THE NATURE HIKE
REVIEW SHEET
A] ECOLOGY
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Ecology – the study of the interactions between organisms and between
organisms and their nonliving environment
Habitat – the physical environment where an organism lives
Levels of ecological organization
o Population – members of one species in a given area
o Community – all of the living things in a given area
o Ecosystem – both the living and nonliving elements of a particular
area that interact and affect the life in that area
B] POPULATION ECOLOGY
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Be able to give an example of a population in a particular habitat and be
able to describe a population level investigation that could be done on
that species
Plant life strategies
o Annual – a plant that lives and reproduces during a 1 year time
span
o Biennial – a plant that lives and reproduces during a 2 year time
span, often reproducing the second year
o Perenial – a plant that lives and reproduces for many years
C] COMMUNITY ECOLOGY
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Be able to give an example of a community in a particular habitat
How plants protect themselves from being eaten
o Physical protection with thorns and needles or detachable body
parts
 Armature – adaptation involving the production of sharp
thorns, spines or needles
o Chemical protection with toxic chemicals produced in parts of the
plant
 Allelochemical – a chemical produced by a plant to inhibit or
repel other plants and/or animals
Competition – type of interaction between organisms as they strive to
capture some sort of limited resource in the environment
o Occurs between both plants and animals
o Plants compete for such things as water, light, & nutrients in the soil
The environment is broken into areas that have different resources
and these can be considered microhabitats
o Microhabitats can allow a great diversity of organisms to occur in a
given area, each better at living in one microhabitat than another
o Examples of microhabitat differences
 In bright light vs. shade; at wet bottom of hill vs. dry top; in
rocky soil vs. soil with lots of compost included, etc.
 Mowed areas vs. areas left alone by humans; areas that are
watered by humans vs. those that are not, etc.
 Area contains organisms that like to eat a certain kind of
plant or animal vs. those without such predators
o Invasive species – a species introduced into a geographical area
where it was not originally found and which thrives and spreads in
the new area, almost “out-of-control”
o Competitive exclusion principle – if two species are competing with
one another for the same limited resource, the species able to use
that resource most efficiently will eventually eliminate the other
species in that location
Symbiosis – the condition in which two or more dissimilar organisms live
together in close association
o Mutualism – a symbiotic relationship in which both participating
species benefit
 Example 1: legumes & nitrogen fixing bacteria
 Legume – type of plant that includes such common
plants as beans, peas, soybeans, alfalfa, clover and
crown vetch
 Plants have specialized nodules on their roots
produced by the plants that provide housing and
moisture to the bacteria
 The bacteria are able to change nitrogen found in the
air into nitrogen compounds that act as fertilizer to the
plants
 Both species benefit
 Example 2: lichens
 Lichens are a composite organism composed of both
algae and fungus
 The algae part can undergo photosynthesis and help
feed the fungus
 The fungus helps to provide housing and moisture
needed by the algae
 Both species benefit
 Example 3: insect pollination of flowers
 Insect pollination vs. wind pollination – be able to describe
the difference we would expect to see in these plants’
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flowers and be able to identify which pollination mechanism
is used if you are shown a flower
o Parasitism – a symbiotic relationship in which one species benefits
while the other species is harmed
 Example: tree and wild grape vine
 The tree spends a great deal of energy and resources
to build a trunk to get its leaves high into the air
 The grape vine climbs up the trunk and takes
advantage of the tree’s trunk to get its leaves high into
the air
 The tree is harmed by the blocking of light caused by
the grape leaves, the energy it needs to support the
grape vines on its trunk and branches, and by the
water taken from the immediate surroundings of its root
system by the parasitic vine
Ecological succession – the change in communities of life in an area over
time after disturbance has occurred
o Secondary succession – the re-colonization of an area that had life
previously and the area is disturbed by man-made or natural events
o Primary succession – the process where life moves into an area that
previously did not have life
o Sedimentation – the gradual filling in of a body of water from the
accumulation of organic materials (dead animals & plants)
 Sedimentation can be greatly accelerated by algae blooms
– the rapid growth of algae in a body of water that occurs
when nutrients (such as fertilizers or animal feces) are
introduced
Fossils
o Common rock in this area is called limestone and it often contains a
wealth of fossilized organisms from this area’s distant past
o Geological timetable – timeline of the history of geological and
biological events of Earth’s history
 Era – largest (major) subdivision of the timetable, usually the
history of life is divided into 5 Eras
 Pre-Cambrian Era
 Paleozoic Era
 Mesozoic Era
 Cenozoic Era
 The common fossils in this area are from the Paleozoic Era
(505-430 million years ago)
o Most common fossils around the Cincinnati area: brachiopods and
bryozoa [be able to recognize and identify]
D] ECOSYSTEM ECOLOGY
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Energy transfer in the living world – trophic relationships (feeding
relationships)
o Producers (autotrophs) – organisms that make their own food
through the process of photosynthesis (e.g. green plants)
o Primary consumers – next trophic level, the organisms that get their
energy by eating plants (e.g. herbivores)
o Secondary consumers – next trophic level, the organisms that get
their energy by eating primary consumers (e.g. carnivores)
o Decomposers – the last trophic level that involves organisms that
break down dead organisms and the waste products of organisms
into simple molecules that can then be used as building materials
for producers (e.g. bacteria & fungi)
Human impact on the ecosystem – introduction of pollutants
o Nonpoint pollution – pollution that enters the environment from
widespread origins, especially as the result of runoff after rain
o Be able to give examples of human initiatives on campus to support
and help the campus, community, and national environment
(“green” initiatives)