Download Geography 1010 Biogeography: the study of the distribution and

Geography 1010
Biogeography:
the study of the
distribution and
diversity of life
on earth
Dan Johnson
Professor of Environmental
Science
Department of Geography
University of Lethbridge
www.uleth.ca/~dan.johnson
Biogeography is the science that attempts to document and understand
spatial and temporal patterns of biodiversity.
It deals with all levels from molecules to ecosystems, with individual
organisms as the key units through with life is expressed.
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Introduction to Biogeography and Biodiversity
* Project: Survey of Attitudes toward Invertebrate Animals
Ecological Biogeography, and Historical Biogeography
Why study biogeography?
Populations, Species, Communities, Ecosystems & Biomes
Biodiversity & Tree of Life – invertebrates, vertebrates, plants
Changes in Life on Earth over Time: Evolution
Historical Biogeography
Plate Tectonics and the Biosphere
Applied Biogeography: Endangered Species and Habitats
Paleoclimate and Modern Climate
* Survey of Attitudes toward Invertebrate Animals
Exam questions – see last three slides.
The world is full of species
(biodiversity), each with its own
intrinsic value, plus value to
human society.
Where do they live, and where
are they going?
Some questions that you as a biogeographer might ask about a living
thing:
-why does it occur where it is, for example, if it is confined to a certain
present range
-why are species separated along gradients, for example altitude
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What questions can biogeography
answer - continued
dry mixed grass
-how is it related to other species
-how does the number of species vary with
location and habitat qualities
-how does colonization and establishment
occur
-why are the plants and animals of remote,
separated areas so distinctive (e.g., lemurs
in Madagascar; marsupials in Australia)
Populations, Species, Communities, Ecosystems & Biomes
Foothills fescue
Biogeography may be divided into
ecological biogeography
and historical biogeography.
History (relevant events, facts and change over time)
and ecology (tolerances) together determine where a
species is found.
What has
been
happening
with this
grassland
species?
Why? They need a habitable place, and they need to
get there, survive and reproduce.
[Note: At the end of the week, I will also post a summary of the main points to
study, on just a few pages. - DJ]
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Examples of things that biogeographers may do:
ecological biogeography depends on ecology:
relationships to the biotic and abiotic environment
In biogeography, we may be concerned with species richness...
example of “species richness” and
abundance at a site
Horned lark
Meadow lark
Savannah sparrow
Long-billed curlew
Sprague's pipet
Swainson's hawk
Cooper's hawk
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102
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individuals
close recent relatives (what we would call family)
populations
communities
ecosystems
biomes (subdivisions may be called ecozones and other names)
biosphere
S = 7 species
biogeographic regions: biomes
Tropical rain forest
6% of surface but 50% of species
Relatively low elevation; high rainfall
ecoregions and classifications.
More examples:
“Climograph”
Eight natural vegetation regions of the world
From de Blij & Miller, 1996, Physical Geography of the Global
Environment. Adaptation by M.J. Pidwirny, Okanagan University College
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Biogeographers may study
environmental impacts.
Biogeographers study scale.
http://collections.ic.gc.ca/abnature/map.htm
A note about species
distributions and
change...
Book:
“After the Ice Age”
E.C. Pielou
A: survival in refuge
B: formerly
widespread, but died
back
Biogeographers study movement,
timing, phenology and biodiversity.
(phenology =
the timing of
life events,
like flowering,
or hatching)
C: jump dispersal
The geographical distribution of a species
Populations are
often endemic or
disjunct. How
did this come
about?
- dispersal
- vicariance
is often determined by:
- ecological tolerances (what conditions are best for it)
- relationships to other species (predators, parasites,
competitors, food, etc.)
- speciation
Same questions
with regard to
Quaternary
biogeography
- history of the region (climate, soils, positions of continents,
watersheds, drought, etc.)
- history of the species (evolution, origin, dispersal,
glaciation, etc.)
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What is a species?
