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Biology II - Final > Chapter 54 > Flashcards

Chapter 54 Flashcards

1
Q

Biological Community

A

An assemblage of populations of various species living close enough for potential interaction. For example, the carrier crab carries a sea urchin on its back for protection against predators.

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2
Q

Ecologists call relationships between (different) species in a community _.

A

Interspecific interactions

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3
Q

Examples of interspecific interactions are:

A
  • Competition
  • Predation
  • Herbivory
  • Symbiosis (parasitism, mutualism, and commensalism)
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4
Q

Interspecific interactions can affect the _ of each species, and the effects can be summarized as positive (+), negative (-), or no effect (0).

A

Survival and reproduction

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5
Q

Interspecific Competition

A

Occurs when species compete for a resource in short supply; -/- interaction

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6
Q

Strong competition can lead to _, local elimination of a competing species (weaker of two species gets excluded).

A

Competitive exclusion

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7
Q

The competitive exclusion principle states that…

A

…two species competing for the same limiting resources cannot coexist in the same place.

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8
Q

Ecological Niche

A

The sum of a species’ use of biotic and abiotic resources

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9
Q

An ecological niche can also be thought of as an organism’s _.

A

Ecological role

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10
Q

Ecologically similar species can coexist in a community if there are one or more significant _ in their niches.

A

Differences

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11
Q

Resource Partitioning

A

Differentiation of ecological niches, enabling similar species to coexist in a community

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12
Q

Fundamental Niche

A

The niche potentially occupied by a species (could theoretically live there)

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13
Q

Realized Niche

A

The niche actually occupied by a species

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14
Q

As a result of _, a species’ fundamental niche may differ from its realized niche. For example, the presence of one barnacle species limits the realized niche of another species.

A

Competition

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15
Q

G.F. Gause’s classic experiment on _ using three Paramecium species shows this principle in action.

A

Competitive exclusion

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16
Q

Sympatric Species

A

Live in the same geographic region

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17
Q

Allopatric Species

A

Live in different geographic regions

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18
Q

Character Displacement

A

A tendency for characteristics to be more divergent in sympatric populations of two species than in allopatric populations of the same two species

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19
Q

An example of character displacement is…

A

…variation in beak size between populations of two species of Galapagos finches.

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20
Q

Predation

A

An interaction in which one species, the predator, kills and eats the other, the prey; +/- interaction

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21
Q

Some feeding adaptations of predators are:

A
  • Claws
  • Fangs
  • Poison
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22
Q

Prey display various defensive adaptations. Behavioral defenses include:

A
  • Hiding
  • Fleeing
  • Forming herds or schools
  • Self-defense
  • Alarm calls
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23
Q

_ and _ defenses protect species such as porcupines and skunks, respectively.

A

Mechanical; chemical

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24
Q

Animals with effective chemical defense often exhibit bright _. Predators are particularly cautious in dealing with prey that display such coloration.

A

Warning coloration

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25
Q

_ makes prey difficult to spot.

A

Cryptic coloration (camouflage)

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26
Q

In some cases, a prey species may gain significant protection by mimicking the appearance of another species. In _, a harmless species mimics a harmful model.

A

Batesian mimicry

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27
Q

_ can also be used by predators to approach prey. For example, the mimic octopus can take on the appearance and movement of more than a dozen marine animals.

A

Mimicry

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28
Q

Herbivory

A

An interaction in which an herbivore eats parts of a plant or alga; +/- interaction

29
Q

_ has led to evolution of plant mechanical and chemical defenses and adaptations by herbivores.

A

Herbivory

30
Q

Symbiosis

A

A relationship where two or more species live in direct and intimate contact with one another

31
Q

What are the three types of symbiosis?

A
  • Parasitism
  • Mutualism
  • Commensalism
32
Q

Parasitism

A

One organism, the parasite, derives nourishment from another organism, its host, which is harmed in the process; +/- interaction

33
Q

Parasites that live within the body of their host are called _.

A

Endoparasites

34
Q

Ectoparasites

A

Parasites that live of the external surface of a host

35
Q

Many parasites have a complex _ involving a number of hosts.

A

Life cycle

36
Q

Some parasites change the _ of the host in a way that increases the likelihood that the parasite will be transmitted to the next host.

A

Behavior

37
Q

Parasites can significantly affect the _ of their host population.

A

Survival, reproduction, and density

38
Q

Mutualistic Symbiosis (Mutualism)

A

An interspecific interaction that benefits both species; +/+ interaction

39
Q

Mutualism can be:

A
  • Obligate, where one species cannot survive without the other
  • Facultative, where both species can survive alone
40
Q

Commensalism

A

One species benefits and the other in neither harmed nor helped; +/0 interaction

41
Q

_ interactions are hard to document in nature because any close association likely affects both species.

A

Commensal

42
Q

In general, a few species in a _ exert strong control on that community’s structure.

A

Community

43
Q

Two fundamental features of community structure are:

A
  • Species diversity

- Feeding relationships (trophic structure)

44
Q

_ of a community is the variety of organisms that make up the community.

A

Species diversity

45
Q

Species diversity has two components:

A
  • Species richness, the number of different species in the community
  • Relative abundance, the proportion each species represents of all individuals in the community
46
Q

Communities with higher diversity are:

A
  • More productive; they produce more biomass (the total mass of all organisms)
  • More stable in their productivity
  • Better able to withstand and recover from environmental stresses
  • More resistant to invasive species, organisms that become established outside their native range
47
Q

Trophic Structure

A

The feeding relationships between organisms in a community

48
Q

Trophic structure is a key factor in _.

A

Community dynamics

49
Q

Food Chains

A

Link trophic levels from producers to top carnivores

50
Q

Certain _ have a very large impact on community structure.

A

Species

51
Q

Such species are _ or play a pivotal role in community dynamics.

A

Highly abundant

52
Q

Dominant Species

A

Those that are most abundant or have the highest biomass

53
Q

One hypothesis suggests that _ are most competitive in exploiting resources. Another hypothesis is that they are most successful at _.

A

Dominant species; avoiding predators

54
Q

Keystone Species

A

Exert strong control on a community by their ecological roles, or niches

55
Q

In contrast to dominant species, _ are not necessarily abundant in a community.

A

Keystone Species

56
Q

Disturbance

A

An event that changes a community, removes organisms from it, and alters resource availability

57
Q

The types of _ and their frequency and severity vary among communities.

A

Disturbances

58
Q

_ and _ are significant sources of disturbance in many ecosystems.

A

Storms; fire

59
Q

Intermediate Disturbance Hypothesis

A

States that moderate levels of disturbance can foster greater diversity than either high or low levels of disturbance

60
Q

High levels of disturbance exclude many _ species.

A

Slow-growing

61
Q

Low levels of disturbance allow _ to exclude less competitive species.

A

Dominant species

62
Q

The large-scale fire in Yellowstone National Park in 1988 demonstrated that communities can often respond very _ to a massive disturbance.

A

Rapidly

63
Q

Ecological Succession

A

The sequence of community changes after a disturbance

64
Q

Primary Succession

A

Occurs where no soil exists when succession begins

65
Q

Secondary Succession

A

Begins in an area where soil remains after a disturbance

66
Q

Abandoned agricultural land may return to its original state through _.

A

Secondary succession

67
Q

_ have the greatest impact on biological communities worldwide.

A

Humans

68
Q

Both terrestrial and marine ecosystems are subject to _.

A

Human disturbance

69
Q

Human disturbance to communities usually reduces species _.

A

Diversity

Biology II - Final (3 decks)

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