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Convervation Bio > CH 6 > Flashcards

CH 6 Flashcards

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1
Q

Extant

A

species that do have at least one individual that is alive somewhere in the world

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2
Q

Extinct

A

species that no longer exits, no member of the species is alive

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3
Q

Locally extinct:

A

species no longer exists in a specific area, but is found elsewhere

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4
Q

Ecologically extinct:

A

species exists, but its numbers are so low that is no longer fills its role in the ecosystem. No impact on prey, not a potential food source

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5
Q

Extinct in the Wild

A

no natural population exists, but the species remains in captivity. Decrease species, decrease diversity

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6
Q

Extirpation

A

local extinction, many species eliminated from parts of their former ranges

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7
Q

Endemic

A

species found in a specific location and nowhere else. Have a greater risk than wide-range species

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8
Q

Why is an endemic species at greater risk of extinction?

A
  • The area they live may be large or small
  • Usually refers to a small area like an island
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9
Q

How does the time of human contact (or arrival) affect the number of species recently extinct and currently threatened with extinction?

A
  • Humans typically allow exotic introductions and accelerate rates
  • Extinction rate increases with initial introduction of humans
  • Increase time in an area, decrease extinct species
  • More sensitive species lost first
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10
Q

How has bird diversity changed with waves of human colonization on Hawaii? What are some of the reasons bird species have been lost?

A
  • As population grew, more species became extinct
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11
Q

Consider the impact of humans on the extinction rate – is this something new for our species?

A
  • Humans accelerate extinction rates
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12
Q

What is the background extinction rate (in MSY)? How is it calculated?

A
  • Calculated by using the fossil record
  • Species exists for an average of 1 my before extinction per species
  • Extinctions/species x 1million/time
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13
Q

How do current rates of extinction compare to the estimated background extinction rate?

A
  • Current extinction rate is higher than the estimated background rate
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14
Q

How is the expected extinction rate projected to change in the future?

A
  • Projected future is to continue to increase
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15
Q

What IUCN categories are used for species that are threatened with extinction? Is the % of threatened species available for most groups of Eukaryotes? Why not?

A
  • International union for the conservation of nature
  • Adequate data
    o Critically endangered
    o Endangered
    o Vulnerable
  • Evaluated
    o Adequate data
    o Near threatened
    o Least concerned
  • All species
    o Evaluated
    o Data deficient
    o Not evaluated
     Most eukaryotes because insects
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16
Q

How many mass extinction events have occurred?

A
  • Ordovician, 500 mya
  • Devonian, 345 mya
  • Permian, 250 mya
  • Triassic, 180 mya
  • Cretaceous, 65 mya
  • Recent times, Anthropocene
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17
Q

What is the threshold for an extinction event to be a mass extinction event?

A
  • 75% of species lost
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18
Q

What is the largest mass extinction event? What may have contributed to it?

A
  • Permian, Paleozoic to Mesozoic era
  • Lost 95% marine species, 50% families
  • Methane producing bacteria became very common
  • Large volcanic eruption
  • Methane and C02 in the air
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19
Q

Using the species area curve covered in lecture, how much of the habitat would you have to protect to preserve 90% of the species? What about 50% of the species?

A

a. To preserve 90% of species, 50% of habitat would be lost
b. To preserve 50% of species, 90% of habitat is lost

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20
Q

What assumptions are included in species -area models?

A

a. Assumes species have typical species area curves
b. Assumes species are eliminated from areas that are cleared of forests
c. Assumes habitat is eliminated at random
d. Fragmentation of area makes a difference

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21
Q

How could these assumptions be violated?

A

i. Estimates may vary for species with wide vs narrow ranges
i. Some species survive deforestation
ii. Survive in isolated patches/second growth forestsi. May be able to preserve critical habitats
ii. Preserve areas with high species richness

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22
Q

What are the basic points of Island Biogeography theory as presented by MacArthur and Wilson?

