BIO 182 Final Exam

• Levels of Ecological Study


  To understand why organisms live where they do and in what numbers, biologists break ecology into several levels of analysis
• Main levels of ecology

  • Organisms
  • Populations
  • Communities
  • Ecosystems
  • Global
• Organismal Ecology


  Study of interaction of an organism with living and non-living elements of its environment
• Organismal ecologists


  • Explore the morphological, physiological, and behavioral adaptations that allow individual organisms to live in a particular area
• American pikas


  • Only live at altitudes higher than 9000 feet in the Sierra Nevada
• Population Ecology


  The study of how and why populations change in size and demography
• Population


  A group of individuals of the same species that live in the same area
• Population ecologists


  • Ask questions about how the numbers of individuals in a population change over time
• Community Ecology


  The study of the nature and consequences of the interactions between species
• Biological community


  Consists of the species that interact with one another within a particular area
• Community ecologists

  • Study predation, parasitism, and competition, and explore how groups of species respond to fires, floods, and other disturbances
• Ecosystem Ecology


  The study of how nutrients and energy move among organisms and between the surrounding atmosphere and soil or water
• Ecosystem


  All living and nonliving components of the environment in a given area at a given time
• Global Ecology


  The study of the effects of human impacts on the biosphere
• Biosphere


  The thin zone surrounding the Earth where all life exists
• Biogeography


  The study of how organisms are distributed geographically
• Abiotic factors

  Non-living components of the environment that affect the distribution of organisms
• Niche


  The set of environmental conditions and resources a species can use
• Biotic factors


  Interactions with other living organisms that affect the distribution of a species
• Biomes


  Regions characterized by distinct abiotic characteristics and dominant vegetation types
• Factors determining biomes


  • Temperature
  • Moisture
  • Sunlight
  • Wind
• Factors governing biome development

  • Average annual temperature and precipitation
  • Annual variation in temperature and precipitation
• Tundra


  Dominated by small woody shrubs, lichens, and herbaceous plants with low plant species diversity, low productivity, and low aboveground biomass. No trees. Found throughout the arctic regions in the Northern Hemisphere. Soils are permafrost, or permanently frozen.
• Boreal Forest (Taiga)

  Coniferous forests. Not diverse (plants or animals). Also called taiga. Forms on subarctic lands just south of the Arctic Circle and is dominated by highly cold-tolerant conifers.
• Temperate Deciduous Forest

  Broad-leaf, deciduous trees. Intermediate species diversity. Compared with grassland climates, precipitation is moderately high and relatively constant throughout the year.
• Temperate Deciduous Forest


  • Seasonal Forests (up through Temperate Deciduous Forests)
• 17% of all trees in the world are found in the Taiga
• Coniferous trees in the Taiga are adapted to survive by having needle-like leaves that reduce water loss and by being able to photosynthesize at low temperatures. They also produce chemicals that deter herbivores.
• Wolverines in the Taiga use a scavenging feeding strategy, feeding on the remains of animals killed by other predators.
• The mass emergence of 17-year cicadas is likely an evolutionary benefit to avoid predation, as the large numbers overwhelm predators.
• Temperate Grassland


  Grasses are the dominant life-form because either conditions are too dry to enable tree growth or encroaching trees are burned out by fires. Often maintained by fire.
• Desert (hot)


  Centered around 30 deg N. and S Latitudes. Surprisingly diverse. Rain sparse, intense.
• Desert (cold)


  Example in U.S. - Great Basin. Lack of plant diversity, much animal diversity, especially rodents. Very dry, undeveloped soils.
• North American Deserts


  • Great Basin Desert - big sagebrush, lacking succulents/cacti

  Mojave Desert - joshua tree

  Sonoran Desert - saguaro

  Chihuahuan Desert - agave lechuguilla. Trees are virtually absent.
• Deserts


  Arid, or dry, receiving <= 25 cm (10 inches) of precipitation/year. Aridity = P/PET, where P = annual precipitation and PET is potential evapotranspiration.
• Chaparral


  Mosaic of shrubs, small trees, open range. Lots of seed-producing plants supports large, diverse bird, mammal, insect populations. Vegetation adapted to withstand fire.
• Savanna


  Grasslands with low-density tree stands. Full of charismatic megafauna.
• Tropical Deciduous Forest


  Lots of rain, but seasonal. Plants drop their leaves in dry season. Very high plant and animal diversity.
• Tropical Evergreen Forest


  Found along the equator. Very wet, continuous rainfall. Extremely diverse (500 tree species/km2).
• Estuary


  Where freshwater streams and ocean meet. Extremely productive biome. Rapidly disappearing.