6th grade Science vocabulary answers

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Unit 1

                                                              

Chapter 1

Section 1

  1. science: process of trying to understand the world around us.
  2. technology: use of knowledge gained through scientific thinking and problem solving to make products or tools people can use.

Section 2

  1. scientific method: step-by-step procedures of scientific problem solving; recognizing the problem, forming a hypothesis, testing the hypothesis, analyzing the data, and drawing conclusions.
  2. observation: bits of information that can be gathered through your eyes, ears, and senses of touch, taste, and smell.
  3. inference: conclusion based on an observation.
  4. hypothesis: statement that can be tested; based on observations, research, and prior knowledge of a problem.
  5. independent variable: the one factor changed by the person doing the experiment.
  6. dependent variable: factor being measured in an experiment.
  7. constant: factor in an experiment that does not change.
  8. control: standard used for comparison in an experiment.

                                                              

Chapter 2

Section 1

  1. measurement: way to describe the world with numbers; can describe objects and events with length, volume, mass, temperature, and rates.
  2. estimation: method of making a rough measurement.

Section 2

  1. SI: International System of Units, which was designed to give a worldwide standard of physical measurement for science, industry, and commerce and uses units such as the meter, cubic meter, kilogram, and kelvin.
  2. meter: SI unit of length.
  3. mass: amount of matter in an object.
  4. kilogram: SI unit for mass.
  5. Kelvin: scale that measures temperature in SI; begins at zero kelvin, which is the coldest temperature possible in nature.
  6. rate: ratio of 2 measurements with different units; (ex: miles per hour-mph).

Section 3

  1. table: tool used to display information in rows and columns so that it is easier to read and understand.
  2. graph: diagram that shows the relationship; tool used to collect, organize, and summarize data in a visual way so that it is easy to understand.
  3. line graph: tool used to show the relationship between 2 variables.
  4. bar graph: tool that uses bars to show the relationships between variables; can be horizontal or vertical and can display any numerical data.
  5. circle graph: tool used to show the parts of a whole.

                                                              

Chapter 3

Section 1

  1. matter: anything that has mass and occupies space.
  2. atom: small particle that makes up most types of matter and is made up of smaller parts called protons, neutrons, and electrons.
  3. law of conservation of matter: matter is neither created nor destroyed, only changed in form.
  4. electron: negatively charged particle found in a cloudlike formation surrounding an atom's nucleus.
  5. nucleus: positively charged, central part of an atom; directs all the activities of the cell and is surrounded by a double membrane.
  6. proton: particle in the nucleus of an atom that carries a positive charge.
  7. neutron: uncharged particle in an atom's nucleus.

Section 2

  1. element: naturally occurring or synthetic material that cannot be broken down to simpler materials by ordinary means, has a unique set of properties, and that is generally classified as a metal, a metalloid, or a nonmetal.
  2. atomic number: whole number that tells how many protons are in the nucleus of each atom of an element.
  3. atomic mass: number that tells how heavy an element's atoms are compared with atoms of other elements.
  4. isotope: two or more atoms of the same element that have different numbers of neutrons.
  5. mass number: sum of an atom's protons and neutrons.
  6. metal: elements that are malleable, ductile, generally have a shiny or metallic luster, and are not as good conductors of heat and electricity.
  7. nonmetal: elements that are usually dull and are poor conductors of heat and electricity.
  8. metalloid: elements that have characteristics of both metals and nonmetals, generally are brittle and dull, and are poor conductors of heat and electricity.

Section 3

  1. substance: sample of matter that has the same composition and properties throughout.
  2. compound: pure substance produced when elements combine, and whose properties are different from those of the elements from which it is formed.
  3. law of definite proportions: a given compound is always made of the same elements in the same proportion by mass.
  4. mixture: combinations of 2 or more substances that have not combined to form new, pure substances; can be uniform, where the individual parts cannot be seen, or nonuniform, where you can see individual parts.

