Unit 2 · Segment 1: Organisms and Nonliving Things Are Made of Atoms · printed p. 40 (PDF p. 76)
Energy and Matter in Ecosystems
Over a period of five years, a local park has grown a lot, acquiring an incredible amount of new matter and energy.
Anchoring phenomenon
Chapters
- 04 Capturing the Sun's Energy
Where do producers get the matter and the energy they use to build their bodies, and how does that supply reach every other living thing?
1 presentation10 worksheets3 labs - 05 Using Stored Energy
How do living things get usable energy and building materials out of food, and where does the matter go?
1 presentation10 worksheets3 labs - 06 Food Webs and Trophic Pyramids
How do matter and energy move through an ecosystem, and why does matter come back around while energy does not?
1 presentation10 worksheets3 labs - 07 Global Cycles of Matter
How does the same matter keep moving through Earth's living and nonliving parts, and what happens to the cycles when people change them?
1 presentation10 worksheets3 labs
Standards in this unit
Unit vocabulary
matterAnything that has mass and takes up space. Matter is made of atoms, and living bodies are matter too.Chapter 4
producerAn organism that builds its own food from simple substances in its surroundings, usually using the energy of light. Plants, algae and cyanobacteria are producers.Chapter 4
photosynthesisThe chemical reaction in which a producer uses light energy to rearrange the atoms of carbon dioxide and water into sugar and oxygen.Chapter 4
chloroplastA tiny green structure inside the cells of plants and algae where photosynthesis takes place. One leaf cell can hold dozens of them.Chapter 4
chlorophyllThe green pigment inside chloroplasts that absorbs light energy. It absorbs red and blue light strongly and green light less strongly, so more green light bounces back to your eye.Chapter 4
reactants and productsIn a chemical equation, the reactants are the substances that go in (written before the arrow) and the products are the substances that come out (after the arrow).Chapter 4
starchA storage molecule made of many sugar units linked in a chain. Producers pack it into roots, seeds and fruits to use when light is scarce.Chapter 4
celluloseA tough material made of long chains of linked sugar units. It forms the walls of plant cells and is the largest single ingredient of wood.Chapter 4
biomassThe total mass of living things, or of the material they are made of. Biomass holds both matter and stored chemical energy.Chapter 4
biofuelA fuel made from biomass, such as plant waste or used cooking oil. Burning it releases the chemical energy that producers stored, and its carbon was pulled from the air by producers recently, not millions of years ago.Chapter 4
criterionA goal that a design should meet as well as possible; a way to judge how good a solution is. The plural is criteria.Chapter 4
constraintA limit that a design must stay inside, such as a cost ceiling or a rule that the source must be renewable.Chapter 4
producerAn organism that makes its own food. Most producers, such as plants and algae, build sugar from carbon dioxide and water using energy captured from sunlight; a few, such as some deep-sea bacteria, use chemical energy instead.Chapter 5
consumerAn organism that cannot make its own food, so it must take both its matter and its energy from other living things, either by eating them or by soaking up their molecules.Chapter 5
chemical energyEnergy held in the arrangement of atoms in a molecule. Reactions that rearrange atoms into new molecules can store this energy or release it.Chapter 5
cellular respirationThe series of reactions inside cells that combines sugar with oxygen, rearranging the atoms into carbon dioxide and water and releasing energy the cell can use.Chapter 5
mitochondrionA structure inside plant cells, animal cells and many single-celled organisms where most of the steps of cellular respiration take place. (Plural: mitochondria.)Chapter 5
reactantA substance that goes into a chemical reaction and is changed by it. Cellular respiration has two reactants: sugar and oxygen.Chapter 5
productA substance formed by a chemical reaction. The products of cellular respiration are carbon dioxide and water.Chapter 5
digestionThe breakdown of food into molecules small enough to pass into the blood. It begins in the mouth, continues in the stomach and is mostly completed in the small intestine.Chapter 5
carbohydrateA molecule made of carbon, hydrogen and oxygen that stores energy or builds structure. Sugars are single units or pairs of units; starch, glycogen and cellulose are long chains of sugar units.Chapter 5
