Download Ecosystem

Chapter 16 notes- Ecosystem
What is an ecosystem?
All of earth’s inhabitants are interwoven in a complex web of relationships.
Ecology explains how living organisms affect each other and the world they live in by studying the interactions
taking place between the organisms and their environment.
An ecosystem consists of a community (organisms) and the physical aspects (environment) of its habitat.
Habitat versus Niche- Habitat is the place where an organism lives and a niche is an organism’s total way of life
Examples:
The nonliving parts of the environment are known as abiotic factors
Examples:
The living pasts of the environment are known as biotic factors
Examples:
Diverse communities in Ecosystems
Biodiversity is the measure of the living species living within an ecosystem
Some of the species living within an ecosystem are more obvious- for example deer, trees, and bunny rabbits.
Others are less obvious, worms in the ground, fungi growing on the trees, bacteria in the soil.
The boundaries of an ecosystem are not always clearly defined and are almost never totally isolated.
organisms can migrate into and out of ecosystems.
Individual
Change in ecosystems over time
Examples of newly formed habitats:
The first organisms to live in a new habitat are known as pioneer species.
These are typically going to be small,
fast-growing plants that make the ground hospitable for other species; many times these species are overtaken by
the plant immigrants that start inhabiting the habitat as time goes by.
This progression of the replacement of species over time is known as succession.
Energy Flow in ecosystems
Ecologists study how energy moves through an ecosystem by assigning organisms in that ecosystem to a specific
level or trophic level based on the organisms source of energy
Energy flow in ecosystems originally comes from the sun
Energy flows through ecosystems from producers (make food) to various levels of consumers (use food by eating
producers or other consumers)
Primary producers are autotrophs (self feeding) which means they make their own food by converting sunlight or
chemicals to chemical energy
Niche of a producer: captures energy and transforms into chemical energy, photoautotroph (plants) use
light energy and chemoautotroph (cyanobacteria) use chemical energy
Consumers are heterotrophs that eat other organisms to obtain energy
Herbivores- eat only plants (cows)
Carnivores- eat only other animals (tigers)
Omnivores- eat both plants and animals (humans)
Detritivores- feed on dead plan and animal remains (buzzards)
Decomposers- cause decay (bacteria and fungi)
The energy flowing through and ecosystem can be charted in one of two ways
1) food chain- simple path through the ecosystem
2) food web- an interconnected group of food chains which provides a more realistic energy pathway
Food chain: sun, plant, animal, animal
Food web: (arrows go towards organism that is eating the other organism)
During every transfer of energy within an ecosystem, energy is lost as heat energy.
Therefore, the amount of
useful energy decreases with every increase in trophic level.
-
only 10% of the energy is transferred to the next trophic level, meaning 90% is lost between trophic
levels
-
Energy pyramid shows the flow of energy by representing each trophic level with blocks, producers
making up the bottom of the pyramid and the top carnivore making up the top.
-
Biomass is the dry weight of tissue and other organic matter found in a specific ecosystem which can
also be represented by a pyramid.
Each level on the pyramid contains only 10 percent of the
biomass of the trophic level below it.
Water cycle:
Carbon Cycle:
Nitrogen Cycle: