Cycles of Matter
Water in the atmosphere as a gas is called this.
Water vapor
Energy for most ecosystems originally comes from this source.
Sun
These organisms must come first in a food chain.
Producers
A relationship where both organisms benefit is called this.
Mutualism
The gradual replacement of one community by another is called this.
Succession
This process changes liquid water into water vapor.
Evaporation
Plants store solar energy in the form of this substance.
Sugar (glucose)
An animal that eats only plants is called this.
Herbivore
Bacteria helping humans digest food while receiving nutrients is an example of this relationship.
Mutualism
This type of succession begins where no soil exists.
Primary succession
This process forms clouds when water vapor cools into droplets.
Condensation
Each feeding level in an energy pyramid is called this.
Trophic level
An organism that eats both plants and animals is called this.
Omnivore
A tapeworm living inside another organism is an example of this relationship.
Parasitism
This type of succession happens after a disturbance like a fire.
Secondary succession
These two biological processes drive the carbon and oxygen cycles.
Photosynthesis and cellular respiration
Only a small portion of energy passes from one trophic level to the next, making this level the largest in the pyramid.
This gives a more complete picture of feeding relationships in an ecosystem than a simple chain.
Food web
A relationship where one organism benefits and the other is unaffected is called this.
Commensalism
Primary succession usually takes longer because it must first form this.
Soil
Organisms need this element to build proteins.
Nitrogen
Energy does not cycle through ecosystems because it is eventually lost as this.
Heat
An omnivore may fit into multiple levels of this ecological model.
Energy pyramid
Scientists often struggle to fully understand these complex connections among organisms.
Fires can sometimes help ecosystems by clearing dead material and returning this to the soil.
Nutrients