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7th Grade Vocabulary by Chapter

Chapter 1 vocabulary


CONCLUSION – a summary of the informatiuon gained from testing a hypothesis

CONTROLLED EXPERIMENT – a scientific experiment that tests how one variable affects another

CONSTANTS – the factors in an experiment that remain the same

CRITICAL THINKING – comparing what you already know with the information you are given in order to decide whether you agree with it

DATA – information that is collected through observation, often a set of measurements

DEPENDENT/RESPONDING VARIABLE – the factor measured pr observed during an experiment

HYPOTHESIS – a possible explanation about an observation that can be tested by scientific investigations

INDEPENDENT/MANIPULATED VARIABLE – the factor that you want to test

INFERENCE – a logical explanation of an observation that is drawn from prior knowledge or experience

OBSERVATION – using one or more of your senses to gather information and take note of what occurs

PREDICTION – a statement of what will happen next in a sequence of events

SCIENTIFIC LAW – describes a pattern or an event in nature that is always true

SCIENTIFIC THEORY – an explanation of observations or events based on knowledge gained from many observations and investigations

VARIABLE – any factor in an experiment that can have more than one value


Chapter 2 vocabulary


BACTERIA - the simplest of creatures that are considered alive, they are often considered decomposers

CELLULAR RESPIRATION – a series of chemical reactions that convert the chemical energy bound in glucose to a usable form of energy

CHEMOSYNTHESIS – the process where some producers use inorganic chemical energy instead of light energy to make food

CHLOROPHYLL – the pigment which captures and stores light/radiant energy

CHLOROPLAST – an organelle in plant cells which is the site of photosynthesis

CONDENSATION – the reverse of evaporation, water vapor changes into liquid water dioxide into the food-energy molecule glucose and release oxygen

ELEMENT - basic forms of matter made from a single type of atom

ENERGY – a measure of how much can happen

ENERGY PYRAMID – a model that shows the amount of energy available in each step of a food chain

EVAPORATION – the process where liquid water changes in to gas called water vapor

FOOD CHAIN – a model that shows how energy flows in an ecosystem through one series of feeding relationships

FOOD WEB – a model of energy transfer that shows interconnected food chains

GLUCOSE – the sugar produced by the process of photosynthesis

NITROGEN FIXATION – the process where nitrogen gas in the atmosphere changes into nitrogen compounds that can be used by living things

PHOTOSYNTHESIS – a series of chemical reactions that convert light energy, water, and carbon

PRECIPITATION – any form of water that falls to the Earth (rain, snow, hail, sleet)

RELEASE – gives off, sets out, produces

TRANSPIRATION – the release of water vapor from the leaves and stems of plants through the stomata


Chapter 3 vocabulary


AMINO ACID – a carbon compound having an amino group

BIOLOGICAL MOLECULE – a large organic molecule in a living organism

CARBOHYDRATE – organic molecules such as sugars, starches, and cellulose.  A source of energy for cells. 

CELLULOSE - a carbohydrate that is composed of glucose and forms most of the cell wall in plants

ENZYME - a biological molecule that increases the rates of chemical reactions

HYDROCARBON – a compound having only carbon and hydrogen atoms

LIPID – a biological molecule such as fats, oils, hormones, waxes, and cell membranes.  They are mostly for energy storage.

NUCLEIC ACID – a polymer that stores and carries genetic information

ORGANIC COMPOUND – a compound found in living things that contains carbon (usually bonded to Hydrogen and may be bonded to sulfur, oxygen, phosphorous, nitrogen)

PROTEIN – a biological polymer made of amino acids


Chapter 4 Vocabulary

Balanced Forces –Forces acting on an object that combine and form a net force of zero

Chemical Energy – Energy that is stored in and released from the bonds between atoms

Contact Force – A push or pull on one object by another object that is touching it

Energy – The ability to cause change

Force – A push or pull on an object

Geotropism/Gravitropism – The growth of the parts of plants with respect to the force of gravity