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What is a species?
naturally-occurring populations of organisms
potentially interbreeding
may have considerable genetic variability
may show geographical variability
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naturally-occurring populations of organisms
potentially interbreeding
may have considerable genetic variability
may show geographical variability
Blue Whale
Beluga (White) Whale
Grey Whale
Barrel Cactus, Engelmann's Prickly Pear, Santa Rita Prickly Pear, Saguaro
http://www.whalesfilm.com/
Species might be closely related, and similar in
DNA, or less so.
Two common grass species in our area:
Stipa comata
Bouteloua gracilis
What is a species?
Eighteenth century
Blue Whale (Balaenoptera musculus)
Carolus Linnaeus (1707-1778)
Beluga Whale (Delphinapterus leucas)
Thought the earth was young.
Grey Whale (Eschrichtius robustus)
- classification of over four thousand
species of animals
- latin binomial (genus and species names)
Blue Whale
Beluga (White) Whale
Grey Whale
http://www.whalesfilm.com/
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The geographical distribution of a species
some species are linked by key relationships
is often determined by:
- ecological tolerances (what conditions are best for it)
- relationships to other species (predators, parasites,
Yucca
(soapweed)
and yucca
moth
competitors, pollination, food, etc.)
- history of the region (climate, soils, positions of continents,
watersheds, drought, etc.)
- history of the species (evolution, origin, dispersal,
glaciation, etc.)
The geographical distribution of a species
The total number
of species (about
10 million) is not
evenly divided
among the
common groups of
plants and
animals.
is often determined by:
- ecological tolerances (what conditions are best for it)
- relationships to other species (predators, parasites,
Insects account for
the largest number
of species known.
competitors, food, etc.)
- history of the region (climate, soils, positions of continents,
watersheds, drought, etc.)
E.O. Wilson,
The Diversity
of Life
Some species are dependent on other
species for food
Our case study example –
Burrowing owl and grasshopper
- history of the species (evolution, origin, dispersal,
glaciation, etc.)
In Saskatchewan (from published OBO data)
(range 685 to 51 pairs)
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
0.74
0.88
0.90
0.64
0.44
0.95
1.16
0.47
1.60
0.58
0.68
0.93
1.35
1.23
1.14
declines may
be related to
factors such as
weather, food
and migration
success
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D, Johnson, J. Schmutz, K. Clayton, M. Cammer, Y. Bousquet, E. deCruz...
The total number
of species (about
10 million) is not
evenly divided
among the
common groups of
plants and
animals.
Burrowing
Owl example
– we will
discuss in
more detail
Insects account for
the largest number
of species known.
E.O. Wilson,
The Diversity
of Life
http://www.uga.edu/srel/Fact_Sheets/biodiversity.htm
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Orthoptera example: most people are aware
of the basic pest grasshoppers
Melanoplus bivittatus
Two-striped grasshopper
Camnula pellucida
Clear-winged grasshopper
Clear-winged grasshopper
Calgary Herald, Aug, 2002. (John Simkin, Hanna, AB)
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Aeoloplides turnbulli (Thomas)
Russian thistle grasshopper, or Turnbull’s grasshopper
Aeoloplides turnbulli, Russian thistle grasshopper
(Starves to death when confined with crops or grass)
Prefers Russian thistle, winter fat, kochia and lambsquarters
10X to 1000X increase
Biodiversity refers the to numbers of species
and genetic variants of living things on Earth.
Biodiversity:
- results from evolutionary & ecological processes.
- changes across environmental gradients (why?)
- increases with increasing area (why?)
- tends to decrease in isolated regions (why?)
- may depend on the history and age of the ecosystem
Sagebrush grasshopper,
Narrow-winged grasshopper,
Melanoplus bowditchi canus
Melanoplus angustipennis
Land mammals in NA have 160 species at 8 degrees N, and
20 species at 66 N.
Breeding land birds have 600 species at 8 N, and 50 species
at 66 N.
