Embed Size (px)
Citation preview
1
Palaeontology Evolution
Ecology
Climatology
Biogeography
Pedology
Geology
GEOG 215Introduction to biogeography
• Why did Western red cedar only become common on the west coast of Canada about 5000 years ago?
• Why is Monterey pine, which was restricted to a few stands on the California coast in the 19th century, now widely planted in the southern hemisphere?
GEOG 215Introduction to biogeography
2
Khaled Hamdan: Who am I? • live in Burnaby
• BSc Biology at LU (2003)
• MSc Environmental Sciences at AUB (2007)
• PhD candidate at Physical Geography SFU (2007-present)
• Sessional Instructor: Fall 2009
• TA (G111, G215, G317, G417),TM (311)
• Currently I‟m a sessional Instructor G215 and a TM G100
GEOG 215Introduction to biogeography
InstructorKhaled Hamdan (RCB 7234)
Office hours: Wednesday 2:30-3:30
phone: 604.729.4334
email: [email protected]
TA Megan Hendershot ([email protected])
Course materials Ian Hutchinson (http://www.sfu.ca/~ianh/)
3
GEOG 215 - Housekeeping
• Course email: [email protected]
• Lecture slides and all handouts will be posted on the course WebCT
• All readings are from the text (MacDonald, 2003).
GEOG 215 - Grades, etc.
• Laboratory assignments: 25%
• Poster project: 25% includes research journal: 5%
• Midterm exam: 25%
• Final exam: 25%
4
Lectures: Tuesday 8:30 - 10:20. Tentative Schedule
Week Topics (chapter/pages; [*optional*])
1 Sept. 7 Introduction to Biogeography (1, 2)
2 Sept. 14 Climate controls (3/45-60)
3 Sept. 11 Soil factors (3/60-69)
4 Sept. 28 Niches, communities, and biomes (3/70-73;4; 6/133-145)
5 Oct. 5 Disturbance and succession (5)
6 Oct. 12 Biogeographic range (10, 13/377-393)
7 Oct. 19 Midterm examination
8 Oct. 26 Evolution, speciation, and extinction (9)
9 Nov. 2 Dispersal, colonization, and invasion (7/191-205,8,13/394-404)
10 Nov. 9 Cenozoic biogeography (7/205-233; [*11*])
11 Nov. 16 Cultural biogeography (12)
12 Nov. 23 Island biogeography (14/428-450)
13 Nov. 30 Biodiversity and conservation (14/406-428)
LABORATORY: GEOG 215, Biogeography, Fall 2009
Tentative Schedule
Week Topic
1 Sept. 7th or 8th No lab
2 Sept. 14th, or15th Morphology and Variation [5%]
3 Sept. 21st or 22nd Morphology and Variation (contd. - due at end of lab. Period)
4 Sept. 28th, or 29th Field Mapping (2h fieldwork) [2%]
5 Oct. 5th or 6th Field Mapping (contd. - due at end of lab. Period)
6 Oct. 12th or 13th Climate and range [4%]
7 Oct. 19th or 20th Climate and range (contd. - due at end of lab. Period)
8 Oct. 26th or 27th Forest succession [4%]
9 Nov. 2nd, or 3rd Forest succession (contd. - due at end of lab. Period)
10 Nov. 9th, or 10th Tertiary range and migrations [5%]
11 Nov. 16th, or 17th Tertiary range and migrations (contd. - due at end of lab. Period)
12 Nov. 23rd, or 24th Late Quaternary range and migrations [5%]
13 Nov. 30st, or Dec. 1st Late Quaternary range and migrations
(contd. - due at end of lab. Period)
- there will be 6 lab assignments to be handed in during the semester
- marks will be deducted (5% of the lab mark per day late) forassignments handed in late (unless discussed beforehand).
5
Term project
• Students will work in groups of two to create a poster in Powerpoint that deals with the biogeography of a plant or animal species native to BC. This includes not only terrestrial plants and animals, but also marine and freshwater species. Depending on the species, the poster should deal with the following topics:
Term project • What is the current distribution and status (in terms of
abundance) of the species?
• Has it distribution changes significantly in the historic period?
• What is the evolutionary history? Is it a recent immigrant, or has it been present in western North America for several million years?
• What strategies are being employed to conserve the populations of the species, or,, in the case of pests, to control populations?