                                                              

Chapter 4

Section 1

  1. physical property: properties, or characteristics, such as color, texture, and shape, that can be observed without changing the makeup of a material.
  2. state of matter: physical property of a sample of matter--solid, liquid, gas, or plasma.
  3. density: physical property that relates the mass of something to how much space it takes up; divide mass by volume.
  4. chemical property: characteristic of a substance, such as the ability to react with oxygen, that allows it to change to a new substance.

Section 2

  1. physical change: any change in the size, shape, or form of matter in which the makeup of the matter remains the same and only the physical properties change.
  2. chemical change: any change where one or more of the original materials changes into other materials.

Unit 2

                                                              

Chapter 5

Section 1

  1. energy: ability to cause change; can affect the temperature, speed, shape, or direction of an object.
  2. kinetic energy: energy of motion; influenced by an object's mass and speed and can be transferred from one object to another when objects collide.
  3. potential energy: energy that is stored and that comes from an object's position or condition.
  4. law of conservation of energy: energy cannot be created or destroyed but only transformed from one form to another.

Section 2

  1. temperature: measure of the average kinetic energy of the particles in any object; the greater the the average kinetic energy, the higher an object's temperature.
  2. thermal energy: total amount of kinetic energy of the particles in a material.
  3. heat: energy transfer due to a difference in temperature.
  4. radiation: energy that travels by waves in all directions from its source; transfer of energy by electromagnetic waves.
  5. conduction: transfer of thermal energy from particle to particle through a material when there is a temperature difference; transfer of energy that occurs when molecules bump into each other.
  6. convection: transfer of thermal energy that happens when particles move from one place to another where there is a temperature difference; occurs in gases and liquids.

Section 3

  1. chemical energy: energy stored within chemical bonds.

                                                              

Chapter 6

Section 1

  1. average speed: distance traveled divided by the time it takes to travel this distance.
  2. rate: ratio of 2 measurements with different units; (ex: miles per hour-mph).
  3. acceleration: rate at which speed or direction changes; can be found by dividing the change in speed by the given time.

Section 2

  1. gravity: attraction between all matter; a force that pulls on all objects that have mass.
  2. force: a push or a pull; can be measured by the amount of acceleration it can give a mass.  
  3. weight: downward pull of gravity on an object.
  4. normal force: upward force of the ground, perpendicular to the surface.
  5. balanced forces: forces acting on an object that cancel each other.
  6. inertia: measure of an object's ability to remain at rest or to keep moving.
  7. mass: amount of matter in an object.

Section 3

  1. Newton's law of motion: 3 rules describing how things move; 1.) an object will move with constant motions if no net force is acting on it. 2.) an object that has an unbalanced force acting on it will accelerate in the direction of the force. 3.) forces occur in equal but opposite pairs.
  2. friction: force that resists motion between 2 objects in contact and that always act opposite to the direction of motion.

                                                              

Chapter 7

Section 1

  1. work: occurs when a force produces movement parallel to the direction in which the force is applied; unit is the joule.
  2. power: measures the rate at which work is done in a certain period of time; unit is watt.

Section 2

  1. simple machine: machine that works with only one motion--inclined plane, lever, wheel and axle, and pulley.
  2. compound machine: combination of 2 or more simple machines.
  3. effort force: force applied to a machine..
  4. mechanical advantage: comparison of the effort force to the resistance force for a machine.
  5. inclined plane: simple machine that is a sloped surface, or ramp; allows heavy loads to be lifted by using less force over a greater distance.
  6. wedge: moving inclined plane with one or two sloping sides.
  7. screw: inclined plane wrapped around a shaft.
  8. lever: simple machine made from a rod or plank that pivots about a point.
  9. fulcrum: point about which a lever pivots.
  10. wheel and axle: simple machine made from 2 rigidly attached wheels that rotate together.
  11. pulley: surface, such as a wheel, that redirects force using  rope; simple machine that allows you to pull down to lift a weight.
  12. efficiency: ability of a machine to convert work input to work output; always less than 100% in real machines due to some loss to friction or heat.

