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Ecology Outline
Living Environment: Ms. Fazio 2006-2007
Upon the completion of this unit the student will:
1. define the term ecology.
2. define the terms population, community, and ecosystem.
3. list examples of populations, communities, and ecosystems.
4. define the term biosphere.
5. explain the difference between abiotic and biotic factors.
7. list some reasons for competition between organisms.
8. list several abiotic factors and discuss ways the influence an ecosystem.
9. define the term carrying capacity.
10. explain the difference between an autotroph and a heterotroph and list examples
of these.
11. define the following terms pertaining to nutritional relationships and list examples of
these; decomposer, herbivore, carnivore, omnivore, predator, and scavenger. .
12. define and list examples for the term parasitism.
13. define the terms food chain and food web.
14. list examples of food chains and food webs.
15. recognize that energy is lost between consecutive steps of a food web to heat and
wastes and becomes unavailable for the next feeding level.
16. describe feeding interactions in the form of a food pyramid.
17. define the term succession.
18. explain how alterations in the environment may lead to successions.
19. recognize that each stage of a succession changes its environment so that the
environment becomes more unfavorable for itself and more favorable for succeeding
successional stages.
20. define the terms niche and habitat.
21. explain the role of photosynthesis and respiration in the carbon-oxygen cycle.
22. discuss the water cycle and correctly include the following terms in this discussion;
photosynthesis, respiration, evaporation, transpiration, condensation, excretion, and
precipitation.
23. define the term biodiversity.
24. explain how increased biodiversity leads to more stability in the environment.
25. list and explain at least two reasons why increased biodiversity is valuable to humans.
1-4. ecology: the study of the interactions of living things with each other and their
physical environment
A. Ecological Organization
1. population: all the members of a species inhabiting a given location
2. community: all the interacting populations in a given area
3. ecosystem: the living community and the physical environment
functioning together as an independent and relatively stable system
4. biosphere: that portion of the earth where life exists
a. The biosphere is composed of numerous complex ecosystems.
5. An ecosystem involves interactions between abiotic (physical) and biotic (living)
factors. The members of the community in the ecosystem and environment must interact
to maintain a balance.
7. Competition: occurs when two different species or organisms living in the same
environment (habitat) utilize the same limited resources, such as food, water, space, light,
oxygen, and minerals.
** All environments, organisms with similar needs may compete with each other for
resources, including food, space, water, air, and shelter. The more similar the
requirements of the organisms involved, the more intense the competition.
8. Abiotic factors: those physical and chemical factors which affect the ability of
organisms to survive and reproduce
A. Some Abiotic Factors:
1. intensity of light
2. range of temperatures
3. amount of moisture
4. type of substratum (soil or rock type)
5. availability of inorganic substances such as minerals
6. supply of gases such as oxygen, carbon dioxide, and nitrogen
7. pH
** Each of the prior listed abiotic factors varies in the environment and, as such, may act
as a limiting factor, determining the types of organisms that exist in that environment.
B. Some examples:
1. A low annual temperature common to the northern latitudes determines
in part the species of plants which can exist in that area.
2. The amount of oxygen dissolved in a body of water will help determine
what species of fish live there.
3. The dry environment of desert regions limits the organisms that can live
there.
Biotic factors: all the living things that directly or indirectly affect the environment
Thus, the organisms, their presence, parts, interaction, and wastes are all biotic factors.
9. Carrying capacity -- the maximum number of organisms the resources of an area can
support
The carrying capacity of the environment is limited by the available abiotic and biotic
resources, as well as the ability of ecosystems to recycle the residue of dead organisms
through the activities of bacteria and fungi.
