Ecology: Organisms and their Environment

• -members of a sp that live in a defined geological space - -studied based on density and dispersion

• -collection of all pop’s of all the species within the same defined geological space • -predatory prey, competition, mutualism

• -ecological community with the surrounding physical environment • -separate related parts function together as a whole • -has biotic and abiotic material • -abiotic: air, water, rocks, soil • -biotic: plants and animals • -influenced by internal and external factors • -biodiversity: measure of ecosystem health • -living community of organisms and abiotic components

• -largest ecosystems on Earth • -dominant form of plant life and groups of animals • -similar climates and sp found within them have shared characteristics • -aquatic, terrestrial, marine ocean biome divided in layers • -benthic (bottom) • -pelagic (open ocean) • -photic (top layer): where life undergoes photosynthesis, phytoplankton (base of food chain) • -coast: lots of life and diversity of life coral reef: coral (invertebrate), secrete calcium carbonate as its exoskeleton • -coral polyps • -algae • -bacteria and fungi • -fish estuary: ocean biomes meet freshwater - -constant water flow - -diversity of life - -phytoplankton and detritus serve as nutrients for consumption by zooplankton - -ocean organisms and birds wetlands: terrestrial area covered in water - -supports aquatic vegetation - -food chain rooted in nutrient rich detritus, supports diversity of life - -supports permanent, migratory, ephemeral (short time), and transitional - - bogs, swamps, marshes streams: freshwater flows from headwater source to ocean - -headwaters :higher oxygen, therefore more life ponds and lakes: • -photic zone • -profundal zone: dark, few life • -littoral zone: productive, shallow, near waters edge, supports vegetation (phytoplankton and rooted plants)

share similar climates and environments, sometimes latitude and geographic location tundra (poles): flat, treeless land, mosses, lichens, grasses shrubs • -layer of permafrost (prevents water drainage) • -harsh cold, wet, windy • -crane flies, caribou, artic hares, lemmings alpine: worlds mountains (10,000 ft or higher) taiga: south of Artic tundra, is the northern boreal forest - -northern hemisphere - -conifers: spruces, firs, pines - -artic hare, caribou - -insects, small mammals, large animals (moose, wolves), migratory birds temperate deciduous: Eastern US, • -trees with leaf loss and regrowth with seasonal changes • -forests with vertical stratification • -tops of tallest trees form canopy that shield lower canopy, understory, shrub layer, ground • -forest stratification, richer soil, and less harsh environ lead to greater diversity of life like reptiles and amphibians grassland: grass sp adapted to rainfall, periodic fires, flat terrain - -invertebrate and vertebrate - -large grazing animals and burrowing rodents - -very fertile soil savanna: tropical grassland, soil poorer in nutrients - -drier, warmer, flatter desert: low rainfall, high evaporation - -cold temperate or hot weather - -shrub like, scattered plant life like succulents and sagebrush - -plants and animals adapted to dry conditions only flowering or exiting dormancy during rain chaparral: dry summers and wet winters - -shrubs (small woody plants) - -complex animal life dependent on shrub stratification tropical rain forests: very productive biome • -half of worlds plant and animals sp • -close to equator • -adequate rain • -series of stratified layers that create microclimates that support many sp • -soil has little nutritional value due to efficient decomposers

• -habitat: physical location where organism lives - -niche: organisms role, includes all biotic and abiotic factors that influence organism

• -predation (predatory and prey) • -essential for energy transfer and pop numbers and growth • -pop size of one sp is dependent on presence, abundance, and absence of another • -niches overlap in terms of food resources, similar habitats, and feeding behavior, competition emerges • -interspecific competition: for food, water, space bw 2 diff sp • -competitive exclusion principle: one pop. will outcompete another when vying for same limited resource and other pop goes extinct • -however, coexistence has occurred due to resource partitioning (using resources at diff times, ways, or locations)

• -growth rate of a pop. that increases at consistent pace • -rate of growth is proportional to number of individuals in a pop. • -J shaped growth curve, gets steeper with time • -assumes resources in an environment are constant and unlimited

• -S shapes curve • -pop. begins to grow at exponential rate • -as limiting factors impact, pop and resources become scarce • -pop. grows at slower rate/ decreases • -growth curve will level off and become stable • -pop has reached max size and density that geographic area can support (carrying capacity)

asexual: arise from single parent - -great number of offspring within short period of time - -pop grows quickly and exploits environ - -loss of genetic variation sexual: fusion of gametes from 2 distinct parents - -greater genetic diversity - -must balance resources to produce and raise offspring

• -amount of time and energy parent expends to support offspring that has neg. impact on parent ability to invest in his or her own biological fitness • -amt of parental investment is inversely proportional to number of offspring • -reduces parents fecundity: ability to produce offspring • -but increases offspring chance for survival

–opportunistic sp: small in size, short life cycle, large number of offspring in short time, no resources put into offspring, high mortality rate –equilibrium sp: fewer offspring produced, great care for offspring, longer life span –constant loss sp: moderate amt of offspring, constant mortality rate throughout lifespan

