Download Midterm Review PPT WKST

BENCHMARK #2 REVIEW
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Defining an Ecosystem
______________ are communities of organisms and their abiotic environment.
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Examples are an oak forest or a coral reef.
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The Components of an Ecosystem
In order to survive, ecosystems need five basic components:
______________, mineral nutrients, ______________, oxygen, and living
organisms.
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Plants and rocks are components of the land ecosystems, while most of the
energy of an ecosystem comes from the sun.
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If one part of the ecosystem is ______________ or changes, the entire system
will be affected.
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Populations
______________ are groups of organisms of the same species that live in a
specific geographical area and interbreed.
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Members of a species may not all live in the same place. Field mice in Maine
will not interact with field mice in Texas. However, each organism lives as part
of a population.
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For example, all the field mice in a corn field make up a population of field
mice.
Habitat
______________ are places where an organism usually lives.
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Every habitat has ______________ that the organisms that live there need to
survive. If any of these factors change, the habitat changes.
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Organisms tend to be very well suited to their natural habitats. If fact, animals
and plants usually cannot survive for long periods of time away from their
natural habitat.
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Evolution by Natural Selection
______________ is the process by which individuals that have favorable
variations and are better adapted to their environment survive and reproduce
more successfully than less well adapted individuals do…”Survival of the
fittest.”
______________ are different traits found within a species ex. Fur color
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English naturalist ______________ observed that organisms in a population
differ slightly from each other in form, function, and behavior.
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Darwin proposed that over many generations, natural selection causes the
characteristics of populations to change.
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______________ is a change in the characteristics of a population from one
generation to the next.
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______________ is the process of becoming adapted to an environment. It is
an anatomical, physiological, or behavioral change that improves a
population’s ability to survive.
Nature Selects
Evolution by Artificial Selection
• ______________ is the selective breeding of organisms, by humans, for
specific desirable characteristics.
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Dogs have been selectively bred for certain characteristics.
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Fruits, grains, and vegetables are also produced by artificial selection.
Humans save seeds from the largest, and sweetest fruits. By selecting for
these traits, farmers direct the evolution of crop plants to produce larger,
sweeter fruit.
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Life Depends on the Sun
Energy from the ______________ enters an ecosystem when plants use
sunlight to make sugar molecules.
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This happens through a process called photosynthesis.
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______________ is the process by which plants, algae, and some bacteria
use sunlight, carbon dioxide, and water to produce carbohydrates and oxygen.
From Producers to Consumers
• Because plants make their own food, they are called ______________ s.
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A producer is an organism that can make organic molecules from inorganic
molecules.
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Producers are also called ______________, or self-feeders.
From Producers to Consumers
• Organisms that get their energy by eating other organisms are called
consumers.
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A consumer is an organism that eats other organisms or organic matter
instead of producing its own nutrients or obtaining nutrients from inorganic
sources.
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Consumers are also called______________, or other-feeders.
What Eats What?
• Organisms can be classified by what they eat.
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Types of Consumers:
• ______________ -plants
• Carnivores-other animals
• ______________ -both plant and animal
• Decomposers-dead material
• With mouth-Scavenger
• Without mouth-______________
The Water Cycle
• Water is a ______________ resource because it is circulated in the water
cycle.
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In the water cycle, water molecules travel between the Earth’s surface and the
atmosphere. Water evaporates at the Earth’s surface. Water vapor rises into
the air. As the vapor rises, it ______________ to form clouds. Eventually the
water in clouds falls back to the Earth as precipitation.
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Water can also runoff the earth’s surface ______________ through the soil.
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Plants can release water to the atmosphere through ______________ while
animals return water through respiration.
The Water Cycle
Burning the Fuel
• An organism obtains energy from the food it eats.
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This food must be broken down within its body.
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The process of breaking down food to yield energy is called ______________.
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Energy Transfer
Each time an organism eats another organism, an energy transfer occurs.
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This transfer of energy can be traced by studying food chains, food webs, and
trophic levels.
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Food Chains
A ______________ is a sequence in which ______________ is transferred
from one organism to the next as each organism eats another organism.
Food Webs
Ecosystems, however, almost always contain more than one food chain.
A ______________ shows many feeding relationships that are possible in an
ecosystem.
Trophic Levels
• Each step in the transfer of energy through a food chain or food web is known
as a trophic level.
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A ______________ is one of the steps in a food chain or food pyramid;
examples include producers and primary, secondary, and tertiary consumers.
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Each time, only ______________ % of the energy is transferred, while 90% of
the energy is lost as heat
The Carbon Cycle
• The ______________ is the movement of carbon from the nonliving
environment into living things and back
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The Carbon Cycle
Carbon exists in air, water, and living organisms.
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Producers convert carbon dioxide in the atmosphere into ______________
during photosynthesis.
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Consumers obtain carbon from the carbohydrates in the producers they eat.
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During ______________, some of the carbon is released back into the
atmosphere as carbon dioxide.
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Over long periods of time, once living organisms may form deposits of coal, oil,
or natural gas, which are known as ______________.
