Download Name Test Date: Friday, Jan. 24th, 2014 6th Grade Science Midterm

Name ______________________________
Test Date: Friday, Jan. 24th, 2014
6th Grade Science Midterm Test Study Guide: G-Quad
A. Organisms:
1. Biotic Factor – the living parts of an ecosystem
Ex: plants, animals, bacteria, and fungi
2. Abiotic Factor – the nonliving parts of an ecosystem
Ex: rocks, sunlight, oxygen, and water
3. Habitat – the place where an organism lives & that provides the things an organism
needs, like food, water & shelter
4. Ecosystem Organization
a. Organism – a single member of a species
b. Population – all members of one species living in a certain area
c. Community – all populations living together in a certain area
d. Ecosystem – all biotic and abiotic factors interacting in a certain area
5. Population Density – the number of individuals in a population in a given area
Ex: 500 ladybugs per square meter
6. Limiting Factor – prevents a population from increasing in number
a. Food
b. Water
c. Space
7. Predation – one organism kills & eats another
a. predator – the organism doing the killing
b. prey – the organism that gets killed
8. Competition – the struggle to survive in a habitat with limited resources
9. Adaptations – the behaviors and physical characteristics of a species that allow
them to live successfully in their environment
Ex: blubber, white fur, and sharp teeth and claws of a polar bear
10. Symbiosis – a close relationship between two species in which at least one of the
species benefits
a. mutualism
b. parasitism
c. commensalism
B. Ecosystems:
1. Food Chain – series of events in which one organism eats another & obtains energy
Ex: grass
rabbit
snake
hawk
2. Food Web – the many overlapping food chains in an ecosystem
3. Producer – an organism that can make its own food through photosynthesis
Ex. trees, flowers, and algae
4. Consumer – an organism that obtains energy by feeding on another organism
Ex. birds, lions, and humans
5. Decomposer – an organism that breaks down waste and dead organisms and
returns the raw materials to the soil
Ex. fungi and bacteria
6. Energy Pyramid – a graphic of the different feeding levels in a food chain
a. Producers (at the bottom level) have the most energy available
b. Only 10% of energy is passed from one feeding level to the next
7. Carbon-Oxygen Cycle – circulation of carbon and oxygen in the atmosphere
a. Plants take in carbon dioxide from the air.
b. Plants release oxygen as a result of photosynthesis.
c. Animals breathe in oxygen from the air.
d. Animals breathe out carbon dioxide and the cycle begins again.
8. Nitrogen Cycle – free nitrogen in the air is changed to a usable form
a. bacteria on root nodules absorb nitrogen gas in process called “Nitrogen
Fixation”
b. nitrogen moves from roots up into plant
c. consumer gets nitrogen by eating plant (or another consumer who ate a
plant)
9. Succession – the series of predictable changes that occurs in a community
a. primary succession – occurs when no ecosystem previously existed
b. secondary succession –when a disturbance removed existing community
C. Living Resources: Biodiversity – the number of different species in an area
1. Biodiversity Factors
a. area – larger area will have more species
b. climate – warmer climates with plentiful water will have more species
c. niche diversity – lots of places to live & food option will bring more species
d. diverse gene pool – genetic variety will make species more able to adapt
2. Biodiversity Threats
a. habitat destruction and fragmentation
b. poaching – illegal hunting or collecting
c. exotic species – non-native species brought in by people increase
competition for food, may overpopulate, and may feed on many native
species
3. Extinction
a. extinct – gone forever
b. endangered – in danger of becoming extinct in the near future
c. threatened – close to being endangered
4. Biodiversity Protection
a. habitat preservation – the best method – saves whole habitats
b. captive breeding – mating in zoos, sometimes released into wild
c. sustainable yield – selective cutting or fishing to maintain future supplies
d. laws & treaties – Endangered Species Act, for example
D. Land Resources:
1. Land Reclamation –process of restoring land area to a more natural state
2. Solid Waste – can be disposed of in a variety of ways:
a. Landfill – burying garbage with possible pollution consequences
b. Incineration – burning garbage may lead to air pollution
c. Recycling – reusing materials such as paper, metal, and plastic
d. Composting –biodegradable materials (like food scraps) become soil
