Chapter 14: Population Ecology p. 648 14.1: Characteristics of Population Organization of Life: 1 Cells 2 Compounds Elements Atoms Organisms 3 Organs systems Organs Tissues Cells Biosphere Ecosystem Community Populations Organisms Ecosystem: interactions between the biotic and abiotic factors Biotic: Living other species Abiotic: Non-living, H2O O2, soil Habitat: the place where an organism or species normally lives (abiotic) Niche: the role an organism plays within its habitat (biotic). Classification: Binomial Nomenclature Human – Homo ↓ Genus Sapiens ↓ Species Kingdom: Phylum: Class: Order: Family: Genus: Species: Animalia Chordata Mammalian Primates Hominidae Homo Sapiens Species: organisms that resemble one another in appearance, behaviour, chemistry, and genetic make up, and that interbreed or have the ability to interbreed, with each other under natural conditions to produce fertile offspring. Population Size: is the number of individuals in a given area. Population Density: the number of given species per unit area. Calculated: Density = Number of individuals Square area D = 480 moose 600 ha = 0.80 moose/ha Population Dispersion - the general pattern in which individuals are distributed through a specific area. 3 Types…. 1. Clump dispersion: the pattern in which individuals in a population are more concentrated in certain parts of a habitat. 2. Uniform dispersion: the pattern in which individuals are equally spaced throughout a habitat. 3. Random dispersion: the pattern in which individuals are spread throughout a habitat in an unpredictable and pattern less manner. Figure 3: a) A clumped pattern of dispersion is evident in fish that live is social groups. b) A random pattern of dispersion, seen here in an Australian rainforest, is rare in nature. This pattern serves as a yardstick for evaluating other dispersion patterns. C) A nearly uniform pattern is demonstrated by creosote bushes near Death Valley, Cailfornia. Measuring Population Characteristics Populations are dynamic and their numbers and geographic locations change over time, generally making a precise count impractical. To over come this biologists sample the population. They count a sample population at a particular time, than estimate a total size. Biologists use a variety of sample techniques to estimate the size and density of a population. a) Quadrat is a common technique for calculating a population for small or stationary organisms. Average estimates of population size and density for the entire area can be extrapolated based on these calculations. b) Mark – Recapture: sampling technique for estimating population size and density by comparing the proportion of marked and unmarked animals captured in a given area: sometimes called ‘captured – recaptured’. Mark – Recapture is common technique for estimating the size and density of mobile wildlife populations. The proportion of marked animals to unmarked animals provides a basis for estimating the size of the entire population. Mark – recapture depends on the following assumptions: - every organism in a population has an equal opportunity of being captured - during the time period between the initial marking and the subsequent recapture, the proportion of marked to unmarked animals remains constant. - The population size does not increase or decrease during the sampling study. Estimating Population Size and Density 1. A biology students want to estimate the size of the slug population on a gulf course, biology students randomly selected five 1.0 m2 quadrat in a 10 X 10 m site. The numbers of slugs in each quadrat were 4, 8, 9, 5, and 1. Estimate the population density and size of slugs in this study site. 2. In a river in British Columbia, 430 sockeye salmon were captured and marked on the fin with a uniquely numbered T-bar anchor tag. Two weeks later, a total of 154 sockeye salmon were recaptured and 15 bore the tags on their fins. a) Estimate the sockeye salmon population in this river during this study. b) Identify conditions that must be met in this study to obtain a valid estimate.