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biology 301 > ch 22 : landscape ecology, biogeography, and global biodiversity > Flashcards

ch 22 : landscape ecology, biogeography, and global biodiversity Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

the field of study that considers the spatial arrangement of habitats at different scales and examines how they influence individuals, populations, communities, and ecosystems

A

landscape ecology

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2
Q

current habitat heterogeneity is a reflection of what?

A

recent and historical events caused by natural human forces

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3
Q

long-lasting influence of historical processes on the current ecology of an area.

A

legacy effects

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4
Q

what can continue to cause habitat heterogeneity?

A

natural forces

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5
Q

how has human activity influenced natural forces?

A

human activity has influenced the intensity, frequency, and ecological influence of natural forces.

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6
Q

why does species richness often increase from the local to landscape scale?

A

because habitat diversity increases along this gradient

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7
Q

the number of species in a relatively small area of homogenous habitat, such as a stream

A

local (i.e. alpha) diversity

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8
Q

the number of species in all of the habitats that comprise a large geographic area

A

regional (i.e. gamma) diversity

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9
Q

the number of species that differ in occurrence between two habitats

A

beta diversity

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10
Q

the collection of species that occurs within a region; serves a source of species of all local sites within a region

A

regional species pool

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11
Q

the process of sorting species in the regional pool among localities according to their adaptations and interactions

A

species sorting

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12
Q

a graphical relationship in which increases in area (A) are associated with increases in the number of species (S)

A

species area curve

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13
Q

equation for species-area curve

A

S = cA^z where c and z are constants fitted to the data

or

log S = log c + z log A

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14
Q

across many different groups of organisms, the slope (z) ranges from 0.20 to 0.35 across scales of 1 m2 to the area of an entire country.

A

slide 12 !!

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15
Q

what have human activities caused throughout the world?

A

widespread fragmentation of large habitats

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16
Q

what are the effects of fragmentation?

A
  • it decreases habitat area and increases patch number, edge size, and isolation
  • small habitats have small populations which are more likely to go extinct
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17
Q

specifically, how does fragmentation effect fragment edges?

A
  • fragmentation causes an increase in the amount of edge habitat compared to the original unfragmented habitat
  • an increase in edge habitat changes the abiotic conditions (e.g., ground temperatures in a forest) and the species composition of a habitat.
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18
Q

what happens to species that prefer edge habitats when fragmentation occurs?

A

they increase in abundance

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19
Q

how can declining populations in habitat patches be sustained?

A

by the dispersal of organisms between patches via habitat corridors

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20
Q

how do habitat corridors help declining populations?

A

they increase gene flow and genetic diversity

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21
Q

what purposes can habitat corridors serve?

A
  1. pieces of preserved habitats
  2. constructed for the specific purpose of allowing species dispersal
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22
Q

small intervening habitat patches that dispersing organisms can use to move between large favorable habitats; useful for flying organisms that do not need continuous corridors to disperse

A

stepping stones

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23
Q

what can help determine whether organisms can move between fragments?

A

the quality of habitat between fragments (i.e. matrix habitat)

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24
Q

are all habitats in the matrix the same?

A

no; some habitats in the matrix may contain favorable conditions for dispersal, whereas others might be inhospitable.

25
Q

CONCEPT : the equilibrium theory of island biogeography incorporates both _____ and ________

A

area and isolation

26
Q

what did MacArthur and Wilson find?

A
  1. species richness increases with island area
  2. islands closer to the mainland appeared to receive more colonizing species
27
Q

how did MacArthur and Wilson test their hypothesis? what did they find?

A
  • to test the hypothesis that species richness is determined by both island area and isolation, they measured bird species richness on
    25 islands in the South Pacific.
  • they found that larger islands contained more species
  • among islands of similar sizes, near islands contained more bird species than far islands
28
Q

t/f the effects of patch size and isolation are very different across multiple types of habitat

A

false, they are similar

29
Q

Daniel S and E.O Wilson’s experiment

A
  • Daniel Simberloff and E. O. Wilson conducted a manipulative experiment to test effects of habitat size and isolation.
  • on a set of islands in the Florida Keys, they observed that islands closer to the mainland had more insect species than islands farther from the mainland.
  • they built tents over selected islands, and fumigated them to kill all insects.
  • they removed the tents and allowed species to naturally recolonize.
30
Q

what did Daniel S and E.O Wilson’s experiment result in?

