Population Ecology and the Distribution of Organisms Lauryn Hepp, Sara Flash, Lorrin Johnson, and Tyra Christopherson DON’T FORGET TO SAY CHAPTER 40!

Biological Hierarchy Biosphere = global ecosystem Landscape = mosaic of connected ecosystems Ecosystem = community of organisms in an area & the physical factors Community = group of populations of different species in an area Population = group of individuals of same species in an area Organism -Goes from least exclusive to most exclusive

40.1 Climate influences terrestrial biomes 4 components of climate (abiotic) Temperature Precipitation Sunlight Wind Factors affecting climate Seasons Bodies of water Mountains

40.1 Terrestrial Biomes Biomes = major life zones characterized by vegetation type or physical environment Ecotone = area of intergradation between biomes Types of terrestrial biomes Tropical forest Savanna Desert Chaparral Temperate grassland Northern coniferous forest Temperate broadleaf forest Tundra

40.2 Aquatic Biomes Zonation Types of aquatic biomes Wetlands and estuaries Lakes Streams and rivers Intertidal zones Coral reefs Oceanic pelagic zone Marine benthic zone

40.3 Distribution of Species Dispersal = individuals’ movement away from area of origin or centers of high density Transplants: Potential range vs. actual range Biotic factors Predators, food resources, parasites, etc. Abiotic factors Temperature Water and oxygen Salinity Sunlight Rocks and soil

40.4 Population Density Density = number of individuals per unit area Changes with births/immigration and deaths/emigration

40.4 Population Dispersion Dispersion = pattern of spacing among individuals within a population Clumped Results from environmental conditions, mating behavior, or effective predation/defense Most common Uniform Evenly spaced Often a result of territoriality Random Unpredictable spacing Occurs in absence of strong attractions/repulsions among individuals

40.4 Population Dispersion

40.4 Population Demographics Life tables = age-specific summaries of survival pattern of a population Survivorship curve = plot of the proportion of a cohort still alive at each age Cohort = group of individuals of the same age Type I Large mammals w/ few offspring but provide good care Type II Some rodents, invertebrates, lizards, and annual plants Type III Organisms w/ large numbers of offspring but provide little/no care Long-lived plants, fish, most marine invertebrates

40.5 Models of Population Growth r = b - m b = annual per capita birth rate m= Annual per capita death rate r= indicates whether a population is growing or declining r > 0 - Population is increasing, r < 0 - population is declining Exponential Growth Happens under ideal conditions (ex. Abundant food source)

40.5 Models of Population Growth Carrying Capacity The max population size the environment can sustain (denoted by K) Limiting factors Energy Shelter Refuge from predators Logistic Growth Model Takes into account carrying capacity Produces an S-shaped curve Nutrient availability Water Suitable nesting sites

40.6 Influences on Population Dynamics Density independent vs. Density dependent Density independent - A birth or death rate that does not change w/ population density. (similar to r - selection) Drought Density dependent - death rate that rises and birth rate that falls with rising density. (similar to K - selection) Toxic Wastes Disease Predation Competition for Resources Territoriality Intrinsic Factors

40.6 Influences on Population Dynamics Population Dynamics = population fluctuations In addition to births and deaths, immigration and emigration are influences Metapopulation - a group of populations linked by immigration and emigration