Unit 3

                                                              

Chapter 8

Section 1

  1. plain: landform that is a large, flat area; interior and coastal plains make up 50% of all land areas in the US.
  2. plateau: landform that is a flat, raised area made of nearly horizontal rocks that have been uplifted by forces within Earth.
  3. folded mountain: mountains that are created when rock layers are squeezed from opposite sides and the layers buckle and fold.
  4. upwarped mountain: mountains that are formed when crust is pushed up by forces inside Earth, and the material on top of the crust is eroded to form sharp peaks and ridges.
  5. volcanic mountain: mountains that form when molten material reaches Earth's surface through a weak area of crust; pile up in layers and forms a cone-shaped structure.

Section 2

  1. equator: imaginary line at 0 degrees latitude that circles Earth halfway between the north and south poles and divides Earth into 2 equal halves.
  2. latitude: distance in degrees either north or south of the equator.
  3. prime meridian: imaginary line representing 0 degrees longitude; runs from the north pole through Greenwich, England, to the south pole.
  4. longitude: distance in degrees east or west of the prime meridian.
  5. International Date Line: transition line for calendar days, located at the 180 degrees meridian.

Section 3

  1. Mercator projection: map projection that has correct shapes of continents, but their areas are distorted; has lines of longitude drawn parallel to each other.
  2. Robinson projection: map projection that has accurate continent shapes and accurate land areas; has parallel latitude lines and curved longitude lines.
  3. conic projection: map projection that is accurate for small areas of Earth and is made by projecting points and lines from a globe onto a cone.
  4. topographic map: shows the changes in elevation of Earth's surface and shows natural features such as mountains and rivers, and cultural features such as roads and cities.
  5. contour line: line on a map that connects points of equal elevation.
  6. contour interval: difference in elevation between two side-by-side contour lines.
  7. map scale: relationship between the distances on the map and the actual distances on Earth's surface; can be represented as a ratio or small bar graph divided into units.
  8. map legend: explains the meanings of symbols that are used on topographic maps and most other maps.
  9. remote sensing: way of collecting information about Earth from a distance--satellites and sonar.

                                                              

Chapter 9

Section 1

  1. mineral: naturally occurring, inorganic, crystalline solid that has a definite chemical composition and an orderly arrangement of atoms.
  2. crystal: solid in which the atoms are arranged in repeating patterns; can form when magma cools and when liquids containing dissolved minerals evaporate.
  3. magma: hot melted rock material that form large crystals when it cools slowly and small crystals when it cools rapidly.
  4. silicate: mineral that contains silicon and oxygen and usually one or more other elements. 

Section 2

  1. hardness: measure of how easily a mineral can be scratched.
  2. luster: describes how light reflects from a mineral's surface; can be either metallic or nonmetallic.
  3. streak: color of a mineral when it is powdered.
  4. cleavage: property of a mineral that allows it to break along smooth, flat planes.
  5. fracture: property of a mineral that causes it to break with rough or jagged edges.

Section 3

  1. gem: highly prized, valuable mineral that is bright and colorful and often is cut and polished and used for jewelry.
  2. ore: mineral or rock that contains a useful substance that can be mined at a profit.

                                                              

Chapter 10

Section 1

  1. rock: dynamic mixture of one or more minerals, mineraloids, glass, or organic matter.
  2. rock cycle: continuous, dynamic process by which sedimentary, igneous, and metamorphic rocks are changed from one form to another by means such as weathering, erosion, compaction, melting, and cooling.

Section 2

  1. igneous rock: rock formed from fast-cooling lava at or near Earth's surface and from slow-cooling magma deep inside Earth.
  2. lava: name given to the thick, gooey, molten material known as magma when it reaches Earth's surface and flows from volcanoes.
  3. intrusive: type of igneous rock with large mineral grains that is formed from slow-cooling magma beneath Earth's surface.
  4. extrusive: type of igneous rock with fine-grained texture that is formed as lava cools quickly at or near Earth's surface.
  5. basaltic: dense, heavy, dark-coloerd igneous rock that is rich in magnesium and iron.
  6. granitic: light-colored, silica-rich igneous rock of a lower density than basaltic rock.