Gravity – An attractive force that exists between all objects that have mass

Hydrotropism – The growth or turning of plant roots toward or away from moisture

Innate - Determined by factors present in an individual from birth

Law of Conservation of Energy – States that energy can be transformed from one form to another, but it cannot be created or destroyed

Mechanical Energy – Sum of the potential energy and the kinetic energy in a system

Noncontact Force – A force that one object applies to another object without touching it

Phototropism/Heliotropism – The orientation of a plant or other organism in response to light (Sun), either toward the source or away from it

Potential Energy – Stored energy due to the interactions between objects or particles

Radiant Energy – Energy carried by an electromagnetic wave

Response – A reaction to something (stimulus)

Thermal Energy – The sum of the kinetic energy and the potential energy of the particles that make up an object

Thermotropism – The turning or bending of a plant or other organism in response to a directional source of heat

Thigmotropism – The turning or bending of a plant or other organism in response to a touch stimulus

Turgor Pressure – The pressure exerted on a plant cell wall by water in the vacuole

Unbalanced Forces – Forces acting on an object that combine and form a net force that is not zero



Chapter 5 (1 of 2 sets)

Air Mass – a large area of air that has uniform temperature, humidity, and pressure

Air Pressure – the pressure that a column of air exerts on the air, or a surface below it

Cirrus - Cirrus clouds are thin, wispy clouds blown by high winds into long streamers. They are considered "high clouds".  They generally mean fair to pleasant weather.

Condensation – the process during which water vapor changes into liquid water

Convection – the circulation of particles within a material.  It is caused by differences in thermal energy and density

Cumulonimbus – the type of cloud that can form thunderstorms

Cumulus - Large, white, puffy clouds that generally appear during fair weather, although they also form thunderheads on hot days.

Evaporation – the process of a liquid changing to a gas at the surface of the liquid

Front – a boundary layer between two air masses

Humidity – the amount of water vapor in the air

Lightning – an electric discharge within a cloud, between clouds, or between a cloud and the ground

Polar Easterlies - dry, cold prevailing winds that blow from the high-pressure areas of the poles in an east to west direction

Precipitation – water, in liquid or solid form, that falls from the atmosphere

Pressure System – a moving air mass with a particular pressure

Stratus - Low clouds that stretch over large portions of sky, creating overcast conditions (above-ground fog); may produce a light drizzle or a small amount of snow.

Thunderstorm – a weather event that includes rain, strong winds, thunder, and lightning

Trade Winds - winds blowing steadily toward the equator from the east; blowing from the tropical high-pressure areas to the low-pressure zone at the equator

Troposphere – the atmospheric layer closest to Earth’s surface   

Westerlies - the belt of winds in the mid-latitudes of the northern and southern hemispheres that blow from the west


Chapter 5 (2 of 2 sets)


Avalanche - (snowslide, snowslip, rockslide) a rapid flow of snow down a sloping surface.  Slides of rocks or debris, behaving in a similar way to snow.

Blizzard - a severe snowstorm characterized by strong sustained by winds of at least 56 km/h (35 mph) and lasting for three hours or more.

Climate – the long term average weather conditions that occur in a particular region

Deposition – the laying down or settling of eroded material

Drought – two or more years of below average precipitation

Earthquake - a sudden and violent shaking of the ground as a result of movements within the earth's crust or volcanic action.

Ecoregion – an area defined by its environmental conditions (climate, landforms, and soil characteristics) as well as characteristic groups of plants, animals, and other species adapted to those conditions

Erosion – the moving of weathered material, or sediment, from one location to another

Flood - an overflowing of a large amount of water beyond its normal confines, especially over what is normally dry land

Ground Water – water that is stored in cracks and pores beneath Earth’s surface

Hurricane – an intense tropical storm forming over the Atlantic Ocean with winds exceeding 119 km/hr (known as Typhoon over the Pacific Ocean)

Storm Surge – rising ocean water along the coast, caused by hurricane winds pushing ocean water higher as the storm approaches land

Surface Water – the water on the surface of the Earth (rivers, lakes, and oceans, etc.)