Reptiles, 60 species at 30 but only 10 species at 45N
Why? Great energy and more stabile environment, longer time
to establish links.
Islands can be actual land in large bodies of water, or ...
lakes, parks or other isolated places.
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TIME FACTOR
The Quaternary Period
Geologic Time Scale
You do not need to memorize
this, but you do need to know
that the
= the geologic time period from the end of the
Pliocene Epoch 1.8 million years ago to the present.
the Mesozoic is the “age of the
reptiles”,
Includes the Pleistocene and the Holocene Epochs.
the Cenozoic is the “age of the
mammals”
and they both came after the
Paleozoic.
Darwin’s Finches
13 species illustrating Adaptive Radiation
Tool-using
Finch
Mangrove
Finch
Large,
Medium and
Small
Insectivorous
Tree Finches
Cactus
ground
Finch
Charles Darwin
(1809-1882)
Alfred Russel Wallace
(1823-1913)
Vegetarian
Tree Finch
Large Cactus
ground Finch
Natural selection
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natural populations produce more progeny than needed for replacement
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organisms have natural variation: some are better adapted than others
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better adapted types will survive and reproduce better than the less well
adapted
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variations are inherited
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this can result in evolutionary changes over long time
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Geographic isolation leads to divergence
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positions of fossils indicated possible evolution, to early biogeographers
evolutionary history = phylogeny; connections with
shared ancestors to lineages of other organisms.
phylogenetic tree
systematics: the science that constructs the tree and
describes the relationships of the history of life on earth
For certain taxa, characteristics are selected to examine
for evidence for relationship are chosen.
Cambrian explosion
Cambrian Explosion
Burgess Shale, near Field, BC
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Burgess Shale, Field, BC
trilobite
Burgess Shale, Field, BC
Scenella, a brachiopod
http://www.flickr.com/photos/dan-j/sets/816232/
Burgess Shale, Field, BC
Burgess Shale, Field, BC
Marella
Anomolocaris
Wiwaxia
Hallucigenia
© 2003 by Karen Carr
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Opabinia
Anomalocaris
Mollusks
Pikaia
(early Chordate)
Ordovician Cephalopods
Ordovician Gastropods
During our discussion of historical figures in
biogeography we briefly discussed:
Alfred Wegener (1880-1930)
Plate tectonics
http://www.ucmp.berkeley.edu/geology/anim1.html
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review
review
• The Cambrian Period was about 500 million years ago, and was a
time of an explosion in diversity of invertebrates
• The Burgess Shale is a fossil site that has numerous invertebrates
from the Cambrian Period
• Ecological biogeography is the study of ecological factors (biotic and
abiotic) that influence the distribution of life
• Historical biogeography is the study of the relationship of current
distribution of life to the recent and ancient history of the earth
• vicariance – splitting of distributions, so that disjunct distributions
may result; not explained by dispersal
• dispersal – the movement of living things away from their point of
origin
• number of species tends to decrease away from the equator, for all
groups of plants and animals; probably because of the greater
stability and energy input to ecosystems near the equator
• phylogeny – the evolutionary relationships between a living thing or
group of living things, and all known ancestors
• biodiversity – the range of variation among species and the
genetical makeup of species
• ecosystem services – values for humans, provided by the biotic and
abiotic components of ecosystems (e.g, clean water and air, food,
fiber, medicine, enjoyment, livelihood, etc.)
review
• People to know:
• Charles Darwin – evolution of species by natural selection
• Alfred Wallace – one of the first and most famous biogeographers
• Carl Linnaeus – Swedish botanist who invented the Genus and
Species (binomial) system
• Alfred Wegener – proposed and largely proved the theory of plate
tectonics
Geologic Time Scale
You do not need to memorize this, but you do need to know that the
the Mesozoic is the “age of the reptiles”, the Cenozoic is the “age of the
mammals” and they both came after the Paleozoic (invertebrates,
fish and amphibians were common life forms).
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