Conditions and Interactions  Conditions may affect The availability of a resource The availability of a resource Coleophora alticolellaColeophora alticolella Development of disease Development of disease GrasshoppersGrasshoppers Corn fungusCorn fungus Outcome of competition Outcome of competition Salmon – tempSalmon – temp Tribolium beetles – temp and humidityTribolium beetles – temp and humidity Barnacles – susceptibility to desiccationBarnacles – susceptibility to desiccation

Conditions May Affect Species Interactions Coleophora alticolella

Conditions and Interactions  Conditions may affect The availability of a resource The availability of a resource Coleophora alticolellaColeophora alticolella Development of disease Development of disease Grasshoppers and fungusGrasshoppers and fungus Corn and fungusCorn and fungus Outcome of competition Outcome of competition SalmonSalmon Tribolium beetles (lab)Tribolium beetles (lab) Barnacles (later with competition)Barnacles (later with competition)

Camnula pellucida Killed by Entomophaga grylli

Conditions and Interactions  Conditions may affect The availability of a resource The availability of a resource Coleophora alticolellaColeophora alticolella Development of disease Development of disease GrasshoppersGrasshoppers Corn fungusCorn fungus Outcome of competition Outcome of competition SalmonSalmon Tribolium beetlesTribolium beetles BarnaclesBarnacles

Corn Leaf Blight

Development of Disease

Conditions and Interactions  Conditions may affect The availability of a resource The availability of a resource Coleophora alticolellaColeophora alticolella Development of disease Development of disease GrasshoppersGrasshoppers Corn fungusCorn fungus Outcome of competition Outcome of competition SalmonSalmon Tribolium beetlesTribolium beetles BarnaclesBarnacles

Salvelinus malma Dolly Varden Salvelinus leucomaenis Whitespotted Char

Temperature Changes Outcome of Competition

Effects on Competition  Thomas Park (University of Chicago, late 1940s and 1950s) Flour beetles: Tribolium confusum and T. castaneum Flour beetles: Tribolium confusum and T. castaneum Many experiments Many experiments A major finding was that environmental conditions can influence the outcome of competition.A major finding was that environmental conditions can influence the outcome of competition. Mechanism: exploitative and interference (cannibalism and predation: larvae eat eggs and pupae; adults eat eggs, pupae, and each other )Mechanism: exploitative and interference (cannibalism and predation: larvae eat eggs and pupae; adults eat eggs, pupae, and each other )  Joseph Connell – barnacles Outcome of competition determined by both biotic and abiotic factors Outcome of competition determined by both biotic and abiotic factors

Competition among barnacles Rocky intertidal zone Adult barnacles immobile on rocks Planktonic larvae settle on rocks at all levels Environment prevents competitive exclusion –Realized niches Joseph Connell (1961) Ecology 42:

Distributions of Balanus & Chthamalus Balanus Adults Larvae Chthalamus Adults Larvae lowest low tide highest high tide Balanus Chthamalus ROCK

Responses to Global Warming  Pitcher plant mosquito Wyeomyia smithii Compared larvae collected in the field in 1972 and 1996, Compared larvae collected in the field in 1972 and 1996, Found that more recent mosquitoes require 14 fewer minutes of light exposure to exit diapause. Wake up earlier and breed earlier. Found that more recent mosquitoes require 14 fewer minutes of light exposure to exit diapause. Wake up earlier and breed earlier. That suggests that the mosquitoes have adapted to spring weather that is arriving earlier than in the past. That suggests that the mosquitoes have adapted to spring weather that is arriving earlier than in the past. Read PNAS article Read PNAS article

Responses to Global Warming  Red Squirrels in Canada Increasing spring temperatures and food supply Increasing spring temperatures and food supply Squirrels have advanced the timing of breeding by 18 days over the last 10 years — six days for each generation. Squirrels have advanced the timing of breeding by 18 days over the last 10 years — six days for each generation.

Responses to Global Warming  These are Evolutionary changes - adaptations  Other examples Birds migrating north earlier Birds migrating north earlier Plants leafing out & flowering earlier in spring Plants leafing out & flowering earlier in spring  What might be a drawback to these trends?