Tornado – a violent, whirling column of air in contact with the ground

Tsunami - an unusually large sea wave produced by a seaquake or undersea volcanic eruption

Volcano - a large, mountain-like vent in the earth's crust through which lava, steam, and ash are expelled, either continuously or at irregular intervals

Watershed – a higher area of land that drains runoff water into a particular stream, lake, or other body of water

Weathering - mechanical (physical) and chemical processes that cause exposed surfaces to break apart

Wildfire - any large fire that spreads rapidly and is hard to extinguish


Chapter 6 Vocabulary


Alpine Glacier – a glacier that forms in the mountains

Aquifer – an area of permeable sediment or rock that holds significant amounts of water

Desalination - Removal of salt (sodium chloride) and other minerals from the sea water to make it suitable for human consumption and/or industrial use.

Divide – the elevated boundary between areas that are drained by different river systems

Estuary – a coastal area where freshwater from rivers and streams mixes with salt water from seas or oceans

Freshwater – water that has less than 0.2 percent salt dissolved in it

Glacier – a huge mass of ice that moves slowly over land

Ice Core – a long column of ice taken from a glacier

Ice Sheet – a glacier that spreads over land in all directions

Lake – a large body of water that forms in a basin surrounded by land

Permeability – the measure of the ability of water to flow through rock and sediment

Porosity – the measure of a rock’s ability to hold water

Riffle – a shallow part of a stream that flows over uneven ground and splashes and swirls, adding oxygen to the stream

Runoff – water that flows over Earth’s surface

Sea Ice – ice that forms when sea water freezes

Stream – a body of water that flows within a channel

Water Table – the upper limit of the underground region in which the cracks and pores within rocks and sediment are completely filled with water

Wetland – an area of land that is saturated with water for part or all of the year; an aquatic ecosystem


Chapter 7


EMU (Extravehicular Mobility Unit) - an independent spacesuit that provides environmental protection, mobility, life support, and communications for astronauts performing work outside a spacecraft in Earth’s orbit

Extremophile - an organism that thrives in harsh conditions that are unsuitable to most life on Earth

Flyby – a type of space probe that travels to distant space objects and collects information without orbiting or landing

ISS (International Space Station) -a habitable artificial satellite in low Earth orbit that serves as a microgravity research laboratory for experiments in many areas of science

Lander - a type of space probe that lands on the surface of a distant space object and collects information

Magnetosphere – The magnetic field of the Earth which prevents most of the particles from the Sun from hitting the Earth

Microgravity - a condition where the force of gravity is so weak that it seems there is no gravity; a feeling of weightlessness

Moon - A natural satellite of a planet; an object that revolves around a planet. 

Orbiter - a type of space probe that collects information while in orbit around a distant space object

Rocket – a vehicle propelled by the exhaust made from burning fuel

Satellite - an object that revolves around a planet; in modern terms, an artificial object which has been intentionally placed into orbit

Space Probe – an uncrewed spacecraft sent from Earth to explore objects in space

Tether - a cord, fixture, or flexible attachment that anchors something movable to a stable object which may be fixed or moving

Transmit - cause (something) to pass on from one place or person to another


Chapter 8

Biome – a geographic area on Earth that contains ecosystems with similar biotic and abiotic features

Coral Reef – an underwater structure made from outside skeletons of tiny, soft-bodied animals

Desert – a biome that receives very little rain

Ecological Succession – the process of one ecological community gradually changing into another

Estuary – a coastal area where freshwater from rivers and streams mixes with salt water from seas or oceans

Eutrophication – the process of a body of water becoming nutrient-rich

Grassland – a biome where grasses are the dominant plants

Intertidal Zone – the ocean shore between the lowest low tide and the highest high tide

