Biology Chapter 3 Flashcards
List the levels of ecological organization, beginning with the lowest.
Species Population Community Ecosystem Biome Biosphere
What is ecology?
The scientific study of interactions among and between organisms in their environment.
True or false: A population consists of all organisms in the same species.
True
What are the three basic approaches scientists use to conduct modern ecological research?
Observing
Experimenting
Modeling
True or false: Ecological models of the environment are extremely unreliable, so they are shunned by ecologists.
False (they are very common and useful)
What is the main energy source for organisms that do not access the sun’s light?
Inorganic chemical compounds
What is the difference between an autotroph and a heterotroph?
Autotrophs produce their own food while heterotrophs do not.
What are plant and animal remains and other dead matter collectively called?
Detritus
What do all different heterotrophs consume?
Herbivore- Plants Carnivore- Meat Omnivore- Plants and animals Detrivore- Dead matter (detritus) Decomposer- Breaks down organic matter
What is a food chain?
A series of steps where organisms eat each other and get eaten
What is a trophic level?
A step in a food chain
What kinds of organisms make up the first trophic level?
Producers
What is an ecological pyramid?
A diagram that shows the relative amounts of energy contained in each trophic level of a food web or chain.
True or false: When heterotrophs consume producers, they only receive about 10% of their energy.
True
What is biomass?
The total amount of living tissue within a given trophic level.
What does a biomass pyramid represent?
The amount of potential food available for each trophic level.
What does a pyramid of numbers show?
The number of relative organisms at each trophic level.
What are the four main elements in the atmosphere?
Oxygen, carbon, hydrogen, and nitrogen
Matter moves through an ecosystem in _____________.
Biogeochemical cycle
What are chemical substances needed in order to sustain life?
Nutrients
What are the three main nutrient cycles that take place in the biosphere?
Carbon cycle, nitrogen cycle, and phosphorus cycle
Why is nitrogen required by all organisms?
Nitrogen helps make amino acids.
What is nitrogen fixation?
The process of converting nitrogen gas into ammonia
What is the process of converting nitrogen into nitrogen gas called?
Denitrificaiton
Why is phosphorus essential to living things?
It forms part of life-sustaining molecules.
What is primary productivity in an ecosystem?
The rate in which organic matter is created by producers.
When does a nutrient become limiting?
When it is scarce or cycles slowly.
When do algal blooms occur?
When aquatic ecosystems get lots of nutrients.
