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Zoology Semester 2 > APS123 Thomas > Flashcards

APS123 Thomas Flashcards

1
Q

A community consists of…

A

all of the individuals of all of the species that inhabit a particular area

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2
Q

Species richness within sites =

A

a - diversity

alpha

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3
Q

Species richness in all sites =

A

y - diversity

gamma

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4
Q

B - diversity (beta) measures…

A

how different the samples are across the sites, or the turnover of species

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5
Q

What is the Jaccard coefficient used for?

A

To compare the community composition of 2 sites

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6
Q

What is the equation for the Jaccard coefficient?

A

a/a+b+c

a = number of species found in both sites (not total)
b = number of species found in site 1 but not site 2
c = number of species found in site 2 but not site 1
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7
Q

When communities are identical, the Jaccard coefficient =

A

1

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8
Q

When communities are completely different, the Jaccard coefficient =

A

0

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9
Q

Communities are often …

A

nested
(smaller community occurs in a larger community, which may occur within an even larger community etc.)

  • but communities can also not be nested (no species in common)
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10
Q

What does SARs stand for?

A

Species area relationships

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11
Q

You expect … islands to have more species, as they contain more …

A

larger, niches

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12
Q

SARs are …-…

A

non-linear (due to limitations e.g. of potential niches)

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13
Q

S =

A

cA^z

S = number of species
A = area
c = intercept
z = exponent
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14
Q

If you take a log of both axes when plotting number of species against area of island, you get a …

A

straight line relationship

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15
Q

y =

A

c + mx

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16
Q

SARs are useful when thinking about habitat….

A

fragmentation (e.g. in forestry and logging)

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17
Q

The slope of SARs is remarkably …

A

consistent (order of 0.25-0.3)

- typically equates to doubling of richness with tenfold increase in area

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18
Q

Intercept is highly …

A

variable

- we require this information (as well as the slope) to calculate species richness

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19
Q

Mountain peaks create “…” of habitats

A

islands

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20
Q

Highest elevation montane habitats of…

A

mixed coniferous forest

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21
Q

Mid altitudes of…

A

pinion-juniper woodland

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22
Q

Alpha diversity was surveyed in pinion-juniper woodland…

A

on different isolated mountain tops

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23
Q

What relationship was found between number of species and area in pinion-juniper mountain woodland?

A

Clear positive relationship as expected

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24
Q

There is a predicted … shift in habitat types with a 3 degree increase in temperature

A

altitudinal - p-j woodland pushed up and restricted to mountain tops (therefore reduction in habitat area)
- decrease in diversity assumes inability to disperse to other mountain tops and migrate

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25
Q

Rare species tend to occur…… and are predicted as more likely to … …

A

where species richness is high (there are lots of other species), go extinct

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26
Q

Mainland SARs tend to have…

A

shallower slopes than island SARs

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27
Q

Why do islands have fewer species than mainland areas of equivalent size?

A

Saturation decreases further away from mainland, smaller proportion of species shared with mainland

28
Q

Saturation by isolation suggests that…

A

area (and by extension habitat diversity) is not the only, or even main, factor driving alpha diversity in island-like systems

29
Q

Many systems display Species Isolation relationships -

A

alpha diversity declines with isolation from the mainland

30
Q

Who put forward the Island Biogeography theory?

A

MacArthur and Wilson (1963)

- thought that the habitat-area relationship was incomplete - developed a model predicting species richness on islands

31
Q

How are island communities formed?

A
  • Species must arrive on an island (immigration)
  • Species must persist on an island (extinction)
  • Species richness is a balance of immigration and extinction
32
Q

As immigration rate to an island increases,

A

species richness decreases

  • consider island with no species - most colonising individuals will be from unrepresented species
  • consider island with many species - most colonising individuals will be from species already present on the island
33
Q

As number of resident species increases,

A

extinction rate increases

- increased competition suppresses population sizes so species extinction rates increase

34
Q

In 1883…

A

a catastrophic volcanic explosion devastated the island of krakatoa - its flora and fauna were completely exterminated

35
Q

Number of species on an island reaches…

A

equilibrium

- dynamic - species change, but number of species remains more or less constant

36
Q

Macroecology focuses…

A

over wide spatial and temporal scales

- SARs, island biogeography and latitudinal gradients are examples of macroecology

37
Q

Who first discussed the latitudinal diversity gradient?

A

Alexander von Humboldt

38
Q

Von Humboldt broadly suggested that biodiversity was higher at..