Pioneer Species – the first species that colonizes new or undisturbed land

Salinity – a measure of the mass of dissolved salts in a mass of water

Taiga – a forest biome consisting of mostly cone-bearing evergreen trees

Temperate – a region between the tropics and the polar circles

Tundra – a biome that is cold, dry, and treeless

Wetland – an aquatic ecosystem that has a thin layer of water covering soil that is wet most of the time

Microhabitat – a very small local habitat

Ecosystem - a system formed by the interaction of a community of organisms with their environment

Biodiversity - the number of different species that live within a particular ecosystem

Climax Community - an ecological community in the final stage of succession, in which the species remain relatively stable until a disturbance such as fire occurs

Primary Succession - The ecological succession of plant and animal communities in a disturbed area where no topsoil exists

Secondary Succession - The ecological succession of plant and animal communities in a disturbed area where topsoil remains


 Chapter 9 


Adaptation – an inherited trait that increases an organism’s chance of surviving and reproducing in a particular environment

Archaea – any of a group of microorganisms that resemble bacteria but are different from them in certain aspects of their chemical structure.  May be the earliest forms of cellular life.

Binomial Nomenclature – a naming system that gives each organism a two-word scientific name (Genus and species)

Cladogram – a branched diagram that shows the relationships among organisms, including common ancestors

Compound Leaf – a leaf composed of a number of leaflets on a common stalk

Dentate – having a toothed margin or tooth-like projections

Dichotomous Key – a series of descriptions arranged in pairs that lead the user to the identification of an unknown organism

Domain – a broad classification category, dividing all life into 3 large groups

Domesticated – to tame (an animal), especially by generations of breeding, to live with human beings as a pet or work animal and usually the animal loses its ability to live in the wild, - to adapt (a plant) so as to be farmed by and beneficial to human beings

Genus – a group of similar species

Kingdom – The second broadest classification category, dividing all forms of life into 5 groups having certain fundamental characteristics in common

Leaf Margin – the outer edge of the leaf

Leaflet – a small leaf-like part or structure

Lobed – having divisions that do not go all the way through

Natural Selection – The process by which organisms with variations that  help them survive in their environment live longer, compete better, and reproduce more than those that do not have the variation

Palmate – shaped like an open palm or like a hand with the fingers extended

Parallel – arranged in lines that do not cross

Pinnate – having leaflets or primary divisions arranged on each side of a common stalk

Protist – one-celled organisms, classified in the kingdom Protista, that are free-moving or grouped into simple colonies

Selective Breeding – the selection of desired traits through the planned mating of individuals

Smooth – having a straight edge

Species – a group of organisms that have similar traits and are able to produce fertile offspring

Trait – a genetically determined characteristic or condition

Variation – a slight difference in an inherited trait among individual members of a species

Veination – the arrangement of veins in a leaf or in an insect’s wing


Chapter 10

Carbohydrate – a group of organic molecules that includes sugars, starches, and cellulose

Cell Differentiation – the process by which cells become different types of cells

Cell Membrane – a flexible covering that protects the inside of a cell from the external environment

Cell Theory – the theory that states that all living things are made of one or more cells, the cell is the smallest unit of life, and all new cells come from preexisting cells

Cell Wall – a stiff structure outside the cell membrane of plants (some fungus, protists, and bacteria) that protects, maintains the shape, and gives support to the cell

Chloroplast – an organelle that uses light energy, water, and carbon dioxide to produce glucose

Cilia - tiny hair-like organelles that line the surfaces of certain cells and beat in rhythmic waves, providing motion 

Cytoplasm – the semi-liquid part of the cell that supports the organelles

Endoplasmic Reticulum - a network of tubular membranes within the cytoplasm (with or without ribosomes) involved in the transport of materials

Eukaryotic - a unicellular organism that contains specialized organelles in the cytoplasm and a membrane-bound nucleus that holds genetic material organized into chromosomes

Flagellum - a long, whip-like appendage that provides motion (similar to a paddle)

