* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Chapter 3: Matter, Energy and Life
Survey
Document related concepts
Photosynthesis wikipedia , lookup
Biological Dynamics of Forest Fragments Project wikipedia , lookup
Pleistocene Park wikipedia , lookup
Restoration ecology wikipedia , lookup
Triclocarban wikipedia , lookup
Ecological resilience wikipedia , lookup
Human impact on the nitrogen cycle wikipedia , lookup
History of wildlife tracking technology wikipedia , lookup
Natural environment wikipedia , lookup
Ecosystem services wikipedia , lookup
Renewable resource wikipedia , lookup
Transcript
Lecture #2 How Ecosystems Work Biosphere Breakdown Organism-any form of life (1 individual) Species- all organisms of the same kind that are genetically similar enough to breed in nature and produce live, fertile offspring Population-individuals of the same species in an area Biological Community-populations of different species living & interacting in a given area Ecosystem-many interacting communities in a specific place including abiotic factors Biome- large terrestrial regions characterized by a distinct climate & specific life–forms, especially vegetation, adapted to the region Ecosphere-(=biosphere)-all of Earth’s biomes together What drives an ecosystem? • Photosynthesis is at the base of all ecosystems so photosynthesizers (usually plants) are called the producers. • Productivity - the amount of biomass produced in a given area in a given period of time. Photosynthesis is called primary productivity because it is basic to all other growth in an ecosystem. • Secondary productivity - manufacture of biomass by organisms that eat plants From Species to Ecosystems • Ecosystem - biological community (biotic factors) and its physical environment (abiotic factors) – The elements are interacting to process energy and cycle materials – Most ecosystems are open in that they exchange materials and organisms with other ecosystems. – It is difficult to define the boundaries of an ecosystem. Major Components of Ecosystems Major components of aquatic ecosystems. © Brooks/Cole Publishing Company / ITP Food Chains and Food Webs Food Chain - A sequence that shows the manner in which energy is transferred from one organism to another , as each organism eats another, in an ecosystem. • Food web –a complex of interconnected food chains in an ecosystem. • These show the many feeding relationships in an ecosystem. • In an ecosystem of average complexity, numerous pathways are possible. • Food webs are a more realistic model of the flow of energy and materials through an ecosystem. Trophic pyramids • Food Chains can also be represented by an ecological pyramid by arranging the organisms at various trophic levels diagrammatically. • Notice that there are many more producers than consumers. • Each trophic level consists of organisms that get their energy in the same way. Which organisms make up each trophic level? • Plants (producers) make up the first trophic level. Animals are consumers. • 2nd trophic level: Primary Consumers:- Animals that eat plants. • 3rd trophic level: Secondary Consumers- Animals that eat primary consumers • 4th trophic level: Tertiary consumers- Animals that eat secondary consumers * Organisms may occupy more than one trophic level! • Organisms can also be identified by the type of food they consume: • What they eat Examples – Herbivores (Plants) {Deer} – Carnivores (Meat) {Wolves} – Omnivores (Plants/Meat) {Bears} – Scavengers (Carcasses) {Crows} – Detritivores (Debris) {Ants} – Decomposers (All) {Bacteria} Ecological Pyramids & Energy Transfer • Due to the Second Law of Thermodynamics, energy is lost at each level of the pyramid. • 10% Rule (Energy / Biomass) - as an organism is consumed, about 90% of the energy at each trophic level is lost or used up along the way (as heat in metabolic processes). • Only about 10% of the energy becomes part of the consumers body. • This 10% is all that is available to the next trophic level when one organism consumes another. Examples » 1 kg fox » 10 kg rabbit » 100 kg clover