A

lower latitudes (nearer tropics)

39
Q

Understanding global distribution of species focuses on predicting causative factors that drive variation in rates of immigration, extinction, emigration and speciation. There are 100s of hypotheses but two main categories:

A
  1. climatic/environmental factors (ecology)

2. Historical factors (evolution)

40
Q

The environment filters the species that can occur in a given area and may determine upper limits on species richness. A couple of these environmental filters are to do with…

A
  1. energy/ productivity

2. spacial and habitat hetergeneity

41
Q

PET is

A

potential evapotranspiration
- amount of water that would evaporate or be transpired from a saturated surface - crude measure of available energy or productivity

42
Q

In general, as energy availability increases,

A

species richness increases

  • for ectotherms, extra atmospheric warmth enhances intake and se of food resources
  • for endotherms, extra warmth means less use of resources to maintain body temperature and more available for growth and reproduction
  • not always clear positive correlation, sometimes u-shaped, negative, no correlation etc.
43
Q

Habitat heterogeneity often is positively correlated to..

A

species richness

44
Q

Climate and environment determine..

A

the number of species that can co-exist, and govern the movement of species into and out of an area (immigration and emigration)

45
Q

What are the 3 hypothesised processes for historical determination of diversity?

A
  1. Tropical cradles of diversity - tropics home to young, rapidly speciating lineages (speciation rate peaks in the tropics + extinction rate invariant with latitude)
  2. tropical museums of diversity - tropics are home to old, relictual species (speciation rate invariant, extinction rate declines in the tropics)
  3. Out of the tropics - species form in the tropics and move to extratropics (speciation rate peaks in the tropics and extinction rate declines in the tropics)
46
Q

What are the 3 hypothesised processes for historical determination of diversity?

A
  1. Tropical cradles of diversity - tropics home to young, rapidly speciating lineages (speciation rate peaks in the tropics + extinction rate invariant with latitude)
  2. tropical museums of diversity - tropics are home to old, relictual species (speciation rate invariant, extinction rate declines in the tropics)
  3. Out of the tropics - species form in the tropics and move to extratropics (speciation rate peaks in the tropics AND extinction rate declines in the tropics)
47
Q

Speciation rate =
Extinction rate =
Net diversification =

A

birth rate
death rate
speciation rate - extinction rate

48
Q

In reality, speciation rates are … in the tropics, and extinction rates are … in the tropics, and transitions … the tropics are much more frequent than transitions … the tropics - consistent with…

A

higher, lower,
out of, into,
the out of the tropics model

49
Q

In marine fish, speciation rates are higher…

A

outside of the tropics

- don’t know, but extinction rates may be particularly low in tropics

50
Q

Evolutionary history at the … level determines … … … (e.g. tropics vs temperate

A

regional, gross diversity patterns

51
Q

Processes of speciation and extinction govern…

A

species available to form local communities

52
Q

What are ecogeographical rules?

A

variation in the traits of organisms over geographical or environmental gradients
e.g. bergmann’s rule describes changes in body size with latitude/ temperature

53
Q

Bergmann observed that…

A

body size increases with HIGH latitudes in mammals

  • suggested advantageous as reduces heat loss from lower SA:V ratio
  • observation based on latitude but proposed mechanism based on temperature gradient
54
Q

In birds, higher species richness with

A

lower body mass

55
Q

What is Allen’s rule?

A

Length of appendages in closely related vertebrates increases in hotter environments
e.g. fennec fox vs red fox vs arctic fox

56
Q

Bird’s bills are a major source of…

A

heat loss

57
Q

Bill size declines with…

A

latitude and altitude

  • consistent relationships within multiple bird families
  • data support both pattern and process
58
Q

For the example, several small reserves accumulate..

A

species faster than 1 large island of equivalent area]

  • even though the data are nested they are not perfectly nested
  • if species are complementary
59
Q

… of global land surface is in protected areas

A
  1. 5%

- but many (20% of) protected species receive no protection at all - worst for amphibians

60
Q

Typically, protected areas have been set up…

A

opportunistically - often on land nobody else wanted

61
Q

Unfortunately, people and biodiversity often like the same places (low …, highly productive …) - and existing reserves are not effectively positioned to protect biodiversity

A

elevation, soils

62
Q

When deciding which areas to protect, choosing sites based only on local species richness (a-diversity) ignores…

A

the important role of community dissimilarity (B-diversity) - instead we should pick the sites that would protect complementary sets of species

63
Q

Random is better than using..

A

hotspots

apart from threatened species

64
Q

Complementary sites much better than

A

random and hotspots

65
Q

Hotspots don’t take … into consideration

A

turnover

66
Q

It is argued that minimising edge-area ration in reserve design is desirable to…

A

protect as much core habitat as possible given onging habitat fragmentation

67
Q

SLOSS:
Several small sites are better for…

But single large site is better for…

Strategy depends on focus.

A
  • Maximum diversity, and persistence of populations if disturbances to sites are independent and especially where individuals disperse between sites
  • Minimising negative impacts of edge effects, and supporting larger populations and allowing long term persistence

Zoology Semester 2 (15 decks)

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