Section 3

  1. metamorphic rock: rock that forms because of changes in temperature and pressure, or the presence of hot, watery fluids in igneous, sedimentary, or other metamorphic rock.
  2. foliated: type of metamorphic rock, such as slate, whose mineral grains line up in parallel layers when exposed to heat and pressure.
  3. nonfoliated: type of metamorphic rock, such as marble, whose mineral grains grow and rearrange when exposed to heat and pressure but do not form layers.

Section 4

  1. sedimentary rock: rock formed by compaction and cementation of sediments or when minerals precipitate out of solution or are left behind when a solutions evaporates.
  2. sediment: loose material, such as rock fragments, minerals dissolved in water, and the remains of one-living plants and animals, that have been moved by wind, water, gravity, or ice.
  3. compaction: formation of solid sedimentary rock in which layers of small sediments build up and are squeezed together by the weight of the overlying sediment layers.
  4. cementation

                                                              

Chapter 11

Section 1

  1. fossil fuel: nonrenewable energy resource that began to form millions of years ago from remains of once-living plants and animals; provides energy and includes coal, oil, and natural gas.
  2. pollution: introduction of harmful waste products, chemicals, and substances into the environment.
  3. acid rain: acidic rain or snow produced when gases released by burning oil and coal mix with water in the air; cause damage and can kill plants and trees.
  4. nonrenewable: resources, such as fossil fuels, that cannot be replace by natural processes in less than 100 years.

Section 2

  1. renewable: energy resources, such as wind and water, that can be recycled or replaced by natural processes in less than 100 years.
  2. solar energy: energy from the sun that is nonpolluting, renewable, and abundant but is available only when the sun is shining.
  3. hydroelectric power: production of electricity by water.
  4. geothermal energy: heat energy from Earth, which can be used to generate electricity.
  5. nuclear energy: energy produced by splitting the nuclei of certain elements.

Section 3

  1. groundwater: water that soaks into the ground and collects in the small spaces between bits of rock and soil.
  2. point source: single, identifiable pollution source.
  3. nonpoint source: pollution that comes from many different sources, such as industries, homes, and farms.

Section 4

  1. conservation: careful use of resources with the goal of reducing damage to the environment. 
  2. ore: mineral or rock that contains a useful substance that can be mined at a profit.

Unit 4

                                                              

Chapter 12

Section 1

  1. troposphere: layer of the atmosphere closest to the ground; contains 75% of the atmospheric gases, dust, ice, and liquid water and is where weather, smog, and clouds occur.
  2. ionosphere: layer of electrically charged particles in the thermosphere.
  3. ozone layer: stratospheric layer with a high concentration of ozone; protects Earth by absorbing harmful ultraviolet radiation.
  4. ultraviolet radiation: type of energy that comes to Earth from the sun and is mostly absorbed by the ozone layer; can cause cancer and other health problems in many types of plants and animals.
  5. chlorofluorocarbon: group of chemical compounds used in refrigerators, aerosol sprays, and foam packaging that destroy ozone molecules.

Section 2

  1. radiation: energy that travels by waves in all directions from its source; transfer of energy by electromagnetic waves.
  2. conduction: transfer of thermal energy from particle to particle through a material when there is a temperature difference; transfer of energy that occurs when molecules bump into each other.
  3. convection: transfer of thermal energy that happens when particles mover from one place to anther where there is a temperature difference; occurs in gases and liquids.
  4. hydrosphere: all the water that is found at Earth's surface, of which 97% is salt water and only 3% is fresh water.
  5. water cycle: the continuous movement of water between Earth's surface and the atmosphere through evaporation, condensation, and precipitation.

Section 3

  1. Coriolis effect: changes the direction of all free-moving objects to the right north of the equator and to the left to the south of the equator; creates wind patterns across the world and results from the rotation of Earth.
  2. jet stream: narrow belt of strong winds that blows near the top of the troposphere.
  3. sea breeze: daily movements of air created when cooler, denser air moving inland from the ocean forces warm air over the land to rise.
  4. land breeze: nightly movements of air created when cold air over the land forces up the warmer air above the sea.