A

a. The number of species on an island tents toward an equilibrium number
b. It is a result of balancing the rate of immigration and extinction

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23
Q

With a few species

A

i. Immigration rate is high
ii. Extinction rate is low
iii. Species pool is high when there are few species on an island
iv. Population size of each species may be high

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24
Q

With many species

A

i. Immigration rate is low
ii. Extinction rate is high
iii. Species pool is low when there are many species on an island
iv. Population size of each species may be small

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25
Large islands
i. Lower extinction rates ii. Increase area, increase population size, less likely to go extinct
26
Small islands
i. Higher extinction rates ii. Lower population size, more likely to go extinct
27
Near other islands
i. High immigration ii. More likely to reach the island
28
Far from other islands
i. Low immigration ii. Less likely to reach the island
29
What effects have been made to the basic theory of island biogeography?
a. Target effect: b. Rescue effect:
30
Target effect
i. Larger island -> increase immigration ii. Smaller island -> lower immigration
31
Rescue effect:
i. More species from the mainland will reach a closer island than a far one ii. Species may have a lower risk of extinction if immigrants keep colonizing the island iii. Extinction may not be detected if colonists keep arriving
32
How can island biogeography be applied monophagous insects
a. The number of species should increase with increasing island size b. The number of species should decrease with increasing distance of the island from the source pool c. The turnover of species should be considerable
33
What are the 3 main predictions from the theory of island Biogeography and which of these are well supported by experimental evidence?
a. The number of species should increase with increasing island size, well supported b. The number of species should decrease with increasing distance of the island from the source pool, well supported c. The turnover of species should be considerable, not well supported
34
The basic theory of island biogeography states that island size (itself) is related to the dynamic equilibrium of species found. Or is the higher number of species (on larger islands) due to the higher number of habitats found on larger islands?? How did Simberloff’s (1976) with Mangroves test this idea?
a. Isolated the effect of area on species richness b. Chose habitats that do not change as you sample bigger islands c. Studied islands of pure mangroves of varying size in the florida keys d. Richness decreased when island size decreased
35
If graphed this equation, what would z represent? log S = log c + z log A
Z represents the slope. How fast species richness increases with increasing area
36
Why is Z typically lower on continents than it is on islands? log S = log c + z log A
Z decreases as animals become more transient between habitats
37
Why would z be different for birds and mammals in alpine environments? log S = log c + z log A
Birds are able to disperse between areas and not be as isolated
38
Population characters?
Small population size Declining population size trends Low population density One or few populations
39
Distribution?
Require a large home range/area Have a narrow geographic range
40
Home Range?
If the habitat size is decreased, or fragmented it may not be able to support the animal
41
Body size?
Larger body sizes often require a larger home range, they’re more obvious to humans, and often have longer generation times
42
Dispersal ability?
Species that cannot cross fragmented boundaries are at a greater risk
43
Migration, aggregations?
Require at least 2 specific habitats Doubles the chance they will be impacted by human action Complicated if they cross international borders
44
Specialists
Slight changes in the environment have a larger impact leading to extinction Species may require specific prey item, and physical conditions Symbiotic associations, such as if one species has a close relationship with another, the loss of one leads to the loss of the other
45
Stability
Species without prior human contact Number of species tends to decline after humans colonize an area Pacific islands previously colonized have fewer recent extinctions
46
History with (and value to) humans?
Overharvesting can lead to decline in population Species may not be able to recover
47
What is the allele effect?
A certain amount of animals are needed for mating/eating efficiency
48
what is the concept of ecological extinction?
The reduction of a species to such a low abundance that, although it is still present in the community, it no longer interacts significantly with other species
49
What is a paleoendemic species
ancient species whose relatives have gone extinct
50
What is a neoendemic species?
recently evolved from close relatives
51
Why might looking for areas of neoendemism be useful for conserving biodiversity?
Neoendemic form in diverse habitats. Common in plants with polyploidy
52
What are the three main factors that put small populations at greater risk of extinction?
a. Reduced genetic variability b. Demographic fluctuations c. Environmental fluctuations
53
How do you calculate the allelic frequency?
a. % of total alleles in the population for a specific gene b. 1000 individuals x 2 alleles/individual = 2000 total alleles
54
