EOG Review 8th Grade Science NC

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Matter
Anything that has mass and takes up spce
Atom
The smallest unit of an element composed of a specific number of protons, neutrons and electrons
Proton
Positively charged subatomic particles found in the nucleus of an atom.
Neutron
A subatomic particle with a neutral (no) charge, that can be found in the nucleus of an atom
Electron
A negatively charged subatomic particle found in the shells surrounding the nucleus of an atom
Nucleus
The center of the atom, composing most of the atoms mass, and containing protons and neutrons
Shells
Orbital pathways surrounding the nucleus of the atom on which electrons travel; composes most of atoms volume
Periodic Table
An organized chart of all the known elements arranged horizontally by increasing atomic number (protons) and vertically by similar chemical properties
Atomic Number
The top number of an element box that indicates the number of protons (also electrons) in an atom
Atomic Mass
The bottom number in an element box, can be subtracted by the atomic number to calculate the number of neutrons
Chemical symbol
1-3 letter used to identify an element in chemical formulas and equations
Period
Horizontal rows on the periodic table indicating the number of electron shells
Group
Also called families, the vertical columns on the periodic tables that indicated shared chemical properties and the number of valence electrons
Valence electrons
The electrons in the outermost shells that can be shared or exchanged to form bonds
Noble gases
Non reactive elements found on the far left of the periodic table, containing a full outer shell of electrons
Metals
To the left of the stair step line, they are typically shiny, good conductors of heat and electricity, malleable, and ductile
Nonmetals
To the right of the stair step line, many are gases, solids are brittle. Poor conductors. Not malleable or ductile.
Metalloids
On the stair step line. Semi conductors, share properties of metals and nonmetals.
Transition Metals
Found in the center of the periodic table. Groups 3-12.
Elements
Pure substances with unique properties that are composed of the same type of atom, and cannot be broken down into a more simple substance.
Compounds
Pure substance composed of one type of molecule that is a combination of 2 or more elements that are chemically combined. Has its own unique properties.
Mixtures
A physical combination of two or more substances
Homogeneous mixture
Also called a solution, particles are evenly distributed throughout.
Heterogeneous mixture
Particles are easily distinguishable, and in a liquid larger particles settle out. Suspensions are an example.
Physical property
A property of matter that can be observed or measured without changing the identity of the substance. Can be used to describe or identify.
Malleability
The ability to be rolled or pounded into thin sheets
Ductility
The ability to be pulled into a wire
Specific Heat
The amount of energy needed to raise the temperature by 1 degree Celsius. Low SH, temp increase quickly. High SH, temp increases slowly.
Density
The ratio of mass to volume. Calculated by D=m/v. Can be used to identify matter.
Examples of physical properties
Color, odor, mass, density, specific heat, malleability, ductility, conductivity, melting point, boiling point, magnetism.
Chemical property
Describes a substances ability to undergo a chemical reaction.
Examples of chemical properties
Flammability, reactivity with water/oxygen/acid/base
Physical change
A change in matter, in relation to the physical properties, that does not alter the chemical composition
Examples of physical changes
Melting butter, tearing paper, crushing a can, freezing water, dissolving koolaid, cutting your hair.
Solubility
The ability of a substance (solute) to dissolve into another substance (solvent)
Chemical change
A change in matter through a chemical reaction in which a new substance(s) is created, which has new properties
Examples of chemical changes
Copper reacts with oxygen and turns green, dying your hair, baking bread
Law of Conservation of Mass
Matter is not created or destroyed, only transformed. The amount of reactants will equal the amount of the products.
Most reactive elements
Alkali metals (group 1), halogens (group 17)
Reactants
Substances that undergo a chemical reaction, found on the left side of a chemical equation
Products
Substances formed from a chemical reaction, found on the right side of the chemical equation
Oxidation
A chemical reaction that occurs when a substance reacts with oxygen (cellular respiration is an oxidation reaction)
Nutrition
Eating a balanced diet with a proper proportion of proteins, lipids and carbohydrates
Protein
Used for growth and repair
Examples of food containing protein
Meat (lean meat -white- is best), fish, seeds, nuts, beans, eggs
Lipids
Also called fats, stored energy
Carbohydrates
Composed of glucose (sugar), they are the bodies primary source of energy
Examples of foods containing carbohydrates
Fruits and vegetables
Prokaryote
Single called organisms lacking a true nucleus and membrane bound organelles
Eukaryotes
Multicellular organisms with membrane bound organelles and a true nucleus
Examples of prokaryotes
Bacteria, some Protists
Examples of eukaryotes
Plants, animals
Photosynthesis
A cell process in producers (autotrophs) where the energy of the sun is used to react water and carbon dioxide to produce glucose (sugar) as food. Oxygen is released as a byproduct.
Photosynthesis Equation
Sunlight + carbon dioxide + water -> glucose + oxygen
Cellular respiration
A chemical process in ALL living organisms where glucose (sugar) is oxidized to release energy as ATP. Water and carbon dioxide are byproducts. Occurs in the mitochondria of eukaryotes and cytoplasm of prokaryotes.
