Download Exam 3 Study Guide

Exam 3 Study Guide
Name_______________________________
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The goal of science is to ________________ and understand the _____________ __________, and to use those
explanations to make useful _________________. In other words, __________ is an organized way of using
___________________ to learn about the natural ___________________.
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A key assumption in science is that ___________________ results can be __________________ because nature
behaves in a consistent manner. When one particular __________________ is manipulated in a given set of
__________________, the result should always be the ___________. Today’s researchers often _____________ a
report of their own work in a scientific ____________. Other scientists review the experimental ________________
to make sure that the design was without ___________. They often repeat _________________ to be sure that the
________________ match those already obtained.
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In science, the word _____________ applies to a well-tested explanation that ______________ a broad range of
___________________. A theory enables scientists to make accurate _________________ about new situations.
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The word biology means the study of _______ (The Greek word bios means “________” and logy means “______
___”) Biology is the science that seeks to understand the ________________ world. A _____________ is someone
who uses scientific _____________________ to study living things.
No single _____________________ is enough to describe a living thing. Living things __________ the following
characteristics: Living things are made up of units called ___________. Living things ____________________.
Living things are based on a universal ______________ code. Living things _________ and _____________. Living
things obtain and use ___________________ and energy. Living things _____________ to their environment. Living
things maintain a stable ________________ environment. Taken as a group living things ____________ over
___________ (evolution).
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Some of the levels at which life can be studied include ______________, cells, ________________,
_______________ of a single kind of organism, ___________________ of different organisms in an area, and the
___________________. At all these levels, _____________ living systems are found within ______________
systems.
Levels of organization in an ECOSYSTEM are species, ________________, community, _______________, biome,
and _______________.
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___________ is the scientific study of __________________ among organisms and between organisms and their
__________________ or surroundings.
__________________ use energy from the environment to fuel the __________ of simple inorganic compounds into
complex organic ___________. These organic molecules combine and recombine to produce living ________.
Because they make their own food autotrophs are also called ___________. Organisms that rely on other organisms
for their ________ and ______ supply are called ___________. Heterotrophs are also called ___________.
There are many different types of ___________. ____________ obtain energy by eating only _______. Carnivores
including snakes dogs and owls eat _________. Humans, bears, crows and other ___________ eat both plants and
animals. ______________ such as mites, earthworms, snails and crabs feed on plants and animal remains and other
dead matter.
Energy flows through an ecosystem in _____ direction from the sun or inorganic compounds to ___________ and
then to various _____________. The energy stored by producers can be passed through an ___________ along a
______ _______, a series of steps in which organisms transfer _________ by eating and being eaten. When the
feeding relationships among the various organisms in an ecosystem form a network of complex interactions,
Exam 3 Study Guide
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Name_______________________________
ecologists describe these relationships as a ______ ______. Each step in a food chain or food web is called a
_________ level. ___________ make up the first trophic level. ___________ make up the second, third or higher
trophic levels. Each consumer depends on the trophic level ________ it for energy. Only about ___ percent of the
energy available within one trophic level is ____________ to organisms at the next trophic level.
o Notes
The remaining 90% of energy that does not get transferred to the next trophic level is ______ in the form of
________.
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Energy and matter flow through the biosphere very differently. Unlike the one-way flow of energy, matter is
________ within and between ecosystems. Elements, chemical compounds and other forms of matter are passed from
one organism to another and from one part of the biosphere to another through _______________ cycles. As the long
word suggest, biogeochemical cycles connect ______________, _______________, and ______________ aspects of
the biosphere.
All organisms require nitrogen to make _______ ________, which in turn are used to build ______________.
Although nitrogen gas is the most abundant form of nitrogen on Earth only certain types of bacteria can use this form
directly. Such bacteria which live in the soil and on the roots of plants called _____________ convert nitrogen gas
into ______________ in a process known as _______________ ___________________.
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Temperatures on Earth remain within a range suitable for life because the biosphere has a natural ________________
blanket – the _________________. Carbon ___________, methane, water _________, and a few other atmospheric
_________ trap heat ____________ and maintain the Earth’s temperature range.
The natural situation in which ________ is retained by this layer of greenhouse gases is called the
___________________ effect.
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Ecosystems are influenced by a combination of ______________ and __________ factors. The biological influences
on organisms within an ecosystem are called ________ factors. These include the entire ________ cast of characters
with which an organism might __________.
Physical and ___________ factors that shape an ecosystem are called _________ factors. For example the climate of
an area includes abiotic factors such as _______________, precipitation, and _______________.
Together biotic and abiotic factors determine the ________________ and growth of an organism and the
__________________ of the ecosystem in which the organism lives. The area where an organism lives is called its
____________. A habitat includes both ___________ and __________ factors.
If an organism’s habitat is its address, its ________ is its occupation. A niche is the full range of ___________ and
____________ conditions in which an organism lives and the way in which the organism uses those conditions.
A _______ includes the _______ of food an organism eats, _____ it obtains this food, and which other species
______ the organism as food.
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Community interactions such as ______________, predation and various forms of _______________, can
powerfully affect an __________________.
Direct competition in nature often results in a winner and a loser – with the losing organism failing to ___________.
A fundamental rule in ecology, the _____________ ________________ _______________, states that no two
species can occupy the same _________ in the same ____________ at the same ________.
An interaction in which one organism captures and feeds on another organism is called __________________.
Any relationship in which 2 species live closely together is called ______________________.
In ____________________ both species _____________________ from the relationship.
