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final Flashcards

1
Q

basic principles of natural selection

A
  • some of that variation is inherited
  • populations generally remain fairly constant
  • offspring that have inherited characteristics that best suit environmental conditions survive to reproduce
  • the others die or at least contribute fewer individuals to the next generation
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2
Q

Natural Selection as a Process: Consequences

A
  • Predictable within generation effect

- Predictable between generation effect

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3
Q

Natural Selection as a Process: given

A
  • Variation in a trait or attribute
  • A consistent relationship between the trait and survivorship or reproduction
  • Inheritance of the trait (a consistent relationship between parents and their offspring)
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4
Q

Sexual Reproduction: Life Cycles

A

Three life cycle plans, with 1 common thread:

  • Alternation of meiosis
  • Net effect – new characteristics can appear (which may be advantageous)
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5
Q

Reproduction

A
  • Variation is the “raw material” for natural selection

- Domestic animals: inbreeding leads to problems

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6
Q

Domestic Plant Crops

A
  • Modern agriculture: prevention of the operation of natural selection
  • Domestic crops – most would not survive in the wild; genetic diversity is very low
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7
Q

Reproduction affects

A
  • Breeding system: cooperative polyandry
  • Smaller islands: greater degree of inbreeding
  • Parasite load is correlated with degree of inbreeding
  • Innate immunity is lower in more inbred populations
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8
Q

Adaptation & Adaptedness

A
  • A trait that increases the ability of an individual to survive or reproduce compared with individuals without the trait
  • Any feature of an organism that substantially improves that organism’s ability to survive
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9
Q

A process of acquiring adaptedness

A

acquiring a collection of traits that together well suit an organism (or a population) for its environment

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10
Q

what is Adaptation?

A
  • an evolutionary process – that changes traits (anatomy, physiology, or behaviour)
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11
Q

what does adaptation result in?

A

resulting in an increased ability of an organism

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12
Q

what does adaptation give?

A
  • Some traits will give some individuals an advantage over others in the population
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13
Q

Acclimation

A

can refer to the changes in the form or behaviour of an organism during its life as a response to environmental stimuli

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14
Q

short-term acclimations eg

A

Acquisition of cold tolerance (resulting from prior exposure to lower temperatures)

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15
Q

Speciation

A

The process in which two or more contemporaneous species evolve from a single ancestor

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16
Q

Species

A

The fundamental taxonomic category for organisms; variously defined and diagnosed using different species concepts

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17
Q

Adaptive radiation

A

evolutionary divergence into a number of very different forms and lifestyles

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18
Q

what does Isolation result in ?

A

Many sub-populations, with local adaptations to local conditions

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19
Q

what can breeding and outbreeding do?

A

can lead to reduced fitness`

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20
Q

what happens if parents are too different?

A

hybrid offspring with intermediate characteristics are not favoured

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21
Q

Prezygotic mechanisms

A

blockages at different steps that prevent the formation of a zygote in the first place
- A combination of ecological and temporal separation

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22
Q

Ecological separation

A

failure to encounter because mating sites are different

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23
Q

Temporal separation

A

differences in the timing of fertile periods

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24
Q

Behavioural separation

A

Darwin’s finches recognize and respond to different songs, by-and-large preventing hybridization

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25
Q

Mechanical & physiological barriers

A

biochemical barriers to the formation of a pollen tube prevents fertilization

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26
Q

Post-zygotic mechanisms can act in these ways

A
  1. The zygote fails to develop properly and dies
  2. zygote lives but fails to reach maturity
  3. The zygote cannot produce viable gametes
  4. The zygote can produce gametes and/or offspring, but overall fertility is greatly reduced
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27
Q

Can two independent populations, which appear to be separate species, hybridize when they meet again?

