Chapter 3 (Ecology)
Transcript of Chapter 3 (Ecology)
Ecology
Chapter 3: The Biosphere
What is Ecology?
• Ecology – the study of interactions among organisms and between organisms and their environment
• Levels of Organization– Biosphere – the largest of the areas of the
earth containing the portion of the planet that life exists, including land, water and air (atmosphere)
Levels of Organization
Levels of Organization• Individual – similar organism (can mate)• Population – group of individuals that live in the
same area• Community – populations that live together is a
defined area• Ecosystem – all the organisms that live in a
similar area along with the nonliving material• Biome – group of ecosystems (similar climate)• Biosphere – entire earth
Ecological Methods• Scientists use 3 basic methods to conduct
ecological research– Observing – qualitative and quantitative
observations– Experimenting – used to test hypotheses, can
set up artificial environments and manipulate conditions
– Modeling – models are made to study events that have occurred over large time periods, or are large in scale
Interactions Among Organisms
• Sunlight is the main energy source for life on Earth
• Producers – autotrophs (make their own energy (using the sun)–Photosynthesis – using light to
produce energy / food–Chemosynthesis – using inorganic
molecules to produce energy / food
Interactions (continued)
• Consumers – heterotrophs (cannot make their own energy)–Herbivores – consume plants–Carnivores - consume meat–Omnivores – consume both–Detritovores – dead or decaying matter
(earthworms, mites, crabs (animals)–Decomposers – dead or decaying
matter (bacteria & fungus)
Energy Transfer / Feeding Relationships
• Food Chain / Food Web – series of steps of energy transfer (web = connected food chains)
• Trophic Levels – each step in a food chain
Ecological Pyramids
• Diagram that shows relative amounts of energy or matter contained within each trophic level in a food chain or food web.
• Energy Pyramid – energy available at each trophic level (10% rule)
• Biomass Pyramid – amount of living tissue
• Pyramid of Numbers - # of individuals
Examples of Pyramids
Biogeochemical Cycles
• Water Cycle– Evaporation, precipitation, condensation,
transpiration, run-off, ground water
Biogeochemical Cycles• Carbon Cycle –
carbon fixation, CO2• Photosynthesis,
respiration• Fossil fuels• Human Activites
– Mining, cutting forests, burning fossil fuels
Biogeochemical Cycles• Nitrogen cycle – nitrogen fixation
(bacteria), denitrification
Nutrient Limitation
• Primary Productivity – rate of production of organic matter by producers
• Limiting Nutrients – nutrient that limits productivity
• Aquatic ecosystems – large input of limiting nutrient can cause an increase of algae or producers = algal bloom