Flashcards in Ch. 36 Communities and Ecosystems Deck (44):
An assemblage of all the organisms living together and potentially interacting in a particular area
The variety of different kinds of organisms that make up a community (Species richness and abundance of each species)
Community's ability to resist change and return to its original species composition after being disturbed
- depends on type of community/distrubance
The feeding relationship in an ecosystem
- determines the route of energy flow and the pattern of chemical cycling in an ecosystem
What are the forces that tie populations together into communities?
Example of Competition
1) Interspecific Competition
2) Competitive Exclusion Principle
a contest between individuals of two populations that require a limited resource (helps structure communities)
Concept that populations of two species cannot coexist in a community if their niches are nearly identical
- using resources more efficiently and having a reproductive advantage, one will outcompete the other
Competitive Exclusion Principle
A population's role in its community
- the sum total of a population's use of the biotic and abiotic resources of its habitat
An interaction between species in which the predator eats the prey
Evolutionary change, in which adaptations in one species acts as a selective force on a second species, inducing adaptations that in turn act as a selective force on the first species
- mutual influence on the evolution of two different interacting species
- evolves thru natural selection
Example of predation
Plants using chemical toxins and antipredator thorns
Bright colors, camouflage, mimicry
A species that a predator eats looks like a different dangerous species.
A mutual mimicry by 2 species, both harmful to the predator
Why is it difficult to assess predation in natural communities?
Predators never drive species to extinction. With so many species, predators are prey too so their numbers are limited. Due to this, it is hard to assess when so many organisms are linked and continue to be linked.
A predator species that reduces the density of the strongest competitors in a community therefore maintain diversity
An interaction between 2+ species in which one species lives in/on another
1) Parasitism 2) Commensalism 3) Mutualism
A parasite (predator) lives in/on the surface of a host, from which it derives its food
One partner benefits without significantly affecting the other
Both partners benefit
A force that changes a biological community and usually removes organisms from it
- small ones tend to have positive effect
Process of biological community change resulting from disturbance
Biological community arises in an area without soil
Occurs where a disturbance has destroyed an existing biological community but left the soil intact
How are disturbances a characteristic of many communities?
Fires (major one) and floods are examples.
In deciduous forest, decomposition occurs fast so no fire fuel. Grassland prairies depend on fire to avoid tree growth.
All the organisms in a given area along with the ABIOTIC factors with which they interact
Passage of energy through components
- continuous new energy from sun
Light -> Chemical -> Heat -> Chemical Cycling
Circular moment of materials within the ecosystem. Involved abiotic and biotic.
sequence of food transfer between trophic levels
An organism that eats tertiary consumers
An organism that eats secondary consumers
An organism that eats primary consumers
An organism that only eats autotrophs
An organism that makes organic food molecules from inorganic raw material
An organism that derives its energy from organic waste
Breakdown of organic material to inorganic
A network of interconnecting food chains
- animals can be multiple consumers
Amount (mass) of organic material in an ecosystem
Rate at which an ecosystem's producers convert solar energy to chemical energy
Part of an ecosystem where a chemical, such as carbon or nitrogen, accumulates or is stockpiled outside of living organisms
An increase in productivity of an aquatic ecosystem
- balance of freshwater is easily upset by this increased
- reduces species diversity if accelerated
An extensive region of land that includes one or more areas that are undisturbed by humans; surrounded by altered lands