10-16. Nutritional Relationships
A. autotrophs: can synthesize their own food from inorganic compounds and a
usable energy source
B. heterotrophs: can NOT synthesize their own food and are dependent on other
organisms for their food
1. Types of Heterotrophs
Predators: animals which kill and consume their prey
a. decomposers: include those heterotrophic plants, fungi, and
bacteria which live on dead matter AKA decomposers
b. herbivores: plant-eating animals
c. carnivores: meat-eating animals
d. omnivores: consume both plants and meat
e. scavengers: those animals that feed on other animals that they
have not killed
12. Parasitism: the parasite benefits at the expense of the host
Ex. athlete's foot fungus on humans, tapeworm and heartworm in dogs
13-14. Food Chains and Webs
- If an ecosystem is to be self-sustaining it must contain a flow of energy.
- Those life activities that are characteristic of living organisms require an
expenditure of energy.
- The pathways of energy through the living components of an ecosystem are
represented by food chains and food webs.
- Producers convert the radiant energy of the sun into the chemical energy of
food.
A. Food chain: involves the transfer of energy from green plants through a series
of organisms with repeated stages of eating and being eaten
B. Food web: In a natural community, the flow of energy and materials is much
more complicated than illustrated by any one food chain.
Since practically all organisms may be consumed by more than one species, many
interactions occur along the food chains of any community.
C. Food Web interactions
1. Producers: (plants) -- the energy of the community is derived from the
organic compounds in plants (grass in the web above)
2. Decomposers: break down organic wastes and dead organisms to
simpler substances (ex. bacteria of decay)
** Through decomposition, chemical substances are returned to the environment
where they can be used by other living organisms.
D. Energy Flow - Energy flows through ecosystems in one direction, typically
from the Sun, through photosynthetic organisms, including green plants and
algae, through herbivores, to carnivores, and finally decomposers.
E. There is a decrease in the overall energy in each level as you move up the
food web. This means that there is much more energy in the producer level in a
food web than at the consumer levels. Also, this means that there is more energy
at the primary consumer level than at the secondary consumer level.
F. Energy Transfer - Each consumer level of the food pyramid utilizes
approximately 10% of its ingested nutrients to build new tissue. This new tissue
represents food for the next feeding level.
**The remaining energy is lost in the form of heat and unavailable chemical
energy. Eventually, the energy in an ecosystem is lost and is radiated from the
earth.
**An ecosystem can not survive without the constant input of energy from the
sun.
**Above is a typical representation of a NY State terrestrial energy pyramid.
17-19. Ecological succession: replacement of populations in habitat as it moves toward a
stable state (determined by changes in plants)
The environment may be altered in substantial ways through the activities of organisms,
including humans, or when the climate changes. Although these alterations are
sometimes abrupt (ex. natural disasters), in most cases species replace others, resulting in
long-term gradual changes in ecosystems.
Ecosystems tend to change with time until a stable system is formed.
The type of ecosystem that is formed depends on the climatic limitations of a given
geographical area.
** Each community modifies its environment, often making it more difficult for itself
and, apparently, more favorable for the following community which infiltrates the first
community over a period of years.
- Ponds and small lakes, for example, fill in due to seasonal dieback of aquatic vegetation
and erosion of their banks.
20. If two different species compete for the same food source or reproductive sites,
one species may be eliminated. This establishes one species per niche in a community.
niche: the organism's role in the community
21-22. MATERIAL CYCLES
** In a self-sustaining ecosystem, materials must be cycled among the organisms
and the abiotic environment. Thus the same materials can be reused.
1. Carbon Cycle -- involves the processes of respiration and photosynthesis
2. Water Cycle: involves the processes of transpiration, evaporation, condensation and
precipitation.
23-25. Evolutionary processes have resulted in a diversity of organisms and a diversity of
roles in ecosystems.
Biodiversity: the differences in living things in an ecosystem
-- Increased biodiversity increases the stability of an ecosystem.
-- Increased biodiversity increases the chance that at least some living things will
survive in the face of large changes in the environment.
What are some other reasons biodiversity is valuable?
1. Biodiversity ensures the availability of a rich variety of genetic material that may lead
to future agricultural or medical discoveries with significant value to humans. (if this is
lost we lose the sources of these materials for discovery)
2. Biodiversity adds aesthetic qualities to the environment.