–Parasitism: parasite and host, parasite quickly reproduces, relies on host for food and for reproductive cycle –Commensalism: little to no effect on host –Mutualism: both benefit, many cases they coevolved together each adapting to changes and adaptations in the other, develop interaction thru evolution

• -competition for resources can lead to territoriality • -happens when populations occupy same habitat or niche • -leads to increased access to resources to promote reproduction and success among that winning pop. • -other organisms have to relocate to place with fewer resources

• -series of behaviors that benefit another organism at the cost of the organism that is displaying the behavior • -organism does to benefit pop as a whole • -prevalent among sp with high levels of parental investment or in pops that have complex social behavior • -examples include: • -aiding weaker of injured member • -group defense mechanisms • -closely tending and protecting offspring

• ecosystems and habitats are always evolving due to internal and external factors • -process of ecosystem change and development over time primary succession: occurs on substrates that have not been colonized or inhabited by life before –soil has little nutrients secondary succession: occurs in areas that once had life, but starting anew after a major environmental disturbance –are good nutrients in soil due to previous life Stages of Ecological Succession --pioneer plant stage \:photosynthetic microbes or plants adapted to living in areas with little resources \:small, reproduce quickly \:invertebrates soon follow --intermediate species \: as organisms die and decompose they add nutrients to soil to support great complex diverse plants \:grasses and shrubs \:reproduce more slowly \:more diversity and biomass \: take advantage of new habitats –climax community :previous organisms die and decompose which enriches soil and supports bigger complex plants :stable, mature plant growth :dominated by few species well suited for habitat :greatest diversity, biomass, and productivity : exist in equilibrium : however natural or human caused events arise, if this occurs secondary succession would begin in the area

Applicable to Ecosystems in General • -each stage marked by major change in nutritional value of soil and development of diff dominant forms of vegetation • -as vegetation changes the diversity of other forms of life change and increase • -results in biomass accumulation (total number of organisms) • -increase in ecosystem productivity • -with each change, more productivity and biomass and stability

• primary producers (plants), bacteria, algae, plant like protists - -have greatest amt of biomass • primary consumers (herbivores or omnivores)-heterotrophs • secondary consumers (carnivores or omnivores) • tertiary consumers (carnivores) • quaternary consumers (carnivores) • -decomposers: does not have own trophic level • -consumes detritus • -breaks down organic into inorganic

• • complex chain of energy transfer in ecosystem composed of multiple food chains which is series of organisms each dependent on the next for source of food • -encompass all individual food chains and feeding relationships

• hydrologic cycle • -moves thru biotic and abiotic pathways • -closed system: amt of water on Earth does not change • -evaporation: liquid water to vapor • -transpiration: water in biotic matter vaporizes and returns • -condensation: water vapor into atmosphere • -precipitation: vapor rises, meets cooler temps and becomes liquid in form of atmospheric clouds, these grow and release their water • -goes to oceans, evaporates back into atmosphere, groundwater or into rivers, lakes, or streams

• -within atmosphere, oceans, land, sediments and rocks • -most essential element • • moves thru biotic and abiotic atmosphere: gas form as CO2 and methane oceans: greater amt here, dissolved CO2 land: within organisms and soil sedimentary: largest amt here, carbonate rocks, volcanic eruptions, fossil fuels • -carbon exits abiotic and enter biotic via plants • -carbon continues in biotic pathways as organisms consume it produced by plants • -animals undergo cellular resp. which returns carbon as CO2 • -rest of carbon stored in organism and released when dies • -some C back to atmosphere or will join sedimentary rock as fossil fuels • -fossil fuels are burned, CO2 is released into atmopshere and intensifies greenhouse effect

• -in atmosphere, 78% • -organisms can not access N in its pure form therefore: Nitrogen fixation • -nitrogen fixing bacteria • -break down nitrogen gas and convert to ammonia during ammonification Nitrification • -ammonia into into usable cmpds by bacteria and archaea • -converted into nitrate • -nitrate taken up by plants in nitrogen assimilation Dentrification • -nitrogen stays stored in plants until dies/decomposes and returns nitrate to soil • denitrifying bacteria convert nitrate back to nitrogen gas • -nitrogen gas back to atmopshere • -nitrate can leach/ runoff

• -sedimentary cycle • -doesnt exist in atmosphere • -abiotic pathway in earths minerals and sedimentary rock • -phosphates in rock are released into soil thru weathering by wind and water • -phosphorus in rock enters soil as minerals as salts • -salts dissolved in water, return biotic pathway as plants assimilate mineral and convert from inorganic phosphorus to organic phosphorous • -organic phosphorus consumed • -organisms die and its returned to soil • -P settles down and becomes stored in sedimentary rock in bodies of water • -at this point it becomes lost, this means P is limited

temporal (time and freq) spatial: size and structure • -some disturbances small and frequent or large and frequent • -can be unpredictable • -some over long periods of time or large changes suddenly –major disturbances lead to deforestation, habitat destruction, population mortality, relocation of sp