Tectonic Plates And Species Distribution Flashcards
to identify what tectonic plates are, how they work and how they influence biogeography both today and in the past.
What occurs when plate margins meet?
Causes: - volcanoes + eruptions - earthquakes - mountain ranges (can change weather systems!) And more ...
What are tectonic plates?
- Rigid plates found on the lithosphere (earths crust)
- they move (0-100mm per year)
- made of 7-8 plates and minor plates
- there movement is slow but constant
What about tectonic plates in the future?
- currently got separate continents
- in about 250mill. Years time the supercontinent will form again
What happened in the history of tectonic plates?
Gondwanaland - supercontinent when all continents were one
- occurred in Permian period (255mill. Years ago)
- great American faunal exchange (GAFE)
How are tectonic plates important to biogeography?
- Continental drift established reason for distribution of present day species
- populations of species moved to different areas of the globe via continental drift
- vicariance biogeography
- causes allopatric speciation
Why are tectonic plates important?
- They are a large scale issue.
- most severe and immediate issue along side climate change
- they shapes and move our continents
- they influence the distribution of species
- tp changes will massively change species distribution / range
What example is there of species distribution changes?
- marsupials
- in Australia and South America
- evolved on Gondwanaland
Cretaceous period - population split into 3 in 3 separate land masses
- populations remain on 2 of 3 landmasses (Australia and South America)
-3rd was Antarctica
What do plate tectonics cause as a result of movement in biogeography?
- Distribution / dispersal changes
- isolation of species
- allopatric speciation (geographical isolation of a large interbreeding population)
What was the Great American Faunal Exchange (GAFE)?
- occurred when N&S America mixed species
- led to a range of outcomes for different species
- 50% of S.American mammal species derive from immigrant lineages - N. America (didelphis marsupialis)
- 10% if N. American mammal species derive from immigrant lineages - S. America
What is continental fusion?
- The opposite of continental drift
- species from 2+ landmasses can mix
4 possible outcomes
1. Active competition
2. Passive replacement
3. Insinuation
4. Toleration
What is active competition?
- occurs between two species with a similar ecological niche
What is passive replacement?
- Occurs when a species replaces another without competition.
- usually chance occurrence
- mainly theoretical but there is some evidence
- South American ungulates (large mammals/hoofed animals) decline around the GAFE seemingly before active competition
What is insinuation?
When an invader species finds previously unoccupied ecological niche and inhabits it.
What is toleration?
- When one or more species cohabit
- fossils GAFE suggest S. American camel cohabited with a camel-like macrauchenids for 2.5million years
What distribution styles are there?
Continuous
- continuous distribution
Discontinuous
- broken distribution
- common distribution (due to tectonic plates)
- geological disjunction
- climatic disjunction
- evolutionary disjunction
- jump distribution disjunction
What is geological disjunction?
- Divide of landmasses
- species or genus continues existence on 2+ different landmasses
What is climatic disjunction?
Climate splits an existing population into 2+ separate populations
Eg magnoliaceae - split due to Ice ages continental drift and mountain formation
What is evolutionary disjunction?
- Occurs when a species evolve from a…
common ancestor –> disperse–> common ancestor dies –> leaves 2+ isolated species - eg woody species
Ficus and acacia
1. Sonoran and chihuahuan desert N. America
2. Chilean and Peruvian deserts in S. America
What is jump dispersal disjunction?
- individuals move over inhospitable terrain in the course of their lives
- founder individuals start a new self-sustaining population
Natural example:
- 160 plant species in America
Many kore due to human aid (alien species)
Why do species move?
- Species require dispersal to colonise new areas if the globe
Routes include: - land bridges both permanent and unterupted (berring bridge)
- stepping stones
- islands
And more I’m sure