A

it depends on

  • time
  • rate of genetic change
  • degree of specialization
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28
Q

Mechanisms of Speciation (4)

A

Allopatric Speciation
Parapatric Speciation
Sympatric Speciation
Polyploidy

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29
Q

Allopatric Speciation

A
  • The formation of new species that occurs when populations are geographically isolated
  • Divergence of populations into separate species as a result of geographic isolation from one another
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30
Q

Allopatric Speciation: key points

A
  • Geographic separation
  • Spatial subdivision of populations
  • Formation and colonization of new habitats
  • Changes are driven by genetic drift and/or natural selection
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31
Q

Allopatric Speciation Via Vicariance

A
  • Vicariance = splitting

- events that result in the geographic isolation of previously connected populations

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32
Q

TECO: TECTONIC, eustatic, climatic, or oceanographic

A

Isolation of a continental island by tectonic plate movements (Tectonic event)

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33
Q

TECO: tectonic, EUSTATIC, climatic, or oceanographic

A

Isolation of a continental island by rising sea levels (Eustatic event)

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34
Q

TECO: tectonic, eustatic, CIMATIC, or oceanographic

A

climatic events causing separation: flood, hurricane

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35
Q

TECO: tectonic, eustatic, climatic, or OCEANOGRAPHIC

A

Separation & isolation of ocean basins because of the drifting together of landmasses (Tectonic + Oceanographic

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36
Q

Peripatric Speciation

A
  • Involves jump dispersal
  • Involves very few individuals (or just 1 fruitfly)
  • peripheral areas that were previously uninhabited
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37
Q

what 3 things are involved with Peripatric Speciation

A

the founder effect, selection, & genetic drift

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38
Q

The Founder Effect

A
  • Small subset of individuals, not necessarily representative of whole original population
  • New population has a quite different genetic makeup compared to original population
  • New population is isolated from original population, and can evolve independently, based on selection pressures in new area
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39
Q

Founder Effect & Genetic Drift

A
  • happen through random processes, chance events

- higher risk of loss of genetic diversity in small populations

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40
Q

the effects of genetic drift in small pop vs big pop

A

The effect of genetic drift is much larger in small populations than in large populations

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41
Q

Speciation: Founder Events

A

a sequence of temporally and spatially isolated founding events

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42
Q

outcome for founder events: Random dispersal of a few individuals to peripheral

A
  • geographically isolated areas
  • Each new population evolves independently
  • meanwhile species a persists in original location
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43
Q

outcome for founder events: A few individuals colonize a nearby isolated area

A

A few individuals of species b colonize the next isolated area; these evolve into species

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44
Q

Parapatric Speciation

A

differentiation occurs when two populations have contiguous but narrowly overlapping ranges
- often representing two distinct habitat types

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45
Q

Parapatric Speciation: key points

A
  • Range expansion into a new habitat
  • Various subpopulations develop – and they become increasingly reproductively isolated
  • Hybrids have reduced fitness
  • Genetic drift and natural selection can both play roles
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46
Q

Sympatric Speciation

A

occurs within the area of distribution of the ancestral species
- differentiation of two reproductively isolated species from one initial population within the same local area

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47
Q

Sympatric Speciation: key points

A
  • No geographic or spatial isolation

- Disruptive selection is most likely mechanism, coupled with assortative mating

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48
Q

Polyploidy

A

The doubling or multiplication of the whole set of chromosomes with the cells of an organism

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49
Q

why is Polyploidy important?

A

polyploidy has been an important mechanism for speciation

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50
Q

Ecological Divergence

A

that increased ecological divergence is associated with increased reproductive isolation

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51
Q

Ecotypes & Reproductive Isolation

A

Within-region same-ecotype compatibility was higher than between-regions same-ecotype compatibility
- indv of different ecotypes were not compatible

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52
Q

microevolution

A

Evolution (change) at the species level, within a single population

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53
Q

reasons for microevolution

A 
Natural selection
Sexual selection
Mutation
Migration
Genetic drift
Restrictions to gene flow
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54
Q

Macroevolution definition

A

Evolution (change) above the species level

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55
Q

Macroevolution key points

A
  • Focuses on changes in morphological forms in the fossil record
  • Often forms seem to have long periods of no change (stasis) interspersed with brief periods of rapid change (new species; punctuated equilibrium)
  • Important patterns are stasis, evidence for character change, speciation, extinction
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56
Q

Microevolution: Outcomes

A
  • A change in gene frequency

- Over time, changes in gene frequency can lead to changes in phenotypic expression

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57
Q

Macroevolution

A

Character change – can be quick, can be slow; can be directional – or not
Lineage-splitting & speciation
Extinction

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58
Q

Macroevolution: Punctuated-Gould, Eldredge

A

proposed that evolution can be punctuated – long periods of stasis followed by relatively rapid periods of considerable change