If the allelic frequency of a gene is 1.0, what does this mean in terms of variability?
a. Everyone has the same allele
55
What is heterozygosity?
a. A measure of genetic diversity that can be calculated in two ways i. The mean percentage of loci heterozygous per individual ii. The mean percentage of individuals heterozygous per locus
56
Is there any evidence that heterozygosity affects fitness?
a. Increase in population size increases heterozygosity
57
What other ways can you measure genetic variation?
Genetic drift: change in frequency of alleles due to sampling, chance
58
What mechanisms of evolution increase heterozygosity?
a. Mutation: new alleles b. Migration: genetic drift
59
Which mechanisms decrease heterozygosity?
migration
60
How does population size effect the strength of these mechanisms?
unequal sex ratio variation in reproduction output population fluctuations/bottleneck population structure
61
Unequal sex ratio
as sex ratio is skewed, smaller group contributes to the next generation. More susceptible to genetic drift
62
Variation in reproduction output:
some individuals contribute to more to the next generation. Smaller individuals may have fewer offspring than larger individuals
63
Population fluctuations/bottleneck
population may fluctuate in response to food, predators, climate, etc
64
Bottleneck
huge reduction in population size can drastically decrease Ne
65
Founder effect:
when small group starts a new population will typically have lower variability than original population
66
Population structure:
numerous sub-populations that go extinct periodically may reduce Ne
67
How can humans play a role here?
a. Humans may harvest one sex over the other
68
Why is inbreeding generally considered to be harmful?
dominance hypothesis heterozygous advantage hypothesis
69
Dominance hypothesis
deleterious alleles usually masked by dominant alleles i. Increased homozygosity leads to the expression of deleterious recessives
70
Heterozygous advantage hypothesis:
genome-wide levels of heterozygosity are the main influence i. Increased heterozygosity increases fitness
71
What is the minimum Ne to prevent inbreeding depression?
50
72
What is the minimum Ne to prevent outbreeding depression?
500
73
What is outbreeding depression?
a. Lack of compatibility of chromosomes and enzyme systems inherited from different parents
74
How can mating between individuals from different populations harm a species?
a. Usually prevented by reproductive isolating mechanisms b. May erode local adaptation diversity obtained from geographic separation
75
Do all endangered species have low heterozygosity?
a. No, manatee, red-cockaded wood pecker, and Indian rhino
76
Why might a population with low heterozygosity now, suffer population declines in the future?
a. A decrease in heterozygosity decreases fitness
77
What does it mean for a species to enter an extinction vortex?
a. As a population declines, it is at higher risk of i. Losing genetic variation due to genetic drift ii. Developing an unequal sex ratio iii. Suffering from inbreeding depression iv. Further loss due to demographic or environmental variation
78
Florida panther has suffered from inbreeding depression – managers decided to bring cougars from the Rockies to FL to breed with the cougars. Based on what you know- what were the potential benefits and risks associated with this plan?
a. Benefit was to add variation and add to the population b. Caused developmental problems i. Deformed tail vertebrae ii. Defected 90% sperm in males
79
How does the effective population size (Ne) change if there is an unequal sex ratio (equation)
Ne = (4NmNf)/(Nm+Nf) Nm = # breeding males Nf = # breeding females
80
the breakdown in social structure within a population that occurs when the population size gets too small is called
the allele effect
81
a species that long ago had a very wide distribution, but is now only found in just a small portion of its former range can be classified as
a paleoendemic
82
the population size of some bees have been reduced so much, that the pollination rates of wild plants are declining thus bees in some areas may be said to be
ecologically extinct
83
the percentage of ____ is typically higher on islands than on continents
endemic species
84
what would likely have the greatest number of monophagous (specialists) insects associated with it
tree species A has a geographic range in the US of 18,000 km ^2 species with large geographic range
85
in the equation S=CA^z, what would likely have the highest value for z
mammals on oceanic islands
86
approx. ___ of the species must go extinct for an extinction event to be considered a mass extinction event
75%
87
what environmental change that is contributed to the largest mass extinction event, is similar to a change we are observing now
increased acidity of the oceans
88
what is a prediction of island biogeography theory by MacArthur and Wilson
distance of an island from the mainland affects the immigration rate
89
the target effect differs from traditional island biogeography theory because this suggests that
island size affects the immigration rate
90
what best describes why the study used mangrove island of varying size
the study was done to isolate the effect of island area on the equilibrium number of species
91
based on what you know of vulnerability, what may be the greatest risk of extinction
bears
92
what characters would make an animal more vulnerable to extinction
a large breeding aggregation

Convervation Bio (8 decks)

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