A

they found that more insects recolonized islands closer to the mainland, and species richness of islands was similar to values before fumigation.

31
Q

a theory stating that the number of species on an island reflects a balance between the colonization of new species and the extinction of existing species.

A

equilibrium theory of island biogeography

32
Q

according to the equilibrium theory of island biogeography, what would happen on an uninhabited island?

A

many species from a nearby source habitat (e.g. mainland) could potentially colonize the island

33
Q

assuming the species pool of potential colonizers is a fixed size, what could be said about the rate of new species colonizing the island?

A

the rate of new species colonizing the island declines as a function of how many species have already colonized the island

34
Q

what happens as more species colonize the island?

A

more species are subject to possible extinction due to change and negative interactions (e.g. competition, predation, parasitism)

35
Q

given that the island continues to experience colonization and extinction of species, what would the opposing forces result in?

A

these opposing forces should result in an equilibrium point of species richness on the island Ŝ.

36
Q

theory of island biogeography: this model only predicts what?

A
  • this model only predicts the number of species at equilibrium—not the species composition at equilibrium.
  • at equilibrium, there is a continuous turnover of species, resulting in a temporally variable species composition.
37
Q

theory of island biogeography : smaller islands should have________ extinction rates; islands nearer to a source habitat should have ________ colonization rates.

A

higher; higher

38
Q

what reveals predictions regarding Ŝ?

A

combining the effects of island area and isolation

39
Q

understanding the effects of what has helped to design nature reserves?

A

island size and shape

40
Q

since large areas can support large populations with low extinction rates, setting aside a single, _________ will better protect biodiversity than will several small areas.

A

large area

41
Q

what are some other things that need to be considered when designing nature reserves?

A
  • reserves also need to be close enough to allow dispersal, but far enough to reduce dispersal of diseases and parasites.
  • the benefits and disadvantages of edge habitat must be considered; round areas have less edge-to-area ratios than rectangular areas.
  • nature reserves are typically a compromise among various options.
42
Q

_________ _______ in diversity are pervasive and extend even to the oceans

A

latitudinal trends

43
Q

in the Northern Hemisphere, species richness of most animal and plant groups increase from __________ to _________

A

north to south

44
Q

in what direction does mammal species richness increase

A

mammal species richness also increases to the west, likely due to the habitat heterogeneity of mountains

45
Q

oceans also have increased species richness at _________ ________

A

lower latitudes

46
Q

at any given latitude, there are________ species where there is a greater ecological heterogeneity

A

more

47
Q

among habitats with _________ __________ ______ ___________, less heterogeneous habitats will support fewer species.

A

similar levels of productivity

48
Q

what rose in response to past environmental conditions?

A

current diversity

49
Q

movement of landmasses across Earth’s surface

A

continental drift

50
Q

the single landmass that existed on Earth ~250 Mya and subsequently split into Laurasia and Gondwana

A

pangaea

51
Q

the northern landmass that separated from Pangaea ~150 Mya and subsequently split into North America, Europe, and Asia

A

laurasia

52
Q

the southern landmass that separated from Pangaea and split into South America, Africa, Antarctica, and India

A

gondwana

53
Q

what did the separation of continents allow species to do?

A

independently evolve in different regions of the Earth; the joining of continents allowed groups of organisms unique to one landmass to move into new areas

54
Q

what did the separation and joining of continents establish?

A

six distinct biogeographic regions that contain unique groups of organisms

55
Q

over the past 250 million years, what have the climates on earth experienced?

A
  • dramatic changes as the continents drifted
  • these changes have had profound effects on the distributions of plants and animals
56
Q

about 2 Mya, gradual cooling of the Earth produced oscillations in climate known as the _______ _______

A

Ice Age

57
Q

what did alternating periods of cooling and warming cause?

A

the advance and retreat of ice sheets over north America and cycles of cool, dry climates and warm, wet climates in the tropics

58
Q

what did the advance and retreats of ice sheets cause?

A

the composition of plant species to change as species migrated back and forth across the landscape

biology 301 (6 decks)

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