BSC 2011 Dixon Exam 4 Study Guide Lecture 26 CONCEPTS 1 Know that ecology is studied at the levels of individuals populations communities ecosystems landscapes and biospheres Individuals organismal ecology how an organism s structure physiology and behavior meet the challenge s posed by its environment Populations population ecology analyzes the factors that affect population size and how and why it changes through time Communities community ecology examines how interactions between species such as predation and competition affect community structure and organization Ecosystems ecosystem ecology emphasizes energy flow and chemical cycling between organisms and the environment Landscapes landscape ecology focuses on the factors controlling exchanges of energy materials and organisms across multiple ecosystems Biospheres global ecology examines how the regional exchange of energy and materials influences the functioning and distribution of organisms across the biosphere 2 Be able to explain how ecology is the study of factors affecting the distribution and abundance of organisms Certain ecological factors can lead to the distribution of animals such as how the red kangaroo is only found in part of Australia with relatively sparse and variable precipitation Barriers also play a role in why certain species are found on only one continent and not another Abiotic factors nonliving factors such as temperature Biotic factors living factors such as the other organisms that are a part of an individual s environment 3 Be able to explain how global climate is determined by the pattern of solar radiation striking the surface and local features such as mountains and bodies of water Earth s curved shape causes latitudinal variation in the intensity of sunlight The sunlight strike the tropics most directly more light and heat of surface area are delivered there Mountains influence the airflow over the land when warm moist air approaches a mountain the air rises and cools releasing the moisture on the windward side of the peak On the leeward side cooler dry air descends absorbing moisture and producing a rain shadow This leeward rain shadow determines where many deserts are found They also affect the amount of sunlight reaching an area which affects local temperature and rainfall Bodies of water Ocean currents influence climate along the coasts of continents by heating or cooling overlying air masses that pass across the land For example the west coast of N Europe has a mild climate because the Gulf Stream carries warm water from the equator to the North Atlantic 4 Know that aquatic habitats are determined by the proximity to shore light bottom vs open water nutrients Lakes standing bodies of water range from ponds a few square meters in area to lakes covering thousands of square kilometers Oligotrophic lakes nutrient poor and generally oxygen rich Eutrophic lakes nutrient rich and often depleted of oxygen in the deepest zone Oligotrophic lakes may tend to become eutrophic over time as runoff adds sediments and nutrients Littoral zone shallow well lit waters close to shore Limnetic zone inhabited by a variety of phytoplankton Wetlands habitat that is inundated by water at least some of the time and that supports plants adapted to water saturated soil Streams rivers the most prominent characteristic is their current Estuaries a transition area between river and sea Intertidal zone periodically submerged and exposed by the tides twice daily on most marine showers Oceanic pelagic zone a vast realm of open blue water constantly mixed by wind driven oceanic currents This biome covers 70 of earth s surface Coral reefs formed largely from the calcium carbonate skeletons of corals Marine benthic zone consists of the seafloor below the surface waters of the coastal or neritic zone and the offshore pelagic zone 5 Know that terrestrial habitats are determined by temperature and moisture Tropical forest rainfall is relatively constant Animal diversity is higher in tropical forests than in any other terrestrial biomes Desert occur in bands near 30 degrees north and south latitude or at other latitudes in the interior of continents Precipitation is low generally less than 30 cm per year Common animals include snakes and lizards Savanna seasonal rainfall warm year round mainly grassy plants include large plant eating mammals Chaparral occurs in mid latitude coastal regions on several continents rainy winters and dry summers dominated by shrubs include animals such as deer and goats Temperate grassland plains and prairies in central N America winters are generally cold dominant plants are grasses and forbs native animals include bison and wild horses Northern coniferous forest taiga largest terrestrial biome on earth dominated by cone bearing trees such as pine animals include moose and brown bears Temperate broadleaf forest found mainly in northern hemisphere has distinct vertical layers including a closed canopy the animals hibernate in winter Tundra covers expansive areas of the arctic winters are cold large grazing musk oxen are resident TERMS Population group of individuals of the same species living in an area Ecosystem community of organism s in an area and the physical factors with Community group of populations of different species in an area which those organisms interact Biome a major regional or global biotic community such as a grassland or desert characterized chiefly by the dominant forms of plant life and the prevailing climate Benthic the bottom of a sea or lake Pelagic any water in a sea or lake that is neither close to the bottom nor near the shore Photic the depth of the water in a lake or sea that is exposed to sunlight Aphotic the portion of the lake or sea that has little or no sunlight exposure Lecture 27 CONCEPTS survivorship 1 Understand that populations can be described by size density dispersal and Size the number of individuals living within those boundaries Density number of individuals per unit area or volume Dispersal the pattern of spacing among individuals within the boundaries of the population Survivorship number of individuals alive at each age 2 Understand that different organisms have differing rates of survival and reproduction 3 Understand that trade offs between different aspects of life history have been important in their evolution 4 Understand that lifespan is subject to natural selection TERMS Mark recapture commonly used in ecology to estimate an animal population
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