Limiting Factors  Limiting factor - the “slowest” factor process depends on several different factors process depends on several different factors speed of process determined by slowest factor speed of process determined by slowest factor can be too little or too much of factor can be too little or too much of factor e.g. photosynthesis limited by too little light in early morning and too much heat in afternoon e.g. photosynthesis limited by too little light in early morning and too much heat in afternoon  Liebig’s Law of the Minimum  Factors can interact: compensation; synergism

Synergistic Factors  Two factors; both depend on elevation Tidal flooding Tidal flooding Soil salinity Soil salinity  Observed Lower in marsh, periodic tidal flooding is important abiotic factor Lower in marsh, periodic tidal flooding is important abiotic factor Plants must be able to tolerate inundationPlants must be able to tolerate inundation Higher in marsh, get increasing salinity Higher in marsh, get increasing salinity Plants must be able to tolerate high salt levelsPlants must be able to tolerate high salt levels Normal Pattern: Plant biomass highest in intermediate elevations; Salicornia grows lower in marsh than Anthrocnemum Normal Pattern: Plant biomass highest in intermediate elevations; Salicornia grows lower in marsh than Anthrocnemum

Synergistic Factors SalicorniaGlasswort AnthrocnemumPickleweed

 Salicornia and Anthrocnemum Both plants do best at intermediate elevation where levels of tidal flooding and salinity were moderate Both plants do best at intermediate elevation where levels of tidal flooding and salinity were moderate Anthrocnemum avoids hypersaline areas of upper elevations and flooded regions of lower regions of the coastal marsh Anthrocnemum avoids hypersaline areas of upper elevations and flooded regions of lower regions of the coastal marsh Salicornia tolerates flooding but may lose out at the intermediate zones due to competition from Anthrocnemum Salicornia tolerates flooding but may lose out at the intermediate zones due to competition from Anthrocnemum

Synergistic(combined) Factors  Pennings and Callaway Common Garden Experiment  Transplanted both species throughout saltmarsh at all elevations Where did plants do best? See graph Where did plants do best? See graph Salicornia grows lower than Anthrocnemum, can tolerate floodingSalicornia grows lower than Anthrocnemum, can tolerate flooding Both species performed best in intermediate regions where flooding and salinity were moderateBoth species performed best in intermediate regions where flooding and salinity were moderate Anthrocnemum avoids hypersaline areas of upper marsh and flooded regions low in the marshAnthrocnemum avoids hypersaline areas of upper marsh and flooded regions low in the marsh Salicornia is probably excluded from intermediate regions by AnthrocnemumSalicornia is probably excluded from intermediate regions by Anthrocnemum

Factors can interact: ex: water and salinity reciprocal transplant experiment with Salicornia and Anthrocnemum

Adaptation  Over time, natural selection can result in adaptation to environmental stress. Individuals with traits that make them best able to cope with stress are favored. Individuals with traits that make them best able to cope with stress are favored. Over time, these unique, genetically-based solutions become more frequent in the population. Over time, these unique, genetically-based solutions become more frequent in the population.

Adaptation  Adaptation is similar to acclimatization/ acclimation but it is the long-term, genetic response of a population to environmental stress that increases its survival and reproductive success.  Acclimation and Acclimitization are shorter term responses  Where does this fit on your table of responses to environmental variation?

Adaptation  Populations with adaptations to unique environments are called ecotypes.  Ecotypes can eventually become separate species as populations diverge and eventually become reproductively isolated.  Animals Orcinus orca – Killer Whale Orcinus orca – Killer Whale Tritema stick insects Tritema stick insects Asellus aquatic benthic invertebrate Asellus aquatic benthic invertebrate

Orcinus orca  Fish eating ecotype Resident Resident  Marine mammal eating ecotypes Transient Transient “Offshore” Transient “Offshore” Transient

The traits examined depicted on representative specimens of each host ecotype Nosil P, Crespi B J PNAS 2006;103: ©2006 by National Academy of Sciences

Why do Organisms Live Where They Do? Environmental Variation