Biogeography Terms Exam 1

biogeography

the study of te distribution of species and ecosystems across geographic space and through geological time.

ecological biogeography

the study of aspects of biogeographical phenomena that focuses on the interactions between the organisms and their environment

historical biogeography

the study of aspects of biogeographical phenomena that focuses on the origins and sebsequent history of lineages and taxa

Linnaeus

1700’s classifying species, species=unchanging. noted where species were found, starting ecological biogeography

Buffon, buffons law

environments that look similar in different regions contain different speices, paving way for historical biogeography

forster

plant diversity decreases as you move away from the equator

humboldt

plant species change with altitude, breast fed his daughter in a rainforest??

candolle

endemic species

Darwin (& wallace)

voyage on the HMS Beagle, galapogos islands, finches different beak shapes

wallace (& darwin)

in the east indies, noticed that butterflies look different do so for a reason, location, or advantages, or evolution

vicariance

barriers arise and split ranges (continents drifting apart)

dispersalism

species move across barriers (birds, floating seeds)

wegener (1912)

continents were once joined, pangaea. glossopteris(the tree) led to and supported this theory.

Glossopteris case study

brought about the idea of pangaea having existed (wegener), this was later proved fact

community

assemblage of interacting species, can be positive, negative, or neutral

ecosystem

community + physical environment + processesco

competition

when 2 organisms use the same limited resource, lowering the fitness for both (ex. two barnacles fighting for space on a rock)

interspecific

competition between different species

intraspecifc

competition within same species

exploitative competition

indirect, via resource depletion (ex. plants absorbing water from soil)

interference competition

direct, via aggressive interactions (ex. territorial fights in animals)

competition can lead to…

resource parittioning and competitive exclusion

predation

one species kills and eats another, regulates pop. size (ex. wolves preying on deer)

herbivory

animals consuming plants or algae, can reduce plant fitness, but also drives adaptations (morphological[ spines/thorns] or chemical [nicotine])

herbivory can lead to…

shaping plant community structure, coevolution between plants and herbivores

predation can lead to…

maintenance of prey pops. prevents dominance of single prey species, predator-prey cycles

parasitism

one organism lives on or in another and benefits at the hosts expense (+, -)

endoparasites

parasites inside the body

ectoparasites

parasites outside of the body

parasitism can lead to…

regulating host pops., alters host behaviors and ecosystem processes

mutualism

both species benefit in a relationship (+,+)

obligate organisms

organisms who can only survive if they have a mutualistic relationship (bees and flowers)

facultative

organisms that benefit from mutualism, but its not essential (clownfish and anemones)

commensalism

one species benefits, other is unaffected (+,o) (ex. barnacles on whales)

facilitation

one species improves the conditions of another without direct interaction, common in deserts, alpines, and marshes (ex. nurse plants - provides shade for seedlings)

neutralism

no significant interaction, the species don’t affect each other, this is RARE (o,o)

Clements vs. Gleason Debate

2 ecologists that had opposing views on how plant communities form

clements view

communitites are discrete, integrated units, they are orderly, conservation

conservation (clements)

protecting one species amy help maintain the whole community (clements view)

gleasons view

communtiies are coincidental, boundaries are arbitrary, they are fluid and ever changing, conservation

conservation (gleason)

focus should be on species and functional traits, not assumed community “wholes” (gleason view)

ecosystem

communities + abiotic factors (micro, meso, macro - small to large)

2nd law of thermodynamics

energy is lost as heat through each level of the trophic pyramid (only 10% of previous energy is actually passed on)

food webs

multiple feeding relationships, omnivory, detritus pathways, etc. keystones important

Gross Primary Productivity (GPP)

total energy fixed by photosynthesis

Net Primary Productivity (NPP)

EQUATION: GPP - energy lost through plant respiration (energy available to consumers)

productivity drives…

species richness and biome distribution

biodiversity

variety of life in an area, measured in species richness, evenness, and functional diversity

stability

an ecosystem’s ability to resist disturbance (resistance) or recover after disturbance (resilience)

The trophic pyramid…

is structured by predators from the top-down, and structured by the resources from the bottom-up

function

the processes and roles performed by species within an ecosystem (nutrient cycling, primary production, etc.)

redundancy hypothesis (diversity and function)

many species are redundant, only some are critical

linear model (diversity and function)

every species contributes equally

rivet hypothesis

some species are keystones, their loss causes damage

biodiversity

genetic variation within a species and number of different species, the diversity of entire ecosystems and habitats

host-parasite ratios

if every plant hosts a certain number of fungi or insects, we can extrapolate

indicator groups

some researchers use butterflies or birds as indicators of broader biodiversity

(Biodiversity) very large animals

only a few species (elephants, whales)

(biodiversity) mid-sized animals

hundreds to thousands

(biodiversity) small insects

millions

Latitudinal Diversity Gradient

The Big Pattern - biodiversity increase from poles to equator

Water + Energy…

= Diversity

Currie & Paquin Finding

Tree Richness best predicted by evapotranspiration

Energy/Productivity

More energy and resources mean more species can coexist

climate stability

stable climates allows species to specialize

evolutionary time

tropics have been stable for longer

niche specialization

competition is intense in the tropics, pushing species into narrow niches

south continents

fragmented (Gondwana breakup)

north continents

relatively stable connections

Case Study: Great American Interchange

was a major event in biogeography occurring approximately 3 to 3.5 million years ago when the Isthmus of Panama formed, connecting North and South America and allowing the exchange of animal and plant species

Tectonics Direct Effects

splitting and collision of landmasses: new barriers and corridors

Tectonics Indirect Effects

Shifts in climate, sea levels, and currents: Creation of deserts, mountains, and shallow seas

latitude matters

continents crossing climate zones, new environments

polar distribution

land at poles, ice sheets forms, cooling Earth

albedo effect

ice and snow reflect sunlight, amplifies cooling

continental fragments

once part of a continent (ex. madagascar)

volcanic arcs

formed at subduction zones (ex. Lesser Sundas)

hot spot islands

fixed mantle plumes form chains (ex. Hawaii)

convergent (continental drift)

trenches, mountain building

divergent (continental drift)

mid-ocean ridges

transform (continental drift)

earthquakes (ex. san andreas)

continental drift

moving landmasses

plate tectonics

whole lithospheric plates (land+ocean)

Hess (Sea floor spreading)

new crust at mid-ocean ridges, destroyed at trenches

Vine & Matthews (sea floor spreading)

magnetic stripes confirm spreading

Why tectonics matter…

shapes continents&oceans, creates connections&barriers for species, and alters climate, sea level, and habitats

neutral theory (Hubbell)

species abundance may result from random processes. assumes species at same trophic level are ecologically equivalent, works well for plants and not for animals

intermediate disturbance hypothesis

moderate disturbance = highest richness. prevents competitive exclusion by dominant species, allows coexistence of early and late successional species

alpha diversity

richness within a single habitat, drives regional biodiversity with beta

beta diversity

turnover between habitats, drives regional biodiversity with alpha

disturbances

storms, fires, floods drive cycles

succession

new species colonize, communities shift

patch dynamics

mosaic of habitats at different stages

rapoparts rule

species ranges are broader at higher latitudes

factors affecting altitudinal diversity

climate variation, human influence, & area effect

vicariance

splitting of populations by new barriers

dispersal opportunities

land bridges, connected continents

habitat shifts

deserts, forests, grasslands expand and shrink

biodiversity patterns

dynamic, shaped by Earth’s crust

Allopatric speciation (common)

geographic isolation