                                                              

Chapter 13

Section 1

  1. weather: present state of the atmosphere, including air pressure, wind, temperature, and the amount of moisture in the air.
  2. humidity: amount of water vapor held in the air.
  3. relative humidity: measure of the amount of water vapor that the air is holding compared to the amount it can hold at a specific temperature.
  4. dew point: temperature at which air is saturated and condensation forms; changes with the amount of moisture in the air.
  5. fog: stratus cloud that forms when air is cooled to its dew point and condenses near the ground. 
  6. precipitation: water falling from clouds, including rain, snow, sleet, and hail.

Section 2

  1. air mass: large body of air that has the same properties as the Earth's surface over which it formed.
  2. front: boundary between warm and cold air masses.
  3. tornado: violent, whirling wind that moves in a narrow path over land, forms a funnel, and can be highly destructive.
  4. Doppler radar: specialized radar system that sends out repeated radio waves, monitors the reflected waves from distant storms, and can tell the direction a storm is moving.
  5. hurricane: large, swirling, low-pressure system that forms over tropical oceans and has winds of at least 120 km per hour.

Section 3

  1. meteorologist: person who studies weather, takes measurements of temperature, air pressure, winds, humidity, and precipitation, and uses information provided by weather instruments to make weather maps and forecasts. 
  2. station model: show the weather conditions at one specific location, using symbols on a map.
  3. isotherm: line drawn on a weather map that connects points of equal temperature.
  4. isobar: line drawn on a weather map that connects points of equal atmospheric pressure.

                                                              

Chapter 14

Section 1

  1. climate: pattern of weather that occurs in a particular area over many years.
  2. tropics: region between latitudes 23.5 degrees north and 23.5 degrees south that receives the most solar radiation and is always hot, except at high elevations.
  3. polar zone: regions extending from 66.5 degrees north and south latitudes to the poles that receive solar energy at a low angle or not at all and may be covered with ice year-round.
  4. temperate zone: regions with moderate temperatures located between the tropic and polar zones.

Section 2

  1. adaptation: any structure or behavior that helps an organism survive in its environment; develops in a population over a long period of time.
  2. hibernation: behavioral adatptation for survival during cold, winter months, wher an animla becomes inactive and its metabolic needs are lowered; in amphibians, involves burying themselves in mud or leaves until temperatures become warmer.

Section 3

  1. season: short-term period of climate change caused by  regular differences in temperature, daylight, and weather patterns that are due to Earth's tilt on its axis as it revolves around the sun.
  2. El Nino: a climatic event that starts in the topical Pacific Ocean and set off changes in the atmosphere.
  3. greenhouse effect: natural heating process caused when gases in the atmosphere trap heat; prevents Earth from being too cold to support life.
  4. global warming: rise in global temperatures because of the increase of greenhouse gases in the atmosphere.
  5. deforestation: destruction or cutting down of trees.

Unit 5

                                                              

Chapter 15

Section 1

  1. compound light microscope: magnifies by allowing light to pass through an object and then through two or more lenses.
  2. electron microscope: bends beams of electrons in a magnetic field and can magnify images up to one million times or more.
  3. cell theory: major theory based on observations and conclusions by many scientists; cell is the basic unit of life, organisms are composed of one or more cells, and all cells come from other cells.

Section 2

  1. cell membrane: structure that allows only certain things to pass into and out of the cell and forms the outer boundary  of the cell.
  2. nucleus: positively charged central part of an atom; eukaryotic organelle that directs all the activities of the cell and is surrounded by a double membrane.
  3. chromatin: long strands of hereditary material within the cell nucleus that are made up of proteins and DNA.
  4. cytoplasm: constantly moving, gelatin-like mixture inside the cell membrane; contains structures that carry out life processes of the cell.
  5. organelle: structure within the cytoplasm of a eukaryotic cell having a specific function or functions.
  6. endoplasmic reticulum: complex series of folded membranes in the cell cytoplasm that is involved in moving cellular products.
  7. ribosome: small, two-part organelles on which cells make their own proteins.
  8. Golgi body: stacks of membrane-covered sacs that package materials and move them to the outside of the cell.
  9. mitochondria: eukaryotic cell organelles where food molecules are broken down and energy is released.
  10. lysosome: eukaryotic cell organelle that contains digestive chemicals that break down food molecules, cell wastes, and worn-out cell parts.
  11. cell wall: rigid structure that supports and protects the plant cell and is made mostly of bundles of cellulose fibers.
  12. chloroplast: green chlorophyll-containing organelle in the cytoplasm of many plant cells, where plants make their own food.
  13. tissue: group of similar cells that work together to do one job.
  14. organ: structure made up of different types of tissues that work together to do a certain job.

