8th Grade Vocabulary Terms
Chapter 1 – Scientific Investigations and Reasoning
Analyze - examine methodically and in detail for purposes of explanation and interpretation
Conclusion - a short paragraph that states the results of an experiment and explains whether the hypothesis was correct or not
Constant – the factors in an experiment that stay the same
Control Group – the part of a controlled experiment that contains the same factors as the experimental group, but the independent variable is not changed
Controlled Experiment - a scientific test that is directly manipulated by a scientist, in order to test a single variable at a time
Critical Thinking – comparing what you already know about something to new information and deciding whether or not you agree with the new information
Dependent/Responding Variable - a variable whose value changes because of another variable; graphed on the y –axis
Experimental Group – the part of the controlled experiment used to study relationships among variables
Hypothesis – a possible explanation for an observation that can be tested by scientific explanations; an “if, then” statement
Independent/Manipulated Variable – the factor that is changed by the investigator to observe how it affects a dependent variable
Inference – a logical explanation of an observation that is drawn from prior knowledge or experience
International Unit - the standard units of measurement defined by the International System of Units
Model - a physical, conceptual, or mathematical representation of something that is difficult to observe directly
Observation – the act of using one or more of your senses to gather information and take note of what occurs
Opinion - a statement describing a personal belief or thought that cannot be tested (or has not been tested) and is unsupported by evidence
Prediction – a statement of what will happen next in a sequence of events
Prototype - a first full-scale and usually functional form of a new type or design of a construction
Qualitative – data is descriptive and conceptual; using words to describe something
Quantitative – data can be counted, measured, and expressed using numbers; using measurements to describe something
Research - the orderly investigation into and study of materials in order to establish facts and reach new conclusions
Science – the exploration and investigation of natural events and the new information that comes from those investigations
Scientific Inquiry - the diverse ways in which scientists study the natural world and propose explanations based on the evidence from their work
Scientific Law – a rule that describes a pattern in nature; it happens the same way every time
Scientific Theory – an explanation of observations or event that is based on knowledge gained from many observations and investigations; not definitively proven
Skeptical - not easily convinced; having doubts or reservations
Variable – any factor that can have more than one value
Chapter 2 – Atoms and the Periodic Table
Atom – the smallest piece of an element that still represents that element
Atomic Number – the number of protons in an atom of an element
Average Mass Number - the average atomic mass of an element based on its isotopes and their natural abundance
Bohr’s Atomic Model - electrons travel in defined circular orbits around the nucleus
Chemical Bond – a force that holds two or more atoms together
Compound – a substance made of two or more elements that are chemically joined in a specific combination
Electron – a negatively charged particle that occupies the space in an atom outside the nucleus
Electron Cloud – the region surrounding an atom’s nucleus where one or more electrons are most likely to be found
Electron Dot Diagram/Lewis Dot Diagram – a model that represents valence electrons in an atom as dots around the element’s chemical symbol
Group/Family – a column on the periodic table where the elements have the same number of valence electrons
Isotope – atoms of the same element that have different numbers of neutrons
Modern Atomic Model - Electrons are in constant motion around the nucleus, protons and neutrons vibrate within the nucleus
Neutron – a neutral particle in the nucleus of an atom
Nuclear Decay - the process by which an unstable atomic nucleus loses energy by radiation
Nucleus (Chemistry) – the region in the center of the atom where most of an atom’s mass is found; contains protons and neutrons
Period – a row on the periodic table that shows the number of energy shells/levels/rings of an atom
Periodic - refers to trends or recurring variations in element properties with increasing atomic number
Periodic Table – a chart of the elements arranged by physical and chemical properties
Proton – a positively charged particle in the nucleus of an atom
Radioactive – an element that naturally emits radiation
Rutherford’s Atomic Model - the atom has a tiny, dense, positively charged core called a nucleus while negatively charged electrons circulate around the nucleus
Thomson’s Atomic Model - atoms are uniform spheres of positively charged matter in which electrons are embedded
Valence Electrons – the outermost electrons of an atom that are responsible for chemical bonding
Chapter 3 – Chemical Bonding and Chemical Reactions
Chemical Bond – a force that holds two or more atoms together
Chemical Change – a change in matter in which substances change into other substances with different chemical and physical properties
