S3: W10 (Prof. Kelsey) Flashcards
1
Q
Background of Biogeography attributes? (6)
A
• Naturalists were biogeographers.
• Distribution & vicariance.
• Up to 1820, the Earth was stasis.
• According to them, species couldn’t all fit in the Ark (landing site?).
• 19th century themes.
• Selection processes are applied differently in new biotas.
2
Q
People involved in research about distribution & vicariance? (4)
A
• Lamark (giraffa hypothesis).
• Lyell (geology).
• Darwin.
• Wallace.
3
Q
List of the 19th century themes? (3)
A
• Distinctness of regional biotas.
• Species origin & spread.
• Factors responsible for species distribution.
4
Q
Benefit of Darwin’s trip?
A
Gave him a good context for thinking what was where & enabled him to compare between different …
5
Q
Alfred Wallace attributes? (3)
A
• Did more trips than Darwin.
• Places included Amazon river basis & Malaysia archipelago.
• Wallace’s line.
6
Q
Alfred Wallace?
A
= father of Biogeography.
7
Q
Question asked under Alfred Wallace in relation to Wallace’s line?
A
Why do we see different complements even though there is no physical, geographical barrier?
8
Q
Wallace’s line?
A
= imaginary line where different species exist on either side of the line.
9
Q
What man-made structure can act as a boundary?
A
Roads.
10
Q
Biogeography attributes? (5)
A
• Initially it started with zoogeography & phytogeography.
• Is not ecology.
• Involves taxonomy, evolution, history of organisms.
• Thinks about how the species assemblage came to be.
• Working in a historical past trying to figure out what will happen in the future.
11
Q
What does Biogeography focus on?
A
Focuses on contingency - taxonomy, history, evolutionary events.
12
Q
How does Biogeography predict/explain how “now” came about?
A
By using history to figure out how “now”/current species assemblage came to be.
13
Q
Biogeography vs Ecology regarding what they focus on? (4)
A
● Biogeography
• focuses on contingency.
• focuses on history.
● Ecology
• focuses on interaction, structure & function.
• focuses on predictability.
14
Q
Biogeography focuses? (2)
A
• Contingency - taxonomy, history, evolutionary events.
• History.
15
Q
Ecology focuses? (2)
A
• Interaction, structure & function.
• Predictability.
16
Q
Biogeography key word?
A
Evolutionary history.
17
Q
Ecology keyword?
A
Predictability.
18
Q
Contingency?
A
= future event (“now”) that is possible but can’t be predicted/planned for with certainty.
19
Q
Miocene attributes? (3)
A
• Expansion & contraction of grasslands with forests.
• As forests expand, grasslands contract & vice versa.
• Affected how many species were present at each occurrence.
20
Q
Eg of how expansion & contraction during the Miocene affected how many species were present at each occurrence?
A
More forests, ie., expansion of forests caused an increase in browsers.
21
Q
Factors that affect Savannas? (2)
A
• Fire.
• Large herbivores (esp. elephants).
22
Q
Large herbivores, particularly elephants, in Savannas/ Elephants in Savannas? (5)
A
• Push over trees.
• Disperse fruits.
• Terrify other species.
• Affect animals that appear on a landscape.
• Ecosystem engineer.
23
Q
Fire in Savannas attributes? (2)
A
• Cretaceous period.
• Fire was a selection pressure that affected plant assemblages (flowering plants, when & how did angiosperms end up where they are today?).
24
Q
Savanna locations? (3)
A
• Predominantly in Africa.
• Northern Australia.
• South America (Brazil & Argentina).
25
How were Savannas distributed in the past?
26
Questions to ask as a Biogeographer (biogeographic perspective) when you see the Image of Savanna with springbok and cattle egrets? (6)
● How did this landscape evolve?
● Why is there a grass/tree coexistence?
● What are the evolutionary processes that are at play?
● Did those evolutionary processes change over time?
● How/Is there a grazer/browser balance?
● Large scale climate change through time?
27
What do we need to do to answer biogeographic questions? (4)
● Observe, record & measure geographic ranges of species.
● Explain how these ranges came to where they currently are.
● Search for commonality in pattern (congruity suggests common history).
● Explain patterns at all levels (diversity gradient).
28
Diversity gradient?
=
29
Questions Biogeographers ask? (6)
● Why is a species confined to its present geographic region?
● Where are close relatives found?
● What prevents species from colonizing other areas?
● Why are some species restricted & others widespread?
● How have historical events shaped current distribution (think migration)?
● Why are some areas species-rich & others species-poor?
