Notes: Ecology
Guiding Questions:
- What determines how many species live in a given place?
- What determines how large each population can grow?
- What is the relationship between sea otters, sea urchins and kelp forests?
ECOLOGY - the study of interactions among organisms with each other and with environment
BIOSPHERE - portion of planet where life exists
LEVELS OF ORGANIZATION
Species - individuals that can breed with one another
Population - all the individuals of the same species (ducks) in an area
Community - all the different species in an area (ducks + maple trees + dragonflies)
Ecosystem - the community plus the physical factors in an area (ducks + maple trees + dragonflies + temperature + soil + rainfall)
Biome - large area that has a particular climate, and particular species of plants and animals that live there (tundra)
Biosphere - the part of the earth that supports life
Ecological methods - how do we study it?
Observing
Experimenting
Modeling
Energy Flow
Autotrophs (producers) - capture energy from environment and convert it into "food"
Heterotrophs (consumers) - must eat things
Herbivores
Carnivores
Omnivores
Detritivores / Decomposers
*SUNLIGHT is the main source of energy*
Photosynthesis - uses light energy to make "food"
Chemosynthesis - makes food from chemicals (some bacteria synthesize food in this way)
FOOD CHAINS AND FOOD WEBS - illustrate the flow of energy in an ecosystem
*Note the direction of the arrows,
they indicate where the energy is going when one organism consumes another.
*Each step in a chain or web is called a TROPHIC LEVEL
Identify the primary, secondary and tertiary consumers on the food web.
Ecological Pyramids
Energy Pyramid
Pyramid of Numbers and Pyramid of Biomass
Consider the kelp forest ecosystem to answer these questions.
What determines how many species live in a given place?
And, what determines how large each population can grow?
Biogeochemical Cycles
(biology + geology + chemical)
matter is not used up, it is transformed, the same molecules are passed around (see images in your book)
Water Cycle
ground water
transpiration (from plants)
evaporation (from bodies of water)
precipitation (from clouds)
Nutrient Cycles
nutrients = all the chemical substances
needed to maintain life
body's chemical building blocks
carbon, nitrogen phosphorous
Carbon Cycle
Respiration (breathing of animals)
Combustion (burning)
Photosynthesis (uses CO2 and converts to oxygen)
Nitrogen Cycle
Nitrogen is a fertilizer for plants
78% of the air is made of nitrogen
Nitrogen Fixation - Bacteria take nitrogen from the air and convert to a form used by plants
Phosphorous Cycle
Part of DNA
Stays mostly in land and rock (not the atmosphere)
NUTRIENT LIMITATION
Primary Productivity - rate at which matter is created by producers
Lots of plants = high productivity
Limiting Nutrient - what limits the amount of productivity (water, light, nitrogen)
Fertilizer adds nitrogen to increase growth
Nitrogen enters water systems --> causes algal blooms
Ecology Activities
Interpeting a Food Web and Trophic Levels
Forest Food Web Label | Prairie Food Web Label II
What Causes Algae Growth in Ponds
Analyze Data and Create a Climate Graph
Exploring Range of Tolerance in Steelhead Trout