Chemical Equation – a description of a reaction using element symbols and chemical formulas
Chemical Formula – a group of chemical symbols and numbers that represent the elements and the number of atoms that make up a compound
Chemical Reaction – a process in which atoms of one or more substances rearrange to form one or more new substances
Coefficient - a number placed in front of an element symbol or chemical formula in an equation
Combustion – a chemical reaction in which a substance combines with oxygen and releases energy
Compound – a substance made of two or more elements that are chemically joined in a specific combination
Covalent Bond - a chemical bond formed when two atoms share one or more pairs of valence electrons
Decomposition – a type of chemical reaction in which one compound breaks down and forms two or more substances
Electron Sharing - when the electrons in the outermost shell from one atom can be used to complete the outermost shell of another atom without being permanently transferred
Electron Transfer - when an electron relocates from an atom or molecule to another
Element – a pure substance made of only one kind of atom
Ion – an atom that has gained or lost an electron and is no longer neutral
Ionic Bond - the attraction between positively and negatively charged ions in an ionic compound
Law of Conservation of Mass – the total mass of the reactants before a chemical reaction is the same as the total mass of the products of the reaction
Metallic Bond – a bond formed when many metal atoms share their pooled valence electrons
Molecule – two or more atoms that are held together by covalent bonds and act as a unit
Physical Change – a change of matter that does not change the matter’s identity
Polar Molecule – a molecule with a slight negative charge in one area and a slight positive charge in another area
Precipitate – a solid that forms when two liquids are combined
Product – a substance produced by a chemical reaction
Reactant – a starting substance in a chemical reaction; ingredient
Replacement – an atom or group of atoms replaces part of a compound; switched
Subscript - numbers that come after and below a symbol; tell you the number of atoms of that element
Substance – matter with a composition that is always the same
Synthesis – a chemical reaction in which two or more substances combine to form one compound
Chapter 4 – Speed, Velocity, and Acceleration
Average Speed – total distance divided by the total time of the trip
Constant Speed – an object moves the same distance over a given unit of time
Instantaneous Speed - the speed of an object at a particular moment (instant) in time when the speed of an object is constantly changing
Negative Acceleration/Deceleration – velocity is decreasing, the action of slowing down
Positive Acceleration – velocity is increasing, the action of speeding up
Speed – the distance an object is moving in a unit of time
Velocity – the speed and direction of a moving object
X-axis - the independent/manipulated variable is on the x-axis (horizontal)
Y-axis – the dependent/responding variable is on the y-axis (vertical)
Chapter 5 – The Laws of Motion
Action Force – Force exerted on an object in one direction
Air Resistance - the force that air exerts on objects moving through it
Balanced Forces – forces acting on an object that combine and form a net force of zero; no change in motion
Centripetal Force – in circular motion, a force that acts perpendicular to the direction of motion, toward the center of a curve
Contact - Touching
Elastic Collision - the kinetic energy before the collision and after the collision remains the same and is not converted to any other form of energy; objects collide and bounce off each other
Force – a push or a pull on an object
Force Pair - As in Newton’s 3rd law, the forces two objects apply to each other
Friction – a contact force that resists the sliding motion of two surfaces that are touching
Gravity – an attractive force that exists between all objects that have mass
Inertia – the tendency of an object to resist a change in its motion
Law of Conservation of Momentum – the total momentum of a group of objects stays the same unless outside forces act on the objects
Law of Universal Gravitation – all objects are attracted to each other by a gravitational force
Mass – the amount of matter in an object
Momentum – a measure of how hard it is to stop a moving object
Net Force – the sum of all forces acting on an object
Newton - force needed to move a mass of one kilogram with an acceleration of one meter per second2
Noncontact – a force that one object applies to another object without touching it
Reaction Force – A force exerted by an object in response to an action force
Reference Direction - the direction you must travel from the reference point toward an object
Sliding Friction - a contact force that resists the sliding motion of two objects or an object and a surface
Static Friction – a force between two surfaces that aren't moving relative to each other
Terminal Velocity - the highest velocity that can be achieved by an object that is falling through a fluid, such as air or water
Unbalanced Forces – forces acting on an object that combine and form a net force that is not zero and therefore results in a change in motion
Weight – the gravitation force on an object
Chapter 6 – Earth’s Motion
