Download Ecology Terms

Oceans 11
Date:___________________________
Marine Biome Ecology Terms
Ecology: the study of the relationships between organisms and their
environment.
Population: a group of individuals of the same species, living in the same area.
Ex. All the cows on a farm
All the humans in Halifax
Community: all living things in an area.
Ex. All things living in Point Pleasant Park
Biosphere: the regions of Earth where life exists (most of it!)
Ecosystem: an interacting system that consists of groups of organisms and their
non-living environment.
Abiotic: all non-living parts of an ecosystem. (“a” = not; “biotic” = living)
Ex. Rocks, soil, water, oxygen concentration
Biotic: All living parts of an ecosystem.
Ex. Plants, animals, bacteria, fungi
Structure of an ecosystem
Habitat: The habitat of an organism is the place in which it lives.
Ex. A lake has many habitats
1. The habitat of a trout is the deep cool water
2. The habitat of a turtle is the edge of a lake
* Overlapping of a habitat  Trout swim into the shallow area to feed.
Niche: The Niche of an organism is its total role in the community.
Ex. The niche of a frog in a pond is to feed on insects and to
become food for snakes and other animals.

Don’t confuse the habitat and niche. Think of the habitat as the address of
the organism and niche as the organisms occupation (job).
Competition: Two species in the same habitat will compete with one another
(interspecific – different species; intraspecific – same species)
Ex. trout and perch, or several trout for same food
Density Dependent/Independent Factors: related to the population density;
such as food/habitat availability. Dependent=caused directly by populations;
independent – change in currents, temperature, overfishing, etc.
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Oceans 11
Date:___________________________
Trophic levels  Feeding levels
Three Levels:
1. Producers  Store the sun’s energy in the form of sugar, starch and
other molecules. These plants contain chlorophyll and carry out
photosynthesis to store this energy. They are called autotrophs because
they can supply their own food. (“self-feeding”)
2. Consumers  Organisms that feed on or consume other organisms.
They cannot make their own food - heterotrophs
3. Decomposers  These organisms are mainly bacteria and fungi such as
yeasts and moulds. They breakdown (decompose) and feed on non-living
matter such as dead plants and animal wastes.
* If aquatic ecosystems had no decomposers the ecosystem would clog up with
wastes and dead organisms. They return valuable nutrients to the water.
An Aquatic Food Chain

Diatoms  Form of algae (producer) growing on the rocks in a
stream

Diatoms are eaten by the Mayfly Nymph

The Mayfly Nymphs are eaten by the Fish
Physical factors affecting the Marine Life in the Oceans
Light
Light is an essential requirement for life. Marine organisms depend on the
mechanical energy of the sun to convert inorganic matter into organic
compounds. Seawater is relatively transparent allowing sunlight to penetrate into
the water column. Blue light is absorbed to the greatest depth while red light is
absorbed near the surface in clear ocean water. The light energy turns to heat.
The depth to which light is absorbed is determined by the concentration and
characteristics of the particles in the water. Near the coasts the waters become
dark at depths of 30-40 m. In very clear tropical waters blue light can be seen up
to 200 m.
Light is not only required for photosynthesis. Some fish use light for body
orientation, feeding, and predator avoidance. Phytoplankton also respond to light
with a physiological rhythm called vertical migration.
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Oceans 11
Date:___________________________
Nutrients
There are many nutrients required for the production of organic matter. The main
nutrients required include: Nitrogen (as Nitrate) and Phosphorus (as Phosphate).
Temperature
The temperature determines the rate of an organism’s metabolism. The
metabolic rate of an organism increases with every 10 degree Celsius increase.
However, there is a threshold when exceeded that metabolism stops.
Many marine organisms are ectothermic meaning that the surroundings control
their body temperature (cold-blooded). This in turn controls their rate of
metabolism. Others are endothermic, where they regulate their own body
temperature.
These endothermic organisms are able to tolerate a wide range of temperatures
and because of it need more food and quicker rates of gas exchange than
ectothermic creatures.
Salinity
Cell membranes are greatly affected by the salinity of the water they live in.
Salinity influences buoyancy of an organism, membrane stability, protein
structure, and water balance.
Dissolved Gases
Oxygen and carbon dioxide are required for virtually all marine organisms.
Oxygen does not dissolve readily in water but quantities are sufficient for life in
most areas. Oxygen is added to the water through current mixing and
photosynthesis. Occasionally, oxygen depletion can occur. This can cause
death of marine plankton and fish.
Carbon dioxide is essential to photosynthesis. The ocean holds about 60 or
more times the amount of CO2 than the atmosphere. Due to this abundance
marine organisms never run out of carbon dioxide.
pH
Seawater is slightly alkaline at about a pH of about 8. This is maintained by the
carbonate buffer system.
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Oceans 11
Date:___________________________
Questions:
1. Define these relationships:
A) Parasite
B) Commensalism
C) Mutualism
Read The Grazers and Predators…
2. What does a “top-down” force mean? Describe and give an example.
3. Why are microscopic organisms in planktonic food webs important?
Describe in detail.
4. What types of ecosystems have the largest amount of primary and
secondary production? Why would this make sense? Explain.
5. Why are “grazers” important? How can the balance be negatively affected
if people introduce foreign species to a lake, such as bass?
6. Describe and explain what the “trophic cascade” is, and how it can be
altered. Provide an example.
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