E. Emissions:
1. Pollution Causes – most pollution comes from human activity
a. burning fossil fuels – creates carbon monoxide, which increases
greenhouse effect and leads to global climate change
b. chlorofluorocarbons (CFC’s) – create a hole in the ozone layer
2. Pollution Dangers
a. acid rain – forms when fossil fuel emissions mix with water vapor in the air
b. destruction of ozone layer, which protects us from harmful ultraviolet
radiation
c. contamination of water supply – only 3% of world’s water is fresh (not salty
ocean water)
3. Pollution Solutions
a. technology – major role is reducing emissions
i. scrubbers – clean air before it comes out of power plant smokestack
ii. catalytic converters – reduce pollutants from car & truck exhaust
b. laws & treaties – in USA, air is cleaner now than 30 years ago
F. Energy:
1. Electricity production – Coal is the most common fuel for electricity production in
USA
a. fuel is burned to heat water
b. water turns to steam
c. steam turns the blades of a turbine
d. turbine causes rotation of a generator
e. generator “sparks” electricity
f. electricity is carried on wires to consumers
2. Nonrenewable Energy Resources – All fossil fuels formed from the remains of
once-living organisms & that took hundreds of millions of years to form
a. coal – formed from ancient forests
b. oil – formed from ancient seas
c. natural gas - formed together with oil
3. Renewable Resources – natural sources of energy that are constantly being
supplied
a. solar power – the sun’s energy can be stored for use at night
b. wind energy – requires steady, reliable movement of air
c. nuclear power – splits uranium atoms in process called fission
d. geothermal energy – uses heat from the Earth’s mantle
e. hydroelectricity – water turns turbine; most commonly used source of
renewable energy
G. Fossils: the preserved remains or traces of living things, usually formed in sedimentary
rock layers
1. Types of fossils:
a. preserved remain – fossil of all or part of an organism with little or no
change to the organism itself
b. petrified fossil – formed when minerals replace all or part of an organism
c. trace fossil – provide evidence of activities – such as tracks
d. molds & casts – hollow areas that form when organism disintegrates (mold)
and the minerals & sediments that fill in the hollow area, taking the form of the
fossil (cast)
2. Index fossils – organism that was widespread, but only for a short time; these are
useful for finding the relative age of the rock layer where they were found
3. Relative Age – age of a rock compared to other rocks
4. Law of Superposition – In horizontal rock layers, each layer is older than the one
above it
H. Geologic Time
1. Geologic Time Scale – a record of the life forms and geologic events in Earth’s history
a. Precambrian Time – Earth was formed; life began on Earth
b. Paleozoic Era – first vertebrates (animals with backbones) evolved
c. Mesozoic Era – known as Age of Reptiles/Dinosaurs; divided into Triassic, Jurassic,
and Cretaceous Periods
d. Cenozoic Era – known as Age of Mammals; era we are living in today
I. Rocks & The Rock Cycle: Any type of rock can undergo geologic processes so that it
turns in to any other type of rock – or even back into the same type again and again
1. Sedimentary – formed from hardened sediment that gets deposited in layers
2. Igneous – formed from cooled magma underground (intrusive) or lava above
ground(extrusive)
3. Metamorphic Rock –formed through tremendous heat and pressure over a long
time
J. Weathering
1. Mechanical weathering (a/k/a physical) – the process of physically breaking
down a rock into smaller pieces
a. plant growth – roots grow in tiny cracks, causing them to expand and
break the rock
b. abrasion – friction caused by wind, water, or animals cause bits of rock to
break off
c. animal actions – animals that dig and tunnel break rocks
d. heating & cooling – the sun’s heat causes the outside of the rock to expand
& then shrink when cooled. This causes pieces of rock to flake off in layers
like an onion
2. Chemical Weathering – the process of changing the mineral composition of a
rock
a. acid rain
b. water – dissolves rock (#1 cause of chemical weathering)
c. plants (exuding a weak acid that weakens rock over time)
d. oxygen
e. carbon dioxide
K. Erosion – the process by which natural forces move weathered rock and soil
1. Material moved by erosion is called sediment
2. Sediment is moved by a force of erosion (wind, water, or ice)
3. Deposition occurs when sediments are moved to a new spot & stay there