Section 3

  1. virus: nonliving structure that consists of a core of hereditary material surrounded by a protein coat.
  2. host cell: cell in which a virus reproduces.
  3. vaccine: preparation made from damaged virus particles that ar4e no longer able to cause disease and that can prevent some viral disease such as polio and measles.    

                                                              

Chapter 16

Section 1

  1. classify: to group information, objects, or ideas based on their similarities.
  2. taxonomy: the science of classification.
  3. kingdom: the first taxonomic category and the group that has the most members.
  4. binomial nomenclature: Linnaeus's system of classification, which gives a two-word name to every organism--the first word of the name is the genus and the second word is the specific name. 
  5. genus: taxonomic group of different organisms with similar characteristics; can have one or more species.
  6. species: smallest, most precise taxonomic classification.

Section 2

  1. phylogeny: evolutionary history of an organism.
  2. phylum: taxonomic group that is smaller than a kingdom but larger than a class.
  3. division: in the taxonomy of plants, the group smaller than a kingdom but larger than a class.
  4. class: taxonomic group that is larger than an order but smaller than a phylum or division.
  5. order: taxonomic group that is larger than a family but smaller than a class.
  6. family: taxonomic group that is smaller than an order but larger than a genus.

Section 3

  1. dichotomous key: detailed list of characteristics used to identify organisms and that includes scientific names.

                                                              

Chapter 17

Section 1

  1. flagella: whiplike tails that help many types of bacteria move around in moist environments.
  2. fission: simplest form of asexual reproduction in which two cells are produced with genetic material identical to that of the parent cell; the method by which bacteria reproduce.
  3. aerobe: organism that requires oxygen to survive--for example humans require oxygen to live.
  4. anaerobe: organisms that are able to live without oxygen--for example, methanogens and thermophiles.

Section 2

  1. saprophyte: any organism that uses dead material as a food and energy source; the decompose dead organisms and recycles nutrients so that they are available for use by other organisms; saprophyte bacteria keeps dead material from building up over all of Earth.
  2. nitrogen-fixing bacteria: bacteria that live in the root nodules of certain kinds of plants and change nitrogen from the air into forms useful for animals and plants.
  3. pathogen: any organism that produces disease.
  4. antibiotic: substance, such as penicillin, produced by one organism that inhibits or kills another organism.
  5. vaccine: preparation made from damaged virus particles that are no longer able to cause disease and can prevent some viral disease such as polio and measles.
  6. toxin: poison produced by a bacterial pathogen.
  7. endospore: heat-resistant, thick-walled structures many bacteria can produce around themselves when conditions are unfavorable.

                                                              

Chapter 18

Section 1

  1. protist: single- or many-celled eukaryotic organism that lives in a moist or wet environment; can be plantlike, animallike, or funguslike.
  2. algae: one-or many-celled plantlike protists, all of which contain chlorophyll and can make their own food; organized into 6 main phyla based on their structure, their pigments, and the way they store food.
  3. protozoan: complex, one-celled, animallike protists that contain special vacuoles for digesting food and eliminating excess water; classified by their method of movement.
  4. pseudopods: temporary, footlike extensions of cytoplasm used by rhizopods for movement and for trapping food.
  5. cilia: short, threadlike structures that extend from the cell membrane of ciiates and are used for movement.