Golgi Apparatus (Body) - an organelle made of layers of flattened sacs, that take up and process ingredients from the endoplasmic reticulum and then either releases the new products into other parts of the cell cytoplasm or ejects them out of the cell

Lipid – a biological macromolecule that includes fats, oils, hormones, waxes, and components of cellular membranes

Lysosome - a cell organelle containing enzymes that digest particles and that disintegrate the cell after its death

Macromolecule – a substance that forms from joining many small molecules together

Mitochondrion - an organelle in the cytoplasm of cells that functions in energy production

Nuclear Membrane (Envelope) - the double membrane surrounding the nucleus of a cell; regulates what goes in and out of the nucleus

Nucleic Acid – a biological polymer that stores and transmits genetic information

Nucleus – the part of a eukaryotic cell that directs cell activity and contains genetic information stored in DNA

Organ – a group of different tissues working together to perform a particular job

Organ System – a group of organs that work together and perform a specific task

Organelle – membrane-surrounded component, having a specialized function, in a eukaryotic cell 

Organism - organ systems working together to carry out all the tasks needed for a multicellular life form to survive

Prokaryotic - any unicellular organism that has no nuclear membrane, no organelles in the cytoplasm (except ribosomes), and has its genetic material in a single continuous strand

Protein – a long chain of amino acid molecules, may contain C, H, O, N, and sometimes S

Ribosome - found in the cell cytoplasm either  in small clusters, or attached to the outer surfaces of endoplasmic reticulum; the site of protein production

Tissue – a group of similar cells that work together to carry out specific tasks

Vacuole - a membrane-bound cavity within a cell, often containing a watery liquid or secretion, used for storage


Chapter 11 Digestive System Terms

Absorption - The process by which nutrient molecules pass through the wall of the digestive system into the blood

Anus - The opening at the end of the digestive system through which wastes are eliminated

Bile - A substance produced by the liver that breaks up fat particles

Digestion - The process by which the body breaks down complex molecules of food into small nutrient molecules

Enzyme - A protein that speeds up chemical reactions in living things

Epiglottis - The flap of tissue that seals off the windpipe and prevents food from entering

Esophagus - The muscular tube that connects the mouth to the stomach

Gallbladder - The organ that stores bile after it is produced by the liver

Large Intestine - The last section of the digestive system where water is absorbed from food and the remaining material is eliminated from the body

Liver - The largest and heaviest organ inside the body; it breaks down substances and eliminates nitrogen from the body

Mucus - A thick slippery substance produced by the body

Pancreas - A triangular organ that produces enzymes that flow into the small intestine

Peristalsis - Involuntary waves of muscle contraction that keep food moving along in one direction through the digestive system

Saliva - The fluid released when the mouth waters that plays an important role in both mechanical and chemical digestion

Small Intestine - The part of the digestive system in which most chemical digestion takes place

Stomach - A J-shaped, muscular pouch located in the abdomen that expands to hold all of the food that is swallowed

Villi - Tiny structures that cover the inner surface of the small intestine and absorb digested food

Rectum - A short section at the end of the large intestine where waste material is compressed into a solid form before being eliminated


Chapter 11 - Circulatory Terms


Aorta – The largest artery in the body

Artery – A thick walled blood vessel that carries blood away from the heart

Atrium – one of the upper chambers of the heart that receives blood entering the heart

Capillary – a tiny blood vessel where substances are exchanged between the blood and the body cells

Cardiovascular – The body system that consists of the heart, blood vessels, and blood, and that carries needed substances to cells and carries waste products away from cells

Heart – a hollow muscular organ that pumps blood throughout the body

Lymph – The watery fluid that the lymphatic system collects and returns to the bloodstream

Lymph node – a small knob of tissue that filters lymph and traps bacteria

Lymphatic – a network of vein-like vessels that returns body fluid to the bloodstream

Platelet – a cell fragment that forms blood clots

Pulmonary system – the portion of the circulatory systems that involves the lungs

Red blood Cell – a cell in the blood that takes up oxygen in the lungs and delivers it to cells throughout the body