In _____________ on member of the association benefits and the other is neither ___________ nor _________.
In __________________ one organism lives on or inside another organism and _____________ it.
Exam 3 Study Guide
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Name_______________________________
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Ecosystems are constantly _______________ in response to natural and human ___________________. As an
ecosystem changes, older inhabitants gradually die out and new organisms move in, causing further changes in the
__________________. This series of predictable changes that occurs in a community over time is called
__________________ _______________________.
On land, succession that occurs on surfaces where no soil exists is called __________________ succession.
When a disturbance of some kind changes an existing community without removing the soil, then _______________
succession can follow.
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Population _____________________ is the number of individual’s per unit area.
Three factors can affect population size: the number of __________, the number of ___________ and the number of
individuals that ___________ or ______________ a population.
_____________________ the movement of individuals ______________ an area.
_________________ the movement of individuals ______ of an area can cause a population to decrease in size.
_______________ ______________ occurs when the individuals in a population reproduce at a constant rate.
Under ideal conditions with unlimited resources, a population will grow _____________________________.
As resources become ___________ available, the growth of a population slows or stops.
_______________ growth occurs when a population’s growth slows or stops following a period of exponential
growth.
The largest number of individuals that a given environment can support is the ____________ _____________.
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In the context of populations, a ______________ factor is a factor that causes population growth to decrease.
A limiting factor that depends on population size is called a density _________________ limiting factor.
Density dependent limiting factors include ______________, _______________, ________________, and
________________.
Density-___________________ limiting factors affect all populations in similar ways, regardless of the population
size.
Unusual _________________, natural _____________, seasonal ____________, and certain human
__________________ – such as damming rivers and clear- cutting forests – are all examples of density-independent
limiting factors.
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The _________ _________________ greatly increased the worlds food supply.
Environmental goods and services may be classified as either _______________ or _____________________.
_________________________ resources can regenerate if they are alive or can be replenished by biogeochemical
cycles if they are nonliving.
A _________________________ resource is one that cannot be replenished by natural processes. The fossil fuels
coal, oil and natural gas are nonrenewable resources.
____________________ development is a way of using natural resources without depleting them and of providing
for human needs without causing long term environmental harm.
Plowing the land removes the roots that hold soil in place. This ___________________ the rate of soil erosion –
wearing away of surface ____________ by water and wind.
In certain parts of the world with dry climates, a combination of farming, overgrazing and drought has turned once
__________________ areas into ___________________. This process is called ______________________.
Loss of forests of _____________________ has several effects. Deforestation can led to severe _____________ as
soil is exposed to heavy rains. Erosion can wash away ____________________ in the topsoil.
Exam 3 Study Guide
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Name_______________________________
There are a variety of ___________________ development strategies for forest management. In some forests mature
trees can be harvested selectively to promote the growth of younger trees and __________________ the forest
ecosystem. In areas where forests have already been cut foresters today often plant, manage, harvest, and replant tree
____________. Tree farms can now be planted and harvested __________________ making them fully
____________________ resources.
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If you live in a large city, you have probably seen _________, a mixture of sulfur and nitrogen that occurs as a graybrown haze in the atmosphere. _______ is primarily due to automobile exhaust and ________________ emissions.
__________ _________ can kill plants by damaging their leaves and changing the chemistry of soils and standing
water ecosystems.
Another word for variety is ________________. Therefore, biological diversity or ____________________ is the
sum total of the genetically based variety of all organisms in the biosphere.
Human activity can reduce __________________ by altering _________________, hunting species to
____________________, introducing ___________ compounds into food webs, and introducing _____________
species into new environments.
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Many forms of __________________ can threaten biodiversity but one of the most serious problems occurs when
toxic compounds accumulate in the ______________ of organisms. The history of ______, one of the first widely
used pesticides explains the situation well. At first, DDT seemed to be a perfect _________________. When DDT
was sprayed it drained into _______________ and streams at low concentrations that seemed harmless. But DDT has
two properties that make it _________________. DDT is ______________________, and when it is picked up by
organisms they ____ _____ ______________ ____ ______ ________ ____________. When an aquatic plants
picks up DDT from the water the DDT is stored in the plants _____________. When herbivores eat those plants they
too store the DDT. In this process called _________________ ________________, concentrations of a harmful
substance _________________ in organisms at higher __________ levels in a food chain or food web.
_________________ species increase their populations because their now habitat lacks the parasites and
________________ that control their population “back home.”
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Between 20-50 kilometers above the Earth’s surface the atmosphere contains a relatively high concentration of
____________ gas called the ozone _________. It absorbs a good deal of _________ violet (UV) radiation from
sunlight before it reaches Earth’s surface. __________________ to UV radiation is the cause of _____________. It
can also cause ___________, damage eyes, and _____________________ an organisms resistance to disease.
___________________________ or ______________ could damage the ozone layer, causing ozone depletion.
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The ____________________ contains nearly all the cell’s ____________ and with it the coded instructions for
making _________________ and other important _____________________.
Plant and animal cells are ____________________ ___________, which have a _____________________.
___________________ _________ do not have a nucleus.
An ________________ system is a group of organs that work together to perform a specific function.
o NOTES
Natural gas drilling, deforestation, and construction and all example of ______________ fragmentation.
Invasive species in Pennsylvania are ________, ________ _______ __________ , and __________________.
A species that is confined to a specific habitat is an ___________________ species.
ESSAY’S TO STUDY
What causes acid rain? What is the effect of acid rain on natural habitats?
What are introduced species? How are they a threat to biodiversity?