30
Eg of Why some areas are species-rich & others species-poor?
Cape Floristic region.
31
Explain Cape Floristic region?
It is species rich due to climate stability which caused heterogenous soils in the region enabling species diversification.
32
What does Diversity gradient involve? (3)
• Area on the globe with its latitude.
• Latitude.
• Diversity.
33
Explain illustration/drawing on Diversity gradient? (2)
● High diversity at the equator.
● Low diversity at the poles.
34
List sub-disciplines of Biogeography? (5)
• Historical biogeography.
• Ecological biogeography.
• Island biogeography.
• Urban biogeography.
• Conservation biogeography.
35
Sub-disciplines of Biogeography layout? (5)
Historical biogeography
__________|____________
| |
Ecological Island
__________|________
| |
Urban Conservation
36
Historical biogeography?
= involves taxonomy, systematics, evolution, geography, palaeogeography, palaeoecology & palaeoclimate.
37
Ecological biogeography?
= studies the range of communities & assumes that communities move as a unit.
38
Questions asked in Ecological biogeography? (3)
● Are communities real?
● If communities are real, do they persist through time?
● How do they persist through time?
39
What is a community according to Ecological biogeography?
= species assemblages in geographic regions.
40
Explain Graph that was shown with lines of different colours? (7)
● x-axis = environmental/geographic gradient.
● y-axis = density of individuals.
● Lines = species or community.
● Shows how species change over different gradients in a geographic space.
● Density is not the same for each species.
● Single dimension.
● As you move through gradients, there is change in physiology, etc, depending on what you define your geographic gradient as (i.e., whether it's savanna, forest, etc).
41
Island biogeography?
= seeks to explain biodiversity on islands.
42
Island biogeography attribute?
Has been extrapolated to habitat patches.
43
Urban biogeography?
= open-space planning & biodiversity management in urban areas.
44
Conservation biogeography?
= design planning of conservation areas.
45
Conservation biogeography attribute?
Pulls everything together.
46
Spatial units in biogeography?
= a region/realm.
47
Spatial units in biogeography attributes? (5)
• Further subdivided into sub-regions, provinces & districts.
• Non-scientists think about geographical boundaries.
• Scientists think about the ecosystems that might span those boundaries.
• Regions are equivalent to a biome in ecology, but it is not the same.
• Biogeographic units are defined by their species assemblages (NOT vegetation maps like biomes).
48
Why are regions not the same as biomes in ecology?
49
What are biogeographic units defined by?
Their species assemblages.
50
Slide of dots attributes? (2)
• I've gone from one species assemblage to another through observation.
• Explains Wallace's line.
51
African map attributes? (2)
• Biogeographic regions overlap onto continents.
• Fine tunes.
52
Keyword for biogeographic regions?
Species assemblage.
53
Things to note about species assemblage? (2)
• Think about how they've changed through time in taxa/groups (herbivores, carnivores).
• Biogeographic patterns.
54
Distribution maps attributes? (7)
● Usually portrayed as a 2D image of occurrence.
● Help you figure out where you're going to find species of choice.
● Presented as a line map, point map, contour map & probability map.
● Type of distribution map to use depends on research question.
● Usually no reference to temporal attributes (on any resolution).
● There are exceptions with temporal attributes.
● Involves data content & amount of interpretation.
55
Types of distribution maps? (4)
• Line map.
• Point map.
• Contour map.
• Probability map.
56
Line distribution map attributes? (2)
• Drawn by an expert of where they think species could be.
• Includes expert interpretation.
57
How do line distribution maps include expert interpretation?
By thinking about habitat requirements & what the organism is looking for.
58
What does the type of distribution map you use depend on?
Your research question.
59
What is the exception with temporal attributes?
Temminck's courser.
60
What does Temminck's courser do?
Shows the distribution of species in different months of the year.
61
Point distribution map attributes? (2)
• Points are QDG.
• Involves absence & presence data.
62
What do the QDG points do?
They show that that organism was in that region, that is, the QDG.
63
Absence data attributes? (2)
• Hard to collect.
• Real absences.
64
Absence data?
= data that shows that the species is absent in a region/grid.
65
Presence data?
= data that shows that the species is present in a region/grid.
66
Why is absence data difficult to collect?
It's because of pseudoabsence.
67
Why pseudoabsence?
It's a consequence of sampling/surveying.
68
Real absences?
= indicate that sampling was good, and therefore you have no pythons.
69
Absence data vs Presence data?
● Absence data
= pseudoabsence & real absences.
● Presence data
= species is there.