Astronomical Unit – a unit of measurement in space equal to 150 million km; the distance from Earth to the Sun
Crescent - the shape of the visible part of the moon when it is less than half full
Equator – an imaginary line at latitude 0o, separates the northern and southern hemispheres
Equinox – when Earth’s rotation axis is not tilted toward or away from the Sun; hours of daylight = hours of darkness
Gibbous - more than half but less than fully illuminated; a term used in describing Moon phases
Lunar Eclipse – an occurrence when the Moon moves into Earth’s shadow; occurs only in the full moon phase
Maria – the large, dark, flat areas on the moon
Moon Phase - the angle from which an observer on earth can see the moon illuminated by the sun as it orbits our planet
Orbit – the path an object follows as it moves around another object
Penumbra – the lighter part of a shadow where light is partially blocked; almost a complete shadow
Revolution – the orbit of one object around another object
Rotation – a spinning motion
Rotation Axis – the line on which an object rotates
Solar Eclipse – when the Moon is between the Sun and the Earth and blocks the sunlight
Solstice – when Earth’s rotation axis is tilted toward or away from the Sun causing the longest/shortest hours (days) of sunlight
Tide – the rhythmic rise and fall of the ocean’s surface that is caused by the gravity between the Earth, Moon, and Sun
Umbra – the central, darkest part of a shadow; light is completely blocked
Waning - to decrease in some way
Waxing – to increase in some way
Chapter 7 – The Universe
Absolute Magnitude - how bright the star appears at a standard distance of 32.6 light-years (roughly 10 trillion kilometers)
Apparent Magnitude - how bright a star appears from Earth
Astronomical Unit – a unit of measurement in space equal to 150 million km; the distance from Earth to the Sun
Aurora – curtains of light that appear when solar wind particles or coronal mass ejections interact with Earth’s magnetic field
Big Bang Theory – states that the universe began from one point and has been expanding and cooling since then
Binary System - consists of two stars that are gravitationally bound and orbit their common center of mass in elliptical or circular orbits.
Black Hole – an object whose gravity is so strong that no light can escape
Chromosphere – the orange-red layer above the photosphere of a star
Convection Zone – layer of a star where hot gas moved up toward the surface and cooler gas moves deeper into the interior
Corona – the wide, outermost layer of a star’s atmosphere
Dark Matter – matter the emits no light at any wavelength
Electromagnetic Spectrum - energy from the Sun that travels to Earth and ranges from very long-length radio waves to very short-length gamma rays
Flare – sudden increases in brightness near the Sun’s sunspots and prominences (looping clouds of gas)
Galaxy – a huge collection of stars, gas, and dust
Hertzsprung-Russell Diagram – a graph that plots luminosity and temperature of stars
Light Year - the distance light travels in one year
Luminosity – the true brightness of an object
Milky Way – a spiral galaxy that contains gas, dust, and the Solar system
Nebula – a cloud of dust and gas
Neutron Star – a dense core of neutrons that remains after a supernova
Nuclear Fusion – when the nuclei of several atoms combine into one larger nucleus
Parallax - when the position or direction of an object appears to differ when viewed from different positions
Photosphere – the apparent surface of a star
Prominence – clouds of gas that loop and jet into the Sun’s corona
Protostar – when gravity causes the densest parts of a nebula to collapse
Solar Wind – charged particles that are always moving away from the Sun
Spectroscope – a tool that spreads light into different wavelengths
Star – a large ball of gas held together by gravity with a core so hot that nuclear fusion occurs
Star Cluster – large groups of stars that are of similar age and distance from Earth
Stellar - relating to a star or stars
Sunspot – regions of strong magnetic activity on the Sun; dark spots on the Sun
Supernova – an enormous explosion that destroys a star; occurs when a star loses its internal energy source and the iron core collapses
White Dwarf – a hot, dense, slowly cooling sphere of carbon
Chapter 8 – Interpreting Maps
Antarctic Circle - latitude on the Earth at approximately 66.5 degrees south of the equator
Arctic Circle - latitude on the Earth at approximately 66.5 degrees north of the equator
Contour Interval – the elevation difference between contour lines that are next to each other on a map
Contour Line – a line on a topographic map that connects points of equal elevation
Equator - latitude on the Earth at 0 degrees; separates the Earth into the Northern and Southern Hemispheres
Geologic Map – a map that shows the surface geology of an area
Global Positioning System (GPS) - an accurate worldwide navigational and surveying system based on the reception of signals from many orbiting satellites
Index Line - the thickest/darker contour lines usually labeled with the elevation
International Date Line – the line of longitude 180 degrees west or east of the Prime Meridian
Latitude – the distance in degrees north or south of the Equator
Longitude – the distance in degrees east or west of the Prime Meridian
Map – a model of an area of land or sea showing physical features
