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Biology 20 Equilibrium in the Biosphere Ecology explain the one-way flow of energy through the biosphere and how stored biological energy in the biosphere is eventually “lost” as thermal energy explain how biological energy in the biosphere can be perceived as a balance between both photosynthetic and chemosynthetic, and cellular respiratory activities Ecology Study of the interactions between organisms and their physical environment and with each other. includes aspects of both the living (biotic) and non-living (abiotic) components of the physical environment. Biosphere Biosphere the part of the earth that is inhabited by organisms. 3 parts: 1 Lithosphere Land 2 Hydrosphere water 3 Atmosphere The gasses that surround the Earth. Living vs. Non-living There are two factors which make up the biosphere. Biotic Factors Living components of the biosphere plants and animals… Abiotic Factors Non-living components of the biosphere minerals, water, weather... Interactions Within the Biosphere Abiotic When a non-living factor affects a living factor. i.e. Biotic vs Biotic The weather affecting a living organism vs. Biotic When a living factor affects another living factor. i.e. Biotic Two organisms fighting for the same food. vs. Abiotic Abiotic vs. Abiotic Levels of Organization Levels of organization Cell Tissue Organ System Organism Population Ecosystem Biome Biosphere Community Levels of Organization Hierarchical Levels within the Biosphere Biosphere World Ecosystem Lake or River Community Lots of different species of organisms Population Lots of same species of fish Organism Fish Important Definitions Population: group of individuals of the same: species, place & time Community: populations of all species in an area Ecosystem: community and its biotic and abiotic factors interactions Biome: large scale ecosystems Can be found around the world tundra, grassland Food Chain a linear illustration that represents the step sequence of who eats whom in the biosphere. used to show: energy transfers cycling of matter through the biosphere Two types: Grazer: plant, herbivore, carnivore Detritus: organic waste Waste – scavengers – decomposers Assignment 1.1 Use your text book and define the following Terms Biodiversity Producer Consumer Read pages 8-10 (new text only) Do Questions 1-7 section 1.1 page 10 Equilibrium Unbalanced Autotrophs “self feeders” Require energy from sun – photosynthesis Convert energy from sun into a form of energy that other living things can use Provides O2 – required by all living things Provide basic molecules for life Carbohydrates, proteins, fats, and nucleic acids PRODUCERS! Heterotrophs Require a source of chemical energy and basic organic molecules NO photosynthesis Feed on plants OR other heterotrophs CONSUMERS! A primary consumer eats a producer A secondary consumer eats a primary consumer A tertiary consumer eats a secondary consumer… General Terms Herbivore An organism that only eats plants. Rabbit, squirrel Carnivore An organism that only eats animals. Wolf, Lion, Tyrannosaurus Rex Omnivore An organism that eats both plants and animals. Bear, Human More General Terms Scavenger An organism that feeds on dead organisms or the wastes of organisms. Vulture, Seagull, Decomposer An organism that breaks down organic wastes and the remains of dead organisms into simpler compounds such as: carbon dioxide ammonia Water Species At-Risk Species At-Risk Species At-Risk Indicator Species – A species sensitive to small changes in environmental conditions Describe why frogs and other amphibians are important indicator species: Frogs live in two different ecosystems Water as a tadpole In forest and grassland as adults Any hazards in either ecosystem will have an effect on the frogs. Also frogs occupy two different food chains. Why Are Frogs Disappearing? The worldwide disappearance of frogs is puzzling scientists around the globe. - Loss of Habitat • Frogs need wetlands, ponds, or lakes with clean water to breed and lay their eggs. • They need a place where they can catch insects such as forest and fields. - Air and Water Quality Frogs can breath through their skin, pollutants can also pass through their skin. Acid of water also has an ability to reproduce. - Climate Change Climate change can cause important changes in local ecosystems. If the climate becomes drier frogs populations will decline. 