Ecology 1
The non-living features of an ecosystem (i.e. the physical and
chemical conditions) that affect the community. They include:
temperature, light intensity, air speed, water current, humidity, pH,
dissolved oxygen, salinity, nitrate, phosphate and other plant
nutrients.
Very acidic rain with a pH of 4.5 or less. Sulphur dioxide (SO2)
dissolves in rainwater to form sulphurous acid (H2SO3) or reacts with
particles in the air to form sulphuric acid (H2SO4).
abiotic factors
acid rain
The conversion of nitrogen compounds (e.g. urea and protein as a
result of excretion and death respectively) into ammonia.
ammonification
Factors that influence the life of the organisms that live in ponds,
rivers and seas, e.g. depth of light penetration, currents and wave
action.
aquatic factors
The direction in which something (habitat) is facing, i.e. north, south,
aspect
east, west, etc.
The mixture of gases that surround the earth. It is divided into zones,
atmosphere
e.g. stratosphere, troposphere.
The process of decomposition by living organisms, usually by
bacteria.
biodegradation
Variety of living organisms. This can be measured in terms of
genetic, species or ecosystem diversity.
biodiversity
Series of groups of questions used to identify one feature at a time
of an unknown organism which eventually leads to its identification.
biological key
Pollutants tend to concentrate as they are passed through a food
chain. The organism at the end of the chain suffers the highest
concentrations.
The total quantity or weight of a species per unit area or volume or
at any level in a food chain. This term is used when expressing
population density and may be measured as either living mass or dry
mass (dry weight).
That part of the earth inhabited by living organisms, including land,
ocean and the atmosphere in which life can exist. It is the global
ecosystem.
These are the living features of an ecosystem that affect the other
members of the community. They include: plants for food and
shelter; predators; prey; parasites and pathogens; decomposers;
competitors; and pollinators.
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biological
magnification
biomass
biosphere
biotic factors
A method used to estimate the size of a population of a given
species of animal in an area.
1. Catch, mark, count and release animals on first visit.
2. Catch and count total number and number marked on second
visit, and release animals.
3. Use following formula:
Size of population = 1st count x total 2nd count
number marked on 2nd count
capture-recapture
technique
The way in which carbon circulates in nature, between the air,
plants, animals, etc.
carbon cycle
An animal or plant that feeds exclusively or mainly on animal flesh. A
meat eater, e.g. fox, dog, ladybird, Venus fly-trap.
carnivore
Factors relating to long term weather conditions that influence the
life and distribution of the organisms that live in a particular
environment, e.g. rainfall, humidity, temperature, light intensity and
day length.
climatic factors
When plants or animals 'take over' new ground (habitat).
colonisation
A symbiotic relationship where one organism obtains benefit from
another and leaves it completely unaffected – neither harmed nor
helped, e.g. the bacterial population in the intestines of humans and
other animals.
A group of interacting populations of different species living in the
same area, i.e. plants and animals in a certain area (e.g. a pond)
where there is interdependence of various species on each other.
The struggle/rivalry/fight between organisms to obtain a sufficient
supply of a resource of limited quantity, i.e. animals vie with each
other for food, shelter and space, and plants vie for space, light,
water and minerals.
The protection, preservation and wise management of natural
resources and the environment. The benefits ensure that:
· existing environments are maintained
· endangered species are preserved for reproduction
· the balance of nature is maintained
· pollution and its effects are reduced.
A heterotrophic organism that feeds on other organisms. It cannot
make its own food. There are three types: Primary, Secondary and
Tertiary.
Involves an active physical confrontation between two organisms,
e.g. two dogs fighting over a bone. One may have stronger muscles
and sharper teeth and so win the bone.
An organism which feeds on and breaks down the dead remains of
organisms (detritus) and excreta into simpler substances, e.g.
bacteria, fungi, etc.
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commensalism
community
competition
conservation
consumer
contest
competition
decomposer
The cutting down of forests without planting any replacement trees,
i.e. forests permanently removed.
deforestation
Removal of nitrates and nitrites from the soil by converting them to
ammonia and then nitrogen gas. This is done by denitrifying
bacteria, e.g. Thiobacillus denitrificans
denitrification
Dead or decaying organisms.
detritus
Food chain composed of animals and plants, which cannot
photosynthesise and so get their food by feeding on dead plant
material. OR
Food chain that begins with dead organic matter or animal waste
(detritus).
detritus food
chain
Refers to an organism that is active during the day. Opposite of
nocturnal.
diurnal
Where changes in the population of a species are in an unchanging
state of balance, without loss or gain of species and the population
of each remaining relatively constant. Any disturbance in population
size tends to return to the equilibrium.
dynamic
equilibrium
A way of comparing different communities of an ecosystem in order
of different trophic levels (feeding levels).
ecological
pyramids
The study of how living things relate to and interact with each other
and their environment.
ecology
A community of living organisms interacting with one another and
their non-living environment within a particular area, e.g. woodland,
hedgerow, seashore, tree, etc. The earth itself is an excellent
example as no part of it is completely isolated from the rest.
ecosystem
A parasite that lives on the surface of an organism, e.g. flea on a dog. ectoparasite
An animal whose temperature changes with that of its surroundings,
i.e. a cold-blooded animal, e.g. fish, frog, reptile. It gains heat by
moving into a warmer area and loses heat by moving into a colder
area.
The physical, chemical and biological characteristics of the soil that
influence the community. The major ones are: available (soil) water,
mineral content, pH, humus, soil texture and structure.
ectotherm
edaphic factors
A parasite living inside a host, e.g. liverfluke, tapeworm, etc.
endoparasite
An animal whose body temperature is maintained usually at a higher
level than that of its surroundings, i.e. a warm-blooded animal, e.g.
human. The source of this heat is from its own metabolism.
endotherm
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The pathway of energy transfer from one organism to the next in an
ecosystem due to feeding, e.g. along a food chain.
The flow of energy into the ecosystem from the sun; and within the
ecosystem through the different trophic levels along food chains,
including detritus, and finally out of the ecosystem into the
atmosphere as heat loss due to respiration.
A condition where lakes become over-enriched with nutrients,
resulting from excess artificial fertilisers washed into rivers and
lakes. There is a rapid increase in the growth of alga (algal bloom) as
they use up the nutrients. When all the nutrients are used up the
algae die and are broken down by bacteria, which use up the oxygen
in the water resulting in the death of aquatic organisms such as fish.
energy flow
energy transfer
eutrophication
The animals in a locality or region.
fauna
The plants of a locality or region.
flora
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