrive some with nitrogen fixing bacteria. Over time wastes and dead material accumulate to add nutrients. Mt. St. Helen’s after disaster and during recovery. Succession Secondary Succession – a disturbed area within a community recovers and moves toward a climax state. Ex: abandoned fields, burned forests. Climax – pattern model: a community is adapted to many environmental factors – topography, climate, soil, wind, interactions, common disturbances. Populations How Populations Grow There are three important characteristics of a population 1. Geographic Location 2. Density 3. Growth rate How Populations Grow Population Density the number of individuals per unit area Geographic location where are they Growth rate how fast are they growing Population Growth Three factors that affect population size 1. The number of births 2. The number of deaths 3. And the number of individuals that enter or leave the population Population Characteristics Immigration the movement of individuals into an area Emigration the movement of individuals out of an area Types of Growth Exponential Growth occurs when the individuals in a population reproduce at a constant rate. Under ideal conditions with unlimited resources, a population will grow exponentially J - curve Types of Growth Logistic growth occurs when a population’s growth slows or stops following a period of exponential growth As resources become less available, the growth of a population slows or stops S - curve Types of Growth Carrying capacity the largest number of individuals that a given environment can support Population Characteristics Limiting – Factor: something that causes populating growth to decrease. Two types: density dependent factors and density independent factors. Density Dependent Factors These factors are limiting only when the population density reaches a specific level. (too many for ecosystem to support) Competition, predation, parasitism, and disease Density – Independent Factors These factors are limiting on all populations regardless of size. Unusual weather, natural disasters, seasonal cycles, human activity. Human Population Growth Increases over time – yet showing exponential growth Most advanced countries have shown demographic transition – death rate and birth rate are equal – no population growth Can analyze a population using an age structure diagram. Humans and the Biosphere Biodiversity All different organisms of this biosphere. Human activity can reduce biodiversity by altering habitats, hunting species to extinction, introducing toxic compounds into food webs, and introducing foreign species to new environments. Habitat Alteration Land development destroys habitats. Habitat fragmentation – splits ecosystems to several sections. Reduces number and variety of organisms that can survive. Pollution Organism can ingest toxic compounds if they are introduced into the water or soil of an ecosystem Biological magnification – concentrations of a harmful substance increases in organisms at higher trophic levels in a food chain or food web. DDT, Hg Introduced Species Invasive species – rapidly reproducing species of organisms that are not indigenous to the ecosystem. Has no natural predators to keep them in check. Nutrias, zebra mussels, leafy spurge Conservation Biology The application of wise management of natural resources, including the preservation of habitats and wild life. Protecting entire ecosystems as well as individual species. Focus on ‘hot spots’ places where large numbers of habitats and species are in immediate danger of extinction due to humans Questions for thought. What is our role as a species in this biosphere? Do we have the right to use the natural resources and destroy ecosystems? Find an article that deals with conservation Biology