Map Legend – a key that lists all the symbols used on a map
Map Scale – the relationship between a distance on the map and the actual distance on the ground
Map View/Plan View – a map drawn as if you were looking down on an area from above Earth’s surface
Prime Meridian – a reference point at 0 degrees longitude which runs through the original site of the Royal Observatory at Greenwich, England, and from which other longitudes are determined
Profile View – a drawing that shows a vertical section through the ground; a side view
Relief – the difference in elevation between the highest and lowest point in an area
Remote Sensing - the scanning of the earth by satellite or high-flying aircraft in order to obtain information about it
Slope – a measure of the steepness of the land
Time Zone –one of 24 areas on Earth’s surface where people use the same time
Topographic Map – a map showing the detailed shapes of Earth’s surface, along with its natural and manmade features
Topography - the arrangement of the natural and artificial physical features of an area
Tropic of Cancer - latitude 23°26ʹ north of the equator
Tropic of Capricorn - latitude 23°26ʹ south of the equator
Chapter 9 – Plate Tectonics
Abyssal – the bottom of the ocean
Basalt – a dense rock that forms oceanic crust; a fine-grained extrusive igneous rock
Compression - decrease in volume of any object or substance resulting from applied stress
Continental Crust – crust that is thicker than oceanic crust with a lower density causing it to ride higher on the mantle; formed from granite; contains the land masses
Continental Drift – the movement of Earth’s continents over time; theory proposed by Alfred Wegener
Continental Rift - a zone of the lithosphere that has become thinner due to extensional forces associated with plate tectonics; area of divergence
Convergent Plate Boundary – the boundary between two plates that move toward each other
Divergent Plate Boundary - the boundary between two plates that move away from each other
Dormant - is a period when physical activity has temporarily stopped
Fault Block Mountain – parallel ridge that forms where blocks of crust move up or down along faults
Fault Zone – an area of many fractured pieces of crust along a fault line
Folded Mountain – mountain made of layers of rocks that are folded
Granite – a rock that is less dense than basalt and forms continental crust; a coarse or medium-grained intrusive igneous rock
Island Arc - a curved chain of volcanic islands located at a tectonic plate margin
Magnetic Reversal – an event that causes a magnetic field to reverse direction
Mid-ocean Ridge – a long, narrow mountain range on the ocean floor; formed by magma at divergent plate boundaries
Normal Polarity – when magnetized objects orient themselves to North
Ocean Trench – a deep, underwater trough created by one plate subducting under another plate at a convergent plate boundary
Oceanic Crust - the relatively thin part of the Earth's crust which underlies the ocean; geologically young compared with the continental crust and consists of basaltic rock covered by sediments
Pangaea – name of a supercontinent that began to break apart 200 million years ago
Reversed Polarity – when magnetized objects reverse direction and orient themselves to South
Seafloor Spreading – the process where new oceanic crust forms at a mid-ocean ridge and older oceanic crust is pushed away from the ridge
Shear - a force acting in a direction that's parallel to a surface
Subduction – the process that occurs when one tectonic plate moves under another tectonic plate
Tension - the force that is transmitted on an object when pulled by forces acting from opposite sides; stretched
Transform Plate Boundary/ Transform Fault – the boundary where two tectonic plates slide past each other
Uplifted Mountain – mountain that forms when large regions rise vertically with little apparent change
Volcanic Arc – a curved line of volcanoes that forms parallel to a plate boundary
Volcanic Mountain - mountains formed by volcanoes; formed when lava erupts, piles upon the surface, and ash and lava cools to build a cone of rock
Chapter 10 – Interactions of the Atmosphere and Oceans
Conduction – the transfer of thermal energy due to collisions between particles
Convection – the transfer of thermal energy by the movement of particles from one part of a material to another
Coriolis Effect – the movement of wind and water to the right or left that is caused by Earth’s rotation
Downwelling/Density Current – carry water from the surface to deeper parts of the ocean; circulate thermal energy, nutrients, and gases
Great Ocean Conveyor Belt – a large global system of ocean currents that affects weather and climate around the Earth; may take 1000 years for one cycle
Greenhouse Effect – the natural process that occurs when certain gases in the atmosphere absorb and reradiate thermal energy from the Sun
Gyre – a large circular system of ocean currents
Infrared - a type of radiant energy that's invisible to human eyes but that we can feel as heat; radiation that Earth bounces back to the atmosphere
Jet Stream – a narrow band of westerly high winds located near the top of the troposphere
Land Breeze – a wind that blows from the land to the sea due to local temperature and pressure differences at the shore; occurs at night since land cools faster than water
Ocean Current – a large volume of water flowing in a certain direction