glycogenA complex carbohydrate that animals build from spare sugar and keep in the liver and muscles as a short-term energy reserve.Chapter 5
fatAn energy-rich molecule used for long-term energy storage and, together with its close relatives, for building cell membranes. Fats that are liquid at room temperature are called oils.Chapter 5
proteinA large molecule built from smaller units called amino acids. Proteins form muscle and other structures, move materials into and out of cells and speed up reactions.Chapter 5
food webA model of the feeding connections among the populations in an ecosystem. Each arrow runs from a food source to the organism that eats it.Chapter 6
food chainOne single path through a food web, starting at a producer and following the arrows to an organism that nothing in the model eats.Chapter 6
producerAn organism that builds its own food from carbon dioxide and water using energy from sunlight. Plants, algae and phytoplankton are producers.Chapter 6
consumerAn organism that gets its matter and energy by eating other organisms, their wastes or their remains.Chapter 6
decomposerA consumer, such as a soil bacterium or a fungus, that feeds on wastes and dead remains and releases simple substances that producers can take up again.Chapter 6
trophic levelA feeding step in a food chain. Producers are the first level, the organisms that eat producers are the second, and so on upward.Chapter 6
trophic pyramidA stacked model of a food chain's levels, producers at the bottom, in which the width of each layer shows how much energy (or biomass) that level receives.Chapter 6
biomassThe total mass of living matter in a group of organisms, such as all the producers in a meadow. Scientists usually measure it dry, with the water removed.Chapter 6
ten-percent rule of thumbThe approximation that only about one tenth of the energy at one trophic level becomes stored energy at the next. Real values range widely around this average.Chapter 6
direct effectA change in one population caused by another population that eats it or is eaten by it, with no other population in between.Chapter 6
indirect effectA change in one population caused by another population acting through a third population that sits between them.Chapter 6
top predatorAn animal at the end of a food chain that no other animal in that model eats. Whether an animal counts as a top predator depends on which organisms the model includes.Chapter 6
law of conservation of matterOrdinary physical and chemical changes never create or destroy atoms. Seal a system so nothing gets in or out, and its total mass holds steady no matter how its contents change form.Chapter 7
closed systemA system that matter does not enter or leave. Energy can still cross the boundary. Earth is very nearly a closed system for matter.Chapter 7
reservoirA place where matter is stored for a time within a cycle, such as the atmosphere, the ocean, soil, living bodies, ice or fossil fuel deposits.Chapter 7
water cycleA model of how water moves among the air, land, oceans, ice and living things, changing among solid, liquid and gas along the way.Chapter 7
carbon cycleA model of how carbon atoms move among the air, water, soil, rocks and living things as parts of different molecules such as carbon dioxide, sugars and proteins.Chapter 7
cellular respirationThe process in the cells of plants, animals, fungi and bacteria that breaks down sugar with oxygen to release usable energy, giving off carbon dioxide and water.Chapter 7
combustionBurning: a fast chemical reaction between a fuel and oxygen that releases energy and sends the fuel's carbon into the air as carbon dioxide.Chapter 7
fossil fuelCoal, oil or natural gas: a fuel formed over millions of years from the remains of ancient organisms buried under sediment and rock and changed by heat and pressure.Chapter 7
nitrogen cycleA model of how nitrogen atoms move between nitrogen gas in the air, nitrogen compounds in soil and water, and the proteins and other molecules of living things.Chapter 7
nitrogen fixationChanging nitrogen gas, which most living things cannot use, into nitrogen compounds such as ammonia that living things can use. Soil and root bacteria do most of it; lightning and fertilizer factories also fix nitrogen.Chapter 7
reforestationGrowing a new forest on land that was cleared or burned. As the trees grow, photosynthesis moves carbon from the air into wood.Chapter 7
criteria and constraintsCriteria are the goals a solution must meet to count as a success. Constraints are the limits it must work within, such as cost, land, labor or laws.Chapter 7