Ecology Behavior, Communities, Ecosystems

 Behavioral ecology Scientific study of behavior in natural environments from an evolutionary perspective Scientific study of behavior in natural environments from an evolutionary perspective Behavior Behavior What an animal doesWhat an animal does How it does itHow it does it Usually in response to stimuli from the environmentUsually in response to stimuli from the environment

 Cost-benefit analysis to determine whether a behavior is adaptive Contribute to direct fitness Contribute to direct fitness Animal’s reproductive success measured by the number of viable offspring Animal’s reproductive success measured by the number of viable offspring When benefits outweigh costs, behavior is adaptive When benefits outweigh costs, behavior is adaptive

 Behavior Results from the interaction of innate behavior and environmental factors Results from the interaction of innate behavior and environmental factors Learned behavior Learned behavior Behavior is modified in response to environmental experienceBehavior is modified in response to environmental experience

Imprinting Establishes a parent-offspring bond Establishes a parent-offspring bond Ensures that the offspring recognizes the parent Ensures that the offspring recognizes the parent

 Selfish behavior Increases individuals chances of survival Increases individuals chances of survival Social groups; selfish herd; dominance hierarchies Social groups; selfish herd; dominance hierarchies  Altruistic behavior Sacrifice for the good of the group Sacrifice for the good of the group Bees Bees Inclusive fitness – passing on the genes that make organism care for relatives Inclusive fitness – passing on the genes that make organism care for relatives

 Social behavior Adaptive interaction, usually among members of the same species Adaptive interaction, usually among members of the same species Animal communication involves exchange of recognizable signals Animal communication involves exchange of recognizable signals Pheromones are chemical signals that convey information between members of a species Pheromones are chemical signals that convey information between members of a species

Are mating and parental behavior under genetic influence?  Those that can attract more mates, reproduce more, pass on those genes  Parenting is an energy consuming role, but it ensures offspring survive to pass on genes

What is the relationship between ecology and evolution?  The reason species evolve is due to environmental pressures Food is scarce – maybe better digestive tract or teeth help some survive – they pass on those traits Food is scarce – maybe better digestive tract or teeth help some survive – they pass on those traits

5 factors that shape community structure  Interaction between climate and topography  Food  Adaptive traits of species  Species interactions  Pattern of population size

 Ecological niche Distinctive lifestyle and role of an organism in a community Distinctive lifestyle and role of an organism in a community Takes into account all abiotic and biotic aspects Takes into account all abiotic and biotic aspects For example, an organism’s habitat is one parameter used to describe the niche For example, an organism’s habitat is one parameter used to describe the niche

 Interspecific competition – between 2 populations Requirements of 2 species are close, but never exactly the same Requirements of 2 species are close, but never exactly the same  Competitive exclusion principle Two species cannot occupy the same niche in the same community for an indefinite period Two species cannot occupy the same niche in the same community for an indefinite period One species is excluded by another as a result of competition One species is excluded by another as a result of competition

Resource partitioning

 Predation Defenses Camouflage Camouflage Warning coloration Warning coloration Mimicry Mimicry Moment of truth Moment of truth Predator response to prey Predator response to prey

Mimicry

Camouflage

 Symbiosis Mutualism Mutualism Both partners benefitBoth partners benefit Commensalism Commensalism One partner benefits and the other is unaffectedOne partner benefits and the other is unaffected Parasitism Parasitism One partner benefits while the other is harmedOne partner benefits while the other is harmed

 Keystone species Present in small numbers but are crucial in determining the species composition and ecosystem functioning Present in small numbers but are crucial in determining the species composition and ecosystem functioning Beaver – creates new ecosystems that animals rely onBeaver – creates new ecosystems that animals rely on  Dominant species Affect the community because they are so common Affect the community because they are so common

 Ecological succession Primary succession Primary succession Occurs in an area not previously inhabitedOccurs in an area not previously inhabited Secondary succession Secondary succession Occurs where there is a pre- existing community and well- formed soilOccurs where there is a pre- existing community and well- formed soil

Energy flow through an ecosystem

 Ecological pyramids Express the progressive reduction in numbers of organisms, biomass, and energy found in successive trophic levels Express the progressive reduction in numbers of organisms, biomass, and energy found in successive trophic levels

Biomagnification

 Gross primary productivity (GPP) Rate at which photosynthesis captures energy Rate at which photosynthesis captures energy  Net primary (ecosystem) productivity (NPP) Energy that remains after plants and other producers carry out cellular respiration Energy that remains after plants and other producers carry out cellular respiration

 Carbon cycle Carbon dioxide is the most important gas Carbon dioxide is the most important gas Carbon enters plants, etc., as CO 2 Carbon enters plants, etc., as CO 2 Cellular respiration, combustion, and erosion of limestone return CO 2 to the environment Cellular respiration, combustion, and erosion of limestone return CO 2 to the environment

 Nitrogen cycle Five steps Five steps Nitrogen fixation – converting N 2 to ammoniaNitrogen fixation – converting N 2 to ammonia Nitrification – convert ammonia to nitrates (which plants use)Nitrification – convert ammonia to nitrates (which plants use) Assimilation – nitrogen taken by organism to make organic compoundsAssimilation – nitrogen taken by organism to make organic compounds Ammonification – ammonia ionsAmmonification – ammonia ions Denitrification – ammonia to N 2Denitrification – ammonia to N 2

 Hydrologic cycle Renews the supply of water Renews the supply of water Involves an exchange of water between the land, ocean, atmosphere, and organisms Involves an exchange of water between the land, ocean, atmosphere, and organisms Water enters the atmosphere by evaporation and transpiration Water enters the atmosphere by evaporation and transpiration Water leaves the atmosphere as precipitation Water leaves the atmosphere as precipitation