Polar Easterlies – cold winds that blow from the east to the west near the North and South Poles
Radiant Energy – energy that travels as electromagnetic waves; can travel through the vacuum of space
Sea Breeze - a wind that blows in from the sea due to local temperature and pressure differences at the shore; occurs in the day since land heats faster than water
Temperature Inversion – a temperature increase as altitude increases in the troposphere
Trade Winds – steady winds that flow from east to west between latitudes 30 degrees North and 30 degrees South
Tropics - between the latitude lines of the Tropic of Cancer and the Tropic of Capricorn
Ultraviolet - situated beyond the visible spectrum at its violet end; having a wavelength shorter than wavelengths of visible light and longer than those of X-rays
Unstable Air – warm air rises rapidly in the atmosphere and forms cumulonimbus clouds that produce thunderstorms
Upwelling – vertical movement of water toward the ocean surface
Westerlies – steady winds that flow from west to east between 30 degrees and 60 degrees in the northern and southern hemispheres
Wind - wind is moving air and is caused by differences in air pressure within our atmosphere
Chapter 11 – Weather
Air Mass – a large area of air that has uniform temperature, humidity, and pressure
Air Pressure – the force that a column of air exerts on the air, or a surface, below it
Blizzard – a violent winter storm characterized by freezing temperatures, strong winds, and blowing snow
Cirrus - cloud generally characterized by thin, wispy strands; high in the troposphere and do not produce rain or snow
Cold Front – area where a cold air mass replaces a warm air mass
Continental Polar – cold air mass that travels over land; cold and dry
Continental Tropical – warm air mass that travels over land; hot and dry
Cumulus – puffy white clouds with flat bases; indicate nice weather
Dew Point – temperature at which air is fully saturated; the atmospheric temperature below which water droplets begin to condense
Doppler Radar – used to detect precipitation and wind speed
Front – a boundary between two air masses
High Pressure System – a large body of circulating air with high pressure at its center; brings “happy” weather
Humidity – the amount of water vapor in the air
Hurricane – an intense tropical storm with winds over 119km/h (74mph)
Isobar – lines that connect all places on a map where pressure has the same value
Lightning – an electric discharge within a cloud, between clouds, or between a cloud and the ground
Low Pressure System – a large body of circulating air with low pressure at its center; brings “lousy” weather
Maritime Polar - cold air mass that travels over oceans; cold and moist
Maritime Tropical - warm air mass that travels over oceans; hot and humid
Occluded Front – a fast moving cold front catches up with a warm front, surrounds it and forces it up into the atmosphere; brings precipitation
Precipitation – any form of water that falls from the atmosphere
Relative Humidity – the amount of water vapor in the air compared to the maximum amount of water vapor the air could hold; a percentage of the water vapor that the air could hold
Station Model – a diagram that uses numbers and symbols to show local weather measurements
Stationary Front – a cold air mass and warm air mass meet and stop moving; brings cloudy days and light rain
Storm Warning – a storm is here, take cover
Storm Watch – the conditions are right for a storm to happen
Stratus – cloud that spreads across the sky and produces a light rain or drizzle; resembles a high fog
Surface Report – weather measurements made on Earth’s surface
Thunderstorm – a weather event that includes rain, strong winds, thunder, and lightning
Tornado – a violent, whirling column of air in contact with the ground
Upper Air Report – describes wind, temperature, and humidity above Earth’s surface
Warm Front – dense, warm air moves toward colder, dense air and rises above it
Weather –local atmospheric conditions, along with short-term changes, of a certain place at a certain time
Chapter 12 – Populations and Communities
Abiotic – non living
Atmosphere – layer of gases surrounding the Earth
Biosphere – all living organisms on Earth
Biotic – living or were once living
Biotic Potential – the possible growth of a population if it could grow in perfect conditions with no limiting factors
Birthrate – the number of offspring produced in a population over a given time period
Carnivore – an organism that eats flesh
Carrying Capacity – the largest number of members of a species that the environment can support
Commensalism – a symbiotic relationship that benefits one species but does not harm or benefit the other
Community – all the populations of different species that live together in the same area at the same time
Competition – the demand for resources, such as food, water, and shelter, in short supply in a community
Consumer – heterotroph; organisms that get energy by eating other organisms
Cryosphere - the places where water is in its solid form, where low temperatures freeze water and turn it into ice
Deathrate – the number of individuals in a population that die over a given time period
Decomposer - an organism, often a bacterium, fungus, or invertebrate that feeds on and breaks down dead plant or animal remains, making organic nutrients available to the ecosystem.
