Ecology

Environmental Factors: Biotic vs. Abiotic

Living Things (organisms) are Nonliving things are Biotic factors Abiotic factors

Levels of OrganizationAtom (smallest unit of matter) Molecule (2 or more atoms put together) Organelle (cell structure made of organic molecules) Cell (smallest unit of life) Tissue (a group of cells working together) Organ (a group of tissues working together for a

common function) Organ System (a group of organs working together

for a common function) Organism (a independently functioning living thing)

Levels of OrganizationOrganism Population (a group of 1 species of organism) Community (a group of 2 or more species of

organisms) Ecosystem (a community + abiotic factors) Biome (a major group of similar ecosystems) Biosphere (all of the areas of Earth that contain life)

Trophic levelsProducer Primary Secondary Tertiary

Consumer Consumer Consumer

Food Web = ALL food chains in an ecosystem

Trophic Levels

10% of energy is available to be TRANSFERRED to the NEXT trophic level. The rest is USED by the organism OR given off as HEAT.

ENERGY Pyramid (Joules or Calories)

Ecological Pyramids

BIOMASS Pyramid (Kilograms)

NUMBERS Pyramid (# of organisms in population)

Niche = Job or Role in the ecosystem/habitat

Trying to get the same RESOURCE in the same PLACE at the same TIME is called COMPETITION.

Competitive Exclusion Principle = No 2 species can have the SAME EXACT NICHE.

Competitive Exclusion Principle

Symbiosis = 2 different SPECIES in a close relationship3 Types = Parasitism, Commensalism, & Mutualism

Organism 1 Organism 2Parasitism Commensalism

Mutualism

Symbiosis

+/-

+/0

+/+

Shark & Remora

Predator/Prey RelationshipWhen PREY population

increases in number, more PREDATORS are

able to survive and reproduce. This causes more prey to be eaten

and the PREY population will

DECREASE. The predator population will

then DECREASE because of a food

shortage.

Population Growth: Exponential Growth Rate

EXPONENTIAL growth = CONSTANT growth rate

Does NOT occur in NATURAL POPULATIONS

because of LIMITED resources.

Population Growth: Logistic Growth Rate

LOGISTIC growth = experiences a period of EXPONENTIAL

growth followed by a period of slowing down as the population

reaches the CARRYING CAPACITY.

Carrying capacity = MAXIMUM number of individuals that can be SUPPORTED by an ecosystem due to LIMITED RESOURCES.

Carrying capacity = 0 growth rate (horizontal line)

LOGISTICEXPONENTIAL

Limiting Factor = anything that limits POPULATION GROWTH

Density Dependent Limiting Factor = resources or issues that are only a problem when there is OVERCROWDING. Examples = FOOD, WATER, MATES, DISEASE, PREDATION

Density Independent Limiting Factor = any issue that affects ALL populations regardless of population SIZE. Examples = HUMAN ACTIVITIES & NATURAL DISASTERS

Ecological Succession = life cycle of an ECOSYSTEM (how it changes in response to disturbances)

Primary Succession = starts on BARE ROCK (NO SOIL) because of GLACIERS MOVING or VOLCANIC ERUPTIONS; takes longer; pioneer species = LICHEN, MOSS, ALGAE

Secondary Succession = starts on BARE SOIL (NO PLANTS) because of AGRICULTURE or NATURAL DISASTER (FIRE)

Climax community = STABLE mature ecosystem