Speciation Ch 27

• Dispersal - when a population moves to a new habitat, colonizes it, and forms a new population, Galapagos finches - with different islands, there are different populations (and then speciation) of finches
• vicariance - a physical boundary isolates populations, antelope squirrels and the grand canyon / Colorado river
• sympatric speciation - when they live in sympatry, but still a speciation event occurs (no physical barrier) , internal event - gene mutation , external event - ecological or outside event
• sympatry - populations that are similar enough and geographically similar enough to interbreed
• finches and disruptive selection (sympatric speciation) - female finches lay in nests of males with songs similar to the ones they know and that continues from generation to generation
• Polyploidism (sympatric speciation) - internal event / gene mutation , Autopolyploidy - all chromosomes come from the same species and doubled so it goes from a 2n to a 4n species and speciation occurs in a single generation , alloypolyploidy - two different species mate and have an offspring with different numbers of chromosomes
• pre-zygotic isolation - when the distinction between two populations is great enough that there is a mutation in a pre zygote state of the offspring
• Reinforcement (when two populations come in contact with e/o and no pre-zygotic isolation) - offspring of two isolated populations have a very low fitness, mate selection traits have to do with post zygotic isolation, so natural selection is like no you don't want to fuck that frog, sympatric species are unlikely to breed and when they do they don't tend to survive or mate
• hybrid zones ( when two populations come together without pre zygotic isolation ) - when there are zones in which hybridization between isolated populations becomes common or a trait that is beneficial to the fitness of the organism, when natural selection prefers a hybrid, this is very common and occationally the two isolated species become extinct (townsend's warbler and hermit warbler)

Ecology

five main levels

• organismal ecology (level) - how do individuals of a species interact with each other and the envoronment around them
• population ecology (level) - how and why do populations change in space and size over titme?
• community ecology (level) - how do species interact with each other and what effects does that have on the envoronment?
• ecosystem ecology (level) - how does the nutrient cycle effect the loval environment?
• global ecology (level) - how is the biosphere effected by the nutrient cycles and everything below that...
• so! side note! when you're studying one level, you're studing the effects that all of the levels below that level have on the one you're currently studying
• the biosphere (define) - the region of the universe that we know to contain life (currently only includes earth)

two major questions that need to be considered:

• what factors limit the distribution of a species?
• what factors determine the abundance of a species?
• the answer's in the environment!

The environment

• biotic components - anything that is alive or once was alive, factors - diseases or other pathogens
• abiotic components - anything that is not and has never been alive, factors - wind, climate, light, pH, water

Dispersal and Species Distributions

• dispersal ability affects the distribution of the species (uh duh)
• special, temporal, means of dispersal, and how long the species has existed are all factors in the dispersal ability
• humans fuck shit up and disperse species all the time (peonies)
• happens naturally too (cattle egrets local to Africa)

Exotic Species and Invasive Species

• sometimes when an exotic species is introduced, a species becomes invasive when it starts causing harm to the biotic and abiotic environment around the species

Climate Patterns

• Why are the tropics wet?
• Hadley cell is a major pattern in global air circulation where warm air rises at the equator and falls at the latitude of the tropics
• global climate patterns - effected by geographical structures regionally and by air circulations and patterns of the like

Biomes

• the organisms that belong in certain climates
• in terrestrial biomes (25%) of the earth the vegetation is usually the distinguishing factor
• NPP (net primary productivity) - are influenced by anual precipitation and temperature, total fixed carbon - carbon from cellular respiration

Terrestrial Biomes

• Temperate grassland - dominated by grasses (like tropical savannah) execpt thy have relitively cold winters - the praries of North America
• when prarie fires are avoided, trees can take over, fires maintain the soil health and the grasses' prevalience

charge calculator and put the formulas in there

I can't fucking believe that I lost all of that

Community Ecology

• community - all of the species that interact within an area
• competition - when two or more of different species have the same need for a resource, but one has a better fitness or something... the other one will die out
• ecological niches - total of the resources (biotic and abiotic) that a species uses in its environment
• warblers in niches - different species of warblers feed in different places in trees as to avoid competition

Competition when niches overlap

• fundamental niche - the possible area that a species could occupy
• realized niche - the actual area that a species occupies

Consumption

• define - when a species uses other living organisms as a source of food
• predation - you have to kill another and there's hunting involved... difficult for prey and predators... prey has evolved to look like another dangerous species to defend themselves (batesian mimicry)
• herbivory - uh duh... plants produce both physical and chemical defenses to predators
• parasitism - usually the host isn't killed, but it's used for nutrition
• parasitoids - they spend part of their life attached to the host and they eventually kill their hosts unlike a true parasite
• mutualism - both species benefit
• commensalism - one species gets a benefit, but there is no net impact on the host species at all
• community structure - not all species contribute equally
• keystone species - have exceptionally great impact on the community and the health thereof around them

Succession

• the change in a community over time
• most apparent after a disturbance
• example glacial succession - primary succession where there is little to no biotic presence... then there's a whole process of what life arises from this state
• secondary succession - disturbance removed and it returns to what was present before *** fires
• species richness - the number of species present in a particular community