Name _________________________________________________ Period _______
Final Exam
8th Grade Science: Monday, June 16th
Ecosystems
1. Vocabulary: ecosystem, biotic, abiotic, niche, habitat, commensalism, mutualism,
parasitism, producers, consumers, herbivore, carnivore, omnivore, scavenger, decomposer,
climate, food web, energy pyramid, photosynthesis, and biome.
2. What is biodiversity? What are the 3 most diverse biomes and what are 2 reasons why
biodiversity is important?
Biodiversity is the amount of differences in living organisms in an area.
3 most diverse biomes are tropical rainforest, coral reef, wetlands
2 reasons why its important- beauty and health (more variety = healthier area- cannot be all
killed off by one disease)
3. Describe five ways biodiversity is being decreased (HIPPO)
H- habitat destruction by logging, building, I- invasive species (organisms not native to the
area move in and take over the native speices), P- pollution, P- poaching, O- over
population
4. Introduced species-what are they? How do they arrive in new areas? What type of damage
can they cause? How can we get rid of them?
Introduced or invasive species are organisms not native to an area. They may be
introduced by humans as pets they released into the wild, may be accidentally brought to an
area with other crops or deliveries/shipments. They can eat local species, attack local
species, and usually have no predators to keep the invasive species from growing out of
control. To get rid of them is very difficult, they may be hunted, harvested, destroyed, but
it will only work if they are completely removed from an area.
5. What are some biotic and abiotic parts of an ecosystem?
Biotic- any living part of the ecosystem- includes plants, animals, bacteria, fungus, and
protists. Abiotic- any non living part of the ecosystem- includes climate, weather, wind
(air), water, temperature, and soil
6. Be able to draw or explain/identify roles in a food web if given some information about the
organisms in it. (producer, consumer, scavenger, etc.)
Producer-an organism that produces or makes it own food (a plant), consumer- organism
that cannot make its own food, it must consume another species (an animal, a fungus, etc),
scavenger- an organism that eats dead or decaying organisms (vultures)
7. What happens if one part of the food web/food chain is removed? Which populations go
up? Which populations go down?
If predator numbers decrease, then the prey that it ate will increase because it is no longer
being hunted. If the prey numbers decrease, then the predator numbers will also decrease
because it has no food.
8. Be able to identify the type of relationship between two organisms (parasitism,
commensalism, mutualism)  
Parasitism-   one organism benefits, the other is harmed (dog and a flea)
Commensalism-   One organism benefits, the other doesn’t care (a bird nesting in a
tree)
Mutualism-   Both organisms benefit (a flower being pollenated by a bee)
9. Be able to explain how the six different abiotic factors affect the living organisms in an
ecosystem. Why is each abiotic factor important? (use your foldable)
Climate- long term weather pattern of an area
Weather- the immediate weather of an area
Temperature- influenced by season, altitude, sun exposure
Air- the wind and type of air (oxygen and air pressure levels)
Water- type of water (fresh/salt) amount of water (rainy/snowy/desert)
Soil- rocky, sandy, fertile, etc. How well and what type of plants can grow in an area.
10. What do food webs and energy pyramids show us?
Shows the flow of energy in a ecosystem- Energy originally comes from the sun, converted
to chemical energy in plants, plants (producers) are eaten by consumers. Energy is used up
by organism for growth (cell division) reproduction, etc. so not 100% is passed on to the
next level. Each level up, less and less energy is available to that level, so that organism
has to eat more and more to get the energy it needs to survive.
11. Why does being a vegetarian make sense using the energy pyramid?
Vegetarians eat plants only, which are the first level of the energy pyramid. The most
energy is available at this level with the least amount of waste. Eating plants helps reduce
energy lost for growing and reproducing animals at the next and third levels of the
pyramid.
12. What do plants produce during photosynthesis? What do they use?
Plants use sunlight energy, water, and carbon dioxide to produce sugar (chemical energy)
and oxygen.
Atmosphere:
13. The layers of the atmosphere in order and explain the key characteristics of each.
Troposphere- weather occurs here, planes fly in this level, breathable gases are found here.
Stratosphere- weather balloons travel to here, ozone layer is found here which protects us
from UV rays which cause burns and cancer
Mesosphere- meteors burn up here, coldest layer
Thermosphere- warmest layer, northern lights occur here, space shuttle flies here
Exosphere- last layer of earth’s atmosphere, very few air molecules exist here, boundary
between earth and outer space
14. Identify the primary gases in the atmosphere and explain which is most abundant, second
most abundant, etc.
Nitrogen (78%) oxygen (21%)
15. What happens to air pressure as you increase in altitude?
Air pressure decreases as you increase in altitude, there are more air molecules at sea level
than there are high in the mountains.
16. Explain the importance and location of the ozone layer. What are the causes and effects of
a thinning ozone layer. Be sure to use the terms Ultraviolet radiation, ozone layer and
chlorofluorocarbons in your answer.
Ozone layer is in the stratosphere, it is made of three oxygen atoms bonded together. This
layer stops harmful UV light waves from reaching earth. CFC’s or chlorofluorocarbons
from air conditioners and aerosol cans are destroying the ozone layer, causing it to thin and
allowing more UV radiation in, this results in higher sun burn rates and more skin cancer
cases.
17. Define and describe the methods of heat transfer discussed in class and your textbook:
a. Conduction transfer of heat through solids in direct contact
b. Convection transfer of heat through liquids through circulating (liquid and gas)
c. Radiation transfer of heat in the form of waves or rays (like from the sun or a
microwave)
18. What is wind? What three things cause wind and wind patterns?
Wind is the movement of air from an area of high pressure (cold) to an area of low pressure
(warm) It is caused by differences in air pressure, density, and temperature.
19. What causes high and low pressure in air? In which direction does air move?
Warm air molecules are more spread out (low pressure), cold air molecules are closer
together (high pressure). Molecules will move from high pressure to low pressure, this
makes wind.
20. What is the Coriolis effect, what causes it, and how does it affect wind in the northern and
southern hemispheres?
As the earth rotates, the winds don’t flow in a straight line. They turn to the right in the
northern hemisphere and the left in the southern hemisphere.
21. Identify the global wind patterns on the map below (polar easterlies, westerlies, trade
winds, douldrums, and jet stream)
22. Why are trade winds important to U.S. history?
Trade winds quickly carried explorers from Europe to North America. Allowing for
settlement and establishing of trade routes.
23. Explain what the jet stream is, where it is, and why it is important to pilots and weather
forecasters
Jet stream is a strong belt of wind in the upper troposphere. It flows from west to east. Pilots
take advantage of this when they fly to the East coast. Looking at weather in the west, we can see
what type of weather will be arriving in the East over the next week.
24. Distinguish between sea breeze and land breeze, how are they formed?
Sea Breeze- occurs during the day when cool air molecules move toward the land to
replace the rising, warm air molecules over the hot land.
Land breeze- occurs usually at night when the cool air molecules from the land move
toward the sea, replacing the rising warm air molecules over the warm water.
Weather
25. What source of energy drives all the
wind and weather of Earth? Be able
to explain how.
The sun is the source of all energy. It heats
the land and the water differently (different heat capacities), heats the poles and equator
differently (direct and indirect light) causing areas of high and low pressure, cold and warm
molecules. Molecules of air and water move causing wind and weather.
26. What is the difference between weather and climate?
Climate is the long term weather patterns of an area. Weather is the state of the atmosphere
at a specific time and place.
27. Identify what four factors are used to describe the weather and what instruments are used to
measure these four factors.
Temperature-amount of movement in particles- measured with a thermometer
Air pressure- amount of force exerted on an area by the air molecules, measured with a
barometer
Wind- movement of air from and area of high pressure to low pressure, speed measured by
anemometer, direction measured by wind vane
Humidity- amount of moisture in the air- measured by a hygrometer
28. What are clouds and how do they form? (think of the cloud lab)
Clouds are masses of small water droplets or tiny ice crystals that float in the air. They
form as warm, moist air rises, expands due to lower air pressure, cools and condenses into a
liquid.
29. How are clouds classified? (3 heights, 3 shapes, know the names for the height levels and
shapes plus the name of the rain forming cloud, and what kind of cloud is fog)
Clouds are classified by height- low to high- strato, alto, cirro; and shape- Stratus (stretched
out), cumulus (puffy), and cirrus (wispy). Nimbus is any rain producing cloud.
30. What are air masses, where do they get their temperature and humidity from?
An air mass is a large body of air that has nearly the same temperature and humidity. If it
forms over land, it is dry (continenetal), over water, it is moist (maritime). If it forms near
the poles it is polar, near the equator, it is tropical
31. What are the names and characteristics (dry/moist, warm/cool) of the four air masses that
primarily affect the US? What type of weather would we feel if a continental polar air
mass were to arrive in NJ? Why?
Maritime tropical, continental tropical, maritime polar, continental tropical
We would feel cool, dry weather if a cP air mass were to arrive in NJ because that air mass
is cool (from poles) and dry (formed over land)
32. What is a front?
When two or more air masses meet.
33. What are the four types of fronts we usually see? Be able to identify a diagram showing
the four different types of fronts and the four symbols used.
34. Be able to identify examples of severe weather and how they form. Why do only certain
types of severe weather occur in certain parts of the world? (Why won’t California see a
lot of tornadoes, will Alaska see a hurricane? Why? What is tornado alley? Why is it
called that?)