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59
Q

Macroevolution: Gradualistic- darwin

A

proposed that evolution takes place at a steady & gradual rate – this called gradualistic evolution

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60
Q

Punctuated reasons by Eldredge & G

A
  • involves “bursts” of extinction & speciation, followed by stasis
  • Species-level selection
61
Q

Why Classify

A

to arrange in classes, to assign to a class

62
Q

what is classification

A

a group of things having some characteristics in common

63
Q

reason for classification

A

a human activity, based on recognition and description of characteristics deemed to be important, and used to organize and simplify complex information – into patterns that ‘make sense

64
Q

Classification in Biogeography

A
  1. A system of identifying and naming entities, both extant and extinct, that mirrors their evolutionary relationships
  2. Recognition and naming of groups of organisms in specific environments
65
Q

Linnaean System of Classification

A
  • the system for naming, ranking and classifying organisms still used today
  • original largely based on morphology
66
Q

how does Linnaean System of Classification work?

A
  • has a unique binomial, a generic name and a specific epithet
  • Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species
67
Q

Classification & Phylogeny

A
  • A hierarchical scheme

- capture degrees of relationship

68
Q

Parallel Evolution

A

independent evolution of similar traits amongst non-related species in response to the SAME kinds of selection pressures, starting from a SIMILAR ancestral condition

69
Q

Phylogenetic Systematics (cladistics)

A

to be quantitative, but also to include biological judgment on importance of particular traits

70
Q

Key points in parallel evolution:

A
  • Species in SIMILAR niches have surprisingly SIMILAR appearance
  • Involves homologous structures
  • Must consider: degree of “non-relatedness”
71
Q

Convergent Evolution

A

Independent evolution of similar traits amongst non-related species in response to SIMILAR kinds of selection pressures, starting from a very DIFFERENT ancestral condition

72
Q

Convergent Evolution:Key points

A
  • the similar biological traits involve analogous structures
  • non-relatedness is very clear
73
Q

Island Types & Formation

A

Continental Islands•Island Arcs•Hotspot Islands•Terranes & Accretion

74
Q

Continental Islands

A

Origin:Part of a continental landmass
Formation:Separated by rising ocean levels (e.g. Newfoundland),Separated by tectonic processes (e.g. Madagascar, New Zealand)

75
Q

island arcs

A

origin: volcanic activity
formation: old ocean crust is subducted, causing stresses nearby on the overlying plate, volcanic eruptions build new islands that rise above the seafloor

76
Q

Hotspot Islands & Seamounts

A

Origin: fixed “hotspots” scattered throughout the earths mantle (hawaii)
formation: volcanoes rise from the seafloor; plate moves creating islands

77
Q

what does erosion do in Hotspot Islands & Seamounts

A

reduces islands to seamounts (guyots)

78
Q

Formation of an Island Chain

A
  • Erosion flattens the tops of the islands & seamounts
  • Seamounts are “islands” of incredible biodiversity
  • Seamounts are poorly known – and are being destroyed rapidly by deep-sea trawling
79
Q

pacific islands

A

All three types of islands:

  • Continental
  • Island arc
  • Hotspot Islands
80
Q

Terranes

A
  • terrane: a small area where geology is different from surrounding regions
81
Q

Accretion

A

a landmass that originated as an island arc or a microcontinent that was later added onto a continent or other landmass

82
Q

The Nature of Islands

A
  • Well-defined boundaries

- Often relatively isolated

83
Q

Study of Islands: Ecological Scale

A
  • biotic and abiotic challenges and interactions

- Island “impoverishment” & species-area relationships

84
Q

Study of Islands: Evolutionary Scale

A
  • Islands and speciation

- The Equilibrium Theory of Island Biogeography (ETIB)

85
Q

Island Biotas: Unique Properties

A 
-community composition
\+Ecological roles
\+Niche breadth & differentiation
\+Population densities
-body size
-growth form
86
Q

Disharmonic Island Communities

A

If non-random processes – you would expect islands to differ from the mainland, and also from each other

87
Q

Island Biota: Which Species?