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The burning of fossils fuels which releases carbon into the atmosphere is
called ______________
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The Nitrogen Cycle
The ______________ is the process in which nitrogen circulates among the
air, soil, water, plants, and animals in an ecosystem.
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All organisms need nitrogen to build proteins, which are used to build new
cells.
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Nitrogen makes up ______________ percent of the gases in the atmosphere.
The Nitrogen Cycle
• Nitrogen must be altered, or ______________ before organisms can use it.
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Only a few species of bacteria can fix atmospheric nitrogen into chemical
compounds that can be used by other organisms.
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These bacteria are known as “nitrogen-fixing” bacteria.
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______________ are bacteria that convert atmospheric nitrogen into
ammonia.
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These bacteria live within the roots of plants called ______________, which
include beans, peas, and clover.
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The Nitrogen Cycle
The Phosphorus Cycle
The ______________ is the cyclic movement of phosphorus in different
chemical forms from the environment to organisms and then back to the
environment.
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Plants get the phosphorus they need from ______________ and water, while
animals get their phosphorus by eating plants or other animals that have eaten
plants.
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Phosphorus may enter soil and water when rocks erode. Small amounts of
phosphorus dissolve as phosphate, which moves into the ______________.
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The Phosphorus Cycle
Fertilizers and the Nitrogen and Phosphorus Cycles
Fertilizers, which people use to stimulate and maximize plant growth, contain
both nitrogen and phosphorus.
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Excessive amounts of ______________ can enter terrestrial and aquatic
ecosystems through runoff.
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Excess nitrogen and phosphorus can cause ______________ of algae.
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Excess algae can deplete an aquatic ecosystem of important nutrients such as
oxygen, on which fish and other aquatic organisms depend.
Ecological Succession
______________ is a gradual process of change and ______________ of the
types of species in a community.
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______________ is a type of succession that occurs on a surface where no
ecosystem existed before. It begins in an area that previously did not support
life. Ex. rock after ______________retreats
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Primary succession can occur on rocks, cliffs, or sand dunes.
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______________ occurs on a surface where an ecosystem has previously
existed. It is the process by which one community replaces another community
that has been partially or totally destroyed.
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Secondary succession can occur in ecosystems that have been disturbed or
disrupted by humans, animals, or by natural process such as
______________, floods, earthquakes, or ______________.
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Ecological Succession
A ______________ is a species that colonizes an uninhabited area and that
starts an ecological cycle in which many other species become established.
Ex. Lichens
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A ______________ is the final, stable community in equilibrium with the
environment.
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Even though a climax community may change in small ways, this type of
community may remain the same through time if it is not disturbed.
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Ecological Succession
What Is a Population?
A ______________ is a group of organisms of the same species that live in a
specific geographical area and interbreed.
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A population is a reproductive group because organisms usually breed with
members of their own population.
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The word ______________ n refers to the group in general and also to the
size of the population, or the number of individuals it contains.
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Carrying Capacity
______________ is the largest population that an environment can support at
any given time.
A population may increase beyond this number but it cannot stay at this
increased size.
Carrying Capacity
An Organism’s Niche
• A ______________ is the unique position occupied by a species, both in
terms of its physical use of its habitat and its function within an ecological
community.
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A niche is different from a habitat. An organism’s ______________ tis a
location. However, a niche is an organism’s pattern of use of its habitat.
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A niche can also be though of as the functional ______________, or job of a
particular species in an ecosystem.
Ways in Which Species Interact
• ______________ between species are categorized at the level where one
population interacts with another.
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The five major types of species interactions are:
• Competition
• ______________
• Parasitism
• ______________
• Commensalism
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Species Interactions
Competition
______________ is the relationship between two species (or individuals) in
which both species (or individuals) attempt to use the same limited resource
such that both are negatively affected by the relationship.
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Intra specific competition-between two individuals within a ______________
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Inter specific competition-between two ______________ species within an
ecosystem
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Predation
______________ is an interaction between two species in which one species,
the predator, feeds on the other species, the prey.
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In complex food webs, a predator may also be the prey of another species.
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Most organisms have evolved some mechanisms to avoid or defend against
predators.
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Mimicry
______________
Coloration
Toxins
Symbiosis
• Symbiosis is a relationship in which two different organisms live in close
association with each other.
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The three types of symbiosis are:
– ______________
– Mutualism
– ______________
Parasitism
______________ is a relationship between two species, the parasite, benefits
from the other species, the ______________, and usually harms the host.
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An organism that lives in or on another organism and feeds on the other
organism is a parasite. Examples include ______________, fleas, tapeworms,
heartworms, and ______________ leeches.
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The organisms the parasite takes its nourishment from is known as the host.
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______________ is most often used to describe a relationship in which at
least one species benefits.
Mutualism
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______________ is a relationship between two species in which both species
benefit.
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Certain species of bacteria in your intestines form a mutualistic relationship
with you. These bacteria help break down food that you cannot digest. In
return, you give the bacteria a warm, food-rich habitat.
Commensalism
______________ is a relationship between two organisms in which one
organism benefits and the other in unaffected.
An example is the relationship between ______________ and a type of fish
called remoras. ______________ attach themselves to sharks and feed on
scraps of food left over from the shark’s meals.