Unit 4 Study Guide Lecture 26 important figures images for chapter 52 figure 52 3 52 5 52 6 52 9 52 10 52 13 Ecology is studied at the levels of individuals populations communities ecosystems landscapes and biospheres Population a group of individuals of the same species that live in the same area and interbreed producing fertile offspring Community all the organisms that inhabit a particular area an assemblage of populations of different species living close enough together for potential interaction Ecosystem all the organisms in a given area as well as the abiotic factors with which they interact one or more communities and the physical environment around them Landscape an area containing several different ecosystems linked by exchanges of energy materials and organisms Biosphere the entire portion of Earth inhabited by life the sum of all the planet s ecosystems Ecology is the study of factors affecting the distribution and abundance of organisms Global climate is determined by the pattern of solar radiation energy striking the surface of local features such as mountains and bodies of water solar radiation varies seasonally surface heating from the sun drives air circulation Rain shadow when warm moist air approaches a mountain the air rises and cools releasing moisture on the windward side of the peak On the leeward side cooler dry air descends absorbing moisture and producing a rain shadow Aquatic habitats are determined by the proximity to shore light bottom vs open water and nutrients Wetland a habitat that is inundated by water at least some of the time and that supports plants adapted to water saturated soil River standing bodies of water covering thousands of square kilometers Estuary coral reef typically a warm water tropical ecosystem dominated by the hard skeletal structures secreted primarily by corals Some coral reefs also exist in cold deep waters Aquatic zones Benthic zone the bottom surface of an aquatic environment Pelagic zone the open water component of aquatic biomes Photic zone the narrow top layer of an ocean or lake where light penetrates sufficiently for photosynthesis to occur Aphotic zone the part of an ocean or lake beneath the photic zone where light does not penetrate sufficiently for photosynthesis to occur Terrestrial habitats are determined by temperature and moisture Biome any of the world s major ecosystem types often classified according to the predominant vegetation for terrestrial biomes and the physical environment for aquatic biomes and characterized by adaptations of organisms to that particular environment Tropical dry forest a terrestrial biome characterized by relatively high temperatures and precipitation overall but with a pronounced dry season Tropical rain forest a terrestrial biome characterized by relatively high precipitation and temperatures year round Desert a terrestrial biome characterized by very low precipitation Temperate Broadleaf Forest a biome located throughout mid latitude regions where there is sufficient moisture to support the growth of large broadleaf deciduous trees Lecture 27 important figures images for chapter 53 1 53 2 figure 53 2 53 4 53 6 Populations can be described by size density dispersal and survivorship Population a group of individuals of a single species living in the same general area Density the number of individuals per unit area or volume Dispersion the pattern of spacing among individuals within the boundaries of the population Different organisms have differing rates of survival and reproduction Survivorship curve a plot of the proportion or numbers in a cohort still alive at each age Type I survivorship curve flat at the start reflecting low death rates during early and middle life and then drops steeply as death rates increase among older age groups ex large mammals humans Type II survivorship curve intermediate constant death rate over the organism s life span ex ground squirrels some rodents various invertebrates some lizards and some annual plants Type III survivorship curve drops sharply at the start reflecting very high death rates for the young but flattens out as death rates decline for those few individuals that survive the early period of die off ex long lived plants many fishes and most marine invertebrates Trade offs between different aspects of life history have been important in organisms evolution Selective pressures influence the trade off between the number and size of offspring Plants and animals whose young are subject to high mortality rates often produce large numbers of relatively small offspring In other organisms extra investment on the part of the parent greatly increases the offspring s chances of survival so primates only produce 1 2 offspring Lifespan is subject to natural selection Mark recapture a sampling technique used to estimate the size of animal populations m number of individuals marked and released in the first sampling n the total number of individuals in the second sampling x the number of marked animals captured in the second sampling N total population size To solve for total individuals population size set up equation as x n m N Fecundity a measure of fertility such as sperm or egg count or the number of live offspring produced by an organism Mortality the death rate the ratio of the total number of deaths in the total population Senescence the growth phase in a plant or plant as a leaf from full maturity to death Immigration the influx of new individuals into a population from other areas Emigration the movement of individuals out of a population Lecture 28 important figures images for chapter 53 3 53 6 figure 53 19 53 24 If there are no constraints on reproduction and survival then population growth will be exponential and the rate of growth is determined by a single variable N population size N t Per capital rate of increase r the difference between the per capita birth rate and the per change in population size with change in time bN dN capita death rate b d r rate of increase Where b and d are the rates of individuals dying or being born over the time interval in question t rN change over time period t N t Described as instantaneous change Under ideal conditions dN dt dN dt rinst N rmax N resources symbolized as K dN dt rmax N K N K The Logistic Growth model the per capita rate of increase approaches zero as the carrying capacity is reached incorporates a single variable the carrying capacity K Carrying capacity the maximum population size
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