70
Sampling for distribution maps attributes? (2)
• Expert sampling.
• You can use data software such as GBIF and iNaturalist.
71
Contour distribution map?
= distribution map that blends presence data with expert interpretation.
72
Probability distribution map?
= distribution map that involves the probability of finding a species in a region.
73
Probability distribution map attributes? (3)
• A correlation method.
• Bases presence/absence of a species on habitat or biotic interactions.
• Continuous as you move from "red to green" for example.
74
What does a Probability distribution map do?
It uses multiple lines of data [presence data (GPS coordinates) paired with habitat/abiotic (biotic interactions)].
75
Attributes of distribution measurement? (2)
• Resolution.
• Scale.
76
Resolution?
= the ground size that a pixel represents.
77
Kinds of grid? (2)
• Fine grid.
• Coarse grid.
78
Fine grid attributes? (4)
• Fine/smooth resolution.
• More detail.
• High resolution.
• Many tiny pixels.
79
Coarse grid attributes? (4)
• Coarse resolution.
• Less detail.
• Low resolution.
• Few, large pixels.
80
Scale attributes? (2)
• Window that you're looking through.
• Resolution is within it.
81
Egs of Scale? (2)
• Country.
• Region.
82
Resolution & Scale attributes? (2)
• When doing this you need to figure out what scale & resolution works for your species.
• Information we get increases as we go from large scale to small scale.
83
Egs of How to figure out what scale and resolution works for your species? (2)
• Plants = small scale.
• Animals = large scale.
84
Abundance attributes? (11)
● A 3rd dimension.
● Most maps are presented as if abundance is binary (presence/absence or presence only).
● Species are more abundant at some sites than others.
● Is auto-correlated in space.
● Changes with time.
● Species tends to be most abundant where niche parameters are most favourable.
● Varies systematically.
● High near the edge if edge is a coastline, has been affected by human encroachment.
● Often a proxy is used to estimate abundance.
● Pseudoabsence.
● Involves even surveying across geographic space.
85
Result of presenting maps as if abundance is binary?
It underestimates the variation in abundance.
86
What do you mean when you say that abundance is auto-correlated in space?
We mean that close sites/sites closer to each other tend to have similar abundance.
87
Niche parameters?
= what's more favourable to that species (realized niche).
88
What do you mean when you say that abundance varies systematically?
We mean that abundance is most often highest in the centre of the distribution & is zero across the edge.
89
When does abundance become high at the edge? (2)
It's high at the edge only if species:
• is at a coastline.
• has been affected by human encroachment.
90
What do you mean that a proxy is often used to estimate abundance?
We mean that we think about observations as a proxy to estimate abundance.
91
Problems of using a proxy to estimate abundance? (2)
• May identify the same animal multiple times.
• Observer bias.
92
Pseudoabsence?
= occurs when you observe the same thing/species more than once.
93
Even surveying across geographic space?
= involves who's surveying, when they're surveying & where they're surveying.
94
Attributes of occurrence? (3)
• Abundance.
• Mass effect.
• Metapopulations.
95
Explain Abundance graph? (5)
● x-axis = distance.
● y-axis = abundance.
● Flat top of graph.
● Uphill afterward.
● As you move away from the transact abundance decreases, then increases maybe due to high nutrients in soil.
96
Mass effect?
= where the range of an organism usually has source and sink areas/populations.
97
Flat top of Abundance graph attributes? (4)
Similar species due to:
• climate.
• habitat.
• similar resources.
98
Mass effect attributes? (5)
• Source areas have better habitat & organisms reproduce at better rates than replacement rates.
• Populations in sink areas are sustained only by input from source areas.
• Usually, some areas are nearer the centre of the distribution (not always the case).
• If a species undergoes reduction in abundance & range, source areas are likely to be the last strongholds.
• More range movement.
99
Source area?
= area that has better habitats & where organisms reproduce at better rates than replacement rates.
100
Source area attributes? (5)
• Nearer to the centre of the distribution (not always the case).
• More likely to be the last stronghold.
• Is a constant part of species range.
• Has more individuals that are better at reproducing.
• Individuals move out towards sink populations.
101
Sink area attributes? (2)
• Consists of individuals coming from source areas.
• Sustained by input from source populations.
102
Why do organisms move out of source areas? (3)
• Limited resources in source areas.
• Pre-saturation (from Ecology).
• Depends on species you're working with.
103
What happens to sink and source populations when climate changes?
Sink populations are the first to be eliminated/to collapse.
104
Why are sink populations the first to collapse when climate changes?
105
Metapopulations attributes? (7)
• Similar concept, but the sink areas don't connect.