Section 2

  1. hyphae: mass of many-celled, threadlike tubes that usually make up the body of a fungus.
  2. spore: reproductive cell that forms new organisms without fertilization.
  3. budding: form of asexual reproduction in which a new organism grows off the side of the parent.
  4. lichen: organism made up of a fungus and a green alga.

Unit 6

                                                              

Chapter 19

Section 1

  1. cellulose: organic compound made of long chains of glucose molecules; forms the rigid cell walls of plants.
  2. cuticle: waxy, protective layer covering the stems, leaves, and flowers of some land plants; is secreted by the plant's cell walls and slow the evaporation of water.
  3. vascular plant: plant with vascular tissue, a "pipeline" that move water, food, and dissolved substances to cells throughout the plant.
  4. nonvascular plant: plant lacking vascular tissue and that absorbs water and other dissolved substances directly through its cell walls.

Section 2

  1. rhizoid: threadlike roots that are only a few cells in length and that anchor liverworts and mosses in place.
  2. pioneer species: first plants to grow in new or disturbed environments and that change environmental conditions so that other plant species can grow there.

Section 3

  1. xylem: vascular plant tissue made up of tubular vessels that transport water and dissolved substances up from the roots throughout the plant.
  2. phloem: vascular plant tissue made up of tubular cells that transport food from where it is made to other parts of the plant where it is used or stored.
  3. cambium: vascular plant tissue that produces new xylem and phloem cells.
  4. stomata: small pores in the leaf surfaces surrounded by guard cells; allow carbon dioxide, oxygen, and water to enter and leave a leaf.
  5. guard cell: in a plant leaf, the cells that surround the stomata and that open and close them.
  6. gymnosperm: vascular plants that produce seeds on the surface of the female reproductive structures, do not have flowers, and generally have needlelike or scalelike leaves.
  7. angiosperm: vascular plants that flower, have their seeds contained in a fruit, and are the most common form of plant life on Earth.
  8. monocot: class of angiosperm that has one seed leaf inside its seeds, vascular tissues arranged as bundles scattered throughout the stem, and flower parts in multiples of three.
  9. dicot: class of angiosperm that has two seed leaves inside its seeds, vascular bundles that occur in rings, and flower parts in multiples of four or five.

                                                              

Chapter 20

Section 1

  1. vertebrate: animal with a backbone; only about 3% of animals are vertebrates.
  2. invertebrate: animals lacking a backbone; about 97% of animals are invertebrates.
  3. symmetry: arrangement of the individual parts of an object; animals with bilateral symmetry have mirror image body parts; animals with radial symmetry have body parts arranged in a circle around a central point; asymmetrical animals have no definite shape. 

Section 2

  1. cnidarians: phylum of hollow-bodied, water-dwelling animals with stinging cells, radial symmetry, a body two layers thick, and both sexual and asexual reproduction.
  2. polyp: vase-shaped body plan of  cnidarians, such as a hydra, that allows it to twist to capture prey and to somersault to a new location.
  3. medusa: free-swimming, bell0shpaed body plan of cnidarians, such as jellyfish, that allows it to drift with the ocean currents.
  4. free-living: organism, such as a planarian, that doesn't depend on one particular organism for food or a place to live.
  5. parasite: organism, such as a tapeworm, that depends on its host for food and a place to live.

Section 3

  1. mollusk: soft-bodied invertebrate that has a mantle, a large muscular foot, a complete digestive system with 2 openings and usually has a protective shell.
  2. mantle: thin tissue layer covering a mollusk's soft body; secretes the protective shell of those mollusks having a shell.
  3. gills: organs that exchange oxygen and carbon dioxide with water.
  4. radula: scratchy, tongue-like organ in many mollusks that acts like a file with rows of teeth to break up food into smaller pieces.
  5. open circulatory system: type of blood-circulation system in which the blood is not contained in vessels but instead surrounds the organs.
  6. closed circulatory system: type of blood-circulation system in which blood is carried through blood vessels.