6
Important dates
• Oct. 19th : Midterm exam (room C9000)
• Oct. 27th: e-mail 1-paragraph outline of your term project topic to your TA
• Nov. 24th : hand the final version of your poster (on a CD) to your TA (by 4:30 pm), don‟t e-mail the poster (the TA‟s mail will overflow).
• Dec. 18th : Final exam (room TBA)
Plagiarism • SFU has policies on doing your own work and
properly referencing others‟ work.
• In G215, there are laboratory assignments, some
of which you may do in groups.
• You must share data with your group, but do
your final write-up by yourself.
• If you get stuck on a point, ask a friend in the course to help you (and you help them).
• We do NOT want to see identical write-ups,
except if you are working in groups and are
instructed to submit your answers together.
7
What is biogeography?
Biogeography:
the study of the geographical distribution of organisms, their habitats (ecological biogeography), and the historical and biological factors which produced them (historical biogeography).
Lincoln , R.J., Boxshall, G.A., and Clark, P.F. 1982. Dictionary of Ecology, Evolution and Systematics. Cambridge University Press.
Goals of biogeography
1. To develop natural laws and concepts that explain biogeographic processes and account for the development of biotic distributions.
2. To provide baseline information on the spatial and temporal distribution of organisms that can be used to conserve and manage Earth‟s biotic resources and heritage.
8
Central questions of biogeography
• What organisms are found where?
• How are these organisms adapted to the local environment?
• How have their distributions changed through time?
“Characteristics of biogeography as a
discipline”
9
Multi-disciplinarity Palaeontology Evolution
Ecology
Climatology
Biogeography
Pedology
Geology
Multi-dimensionality
Time: past future
global
local
SPACE
Why are the pieces laidout as they are, and how aretheir distributions changing?
Evolving and mobile pieces(life-forms)
Changing table-top(environment)
10
Biogeography
ENVIRONMENT BIOTA(climate, soil, . . .)
Time
Present = ecological biogeography
Past = historical biogeography
ENVIRONMENT BIOTA(climate, soil, . . .)
observation
experiment
inference
GEOG 215: Course themes
Life forms
Geological history and evolution
The physical template(climate, soils, landforms)
Recent and futureenvironmental change
Ecological communities and their dynamics
11
Given the dazzling array of life forms on the planet,
how do we proceed to answer the
“central questions”
Search for an “atomic” unit“Of what then is biodiversity composed? Since antiquity biologists have felt a need to posit an atomic unit by which diversity can be broken apart, then described, measured, and reassembled… Western science is built on the obsessive … search for atomic units with which abstract laws and principles can be derived. Scientific knowledge is written in the vocabulary of atoms, subatomic particles, molecules, organisms, ecosystems, and many other units, including species. The metaconcept holding all the units together is hierarchy, which presupposes levels of organization.”
Wilson, E.O. 1992. The Diversity of Life, Penguin. p. 35
12
Biological hierarchiesTaxonomic Ecological Trophic
order (etc.) biome top carnivores
family community carnivores
genus association herbivores
species species primary producers
Subspecies
population
individual
Only in trophic hierarchies where the focus is energy
flow are species not an essential unit
Some basic terminology
• Taxonomy: classification & naming of organisms [taxis (Gr.) = “order”]
• Systematics includes evolutionary relationships of organisms
• Ecology: how organisms interact and are affected by their environment
• Trophic: how energy flows in an ecological community
13
Towards a scientific taxonomy
Folk taxonomy (common names):1. Inuit in one district of Arctic Canada
have 100 names for local birds.2. Tzeltal-language speakers in Chiapas
have 1100 names for local plants.
Sources:Irving, L. 1953. The naming of birds by Nunamiut Eskimo. Arctic, 6, 35-43.Berlin, B. 1966. Folk taxonomies and Biological Classification. Science, 154, 273-275.
Taxonomy in the “Classical World”
Aristotle (384–322 BC ). formulated two classifications, genos and eidos. Genosreferred to broad categories of animals, (e.g. reptiles), while eidos were animals in a genos. Aristotle's system was intentionally hierarchical with mammals placed at the top of the hierarchy. Aristotle‟s ideas held sway (in Europe) until the 17th century.
14
Early modern taxonomy
John Ray (1627–1705) introduced the term species, which he defined (following plant and animal breeders) as a group of organisms capable of interbreeding and producing fertile offspring. His taxonomy used multiple morphological characters to classify species (e.g. flowers, seeds, fruits and roots for plants).