Thunderstorm- a storm with thunder and lightning and heavy rain or hail. Caused when
moist, unstable air, and lift. Likely to form in spring and summer months and afternoon
and evening hours. Tornadoes are a violent, rotation column of air extending from a
thunderstorm to the ground. Mostly occurs in spring and summer months (during
thunderstorm time) in areas where two air masses meet (Tornado Alley). Hurricanes are a
system of strong winds spiraling around a low pressure center. They have to form over
warm water, so they are most common in the summer and fall in the ocean and coastal
areas. Blizzards are severe winter snow storms with high winds (35+mph) and intense
snow fall.
35. What type of weather is associated with high and low pressure areas?
High pressure- dense air sinking and good/fair weather. Low pressure= warm, moist air
rising and forming cloudy = stormy/poor weather
36. What are isobars and isotherms? Can you construct/read a map made of these lines?
Isobars- lines connecting areas on a map of equal air pressure
Isotherms- lines on a map connecting areas of equal temperature
Water
37. Read and interpret a chart showing the distribution of water on earth (fresh vs. salt, solid vs
liquid)
38. Identify ways in which water is important to humans, plants, climate, cultures, and life.
Water is used to irrigate crops for agriculture, for shipping transportation, for
manufacturing, for many of our body’s processes, by plants for photosynthesis, it helps
keep temperatures on earth steady, etc.
39. Be able to describe the unique chemical formula and structure of water- why is it a “polar”
molecule? What does this polarity allow water molecules to do?
H2O, the oxygen end pulls more electrons to it, making it have a positive and negative end.
Multiple molecules can then “stick” to
one another and
allows for cohesion (to other water
molecules), adhesion
(sticking to other substances), surface
tension and capillary
action.
40. Three phases of water: temperatures at which they change phase, how active are the
molecules in each phase, what do we call each type of change (melting, condensing, etc)
41. What is cohesion and what are some examples?
Two alike molecules sticking together. Water forming a bubble on top of a penny.
42. What is adhesion and what are some examples?
Two different molecules sticking together. Water molecules sticking to the side of a
graduated cylinder and forming a meniscus.
43. What is surface tension and what are some examples?
Water molecules sticking together to form a “film” on the surface of water that allows
some bugs to walk across the top of it or lets you float paper clips on the surface.
44. What is capillary action and what are some examples?
Water molecule sticking to another surface, like a paper towel, and climbing up against
gravity to get water to the top of a tall tree.
45. Parts of the water cycle including transpiration. Does the total amount of water on earth
change or stay the same?
The total amount of water in the system is consistent, water just changes form and is constantly
recycled.
46. What is heat capacity and why is it important to the climates of coastal areas?
The amount of energy it takes to raise the temperature. Water has a high heat capacity and
is very slow to heat up and cool down. The climate is coastal areas is much more steady as
a result of the heat capacity of the near by water.
47. Why are oceans important to humans?
Transportation, irrigation, food source, mineral and energy source, drinking water source,
etc.
48. What does salinity mean? How can the salinity of the ocean increase or decrease?
Salinity is the amount of salt in the water. Salinity will decrease if there is a lot of
precipitation. Salinity will increase if there is a lot of evaporation or freezing of water, or
more minerals with salt in them dissolve.
49. What is desalination? How is it done?
Desalination is the removal of salt from the sea water to have fresh drinking water. Fresh
water can be obtained by heating salt water, catching the fresh water vapor, condensing the
water vapor back into a liquid to drink
50. What is a current? What is the difference between a surface current and a deep ocean
current? How does each of them form?
Currents are the large scale movement of water in a specific direction. Surface currents
(gulf stream, Alaska current, etc) occur due to the wind and coriolis effect. Deep ocean
currents occur due to the sinking of denser water and the rising of less dense water.
51. What are some examples of surface currents?
Gulf Stream, Alaska current, Labrador current
52. What makes water more dense (salty and cold) in deep ocean currents? What is a
thermohaline current?
Sea water becomes denser when it is cold and water freezes forming ice in the poles. This
colder, saltier water sinks and flows toward the equator. Thermo (temperature) haline (salt)
currents are the name given to these types of deep ocean currents.
53. What are tides and what causes them? What is a spring vs. a neap tide?
Tides are the regular rise and fall of the ocean water levels due to the gravitational pull of
the moon and sun. Spring tides occur when the moon, earth and sun are all lined up (new
and full moons) and their gravitational pull is combined, causing higher than normal high
tides and lower than normal low tides. Neap tides occur when the moon, earth and sun are
at 90 degree angles (1st and 3rd quarter) and tides are not as high or low as normal.
54. What are gyres?
Large circular currents. Trash and other objects can get trapped in these gyres.
55. How do ocean currents affect the climates of coastal areas?
Currents bring warm or cool water to coastal areas. Warm currents also bring moisture and
humidity, cool currents can bring dryness and drought.
56. What are waves and how are they different from currents and tides?
Waves are the large scale movement of energy through water molecules. Wave energy
moves forward, the water molecules do not. In currents and tides, the molecules of water
are moving forward.
57. What are the parts of a wave?
Crest- highest point, trough- lowest point, wave length- distance from crest to crest, wave
height- distance from crest to trough.