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Biology Chapter 3 Studyness

Terms in this set (36)

All of life on Earth exists in a region known as
the biosphere
Groups of different species that live together in a defined area make up a
community
Autotrophs are organisms that
use energy they take in from the environment to convert inorganic molecules into complex organic molecules
The series of steps in which a large fish eats a small fish that has eaten algae is a
food chain
The total mass of living tissue at each trophic level can be shown in a
biomass pyramid
Nutrients move through an ecosystem in
biochemical cycles
In the nitrogen cycle, bacteria that live on roots of plants
change nitrogen gas into ammonia
Which biochemical cycle does not involve a stage where the chemical enters the atmosphere?
phosphorus cycle
When an ecosystem is limited by a single nutrient that either is scarce or cycles very slowly, this substance is called a
limiting nutrient
What is the definition of ecology?
the scientific study of interactions among organisms and between organisms and their environment or surroundings
Name the different levels of organization within the biosphere, from smallest to largest
individual, populations, communities, ecosystems, biome, and biosphere
How do scientists use modeling to study ecological changes?
to gain insight into ecological changes that are too complex or long range to study
How is sunlight important to most ecosystems?
It's the main source of energy for life
What is chemosynthesis?
which organisms use chemical energy to produce carbohydrates
Distinguish between autotrophs and heterotrophs. Give an example of each.
Autotrophs use natural energy, such as sunlight or chemicals to produce food (plants); heterotrophs rely on organisms fro food and energy (animals)
What is a decomposer?
an organism that breaks down organic matter (fungi)
Which group of organisms is always from at the base of a food chain or food web?
autotrophs
What is an ecological pyramid?
a diagram that shows the relative amounts of energy or matter contained with in each trophic level
Energy pyramid
shows the relative amount of energy within each trophic level
pyramid of numbers
shows the number of organisms at each trophic level
Biomass Pyramid
shows the total biomass at each successive trophic level
Why is the transfer of energy and matter in a food chain only about 10 percent efficient?
because the rest of the energy is used up by that organism from life processes and or is released as heat
What is a biochemical cycle?
a diagram that shows elements, chemical compounds, and other forms of matter from one organism to another and from one part of the biosphere to another
List two ways in which water enters the atmosphere in the watercycle
evaporation and transpiration
Explain the process of nitrogen fixation
bacteria converting gas into ammonia
What are some similarities between the carbon and nitrogen cycle?
in both cycles, the atmosphere is a major reservoir, and both involve plants as transformers of the nutrients
What is meant by "nutrient limitation"?
What an ecosystem is limited by a single nutrient that is scarce ad cycles very slowly
How does the way matter flow through an ecosystem differ from the way that energy flows?
energy flows one way but matter cycles
Why do living organisms need nutrients?
to build tissues and carry out life functions
Explain how a nutrient can be a limiting factor in an ecosystem.
If a nutrient is in short supply, it'll limit its growth
Describe the path of nitrogen through its biochemical cycle
nitrogen in the soil is converted to ammonia by bacteria, producers use from protein, consumers eat producers, and when consumers die, they decompose back into the soil
Describe the three basic methods of ecological research
observing: using the five senses to gather information; experiment: testing a hypothesis; modeling: making models to gain insight and contain information
What are the two main forms of energy that powers the living systems?
solar and chemical
Briefly describe the flow of energy among organisms in an ecosystem
energy flow is a one way flow from autotrophs to consumers (chain)
What proportion of energy is transferred from one trophic level to the next in an ecosystem?
10%
Limiting nutrient
- ocean: nitrogen (or silica or iron)
- streams, lakes, and freshwater environments: phosporus
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