Ecology Levels of Organization in Living Things A Look at Ecology as a science •  Ecology - study of interactions between biotic and abiotic factors of organisms in environmental systems – Biotic factors -living things (plants, animals, and decomposers) – Abiotic factors - nonliving things (air, water, sunlight, and land) Levels of Organization The Biosphere •  Living things are part of a whole The parts in levels of organization are: • Biosphere - the living world and all Biotic and Abiotic Factors that affect life within it –  –  –  –  –  –  –  –  The Biosphere Ecosystems = Biomes Communities Populations Organism Organ Systems Organs Tissues –  Cells Ecosystems = Biomes Ecosystems in Biomes •  Ecosystem – several types of living things live in environment and interact between themselves and nonliving surroundings •  Biome - global ecosystem located in a specific portion of the world •  A deer, rabbit, and all the plant populations that live in a grasslands area and the lake, air, and rocks are part of an ecosystem –  Deserts, oceans, and forests are examples of ecosystems and Biomes –  Biomes are characterized by the quantity of rainfall per year Communities Populations •  Community - made up of populations that interact with each other • Population - a group of organisms that mate with one another and live in the same place at the same time – Rabbits and hawks may be part of a community – There are many communities in a Biome – Communities may be separated by living or non-living matter (mountain or other boundaries are common) – A deer or several deer may belong to a population as long as it can interact with other deer in the same area Organisms Smaller Than Organisms • Organism - a specific species of plant, animal, bacteria, fungus or other living thing that lives in a specific area •  There are two types of organisms – You and I are both organisms So too can be said for my pet cat –  single cellular or multi-cellular organisms –  multi-cellular organisms have may be broken down into the following components: – Organ systems - a set of organs inside an organism that carry out a specific function (digestion, circulation, respiration, etc.) – Organ - a set of tissues connected tthat carry out a specific function for a living thing (an example of an organ may include the heart, the lung, the brain, etc.) Smaller Components Yet Organisms in Ecosystems •  Tissues - or more cells carry out a specific function for an organism •  Cell - the smallest unit of life that has all the characteristics of living things •  Habitat - the place where an organism lives •  Niche - the role a species has in its environment •  Cooperation and competition for biotic and abiotic parts of the environment is what ecology is about –  Habitat and niche are a function of both –  In multi-cellular organisms there are several types of cells located in different parts of the living organism that carry out specific functions Relationships Symbiosis • Symbiosis - a relationship where two or more organisms depend on each other for resources •  A relationship between two organisms where one organism benefits while the other is harmed - parasitism •  A relationship between two or more organisms in which both organisms benefit - mutualism •  A relationship in which one organism benefits but the other is neither harmed nor helped - commensalism – Resources serve an organism (such as food, shelter, etc.) Food and the Trophic Levels More About Feeding •  Trophic level - steps in the passage of energy and matter through an biotic and abiotic aspects of an ecosystem •  Matter and energy are passed from pieces of the living system through the feeder levels •  Levels of heterotrophs – –  Autotroph - uses energy from the sun or energy stored in chemical compounds to make its food (carbohydrates) –  Hetertroph - an organism feeds on other organisms – Primary consumers (herbivores) – Secondary consumers (eat herbivores) – Tertiary consumers (eat the organisms that eat herbivores) – Scavanger - a heterotroph that eats dead organisms – Decomposer - a heterotroph that breaks down and absorbs nutrients from dead organisms Primary, Secondary, Tertiary •  Carnivores eat meat and include secondary and tertiary consumers •  Herbivores eat plants and include primary consumers •  Omnivores eat everything and anything and include primary, secondary and tertiary consumers Energy Flow Energy Flows, Matter Cycles •  Food chain - linear flow of matter through an ecosystem •  Food web – non-linear flow of matter and food through an ecosystem •  Why does energy flow and matter cycle? •  Matter Cycles are part of the abiotic materials flow in an ecosystems: – Expresses all possible feeding relationships in each trophic level – Expressed at the community level within an ecosystem Water Cycle – Matter moves through ecosystems – How matter moves will determine how life can be supported within the system The Water Cycle •  Water cycles between the atmosphere, ocean and land •  All living things require water to maintain homeostasis •  The Cycle – –  Evaporation - vapors rise •  Transpiration – plants evaporate water through their leaves –  Condense – particles come together into clouds –  Precipitation – water particles drop out, and –  Percolation – water drains into and through the dirt The Water Cycle Continued The Water Cycle Continued •  Water's state (solid, liquid or gas) is determined mostly by temperature •  Surface Runoff –  The water cycle is determined then by the kinetic energy of the particles and thus is also determined by temperature •  The amount of water on Earth remains constant –  Much of the water that returns to Earth as precipitation runs off the surface of the land, and flows down hill into streams, rivers, ponds and lakes –  Small streams flow into larger streams, then into rivers, and eventually the water flows into the ocean –  Surface runoff is an important part of the water cycle because, through surface runoff, much of the water returns again to the oceans, where a great deal of evaporation occurs The Carbon Cycle The Carbon Cycle •  Carbon exists in the nonliving environment as: •  Carbon enters the biotic world through the action of autotrophs: – photoautotrophs – carbon dioxide in the atmosphere and dissolved in water – in rocks like limestone an coral – deposits of coal, petroleum, and natural gas derived from onceliving things – dead organic matter, e.g., humus in the soil •  plants, bacteria and algae •  Use energy of light to convert carbon dioxide to organic matter – photoautotrophs •  Bacteria •  Use chemical energy to convert substances into organic matter The Carbon Cycle The Carbon Cycle •  The Carbon cycle takes in carbon dioxide and water and produces oxygen and carbohydrates (sugar) • Carbon returns to the atmosphere and water by respiration •  This process is called primary productivity •  Since there is so much water on the earth, organisms in the ocean produce more oxygen and that ANY OTHER organism in the world – All living things respire –  Carbon dioxide, burning, decay all produce carbon dioxide (if oxygen is present) • Complete versus incomplete combustion The Nitrogen Cycle •  All life requires nitrogen-compounds for protein and nucleic acid production •  Air is made of 78% nitrogen (N2) –  Most organisms can’t use nitrogen in this form •  Plants get nitrogen by taking it and incorporating it into compounds such as: –  nitrate ions (NO3)ammonia (NH3), urea (NH2)2CO •  Animals get nitrogen compounds from plants (or animals that have fed on plants) •  Four processes participate in the cycling of nitrogen through the biosphere: –  nitrogen fixation, decay, nitrification, denitrification