Valve – a flap of tissue in the heart and veins that prevents blood from flowing backwards

Vein – a blood vessel that carries blood back to the heart

Ventricle – a lower chamber of the heart that is very muscular and pumps blood

White blood cell – a blood cell that fights disease


Chapter 11 Respiratory and Excretory Terms


Alveoli – tiny sacs of lung tissue specialized for the movement of gases between the air and the blood

Bronchi - The passages that branch from the trachea and direct air into the lungs

Diaphragm – a large dome-shaped muscle that has an important function in breathing

Excretion - The process by which wastes are removed from the body

Kidney – a major organ of the excretory system; eliminates urea, excess water, and other waste materials

Larynx - the organ that produces voice, located in the top of the trachea

Lungs – the main organs of the respiratory system, where gas exchange takes place

Nephron - a tiny filtering structure found in the kidneys that removes wastes from blood and produces urine

Pharynx – a part shared by the respiratory and digestive systems; the throat

Respiration - The process by which cells break down simple food molecules to release the energy they contain - NOT breathing

Trachea - A passage through which air moves in the respiratory system; windpipe

Urea – A chemical that comes from the breakdown of proteins, removed by the kidneys

Ureters – Two narrow tubes that carry urine from the kidneys to the urinary bladder

Urethra – the tube through which urine flows from the body

Urinary Bladder - A muscular organ that stores urine until it is eliminated from the body

Urine – a watery fluid produced by the kidneys that contains urea and other waste


Chapter 11 - Nervous, Integumentary, Muscular, and Skeletal

Cardiac Muscle – Muscle tissue found only in the heart

Cartilage – A connective tissue that is more flexible than bone and that gives support to some parts of the body

Central Nervous system – The brain and the spinal cord; the control center of the body

Epidermis – The outmost layer of the skin

Follicle – A structure in the dermis of the skin from which a strand of hair grows

Hormone – A chemical product of the endocrine system that speeds up or slows down the activities of an organ or tissue

Involuntary Muscle – A muscle that is not under conscious control

Ligament – Strong connective tissue that holds together the bones in a movable joint

Marrow – The soft tissue that fills the internal spaces in bones and is the site of blood cell production

Neuron – A cell that carries messages through the nervous system

Peripheral Nervous system – All the nerves located outside the central nervous system; connects the central nervous system to all parts of the body

Pore – an opening through which sweat reaches the surface of the skin

Skeletal Muscle – A muscle that is attached to the bones of the skeleton

Smooth Muscle – Involuntary muscle found inside many internal organs of the body

Synapse – The tiny space between the tip of a neuron axon and the next structure

Tendon – Strong connective tissue that attaches a muscle to a bone

Vertebra – The bones that make up the backbone

Voluntary Muscle – A muscle that is under conscious control


Chapter 11 – Reproduction and Genetics Vocabulary

Cell cycle – A pattern of growth, development, and replication in most cells

Centromere – a structure that holds chromatids together

Chromatid - one-half of two identical threadlike strands of a replicated chromosome

Cytokinesis – the process of a cytoplasm dividing

Daughter Cell – the identical cells that are produced by mitosis and cytokinesis

Dominant – the gene that is expressed if it is present

Egg – the female reproductive cell also known as ovum

Fertilization – when sperm and egg join

Gene – a section of DNA that codes for a trait

Genotype – The alleles of all genes on a chromosome

Hybrid/Heterozygous – different alleles for a particular trait.

Interphase – the period in which a cell grows and develops and performs it’s function

Meiosis – The form of cell division resulting in 4 sex cells

Mitosis –division of the nucleus

Mutation – a permanent change in the DNA of a gene or chromosome

Phenotype – how a trait appears or is expressed

Purebred/Homozygous – matching alleles for a particular trait

Recessive – The gene that is masked if a dominant gene is present

Sexual Reproduction – reproduction involving two parents

Sperm – the male sex cell

Trait – a distinguishing characteristic

Zygote – a fertilized egg