Ecology: Distribution and Adaptation of Organisms

Topics

Reminders

• Text; Campbell chp 46, pp 1052-1080
• Examine study outline on pp 1080-1081, Study questions on 1081-1082

1. Introduction

• Ecology
  • the scientific study of the interaction between organism and their environment
  • very difficult to examine ecological questions
  • multidisplinary, ecology includes geology, chemistry, physics plus all the biological disciplines, physiology, genetics, morphology
• Environment
  • abiotic factors, light, water, temperature and nutrients
  • biotic factors, other organisms such as predators, prey, safety
• Interactions of environment and organisms

2. Scope of Ecology

• The study of the distribution and abundance of organisms
• Levels of organization for ecological studies
  • organismal ecology, an organism's limitof
  • tolerance for environmental stress
  • population ecology, factors which affect size and composition of population
• community ecology, interactions of populations within a particular area
• ecosystem ecology, includes the community and all abiotic factors
• evolution

3. Biosphere

• What is a Biosphere?
  • sum of all the planet's communities and ecosystems
  • includes all seas, lakes, rivers and streams
  • includes a few meters of all soil
  • includes a few kilometers of atmosphere

4. Environmental Diversity of the Biosphere

• Climate and the Distribution of Biomes
  • The prevailing weather condition at a ocality
• Global Climate Patterns
  • - solar input
  • - planet movement in space
• Local and Seasonal Effects on Climate
  • ocean currents
  • large bodies of water
  • mountains
  • seasons
  • microclimate

5. Terrestrial Biomes

• Tropical Forests - found near the equator, average temperature 23oC (75oF) and daylight is 12 hrs
  • rainfall is variable
  • tropical thorn forests
    tropical deciduous forests
    tropical rain forests
  • great diversity of species
    • typical 4 sq mi of Brazil rainforest:
      • 750 species of trees
      • 125 mammals
      • 400 birds
      • 100 reptiles
      • 60 amphibians
  • one tree may contain 400 species of insects
  • the loss of the Amazon rain forest would result in the extinction of one millionspecies of plants and animals
  • animals are tree-dwellers: monkeys, snakes,bats, birds, insects and amphibians
  • plants are very dependent on animals for dispersal of seeds and fruits
• Savanna
  • - grasslands with scattered trees in tropical and subtropical regions with three distinct seasons:
    • cool and dry
      hot and dry
      warm and wet
  • - high or low-growing grasses and forbs
  • - worlds largest herbivores: giraffes, zebra, antelopes, elephants, kangaroo
  • - can form a narrow band between forests and grasslands
  • - wind and insect pollination common
• Desert - characterize by very low precipitation (<30cm)
  • - hot desert, southwest USA-
    - cold desert, central Asia and eastern Argentina
• Chapparal
  • coastline of California, Mediterranean, Chilisouthwestern Africa and Australia
  • mild rainy winters and long hot dry summers
• Temperate Grassland
  • prairies of the US, midwest
  • - buffalos
  • - wind pollination
• Temperate Deciduous Forest
  • - eastern US, middle Europe, and eastern Asia
  • - characterized by warm summers and cold winters, temperature range -30oC to 30oC
• Taiga
  • - coniferous or boreal forests, domination by one or a few species of spruce, pine, fir, hemlock, redwood
• Tundra
  • - northernmost limits of plant growth
  • - many migratory birds nest in this area

6. Freshwater Biomes

• Ponds and Lakes
  • - standing bodies of fresh water
  • - thermocline
  • - oligotrophic and eutrophic
• Streams and Rivers
  • - bodies of water moving continously in one direction
  • - headwaters and mouth

7. Marine Biomes

• Estuaries
  • - fresh water streams and rivers merge with ocean
  • - blue crabs and oysters- Chesapeake Bay, Delaware Bay, San Francisco Bay, Galveston Bay
• The Intertidal Zones
  • - between low and high tides
• Coral Reefs
  • warm tropical waters
  • - clear water
• The Oceanic Pelagic Biome
  • - plankton, zooplankton and phytoplankton
  • - nekton, animals moving independently of the ocean currents to find food
• Benthos
  • - below the neritic and pelagic zones

8. Responces of Organisms to Environmental Variation

• Homeostasis
  • regulators
  • conformers