Ecosystems Exam Review
1. Definitions:
Ecology- The study of all the interactions between biotic and abiotic things.
Ecosystem- All the living organisms in an environment.
Environment- The surroundings in which organisms live in.
Abiotic- Non-living parts of an environment (e.g., water, temperature)
Biotic- Living parts of an environment (e.g., plants, animals)
Producer- Plants and some bacteria that use photosynthesis for energy.
Consumer- Organisms that eat the producer to gain energy.
Heterotroph- An organism that requires an autotroph to gain its energy. (e.g., wolves)
Autotroph- An organism that makes its own energy from light or water etc. (e.g., plants )
Herbivore- An organism that only eats plants.
Carnivore- An organism that only eats meat.
Omnivore- An organism that eats both plants and meat.
Detritus- Waste of any kind.
Scavenger- Organisms that consume leftovers and scrap materials.
Decomposer- Various bacteria and fungi that breaks down dead material and waste and
extracts the nutrients from it.
Trophic Level- The feeding level based on energy in a food web.
Community- A collection of all populations in an ecosystem.
Population- All the members of the same species living in the same ecosystem.
Species- A group of living organisms.
Biotic Potential- The ability of an organism or species to survive and reproduce.
Carrying Capacity- The quantity of things that can he held in one area.
Population Density- The average number of organisms who live in an area.
Percent Growth- Growth in which some quantity (population size) increases by a constant
percentage.
2. Name 3 Biotic things and 3 Abiotic things.
Biotic: Bird, Wolf, Shark.
Abiotic: Sunlight, Wind, Water.
3. What are 3 types of Consumers?
Grasshoppers, Deer, Bears.
4. What is the difference between a community and a population?
A community has a variety of populations within it. (Insects, Birds in one community)
5. Define the three types of relationships between organisms.
Commensalism: An association between 2 organisms in which one benefits and the other
stays the same. (Birds and Buffalo)
Parasitism: An association between 2 organisms in which one benefits and the other is
harmed. (Ticks and Humans)
Mutualism: An association between 2 organisms in which both of them benefit. (Humans
and Plants)
6. What is Biodiversity?
The variety of life within an ecosystem.
7. What % of energy in food chains passes on from one level to the next?
10% of energy is passed from one to the next.
8. What is the difference between a food chain and a trophic level?
Trophic levels refer to basic energy levels within a food chain. Ie: producer, primary
consumer, secondary consumer, tertiary consumer
9. What is the difference between a food chain and a food web?
A food chain refers to the transfer of energy through single stages whereas food webs
are two or more food chains interconnected.
10. What is the trophic level of a tertiary consumers?
The fourth level. These are animals that eat secondary consumers.
11. What is the difference between an open and a closed ecosystem?
An open ecosystem is influenced by biotic and abiotic factors outside of the ecosystem
while a closed ecosystem has no influence from the outside of it.
12. What is a biogeochemical cycle?
The flow of chemical elements between living things and the environment.
13. Describe the Carbon cycle with a diagram.
The carbon cycle is one of the biogeochemical cycles, and it is the movement of carbon
between the (bio/atmo) sphere and the oceans and geosphere. (see handout for diagram)
14. Describe the Nitrogen cycle with a diagram.
The Nitrogen cycle is also a biogeochemical cycle, and it is the movement of nitrogen from
the air and soil to the living things and back. (see handout for diagram)
15. What is bioaccumulation? Describe an example of its consequences.
The aquiring of a substance, such as a toxic chemical, or radioactive element, etc. (e.g.,
Mercury in fish). Mercury can cause problems when humans eat the fish and their nervous
system is affected.
16. What is the difference between bioaccumulation and biomagnification.
Biomagnification is the concentration of a substance in an organism while bioaccumulation
is the build up of toxins after longer periods of time in a top carnivore.
17. Describe the effects of introducing a new species into an ecosystem.
The new species will have to compete with the others to gain energy and food possibly
driving other species to extinction.
18. What is biotic potential mean?
The ability of an organism or species to survive and reproduce.
19. Identify 4 factors that affect biotic potential.
Predation, Competition, Disease and Weather.
20. What are some abiotic limiting factors on a population?
Competitors, Predators, Density and available food.
21. What are some biotic limiting factors on a population?
Temperature, Natural Disasters, Physical characteristics and sunlight.
22. What is the difference between density dependent and density independent limiting
factors for a population?
Dependent Density can only affect a population when it reaches a certain density while
Independent Density can affect the population no matter what density it is. (DDCompetition, DI- Temperature)
23. What are the four factors that affect the carrying capacity of an ecosystem?
Food availability, water, environmental conditions, health and space.