Biol 413 Pre MT Flashcards
Dispersal Hypothesis
Sea turtle example:
arrived recently
Some females strayed from natal beach and established nests on beach
Vicariance Hypothesis
Sea turtle example:
arrived a long time ago
turtles nested on beaches of adjacent slands - islands have been displaced by sea floor spreading
Time periods of biogeography
Exploration: 1700-1900
Integration: 1900 to 1960
Maturity: 1960 to present
Exploration
classified geographic regions based o biotas
recognized patterns in species diversity
Linnaeus
Father of binomial nomenclature and taxonomy
Believed in immutability of species
Taxa have centers of origin (ex. indo-west pacific is center of origin for marine fishes)
Geogrges-Louis Leclerc, Comte de Buffon
1) Earth must be older than biblical claim
2) taxa changes through time therefore must have a relationship with geology and biological histories of earth
1st law of biogeography
1st law of biogeography
Environmentally similar but isolate regions have distinct species assemblages
Alexander von Humboldt
Extended 1st law to plants and terrestrial animals
“floristic belts” - promoted the idea that plant distribution is determined by climate
first to note south america fitting with west africa
Charles Lyell
Principles of Geology
Stratagraphic layers and fossils suggest earth is changed through time and gradually
Uniformitarianism
Uniformitariamism
basic natural laws and processes have always acted on the earth and understanding present geological processes is key to understanding the past
Charles Darwin
Natural selection is key factor in the origin of species
Dispersalist
Dispersalist
Rare long-distance dispersal events establish isolated populations that ten differentiate
Extentionist
land bridges (now submerged) facilitated the extension of distributions between land masses
Phillip Sclater
made connection between low dispersal ability and ability to construct biota from current composition
biogeographic line
a geographic boundary that animals
(or plants) tend not to cross. Some lines are more
permeable that others, some taxa less constrained.
6 biogeographic regions
Nearctica (North America and parts of Mexico)
Palearctica (Eurasia)
Neotropical (tropical central America and S. America)
Aethiopica (Africa)
Indica (Indian subcontinent)
Australiana (Australia)
Alfred Wallace
Described observations on distribution, diversity, extinctions, diversity, etc.
Refined sclater’s regions
Wallace’s Line
which separates fauna of southeast Asian origin from those of Australian origin.
Bergmann’s Rule (1847):
Body size tends to increase with increasing latitude
Allen’s Rule (1878):
Species at higher latitudes tend to have shorter, smaller limbs
than those at lower latitudes.
Jordan’s Rule (1881):
Fish species / populations at higher latitudes have more and
smaller vertebrae than those from lower latitudes
Evolutionary Synthesis
Classical Mendelian genetics, theoretical population genetics, systematics,
and taxonomy unified into a comprehensive body of theory of evolutionary
change – how factors such as genetic drift, mutation, and natural selection
could drive evolutionary change
4 key developments after 1960:
1) Acceptance of continental drift + plate tectonics
2) Phylogenetic systematics: the basic philosophy of reconstructing the
historical and evolutionary relationships among taxa
3)Ecological biogeography: contemporary interactions and species
relationships are important in the determination of species range limits.
4)Technological advances allow old hypotheses to be tested rigorously
and expand the spatial scale of biogeographic inference: Computers,
Satellites and remote sensing, Geophysics, Geographical Information
Systems (GIS), Molecular biology technology
Phylogeny:
the evolutionary relationships between an ancestor taxa
and all its known descendant taxa
Phylogeography:
an approach to biogeography that studies the
geographic distributions of lineages within and among species
Changes in the crust are driven by two engines:
1) Energy stored in the earth’s core dissipates through the mantle and the crust shaping the earth’s crust
2) Energy from the sun strikes the earth’s surface and is absorbed and converted into heat
Spherical shape of the earth: heating
causes a latitudinal gradient of thermal radiation
Close the the equator the area of radiation and distance travelled is smaller so heat energy is maximized
Cooling effects of elevation
pressure and density of air decreases with altitude - with reduced pressure air expands and undergoes adiabatic cooling
Coriolis Effect:
the tendency for moving objects (e.g., wind and currents)
to veer clockwise in the NH and counterclockwise in the SH. We see this
effect easily between 0 and 30 degrees North and South latitude
Trade winds and westerlines
Trade winds: blow west to east at high latitudes
Westerlies blow: east to west at equator
Causes clockwise in Nhemisphere and counter in S hemisphere
Horse Latitudes:
warm, dry surface winds
“dry-out” the land and create most of our
great deserts near 30o
N and S latitude (e.g.,
Mojave, Sonoran, Sahara, Gobi, and Great
Sandy deserts).
-The land is cooler than ocean in these areas and as a result in the winter the warm air brings rainfall to the area. (opposite is true in summer)
Rain occurs where
the air is warm and rising: warm air is able to store more moisture… them more it rises the more saturated it gets until it will precipitate as rain or snow at its peak- and as it falls and cools down
Areas where the air is cooling and falling is dry air that is taking moisture from those areas (i.e. deserty areas)
The adiabatic lapse rate
is the rate at which air cools as it rises. This lapse rate
varies for many reasons, but generally, the lapse rate differs with and without
condensation
El Nino Southern Oscillation (ENSO)
period of weather change that occurs every 5-7 years due to the strengthening of the equatorial countercurrent (cause unknown). Increased rain (often 10x) in arid coastal regions of SA, and reduced coastal upwelling.
Geographic range
basic observational unit of biogeography, encompasses the
maximum geographic extent of occurrences of a taxon during part or all of its
life cycle.
Ways to describe distribution
Dot maps, outline maps, contour maps, seasonal range maps,
Way to quantify distributions
extent of occurrence
area of occupancy
Extent of occurrence
Uses polygon method:
may encapsulate areas that are uninhabited
Area of occupancy
using a grid ,
using geo-political boundaries
Challenges: outbreak times are usually much larger than regular times
-breeding/overwintering areas are much different
