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SUMMER ASSIGNMENT Ch. 34 & 35 AP BIOLOGY Shipley CH. 34 THE BIOSPHERE: AN INTRODUCTION TO EARTH’S DIVERSE ENVIRONMENTS Population- an interbreeding group of individuals belonging to the same species and living in a particular geographic area Community- all the organisms in a particular area Ecosystem- all the life-forms in a certain area and all the non-living factors Abiotic- non-living factors in an ecosystem Biotic- organisms in an ecosystem Biosphere- the global ecosystem, all the planet’s ecosystems combined The biosphere is self-contained or closed, except that its photosynthesizers derive energy from the sun, and loss heat to space Habitat- environmental areas in which organisms live Biome- a terrestrial ecosystem, largely determined by climates, classifieds by predominant vegetation, and characterized by organisms adapters to the particular environments. Physical and chemical factors that influence life in the biosphere: Solar energy- powers nearly all surface terrestrial and shallow-water ecosystems Water- essential to all life Temperature- effects metabolism Wind- physically effects ecosystems and increases organism’s water loss by evaporation Earth’s global climate patterns are largely determined by the input of solar energy and the planet’s movement in space. The seasons of the year result from the permanent tilt of earth on its axis as it orbits the sun. Tropics- latitudes between 23.5° north and south, experience the greatest annual input and least seasonal variation in solar radiation Doldrums- an area of calm or very light winds High temperatures throughout the year and ample rainfall largely explain why rain forests are concentrated near the equator. Temperate zones-have seasonal variations in climate and more moderate temperatures Ocean currents- created by a combination of the prevailing winds the planet’s rotation, unequal heating of surface waters, and the locations and shapes of the continents Oceans Life began in the oceans and lived for 3 billion years before live moved onto land. Oceans cover 75% of the earth’s surface. Estuary- an area where a freshwater stream or river merges with the ocean, it is one of the most productive type of biome Wetland- between an aquatic ecosystem and a terrestrial one Intertidal zone- where water meets land, biologically most productive zone Pelagic zone- open ocean Phytoplankton- algae and photosynthetic bacteria that drift in aquatic environments Zooplankton- animals (usually microscopic or very small) that drift in aquatic environments. They eat phytoplankton and are then consumed by larger animals. Benthic zone- sea floor Coral reefs- built by generations of coral animals, support a huge diversity of animals Freshwater biomes Light significantly impacts fresh water bodies (lakes, ponds, rivers, streams, wetlands), there is a distinct photic (lighted) zone and an aphotic zone. Nitrogen and phosphorus are nutrients that limit phytoplankton growth. Terrestrial biomes Tropical forests- near equator, temperature is warm with long days (11-12 hrs.) year-round, the most complex and diverse biome, poor soil Savanna- dominated by grasses and scattered trees, large herbivores (antelope, giraffe) Desert- driest biome, low rainfall Chaparral- dense, spiny shrubs, climate results from cool ocean currents, mild, rainy winters and long, hot, dry summers Temperate grasslands- mostly treeless, regions of cold winter temperatures, most productive farmland Temperate deciduous forests- sufficient moisture to support the growth of large trees, eastern U.S. (where we live) Taiga- coniferous forests (cone-bearing evergreens), largest terrestrial biome, long, cold winters, short, wet summers Tundra- northernmost limits of plant growth, characterized by permafrost- continuously frozen subsoil (Alaska, Siberia) CH. 35 POPULATION DYNAMICS Population density- the number of individuals of a species per unit area or volume, gives an idealized picture of the unregulated growth of a population Exponential Growth Model- the rate of expansion of a population under ideal conditions G = rN G = growth rate of population N = population size (# of individuals) r = intrinsic rate of increase, an organism’s maximum capacity to reproduce Population-limiting factors- environmental factors that restrict population growth Logistic growth model- idealized population growth that is slowed by limiting factors G = rN (K-N) K (K-N) = the overall effect of population-limiting factors K K = Carrying capacity- the maximum population size that an environment can support This model predicts that a population’s growth rate will be small when the population size is either small or large, and highest when the population is at an intermediate level relative to the carrying capacity. Factors that limit population size Density-dependent rates- decreasing birth rates and increasing death rates (with an increase in population size) Competition for limited resources Availability of space Health and survival of organisms Predation Climate and weather Environmental factors (fire, floods, storms, habitat disruption by humans) Boom-and-bust cycles- regular fluctuation in density (insects, birds, mammals) Survivorship curves- plot the proportion of individuals alive at each age Type I curve- produce few offspring, but give them good care, increasing survival to maturity (humans and large mammals) Type II curve- intermediate, mortality constant over life span (invertebrates and rodents) Type III curve- high death rates for young, low death rates for individuals who survive, produce very large numbers of offspring, but provide little or no care (insects, shellfish) Life histories Life history- the series of events from birth through reproduction to death r-selection- selection for traits that maximize reproductive success in and uncrowded, unpredictable environment Individuals mature early and produce large numbers of offspring (insects, weeds) k-selection- larger-bodied, longer-lived species Populations that live at densities close to their carrying capacity (K) Produce few, well-cared for offspring (large terrestrial vertebrates ZPG = zero population growthwhen birth rates equal death rates Two ways to reach ZPG: 1. High birth rates - high death rates 2. Low birth rates - low death rates Demographic transition- the movement from #1 to #2 (seen in human population of developed countries) Renewable resource managementharvesting crops without damaging the resource Maximum sustained yield- harvesting at a level that produces a consistent yield without forcing a population into decline THE END STUDY YOUR NOTES LOOK OVER CH. 34 & 35 STUDY A LOT TEST WILL BE 35 MULTIPLE CHOICE QUESTIONS IN AP EXAM FORMAT GOOD LUCK!