4. Ultraviolet Radiation The thin skin of the frog is susceptible to ultraviolet radiation. The amount to UV radiation reaching Earth's surface is increasing because of damage to the protective ozone layer surrounding Earth. Biology 20 Ecology Energy and Matter Exchange 27 General Terms Ecosystem A community of organisms interacting with each other and with their nonliving surroundings. Autotrophs –Producers Heterotrophs - Consumers Input energy Biogeochemical Ecosystems are OPEN SYSTEMS. Energy and matter can flow in and out of system Cycles Energy Lost Ecosystem Models Explain the structure of ecosystem trophic levels, using models such as food chains and food webs Food chains Food Chain step sequence of who eats whom in the biosphere. used to show: energy transfers Characteristics: Energy is transferred from organism to organism Each time energy is transferred about 90% is lost as heat or used for life processes Food Chain Note that: the arrow points at the eater the arrows separate trophic (eating) levels Trophic Levels Trophic level: how far an organism is from the original energy source Plants – first trophic level Original When energy is from the sun an organism is ingested by another, energy is transferred Plant – mouse – owl Producer – primary consumer – secondary consumer (top carnivore) T1 – T2 – T3 Food Webs What would happen if we relied on deer for our food? In reality, a consumer relies on more than one food source If one source is scarce, consumer can eat more of something else Food web: a series of interlocking food chains more accurately represents energy pathways who eats whom… really Food Web ABCD represent different trophic levels. Level D represents the decomposers Laws of Thermodynamics Biosphere requires a constant flow of energy Energy flows one way through the biosphere following basic scientific principles called the laws of thermodynamics Laws of Thermodynamics First Law Energy can be changed in form, but not created or destroyed. (Law of conservation of energy) Energy input = Energy Output Second Law Any energy change results in loss of energy as heat Energy input desired energy + waste energy Energy Flow About 10% of the energy is transferred from one trophic level to the next. During any change, some of the energy is lost as waste energy or heat. Applied to an ecosystem, as energy flows through the community there is energy loss at each trophic level. Much of this loss is in the form of heat which is lost when food molecules are broken down in the cells. There would be less energy loss in the community if only herbivores fed on the producers Energy Flow in the Ecosystem •explain quantitatively, energy exchange in ecosystems, using models such as pyramids of energy , biomass, and numbers •explain the interrelationship of energy, matter and ecosystem productivity (biomass production) Ecological Pyramids Ecological pyramids illustrate the energy loss through the trophic levels Solar radiation transformed in plants Plants create chemical energy Plant eaten by consumer Energy lost at each transformation Higher trophic level = less energy available Number of trophic levels limited b/c of loss of energy Ecological Pyramids In ecological pyramids, Base -the producer populations Next Level - the primary consumers Higher levels and above -the secondary, tertiary etc. Ecological Pyramids Three types: Numbers: total number of organisms in each trophic levels Biomass: mass of dry tissue of organisms at each trophic level shows how mass decreases as you move up the food chain Energy: based on energy produced at each trophic level Ecological Pyramids Pyramid of Numbers Pyramid of Biomass Human Interference in the Ecosystem Fire Hunting and fishing Monoculture Pesticide usage and biological amplification (magnification) Fire Before the Europeans settlement, wildfires swept across the land. Fire destroys vegetation, returning nutrients to the soil Fire usually only destroys vegetation above ground. Allowing new growth. Fire prevents the over growth of aspen parkland into the grassland ecosystem Fire European settlement Impact upon grasslands. Fire control (More Aspen Parkland) Introduction of many new species of plants (Mustard, pepperfrass, Russian thistle, pigweed, and stinkweed) Hunting and fishing New technology has improved ways of finding animals. Which has resulted in: Over hunting and fishing Reducing the number of animals. Monocultures Monoculture: growing a single species of plant, excluding others Huge diversity of species on earth 6 - 15 million Ecological change = species extinction Humans = biggest change maker Monoculture Effects Impact? Humans rely on a small variety of species Other species being decimated At what cost? Loss of diversity Loss of possible cures Rainforests: needs soil not suited to human loses productivity in a few years Pesticides Pesticides used to kill pests mosquitoes - malaria pesticides in food chain accumulate causes loss of diversity. Example DDT: dichloro diphenyl trichloroethane developed as a biological weapon in WWII 1950’s - used as a pesticide for insects DDT also affects human pops found in breast milk came from sprayed crops animals that ate crops Banned in Canada and US in 1970’s Not banned in other areas - Mexico, Central America Continues to be produced as a cheap pesticide in poorer nations Biological amplification Pesticides accumulate at the top level of the pyramid toxins accumulate in fatty tissue not released in wastes accumulates each time you move up higher trophic level - higher concentration Biogeochemical cycles explain and summarize the cycling of carbon, oxygen, nitrogen, and phosphorus and relate it to the reuse of all matter in the biosphere explain water’s role in the matter cycles, using its chemical and physical properties explain how the equilibrium between gas exchanges in photosynthesis and cellular respiration influences atmospheric conditions