A

Harmonic, or balanced – species composition similar to mainland composition•Disharmonic, or unbalanced – species composition is differentthan mainland composition

88
Q

Harmonic biotas

A

species are ‘assembled’ randomly from mainland source pools

89
Q

Disharmonic biotas

A

done so by non-random processes

90
Q

Typical non-random processes

A

differential ability amongst taxa to migrate & colonize, or to persist once established

91
Q

Differential Dispersal Abilities

A
  • Active dispersal
  • Passive dispersal
  • Active dispersers
  • Passive dispersers
92
Q

Active dispersal

A

light, ability to cope with seawater

93
Q

Passive dispersal

A

high altitude winds, high velocity winds, ocean currents, “hitch hiking” on

94
Q

Active dispersers

A

bats, birds, insects

95
Q

Passive dispersers

A

via spores (microbiota, fungi, ferns), via fruits and seeds (flowering plants), via egg masses (insects, some vertebrates)

96
Q

Island Biota: Ecological Roles

A

Many island species are generalists rather than specialists

97
Q

Species–Area Relationship for islands

A
  • isolation
  • that the number of species supported is less than the number in a comparable area of mainland – most islands suffer some degree of species impoverishment
98
Q

reasons for Island Biota: Ecological Roles

A
  • Role of resource limitations compared to mainland areas – “food” resources have lower standing stocks and renewal rates
  • Organisms that have lower demands and are less “fussy” have a greater probability of establishing a persisting population
99
Q

Advantages of Being a Small-Bodied Generalist

A
  • Small animals need less
  • Generalists use many different sources
  • Small animals can maintain higher maximum population densities
100
Q

Island Biota: Higher Densities

A
  • Niche breadth & density both increase

- Similar trends seen for many birds on small islands

101
Q

Density “overcompensation” on small islands is common

A
  • Large vertebrates, top predators – tend to be absent
  • Absence of congeners; absence of other members of the feeding guild; net result, reduced competition
  • Absence of other predators and/or parasites
102
Q

Body Size: the “Island Rule”

A
  • A graded trend, within and among taxonomic groups

- The tendency for small animals to become bigger, and for big animals to become smaller

103
Q

Island Biota: Body Size

A

Dwarfism:
‘Normally’ big animals became smaller
Gigantism:
‘Normally’ small animals became bigger; a trend very often seen for herbivores & seed eaters – e.g., rodents, iguanas, tortoises

104
Q

ecological release

A
  • Few or no predators, therefore little or no selective pressure for large size for protection
  • More intense intraspecific competition for limited resources
105
Q

immigration selection

A
  • Biased initial breeding stock

- In absence of predators herbivores can feed more often & more rapidly

106
Q

how might Isolation effect species richness?

A
  • – as distance increases, non-volant mammal species richness decreases for islands
107
Q

Temporal isolation

A

in the Gulf of California, so-called land-bridge islands that have been isolated for longer periods have fewer species

108
Q

The ETIB: Background

A

Islands are recipients of species from a source pool of species living on a mainland area

109
Q

The number of species received by an island depends on

A
  • Island size (area)
  • Island distance from mainland (isolation)
  • The source pool of species & their characteristics
110
Q

Why might distance matter?

A
  • Takes more time & energy to reach a far island
  • More likely to die before reach a far island
  • Fewer individuals actually make it to the island
111
Q

distance conclusion

A

islands that are far away have lower rates of immigration than islands that are closer to source pools of species

112
Q

Why might area (size) matter?

A
  • Greater variety of topography
  • Greater variety of possible habitats
  • Perhaps higher resource levels (larger islands “collect” more energy)
  • Potentially larger populations
113
Q

area conclusion

A

larger islands would have lower rates of extinction, smaller islands would have higher rates of extinction

114
Q

MacArthur and Wilson 1967: main parameters

A

distance (isolation) affects the rate of immigration, size (area) affects the rate of extinction

115
Q

MacArthur and Wilson 1967: Mechanism

A

balance between rates of immigration and rates of extinction, and development of “most probable curves”

116
Q

Predictions at Equilibrium: Species #

A

at equilibrium, drop a perpendicular from crossing-points of “rates” to X-axis, Ŝ (S-hat)

117
Q

Predictions at Equilibrium: Turn-over Rate

A

at equilibrium, draw a horizontal line from crossing-points of “rates” to Y-axis, T (T-hat)

118
Q

Effect of Distance (Isolation): Two equal-sized islands

A

that differ in distance from the source pool have the same extinction rates, but different immigration

119
Q

Effect of Island Area: Two different-sized islands

A

experience the same rate of immigration (colonization) (identical curves for I), but extinction rates are greater on the small island

120
Q

ETIB: Assumptions

A
  • New species immigrate and old species die out at random
  • Immigration and extinction are independent processes; one does not influence the other
  • The source of colonists is the mainland
121
Q

ETIB: Overall Predictions 1.