Cellular respiration equation
Glucose + oxygen -> water + carbon dioxide + ATP
Pathogen
A microscopic agent that can causes disease
Bacteria
A single-celled (prokaryotic) microbes, 3 shapes
Binary fission
A process of reproduction for bacteria that is similar to mitosis. Can occur as often as every thirty minutes, and is best in warm, moist environments
Antibiotics
A treatment for a bacterial infection, slows or stops the reproduction of the bacteria
5 Signs of a Chemical Rxn
1. Change in color, 2. Change in odor 3. Release of energy as light/heat/sound 4. Formation of a gas (bubbling/fizzing) 5. formation of a precipitate
Precipitate Rxn
A solid formed when mixing two liquid solutions
Virus
A non-living particle consisting of a nucleic acid enclosed in a protein coating, 4 shapes, requires a host for survival and reproduction
Examples of bacterial diseases
Strep throat, pneumonia, leprosy, tuberculosis, Lyme disease
Vaccine
A method of preventing a viral disease
Examples of viral diseases
Influenza (flu), common cold, chickenpox. measles, AIDS, yellow fever
Fungi
A eukaryotic organism that obtains nutrition through its environment or by acting as a parasite
Spores
One method of fungal reproduction
Examples of fungal disease
Athletes foot, ring worm, candida
Parasite
An organism that uses a host for nutrition or habitat, but does not destroy the host because of its dependency on the organism
Examples of parasitic disease
Amoebic dysentery, malaria, African sleeping sickness
Vector
An organism that transmits a disease (mosquito, fly, tick, flea)
Carrier
An organism that passes a disease without showing signs or symptoms (HPV or HIV)
Epidemic
Local/regional spread of disease
Pandemic
Worldwide spread of disease, greatly increased by ease of world travel
Biotechnology
Use and manipulation of cells, genes or proteins to solve problems
Genetic Modification
makes changes in the genetic material of an organism, often to obtain a desired trait
Cloning
producing an organism that is an exact genetic copy of another, ex: Dolly the sheep
Ecosystem
includes all of the living and nonliving parts of an environment, as well as the interactions among them
Biotic Factors
the living parts of an ecosystem
Examples of Biotic Factors
plants, animals, fungi, protozoa, parasites
Abiotic Factors
the nonliving parts of an ecosystem
Examples of Abiotic Factors
light, temperature, weather, soil, water
Habitat
the place where an organism lives
Niche
an organisms role within the ecosystem
species
a group of organisms that share most characteristics and can breed with one another
Population
all of the organisms of a species that live in the same place at the same time
Biosphere
all of Earth's land, water and the lower part of the atmosphere
Autotrophs (producers)
an organisms that produces its own food through the process of photosynthesis
Heterotrophs (consumers)
organisms that cannot make their own food, and must obtain nutrition by eating other organisms
Decomposers
an organism that gets energy by breaking down the remains of dead organisms and the wastes of living things
Food web
A network of interconnected food chains showing the flow of energy through the ecosystem
Carbon cycle
carbon moves through the air, ground and plants and animals within the ecosystem
Way carbon is removed from the environment
photosynthesis
Ways carbon is released into the environment
burning of fossil fuels, cellular respiration, death/decay
Nitrogen Cycle
nitrogen, used by living things to produce proteins, is recycled within the ecosystem
Nitrogen Fixation
the process of turning nitrogen gas into usable compounds, performed by bacteria or lightning
Denitrification
the process of splitting nitrogen compounds, and releasing nitrogen gas into the atmosphere, performed by bacteria
Water cycle
continuous movement of Earth's water between Earth's surface and it's atmosphere
Evaporation
process by which liquid water is heated and changes to a gas, rising into the atmosphere
Transpiration
water vapor is released through tiny openings in plant leaves
Condensation
as water vapor in the atmosphere cools it changes into a liquid
Precipitation
water falls to the Earth's surface as rain, snow, sleet or hail
Percolation/Infiltration
water soaks into the ground and collects in underground layers of permeable, sedimentary rock called an aquifer
Runoff
water runs downhill to the lowest elevation and collects in a body of water
Competition
organisms in an ecosystem rely on, and try to get, the same resources
Coexistence
organisms live in the same habitat, but rely on different resources
cooperation
helpful interactions among organisms within the same ecosystem
Mutualism
a symbiotic relationship in which both organisms benefit
Commensalism
a symbiotic relationship in which one organism benefits and the other is not helped or harmed
Parasitism
a symbiotic relationship in which one organism benefits at the expense of another
Estuary
an area where fresh water from a river meets the salt water of the ocean forming brackish water
watershed
areas of land that drain into smaller rivers, lakes or streams that lead to a river within a river basin
river basin
all the land, and its tributaries, in which water drains to the lowest point forming a river
salinity
the measure of dissolved salts in water
upwelling
cold, nutrient-rich water is brought up from the ocean floor, increasing the growth of producers, which attracts aquatic organisms
chemosynthesis
process in which bacteria use the chemicals released by vents or seeps to produce glucose without sunglight in the deep ocean
oceanic zone