Detritivore/Scavenger – heterotrophs that eat dead plant and animal matter to obtain energy
Ecosystem – all the living and nonliving things in a given area
Endangered species – a species whose population is a risk of extinction
Energy Pyramid – a model that shows the amount of energy available in each link (trophic level) of a food chain
Extinct – a species that has dies out and no individuals are left
Food Chain – a model that shows how energy flows in an ecosystem through feeding relationships
Food Web – a model of energy transfer that can show hot the food chains in a community are interconnected
Geosphere – the solid part of the Earth
Habitat – the place within an ecosystem where an organism lives; provides the biotic and abiotic factors an organism needs to survive and reproduce
Herbivore – get their energy by eating plants; primary consumers
Host – the species that is harmed in parasitism
Hydrosphere – all the water that is on the surface of the planet, underground, and in the air
Limiting Factor – anything that restricts the size of a population
Migration – the instinctive seasonal movement of a population of organisms from one place to another
Mutualism – a symbiotic relationship in which both partners benefit
Niche - the role an organism plays in a community; all of the interactions of a species with the other members of its community and the ecosystem
Omnivore – heterotrophs that get their energy by eating plants and animals
Overpopulation – when the size of a population becomes larger than the ecosystem can support
Parasite - the species that benefits from harming its host
Parasitism – a symbiotic relationship that benefits one species and harms the other
Population – all the organisms of the same species living in an area
Population Density – the size of a population compared to the amount of space available
Predation - a biological interaction where one organism, the predator, kills and eats another organism, its prey
Producer - autotroph; an organism that can use chemical or radiant energy to produce its own food
Species – a group of organisms that have similar traits and are able to produce fertile offspring
Symbiosis – a close and long-term relationship between two species that involves an exchange of resources
Chapter 13 – How Organisms Affect Environments
Acquired Trait – a trait that an organism acquires or develops over time; not genetically determined
Adaptations – an inherited or learned trait that increases an organism’s chance of surviving and reproducing in a particular environment
Algal Bloom – when algae grow and reproduce in large numbers
Allele – a gene for a single trait
Asexual Reproduction – a type of reproduction in which one parent organism produces a genetically identical offspring
Camouflage – an adaptation that enables a species to blend in with its environment
Chromosome - microscopic threadlike part of the cell that carries hereditary information in the form of genes
Deoxyribonucleic acid (DNA) - a molecule that encodes an organism's genetic code; contains all of the information required to build and maintain an organism
Dominant - an allele or a gene that is expressed in an organism’s phenotype, masking the effect of the recessive allele
Fertilization – a reproductive process in which a sperm joins an egg
Gene – a section of DNA on a chromosome that has genetic information for one trait
Genotype – the alleles of all the genes on an organism’s chromosomes
Homoeostasis – an organism’s ability to maintain steady internal conditions when outside conditions change
Inheritance – the passing of traits from one generation to another
Marine - having to do with the ocean
Meiosis – a process in which one diploid cell divides to make 4 haploid sex cells
Mimicry - external resemblance of an animal or plant (or part of one) to another animal, plant, or inanimate object
Mitosis – a process during which the nucleus of a cell and its contents divide
Mutation – a permanent change in the sequence of DNA in a gene or chromosome
Natural Selection – the process by which organisms with variations that help them survive live to reproduce
Nonpoint Source – a source of pollution that cannot be easily identified; pollution that comes from many places, all at once
Nucleus (biology) – a part of a eukaryotic cell that directs cell activity and contains genetic information stored in DNA
Point Source - any single identifiable source of pollution from which pollutants are discharged, such as a pipe
Punnett Square - a square diagram that is a grid of usually four boxes and is used to calculate and depict all the possible combinations of the different genotypes and phenotypes among the offspring
Recessive – genetic code that is not expressed if a dominant allele is present
Selective Breeding – the selection and breeding of organisms for desired traits
Sexual Reproduction – type of reproduction where the genetic material from two different cells (sperm and egg) combine to produce a unique offspring
Trait – a distinguishing characteristic of an organism
Variations – a slight difference in an inherited trait among individual members of a species
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