• Lower rate of individuals moving to sink populations.
• "Source populations" are isolated from each other (no exchange between individuals).
• Nodes are genetically isolated.
• Isolated populations are allopatric or disjunct.
• Selection pressures across species range can change.
• Think about the types of selection acting (disruptive, etc).
106
Why are isolated populations allopatric or disjunct?
It's a consequence of vicariance if the range has reduced & split.
107
Types of species responses to change in climate? (4)
● May be completely unaffected by change.
● Adapt to new conditions so that distribution stays the same.
● Species can track climate change.
● Decline towards extinction.
108
May be completely unaffected by change ?
= high genetic variation enables species to handle change.
109
Adapt to new conditions attributes? (2)
• To ensure that distribution stays the same.
• Responds via its distribution.
110
Why do species track climate change? (2)
So that:
• The range moves spatially.
• The species remains in the same climatic envelope.
111
Decline towards extinction?
= where sink areas are the first to go.
112
What does response to change depend on? (4)
• Amount of genetic cohesion (genetic variation).
• Presence of physical barriers.
• Rate of climate change.
• The species (species generation time, slow generation time, slow response).
113
Modes of spread? (4)
• Long jump dispersal (LJD).
• Diffusion.
• Secular migration.
• Negative spread.
114
LJD?
= movement of individuals over inhospitable terrain over long distances with eventual establishment of the population at the destination.
115
LJD attributes? (6)
• Rapid, far, random dispersal event.
• Common in plants, less common than expected in animals.
• Only explanation for original populations on volcanic islands.
• Consider what the organism needs to move through to do long jump dispersal.
• Ability to jump disperse is predictable to an extent.
• Happens continuously.
116
Why is LJD most common in plants?
It's because most plants are wind-dispersed.
117
Types of islands? (2)
• Continental islands.
• Volcanic islands.
118
Continental island?
=
119
Volcanic island?
=
120
Inhospitable terrain?
= bodies of water for birds.
121
Result of LJD?
Some taxonomic randomness, although close biota are more likely to jump disperse.
122
Eg of organisms that are bad at LJD?
Amphibians.
123
Why are amphibians bad at LJD?
It's because they physiologically can't adapt to salt water, sand, etc, unless human-assisted.
124
Egs of LJD? (3)
• Tropical house gecko.
• Flowerpot snake.
• Distribution of Juncus on southern islands.
125
Explain the Tropical House gecko? (3)
● Is an eg of human-assisted long jump dispersal.
● Transported from East Indies to South Africa (and all over the world).
● Good at establishing a population.
126
Explain Flowerpot snake? (3)
● From South East Asia to Durban, SA.
● Good at human-assisted long jump dispersal.
● Successful long jump disperser.
127
Why is the Flowerpot snake a successful long jump disperser?
It is parthenogenic (females can reproduce & this organism homogenizes overtime).
128
Explain Distribution of Juncus on southern islands? (2)
● High winds are key to long jump dispersal (roaring 40s).
● Genetic structure is similar.
129
Why is the genetic structure of Juncus similar?
It's because of repeated movement (gene flow).
130
Diffusion?
= gradual expansion of range over hospitable terrain over generations.
131
Diffusion attributes? (2)
• Gradual extension.
• Achieved over several generations.
132
LJD vs Diffusion?
● LJD
= achieved over one generation.
● Diffusion
= achieved over several generations.
133
Egs of Diffusion? (2)
• European starlings.
• Cattle egrets.
134
Explain European starlings? (2)
● Started at New York & diffused out.
● Human-assisted.
135
Explain Cattle egrets? (3)
● LJD event during the late 1800s, followed by diffusion.
● Got blown over by winds.
● From South America & North America.
136
Secular migration attributes? (5)
• Slower than diffusion.
• May include some adaptation in population.
• Adaptation may lead to species diversification over time.
• No clear difference between it & diffusion as it's on a continuum.
• Take into account fossil evidence (temporal/time component).
137
Eg of Secular migration?
Camels, lamas & alpacas.
138
Explain Camels, lamas & alpacas? (3)
● Fossil evidence.
● From N. America to Africa & S. America.
● Lineages are diversifying through adaptations as they are dispersing.
139
Negative spread attributes? (3)
• Results in isolated populations (vicariance - allopatry).
• Local populations may die out (extirpation).
• Can ultimately lead to extinction.
140
Extirpation vs Extinction?
● Extirpation
= loss of local population.
● Extinction
= loss of entire population.
141
Eg of Negative spread?
Polar bears.