Section 4

  1. arthropod: animals that have jointed appendages, such as an insect or a crustacean, that is classified by the number of body segments and appendages, and that has a protective exoskeleton.
  2. appendage: jointed structures, such as legs, claws, and antennae, that grow from a body.
  3. exoskeleton: lightweight body covering that protects and supports an arthropod's body, prevents it from drying out, and is shed by molting.
  4. metamorphosis: process in which insects change their body form as they mature; can be complete (egg, larva, pupa, and adult) or incomplete (egg, nymph, and adult).

                                                              

Chapter 21

Section 1

  1. chordate: animal with a notochord, a dorsal hollow nerve cord, and gill slits.
  2. endoskeleton: internal system of bones that protects and supports an animal's internal organs and also provides a place for muscle attachment.
  3. ectotherm: vertebrate whose body temperature changes with  the temperature of its surroundings.
  4. endotherm: vertebrate that maintains a constant body temperature.
  5. fish: ectotherm that lives in water and uses gills to get oxygen; usually has fins and scales.
  6. fin: fanlike structure of most fish that are used for balancing, steering, and moving, and usually are paired.
  7. cartilage: tough, flexible tissue that is similar to bone but is not as hard.

Section 2

  1. amphibian: ectotherm vertebrate that spends part of its life in water and part on land. 
  2. hibernation: behavioral adaptation for survival during cold, winter months, where an animal becomes inactive and its metabolic needs are lowered; in amphibians, involves burying themselves in mud or leave until temperatures become warmer.
  3. estivation: behavioral adaptation for survival during hot, dry summer months, during which an animal becomes inactive; in amphibians, involves hiding in cooler, more humid ground.
  4. reptile: ectothermic vertebrate that has thick, dry, scaly skink, and does not depend on water for reproduction.

Section 3

  1. bird: endothermic vertebrate with feathers, two legs, two wings, and bills or beaks, and that lay hard-shelled eggs.
  2. contour feather: strong, lightweight feathers that give birds their coloring and streamlined shape and that are used to fly and to steer.
  3. down feather: soft, fluffy feathers that provide an insulating layer next to the skin of adult birds and that cover the bodies of young birds.

Section 4

  1. mammal: endothermic vertebrate that has hair and produces milk to feed its young.
  2. monotreme: mammal that lay eggs with tough, leathery shells; the duckbilled platypus and 2 species of spiny anteaters.
  3. marsupial: mammal that gives birth to immature offspring and that has a pouch in which its young complete there development. 
  4. placental mammal: mammal whose embryo develops in the uterus of the female.
  5. herbivore: grazing animal that eats only plants.
  6. carnivore: flesh-eating animals.
  7. omnivore: animals that eat both plants and animals.

                                                              

Chapter 22

Section 1

  1. behavior: way an organism acts toward its environment; can be innate or learned.
  2. innate behavior: behavior that an animals is born with and does not have to learn.
  3. reflex: automatic response, such as shivering, that does not involve the brain.
  4. instinct: complex pattern of innate behavior. 
  5. imprinting: type of learning in which an animals forms a social attachment to another organism soon after birth or hatching.
  6. conditioning: process in which behavior is modified so that a response associated with one stimulus becomes associated with another stimulus.

Section 2

  1. territory: area that an animal defends from other members of the same species and that contains food, shelter, and potential mates.
  2. aggression: forceful act, such as fighting and threatening, that is used to dominate or control another animal.
  3. courtship behavior: behavior that animals perform before mating; allows male and female members of a species to recognize each other and to be ready to mate at the same time.
  4. social behavior: interaction among organisms of the same species, including courtship and mating, caring for the young, and getting food.
  5. society: group of animals of the same species that live and work together in the same way and in which each member has a certain job.
  6. pheromone: powerful chemical produced by an animal to influence the behavior of another animal of the same species.
  7. cyclic behavior: innate behaviors, such as migration and hibernation, that occur in a repeated pattern, often in response to changes in the environment. 
  8. hibernation: behavioral adaptation for survival during cold, winter months, where an animal becomes inactive and its metabolic needs are lowered; in amphibians, involves burying themselves in mud or leave until temperatures become warmer.
  9. migration: instinctive seasonal movement of animals, usually t find food or to reproduce in a better environment.