APES Review 4 Ecosystems Ecosystem Structure - - - - Population Dispersal all biotic and abiotic factors in an area that functions together -clumped organisms -linear species populations - communities - - ecosystems -random -uniform biosphere Ecosystem Characteristics *niche structure- # of niches, how they resemble each other or differ, includes species interactions *physical appearance-relative size,stratification, distribution of populations and species *species diversity-number of different species *species abundance-# of individuals of each species Specialist Species Generalist Species Symbiosis -live in narrow niches -more prone to extinction than generalist -in stable environmental conditions, specialist have an advantage b/c few competitors as each species occupies its own niche. - Ex. Giant Panda -live in broad niches -able to withstand a wide range of environmental conditions -close and often long-term interactions between different biological species -ectosymbiosis: organism lives ON another (Ex. Mistletoe, tick) -endosymbiosis: organism lives IN another (Ex. Bacteria in human, zooxanthelles in coral) Amensalism Commensalism -when rapid habitat change, generalists fare better b/c they are more adaptable -Ex. Cockroaches, mice, humans Competition -driving force of evolution -interspecific -intraspecific Types (examples) of Competition Competitive Exclusion Principle -Interference -Apparent - two species competing for the same resources cannot coexist if the ecological factors stay the same. 1. 1 species will become extinct 2. 1 species will be forced into evolutionary or behavioral shift toward a different ecological niche. Ex. Two species of paramecium Mutualism Parasitism -Exploitation -Ecto-Endo-Epi-Biotrophic -Nectotrophs -Social parasites- Predation Saprotropism Keystone Species -Species whose presence contributes to Aquatic Biomes Terrestrial Biomes Major Biome – Grassland Major Biome – Savanna Major Biome – Taiga (Boreal) -Between 45 and 60 Major Biome – Temperate Deciduous Forests Major Biome – Temperate Scrub(Chaparral) Major Biome – Tropical Rain Forest Major Biome – Tundra Aquatic Organisms & Diversity Desert Animals & Diversity -small, small surface areas to prevent Desert Plants & Diversity Grassland Animals & Diversity -spread apart due to limiting factors -succulents store water -small surface area, aligned vertically to decrease sun exposure -open stomata at night -waxy leaves -deep roots to reach ground water -shallow roots to absorb limited rainfall -spines discourage herbivores -secrete toxins to reduce interspecific competition -store biomass in seeds -wildflowers have short life spans -grazers and browsers eat vegetation at different heights -smaller animals migrate to find water -some become dormant -some survive on seeds during dry season -some live in burrows to hide -fur color acts as comouflage a diversity of life and whose extinction would lead to extinction of other forms of life. -Large and disproportionate impact on how ecosystems function Ex. Grizzly (nutrients from ocean to forest, Sea Star (keeps pop. Of urchins, mussels, etc. in check), Prairie Dogs… Major Biome – Desert -Between 15° and 25° N & S latitudes -20% of land surface -< 20 in. (50cm) rainfall/year - descending air, so not as much rain. -soil=sand, nutrient rich but lack of organic matter and little humus. water loss -spend time in burrows -often nocturnal -aestivation (reduced metabolic act.) -able to metabolize dry seeds -Kangaroo rats secrete concentrated urine -Insects and reptiles have thick outer scales Grassland Plants & Diversity Forest Animals & Diversity Forest Plants & Diversity -grasses grow from bottom so they grow again after being nibbled by grazers -grasses are drought resistant -deciduous trees and shrubs shed leaves during dry season to conserve water -some hibernate to conserve energy when food is scarce. -some live in canopies (abundant food and protection from predators) -Birds may migrate when food resources become scarce -nuts and seeds stored by rodents and birds for use during winter months. -epiphytes(orchids and bromeliads) live in branches to catch falling debri or rainwater. -large leaves to capture limited light -tree roots are shallow to capture limited nutrients -buttresses aid in support -flowers have elaborate devices to attract pollinators (wind is limited) -temperate deciduous trees lose leaves to conserve water and energy -shift metabolic pathways due to temperature -coniferous trees have small, waxy-coated needles and continually replace needles. -decomposed needles create acidic soil to reduce competitors. Temperate Scrub (Chapparal) Animals -rodents are common and store seeds Temperate Scrub (Chapparal) Plants Tundra Animals in burrows -nocturnal, burrow underground to escape heat in the day, feed at night. Will save water and energy and stay safe during fires. -some mice and lizards secrete a semisolid urine in order to reduce water loss -small waxy-coated leaves help to reduce transpiration -some plants release toxins that enter the soil -vegetation becomes dormant during dry season -leaves do NOT fall during dry season to reduce stress of replacement -thorns are adaptations for protection -plants are adapted to fires due to high oil content -fires reduce competition -have extra layers of fat; chemicals in blood to keep it from freezing -compact bodies to conserve heat -thick skin and/or fur -waterproof feathers and/or downy insulating feathers -most migrate in winter to avoid limited resources during winter -lemmings live underground during winter Tundra Plants Edge Effect Photosynthesis Carbon flux in Ecosystem Cycle Primary Producers -Polar grasses are adapted to low levels of sunlight, low amounts of free water, high winds, and low temperatures -Grasses primarily grow in summer months -Leaves have waxy coatings to reduce water loss -Plants can survive as roots, stems, bulbs, or tubers -Lichens dehydrate during winter to avoid frost damage Respiration -defense mechanisms Desert Food Web Oceanic Food Web Coniferous forest Food Web Deciduous forest Food Web Tropical rain forest Food Web Temperate rain forest Food Web Tundra Food Web Biomass Energy Pyramid Aquatic Ecosystem Biomass Pyramid (exception) Biodiversity Biodiversity Hotspot Natural Selection Types of Natural Selection Speciation -adaptive radiation Convergent Evolution Evolutionary Relay Parallel Evolution Gradualism and Punctuated Equilibrium Ecosystem Services Valuation of E.S. 1 Valuation of E.S. 2 -Processes by which natural ecosystems produce needed resources for humans such as clean water, timber, habitat for fisheries, and so on. -Provisional -Avoided Costs: society avoids costs that may have incurred if service was not available. Ex. Waste water treatment by Wetlands as apposed to a Municipal treatment Plant -Replacement Costs: Service replaced with some man-made system. Ex. Restoration of watershed costs less than construction of a water purification plant -Income: Services provide for increase in incomes. Ex. Improved water quality increases # of fish, improves income of fishers. -Travel Costs: service demand may require travel, whose costs can reflect the implied value of the service. Ex. Value of ecotourism experience is sufficient that a visitor is willing to pay to get there. -Hedonic Pricing: service demand may be reflected in the prices people will pay for associated goods. Ex. Coastal housing prices exceed prices of homes that are inland -Contingent Valuation: service demand may be elicited by posing hypothetical scenarios that involve some valuation of alternatives. Ex. Visitors willing to pay for increased access to national parks Major Climatic Periods Ecological Succession -Regulating -Supporting -Cultural -Preservation Natural Ecosystem Changes Characteristics of Succession Plant Communities