A

The number of species on an island stabilizes at a constant value (an equilibrium)

122
Q

ETIB: Overall Predictions 2.

A

The stabilized value is dynamic, because there is a continual turnover of species, due to immigrations and extinctions

123
Q

ETIB: Overall Predictions 3.

A

If degree of isolation is the same, large islands will support more species than small islands, but small islands will return to equilibrium more quickly

124
Q

ETIB: Overall Predictions 4.

A

If island size (area) is the same, the number of resident species will be higher on the nearby island, and the nearby island will return to equilibrium more quickly

125
Q

What the ETIB Does Not Do

A
  • identity
  • timing of those changes
  • relative species abundances
  • speciation in the past, present or future
126
Q

MacArthur on the ETIB

A

a theory is a lie which makes you see the truth

127
Q

Effects of Scale: Size & Time

A
  • sigmoidal, based on different scales of investigation
128
Q

Very large islands

A

where in situ speciation becomes important (evolutionary forces become more important)

129
Q

Very small islands

A

may be different (no species-area effect)

130
Q

Intermediate islands

A

– the familiar species-area relationship (largely ecologically determined)

131
Q

Modifying the ETIB

A

Non-interactive (1)
Interactive (2)
Assortative (3)
Evolutionary (4

132
Q

Incidence & Assembly Rules

A
  • Jared Diamond proposed communities & ecosystems are not randomly constructed
  • Only some species combinations occur out of all possible combinations
133
Q

what was Incidence & Assembly Rules theory based on

A

studies of bird communities of island archipelagos

134
Q

Diamond’s Incidence Rules: A sedentary species

A

occurs only on species-rich islands (example, a cuckoo, Centropus violaceus)

135
Q

Diamond’s Incidence Rules: An intermediate tramp species

A

occurs on a wider variety of islands, but still not on the species poor-islands

136
Q

Diamond’s Incidence Rules: A supertramp species

A

is absent from species-rich islands; such a species occurs only on small, species-poor islands

137
Q

Diamond’s Assembly Rules

A
  • Some pairs of species are never found together

- Restriction on ‘allowed’species pairs – due to competition

138
Q

main ETIB idea (species sorting hypothesis)

A

that compatible species, each with its distinctive and individual niche, become sorted over the course of time to assemble themselves into a stable equilibrium community

139
Q

new theory should include

A
  • evolution (speciation)
  • immigration filters, geology, climate
  • species-based (eg. dispersal)
  • place-based eg. changes of the island
140
Q

General Dynamic Model Approach-Whittaker & colleagues (2008)

A

for oceanic islands:

  • geological life history
  • biological life history
  • Consequences for rates of immigration, colonization (carrying capacity), speciation, extinction
  • The concept of Single-Island Endemics (SIEs)
141
Q

geological “life history” of islands

A

role of erosion, subsidence, land slips

142
Q

Early history

A

area & altitude increase to a maximum then decrease

143
Q

Mid history

A

topographic complexity increases to some maximum value

144
Q

Late history

A

area, altitude & topography all decrease

145
Q

The biological “life history” of islands

A
  • Habitat diversity – more opportunities, more niches

- Greater species diversity (dotted line, via immigration, via speciation)

146
Q

In late biological stages

A
  • Biotic interactions increase
  • Opportunities decrease
  • Effect of isolation decreases
147
Q

overall General Dynamic Model

A
  • With time, new species evolve
  • With time, more of the biota of islands will consist of single-island endemics (SIEs)
  • The number of SIEs should change in a predictable way over the life-time of an island
148
Q

General Dynamic Model: letter chart

A
  • K … carrying capacity
  • I … immigration rate
  • S … speciation rate
  • R … realized species richness
  • E … extinction rate

bi 301 (1 decks)

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