Formalized species descriptions based on diagnostic traits
Linnean taxonomy
Carl Linnaeus(1707-1778)
(aka Carl von Linnéand Carolus Linnaeus)
Hierarchy based on groupings of species and genera, not splitting of
larger classes
Latin binomials (Genus, species)[following the Swiss botanist Bauhin {1560-1634}]
replace long Latin descriptions(e.g. Sturnella magna = „big lark‟)
15
Linnean taxonomy:Eng: eastern meadowlark
Sp: pradero tortilla-con-chile, Fr: sturnelle des prés
Kingdom: Animalia
Phylum: Chordata
Subphylum: Vertebrata
Class: Aves (birds)
Order: Passeriformes (perching birds)
Family: Fringillidae (finches)
Genus: Sturnella
Species: Sturnella magna
(Linnaeus, 1758)
Subspecies: Up to 17 subspecies recognized (indicates local variation)
Image: Delbert Rust
Linnean taxonomy: diagnostic morphologies of related species
Eastern meadowlarks (Sturnella magna)
can be distinguished from western meadowlarks
(S. neglecta) by the white (as opposed to
yellow) feathers behind the lower
mandible.
Sturnella magna S. neglecta
Images: http://birds.cornell.edu/crows/mlarkdiff.htm
16
Why did Linnaeus base his classification on species?
Are species real?
1. There is general agreement amongst disparate human groups as to what constitutes separate “sorts” of organisms, based on differential morphology, and
2. “Like begets like” - intermediate forms are rare.
The importance of the species concept
“The species concept is crucial to the study of biodiversity. It is the grail of systematic biology. Not to have a natural unit such as the species would be to abandon a large part of biology into free fall. ….. Without natural species, ecosystems could be analyzed only in the broadest terms, using crude and shifting descriptions of the organisms that compose them.”
Wilson, E.O. 1992. The Diversity of Life. Penguin. p. 36
17
“Species” in folk vs. scientific taxonomies
Birds (Inuit)102 birds
4 (2 names)
98 0
Plants (Tzeltal)sample of 200 plants
82 68 50
under- 1:1 over-differentiated differentiated
under-differentiated = fewer names for organisms than species recognized by science; 1:1 = correspondence; over-differentiated = more names, etc. (mainly cultivated plants; e.g. four varieties of beans)
Linnean taxonomy: diagnostic morphologies of related species
Eastern meadowlarks (Sturnella magna)
can be distinguished from western meadowlarks
(S. neglecta) by the white (as opposed to
yellow) feathers behind the lower
mandible. Or can they?
Sturnella magna S. neglecta
Images: http://birds.cornell.edu/crows/mlarkdiff.htm
18
Intra-specific variation in domesticated plants and animals
Broccoli, cabbage, cauliflower… Brassica oleracea Dogs: Canis familiaris
Intra-specific variation in snow geese
separate species? orjust morpho-colour phases of the same species?
“lesser”
Eng: “greater”Inuit: k(h)anguk
Eng: blue gooseInuit: khavik
19
http:// www.qc.ec.gc.ca/faune/guide/html/oie_neiges_e.html
Difficulties in defining species strictly on morphological traits led to the adoption
of the
biological species concept.
“Species are groups of actually (or potentially) interbreeding natural
populations which are reproductively isolated from other such groups.”
Ernst Mayr (1953)
(apply this to previous examples)
20
Meadowlarks
• Western and eastern meadowlarks are almostidentical in appearance.
• Their geographical ranges overlap, but their distinctsongs prevent inter-breeding.
• The species are maintained by sexual signaling.
Images: http://evolution.berkeley.edu/evosite/evo101/
western eastern
Merits of the biological species concept
• Emphasises the critical importance of evolutionary descent,
• Emphasises that species act as discrete breeding groups - they breed “true to type”.
• Provides a testable hypothesis - can they produce viable offspring?
21
Drawbacks of the biological species concept
• Some organisms that are morphologically ± distinct can interbreed (=“bad species”; e.g. pines)
• We have knowledge of the breeding behaviour of only a tiny proportion of the living species on Earth.
• Impossible to apply to extinct species; interbreeding cannot be directly observed.
Is DNA the answer?