area of the open ocean where free swimming creatures live, supported by phytoplankton living at the ocean surface
intertidal zone
area where ocean meets land, organisms survive tides, waves and currents
neritic zone
area where ocean floor slopes, home to coral, sea turtles, colorful fish
benthic zone
area of the deep ocean, extreme pressure, low temperature, no sunlight
plankton
free-floating producers of the ocean, that use photosynthesis to make food, produce the majority of the worlds oxygen
nekton
free-swimming organisms of the ocean
benthos
organisms that live on or in the ocean floor
indicators of water quality
1. temperature 2. dissolved oxygen 3. nitrates 4. pH 5. turbidity 6. bioindicators
Turbidity
a measure of the amount of sediment suspended in water (dirty), raises water temperature which decreases DO
Nitrates
from fertilizer runoff and animal waste, used by aquatic organisms to build proteins, excessive nitrates cause overgrowth of algae, which raises water temperature and decreases DO
pH
a measure of how acidic/basic (alkaline) a substance is, 7 is neutral, 0-6.9 is acidic, 7.1-14 is basic
bioindicators
collecting, counting and categorizing living organisms (plants/animals/etc) to determine the health of a water system, the more diversity the more healthy
tectonic plates
large pieces of the Earth's lithosphere move in many directions, driven by convection currents
Theory of Continental Drift
belief that a single landmass, called Pangea, once existed, then broke into pieces forming the continents that have drifted to their present day locations
support for continental drift
sea-floor spreading, tectonic plate movement, fossils found in the same rock layer on multiple continents, glacial deposits, ice cores
ice cores
drilling of ice from arctic regions to study climate, weather, precipitation, and trapped atmospheric gases
convergent
area where two tectonic plates push together, if the same type of crust it will form folded mountains, if opposite types of crust it will form a subduction zone
divergent
area where two tectonic plates pull apart, forms the mid-ocean ridge, causes sea-floor spreading
transform
area where two tectonic plates slide past each other, causes earthquakes
faulting
a break in the crust in which one piece slides relative to the other
intrusion
molten rock rises into open space in sedimentary rock layers and cools
hot spot
area of volcanic activity in the middle of a tectonic plate
sedimentary rock
forms when sediment is laid down in layers and the compacts and cements together
igneous rock
forms when melted rock cools and hardens
metamorphic rock
forms when existing rock undergoes extreme heat and pressure
fossil
preserved remains or evidence of organisms from the distant past
absolute dating
any method for determining the exact age of a preserved organism or rock layer
radiometric dating
the use of isotopes, and calculation of decay, to measure the age of a preserved organism or rock layer based on half-life
carbon-14
the most common half-life measurement, used to date living organisms
relative dating
any method of determining if an event or object is older than another
Law of Superposition
states that the oldest sedimentary rock layers will always be on the bottom unless they have been disturbed by geologic forces
index fossil
a fossil of a commonly found, widely distributed organism that lived in a specific time period, used for relative dating
ammonites and trilobites
most common index fossils
transitional fossil
a fossilized organism that shows a link between a present species and an ancestral species
geologic time scale
a timeline that organizes major events of Earth's history
precambrain
the earliest eon of geologic time Bacteria appear
evolution
the process by which a species changes over time
adaptation
a trait that helps an organisms survive in a given environment, ex: white fur of a fox in the arctic
variation
differences that exist naturally among a species, ex: humans have different eye colors
mutation
a change in a gene or chromosome that can cause a genetic variation that gives the offspring a trait different from either parent organism
natural selection
the process by which organisms best suited for the environment survive and reproduce
homologous structures
body parts with a similar structure but a different function
analagous structures
body parts with a similar function, but different structures
vestigial structures
body part that no longer has a useful function in an organism
classification
the systematic grouping of organisms based on shared characteristics
Levels of classification
domain -> kingdom -> phylum -> class -> order -> family -> genus -> species
energy
the ability to make things move or change, the ability to do work
energy transfer
energy moves from one place to another
energy transformation
energy changes from on form to another
nonrenewable energy source
resource that is used faster than it can be replaced
nonrenewable resources
minerals, diamonds, metals, fossil fuels
nonrenewable energy
fossil fuels - coal, oil, natural gas, nuclear power
fossil fuels
an energy resource that formed over millions of years from the decayed remains of ancient plants and animals
renewable energy source
can be replaced as it is used, or cannot be used up
renewable resources
sunlight, living organisms, water
renewable energy sources
solar, biomass, hydropower, geothermal, wind, wave, tidal
Hydrothermal Vents
Vents that provide energy source for life in the deep ocean
Speciation
The formation of a new species from an existing species. Ex: Arctic Fox and Darwin's Finches