Midterm 1

• What is ecology?


  Ecology is the scientific study of the interactions among organisms and their environment
• The hierarchy of organization in ecological systems:

  Individual, population, community, ecosystem and biosphere
• Individual - a living being, the most fundamental unit of ecology
• Every individual:

  • Every individual acquires nutrient and energy from the environment.
  • Every individual has membrane across which it exchanges energy and materials with its environment: heat/water balance and diffusion of gases
• Population - individuals of the same species living in a particular area
• Examples of population:

  • Catfish in a pond
  • Tubeworms in a hydrothermal vent
• Natural boundary population - population of mussels in a lake
• Political boundary population - population of red squirrels in Alberta
• Populations have five distinct properties that are no exhibited by individuals: geographic range/distribution, abundance, density, change in size, composition
• Geographic range/distribution - extent of land or water within which a population lives, example: range go grizzly bear in western Canada and Alaska
• Abundance - total number of individuals
• Density - number of individuals per unit area
• Change in size - increase or decrease in number of individuals in an area over time
• Composition - make up of the population in terms of gender, age, genetics
• Community - all populations of species living together in a particular area
• A community may cover large areas (forest, lake) or small enclosed area (microbial populations in the gut)
• Populations interact within a community; predator/prey relationship and symbiotic associations
• Ecosystem - one or more communities of living organisms interacting with their nonliving physical and chemical environment
• Abiotic components includes: air, water, temperature, sunlight, nutrient, etc
• The ecosystem focuses on movement of energy and matter between biotic and abiotic environment components; energy input - sunlight and energy escapes as radiated heat
• Biosphere - all the ecosystem on Earth
• Distinct ecosystems are linked together by exchange of: energy, nutrients (wind, water, movement of organism)
• All transformations of the biosphere are internal and the movement of materials connects aquatic and terrestrial ecosystems
• Energy enters from the sun and the energy is lost as heat via radiation
• Morphology - studies of size, shape and structure (unique)
• Physiology - function of organ and organ systems
• Behaviour that enable it to survive in its environment is an individual approach
• Why are tress in tropical environment whereas shrubs with small, tough leaves are dominant in temperate climate?

  Tropic grassland has thin soil, thin organic layer and grassland has thick soil and thick organic layer
• Adaptation - a characteristic of an organism that makes it well suited to its environment
• Example of adaptation; desert animals have enhanced kidney function to help conserve water and cryptic coloration of animals help to avoid predation
• Population approach - emphasizes variation over time and space in the: number/abundance/size, density and composition of individual
• In population approach, composition of individuals include: sex ratios, distribution and genetic make up
• In population approach,

  • the changes in number or density of individuals can reflect; balance of birth and deaths and immigration and emigration of individuals
  • carrying capacity
• Community approach - shows diversity and relative abundance of different kinds of organisms living together in the same place
• Ecosystem approach - the storage and transfer of energy and matter
• Biosphere approach - involves movement of matter (air & water), energy and nutrients
• What is a producer?

  An organism that uses photosynthesis to convert solar energy into organic compounds or chemosynthesis to convert chemical energy into organic compounds
• What is a consumer?

  an organism that obtains its energy from other organisms (heterotroph)
• What is a mixotroph?

  An organism that obtains its energy from more than one source and it combines photosynthesis and heterotrophic nutrition; eg: anabaena sp, carnivorous plants
• What is a predator?

  An organism that kills and partially or entirely consumes another individual (prey)