• Mitochondrial DNA indicates the genetic similarity
between organisms and can be used to establish
an evolutionary time frame;
• mtDNA is passed on from mother to offspring. If
the mutation rate is known, the ancestry of the
lineage can be estimated (e.g. “Mitochondrial Eve”
lived about
~140 000 years ago])
• Many copies per cell; a single gene is all that is
required for “barcoding” plants or animals.
22
How much variation in mtDNA is there in a taxon?
Cytochrome c oxidase subunit I
(COI) gene
Within species
Within genus
moths 0.25% 6.5%
birds 0.4% 7.9%
~20x
DNA barcodes: meadowlarks
• mtDNA sequencing indicates that the eastern meadowlark (remember the 17 subspecies!) consists of two “cryptic” species (COI divergence between the two = 4.8%)
Images: http://evolution.berkeley.edu/evosite/evo101/
Hebert et al., 2004, Pub. Lib. of Science, Biology, vol 2; issue 9
23
DNA barcodes: skippers
• Neotropical skipper butterfly (Astraptes fulgerator)
• First described in 1775• Ranges from south
Texas-northern Mexico to Argentina
• Is it one species or are there many “cryptic” species?
Hebert et al., 2004, Proc. Nat. Acad. Sci., 101, 14812-14817
DNA barcodes: skippers• Single gene tested
from adults reared from caterpillars in laboratory.
• 10 species identified based on significant differences in COI gene. Matched to caterpillar colour patterns and food plants.
Hebert et al., 2004, Proc. Nat. Acad. Sci., 101, 14812-14817.
24
How does a palaeontologist assign a species name to a fossil?
Evidence: shell or bone beds …….. tracks or burrows.
Taxon named from:Morphology -- yes (hominid fossils illustrate difficulties) Breeding behaviour -- nomtDNA -- yes (recent fossils that have not degraded )
Naming fossils:South African hominids
Paranthropus crassidens?
or are they all Paranthropus robustus?
Australopithecusrobustus?
Australopithecusafricanus?
Images: http://www.modernhumanorigins.com/robustus.html
25
The Homo
floresiensis
controversy:
A new human species or
just a local population
(individual?) of Homo
sapiens?
How much morpho-
variation should a
paleontologist allow?
See: Hopkin, M. 2006; Will the hobbit argument ever be resolved?
Nature, 25 August; doi:10.1038/news060821
Species definition in use today
Organisms that share at least one diagnostic morphological trait; that can interbreed freely under natural conditions, and whose direct ancestors or descendants can be traced in the fossil record.
26
Naming species in the field
Biogeographers and field biologists recognize
the superiority of the biological species
concept, but base their field identifications
almost entirely on diagnostic morphological
criteria.
The DNA barcode project envisages that by
the end of this century everyone will own a
mini mtDNA analysis kit that will return a
species name for every organism encountered
on a walk in the woods.
Continuing problems:what is a sub-species?
A sub-species is a geographical race that has distinctive traits which interbreeds with
other subspecies where their ranges overlap.
“sub-species are recognized according to whatever traits taxonomists choose to
study”
27
Designating sub-species
Thousands of geographical races possible because in most species thousands of genes in
operation, and many segregated populations! The sub-species (as a formal concept) is therefore now essentially abandoned, but some organisms covered by the Species-At-Risk Act (Canada) and Endangered Species Act (U.S.) are sub-
species.
*genetic analysis suggests the latter; i.e. that the Vancouver Island marmotis just a darker phase of the relatively common haory marmot of the mainland
Protecting sub-species: island populations
Q: What is the most
endangered mammal in
Canada?
A: M. vancouverensis?,
or
M. caligata
vancouverensis?*
See also: VI ermine (Mustela erminae anguinae)VI water shrew (Sorex palustris brooksi)VI wolverine (Gulo gulo vancouverensis)
28
Cutthroat Trout [Oncorhynchus clarkii]
The most widespread and diverse trout species in the western hemisphere
15 sub-species in North America as a result of genetic isolation (one recently extinct)
Many of the subspecies are protected
Rocky Mountain cutthroat [O.c. virginalis, pictured] is but one example.
Protecting sub-species: local populations
Restricted to Everglades of
southern Florida
The subspecies is now a
hybrid of a population of
native North American
“cougars” and South
American “panthers”
released into the wild
Florida panther[Puma (Felis) concolor coryi]
Protecting sub-species: hybrids
