Module 3

• Ecology is the study of how organisms interact with each other & their environment- intertwined & co dependent with evolution
• Primary goal of ecology- understand the distribution & abundance of organisms
• Ecology is increasingly focused on human impacts- environments are changing more rapidly now than in the past 3.5 billion years
• Extinction risk factors- habitat temperature flux of >7 degrees celsius- regions in climatic extremes- small geographic range size- small body size
• Anthropogenic noise directly disrupts & affects the acoustic modality of communication in organisms- boats & motorways etc- bat echolocation- pronged ear deers spend less time foraging due to sound
• Types of ecology- organisms (specific level)l- population (school of salmon)- community (other organisms in the ecosystem interaction- ecosystem (facilitation of nutrients of different areas)- global
• Conservation biology- uses all 5 levels of ecology- study, preserve & restore threatened genetic diversity in populations, species diversity in communities & ecosystem function
• Ecology is the basis of biodiversity
• Why is biodiversity important- contributes to healthy environments; cleaner air & water, nature based solutions to climate change, resilience to storms & flooding- contributes to healthy humans; food security & nutrition, natural medicine & pharmaceuticals, promotes mental health & connectivity- contributes to healthy economies; resistance to shocks, recreation & tourism, livelihoods & job creation
• Biodiversity is the infrastructure supporting all life
• What determines the distribution & abundance of organisms- biogeography- abiotic factors- biotic factors
• Biogeography- the study of how organisms are distributed geographically (phytogeography: plants, zoogeography: animals)
• Abiotic factors influences an organism’s niche, which is all the conditions a species can survive in, i.e an arctic microbe has a relatively wider cold niche (high tolerance)
• Cold adapted niche organisms typically have wider tolerances than hot adapted niche organisms
• Niche models show the range of conditions occupied by a given species
• Niches are sensitive to climate change; an organism’s regular environment may change & the animal/plant is not adapted to this temperature range niche
• Diseases are biotic factors
• Abiotic & biotic factors are dynamic- past influences present- constant flux over geological time- affected dispersal
• Isthmus of panama creates opportunities for dispersal between north america & south america
• The wallace line- alfred russel wallace- Northwest: tigers rhinos, elephants- to the southeast: kangaroos, marsupials & platypuses etc- a deep trench in the ocean maintained a water barrier to dispersal of organisms across these regions
• Alfred russel wallace co discovered evolution by natural selection & founded the study of biogeography
• The wallace line lies between australia & the rest of oceana 
• Humans affect the distribution of species via hunting, deforestation and physically moving animals
• Introduced or exotic species- occur outside their natural range due to human activities- most do not become invasive due to unsuitable habitat & cannot become established
• Invasive species- introduced species that are experiencing rapid increases in abundance- can displace native species– can overexploit natives- can alter habitats so natives cannot persist
• Over 50% of all recent extinctions are partially or completely the results of effects of invasive species
• Species become invasive when they go thru ecological release- when a species expands its niche within its own habitat or into a new habitat where there is little competition for resources, which remains abundant
• Invasive species are exotic species that experience ecological release- absence of the factors that kept population in check in native lands, so the species expands into new niches- many species introduced to islands experience ecological release and become invasive- invasive species have often been introduced via human actions, deliberate or accidentally
• Interaction of biotic & abiotic factors- Argentine ant, Linephithema Humile is native to south america and is invasive around the world- most successful at invading mediterranean like ecosystems with adequate moisture (abiotic) & lack of competitors/predators (biotic)
• Weather- specific, short term atmospheric conditions of temperature, precipitation, sunlight & wind
• Climate- prevailing long term weather conditions
• Climate occurs in relatively predictable global patterns- insolation of different latitudes- hadley cells- coriolis effect
• Hadley cells- because the landmasses near the equator are really insolated, they get hot- the air rises & rises until it cools & condenses- blown away north & south by more rising hot air- the reason why there is a lot of rainfall  up to 30 degrees latitude N & S of the equator and then a dry zone persists- process repeats at ferrel cells further north & south & dry air moves to the poles
• Coriolis effect- air goes north-south & east-west direction due to the earth rotating 
• Seasonality is another factor influencing the distribution of organisms- regular, annual fluxes in temperature, precipitation or both- earth is tilted on its north to south axis by 23.5 degrees- as the earth orbits the sun, one side will inevitably be tilted away (winter)
• No tilt means no seasons
• Broad climatic patterns are dictated by insolation, air circulation & seasonality and are further modified by regional effects- mountains can create rain shadows- ocean have specific heat capacity (absorb heat) (gyre)
• Rainshadow- warm moist air rises against a mountain- it cools and condenses, emptying the moisture- air descends and is drier
• The north atlantic gyre circulates warm equatorial water up north
• The spherical nature of the globe is what drives latitudinal insolation temperature-  latitudinal temperature gradient