Ch. 36 Communities and Ecosystems Flashcards Preview

AP Biology > Ch. 36 Communities and Ecosystems > Flashcards

Flashcards in Ch. 36 Communities and Ecosystems Deck (44):
1

Community

An assemblage of all the organisms living together and potentially interacting in a particular area

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Diversity

The variety of different kinds of organisms that make up a community (Species richness and abundance of each species)

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Stability

Community's ability to resist change and return to its original species composition after being disturbed
- depends on type of community/distrubance

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Trophic Structure

The feeding relationship in an ecosystem
- determines the route of energy flow and the pattern of chemical cycling in an ecosystem

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What are the forces that tie populations together into communities?

1) Competition
2) Predation
3) Symbiosis

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Example of Competition

1) Interspecific Competition
2) Competitive Exclusion Principle

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a contest between individuals of two populations that require a limited resource (helps structure communities)

Interspecific Competition

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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

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Niche

A population's role in its community
- the sum total of a population's use of the biotic and abiotic resources of its habitat

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An interaction between species in which the predator eats the prey

Predation

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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

Coevolution

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Example of predation

Plants using chemical toxins and antipredator thorns
Bright colors, camouflage, mimicry

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Batesian Mimicry

A species that a predator eats looks like a different dangerous species.

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Mullerian Mimicry

A mutual mimicry by 2 species, both harmful to the predator

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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.

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Keystone Predator

A predator species that reduces the density of the strongest competitors in a community therefore maintain diversity

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Symbiotic Relationship
3 types

An interaction between 2+ species in which one species lives in/on another

1) Parasitism 2) Commensalism 3) Mutualism

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Parasitism

A parasite (predator) lives in/on the surface of a host, from which it derives its food

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Commensalism

One partner benefits without significantly affecting the other

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Mutualism

Both partners benefit

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A force that changes a biological community and usually removes organisms from it
- small ones tend to have positive effect

Disturbance

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Process of biological community change resulting from disturbance

Ecological succession

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Primary succession

Biological community arises in an area without soil

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Secondary Succession

Occurs where a disturbance has destroyed an existing biological community but left the soil intact

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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.

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All the organisms in a given area along with the ABIOTIC factors with which they interact

Ecosystem

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Passage of energy through components
- continuous new energy from sun

Energy Flow
Light -> Chemical -> Heat -> Chemical Cycling

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Circular moment of materials within the ecosystem. Involved abiotic and biotic.

Chemical cycling

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Food Chain

sequence of food transfer between trophic levels

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Quaternary Consumers

An organism that eats tertiary consumers

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Tertiary consumers

An organism that eats secondary consumers

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Secondary Consumer

An organism that eats primary consumers

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Primary Consumer

An organism that only eats autotrophs

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Producers

An organism that makes organic food molecules from inorganic raw material

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Detritivores

An organism that derives its energy from organic waste

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Detritus

Nonliving matter

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Decomposition

Breakdown of organic material to inorganic

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Food Web

A network of interconnecting food chains
- animals can be multiple consumers

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Biomass

Amount (mass) of organic material in an ecosystem

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Primary Productivity

Rate at which an ecosystem's producers convert solar energy to chemical energy

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Part of an ecosystem where a chemical, such as carbon or nitrogen, accumulates or is stockpiled outside of living organisms

Abiotic Reservoir

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An increase in productivity of an aquatic ecosystem
- balance of freshwater is easily upset by this increased
- reduces species diversity if accelerated

Eutrophication

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An extensive region of land that includes one or more areas that are undisturbed by humans; surrounded by altered lands

Zoned Reserves

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What are the dominant pathways of water, carbon, nitrogen, and phosphorous cyclic movements?

Water is driven by solar heat and the ocean.
Carbon is ran by plants but increased excessively by fossil fuel burning.
Nitrogen is from the atmosphere as main reservoir and driven by plants/soil bacteria though there can be excess by humans.
Phosphorous has a reservoir of rock in which it relies on weathering.