Chapter 3. The Biosphere. Section 3-1: What is Ecology?. Ecology - Study of interactions among organisms, between organisms, and their surroundings. The environment contains two factors: Biotic Factors: all of the living things Abiotic Factors : all of the nonliving items.
Ecology - Study of interactions among organisms, between organisms, and their surroundings.
The environment contains two factors:
What is the biosphere?
1. Part of earth where all life exists
2. It’s range is 11 km(6.83 mi) below the surface ocean to 8 km(4.97 mi) above the surface of the ocean.
What are the levels of organization?
2. Population - groups of organisms of same species living in same area
3. Community - groups of different populations living in same area
4. Ecosystem - all organisms that live in same area along with environment
5. Biome - group of ecosystems with same climate & similar dominant communities
6. Biosphere - highest level of organization; where all life exists
What are the methods used to study ecology?
A. Setting up an artificial environment in the lab
B. Conducted within the natural environment
A. Often based on mathematical formulas based on data collection.
B. Models are used to make predictions
What are primary producers/autotrophs?
Organisms that make their own food from sun/inorganic chemicals
They produce their food in two possible ways:
6CO2 + 6H2O → C6H12O6 + 6O2
What are consumers/heterotrophs?
Organisms that can’t make their own food; they have to eat other organism for food/energy.
There are five types of consumers:
1. Herbivores – only eat plants
2. Carnivores – eat animals/meat
3. Omnivores – eat both plants & animals
4. Decomposers – break down dead/organic matter; recycle nutrients (bacteria, fungus)
5. Detritivores- eat decaying stuff (worms)
How does energy flow in an ecosystem?
It flows in one direction, from the sun to producers, and then to the consumers and decomposers.
What is a food chain?
A simple series of who eats who.
What is a food web?
A complex interaction of all of the food chains in an ecosystem.
What is a trophic level?
1. One step in the food chain or the food web.
2. Producers always occupy the first trophic level.
3. Consumers occupy every level after the first.
4. Primary consumers are always herbivores.
What is an ecological pyramid?
It is a model to show the amount of energy or matter in each trophic level.
There are three types of ecological pyramids:
The pyramid shape implies that there is less at each successive level.
What is an energy pyramid?
What is a biomass pyramid?
What is a pyramid of numbers?
Key idea: Matter is recycled within an ecosystem & between different ecosystems.
Recycling in the biosphere is done through the biogeochemical cycles.
Types of biogeochemical cycles:
A. Carbon Cycle
B. Nitrogen Cycle
C. Phosphorus Cycle
Section 3-4: Cycles of Matter
CO2 in the air
CO2 in ocean
N2 in air
NO3- & NO2-
Nitrogen Fixation – some bacteria turn N2 into the useable forms of NO3- & NO2-.
Denitrification – some bacteria convert nitrates into N2.
What is primary productivity?
The rate at which producers create organic matter.
What controls primary productivity?
Availability of nutrients. This is why fertilizer is added by farmers to their fields.
What is a limiting nutrient?
A single nutrient that is scarce or slowly cycled through the ecosystem. For most land ecosystems, the limiting nutrient is nitrogen (N is required for protein production).
What is an algal bloom?