ecological succession

ecological succession

process of gradual and predictable changes in the composition and structure of an ecological community over time

pioneer species (definition)

first to colonize an area with no soil

primary succession (definition)

occurs and area where NO previous community or SOIL exists

primary succession (examples)

newly found volcanic islands, glacier retreats, bare rock surfaces

secondary succession (definition)

occurs in an area that HAS been previously inhabited by a community or had SOIL, but has experienced a disturbance.

secondary succession (examples)

fire, logging, natural disaster that clears existing vegetation

Gross Primary Production, GPP (definition)

the total energy fixed by a plant during photosynthesis

Gross Primary Production, GPP (equation)

= energy production per unit area / units of time

Net Primary Production, NPP (definition)

represents the amount of stored chemical energy that will be available to consumers in an ecosystem

Net Primary Production, NPP (equation)

= GPP - R x (loss of energy through respiration)

Biomass

the collective amount of this of a living matter in a given place or time.

High biomass equals

high NPP

Low biomass equals

low NPP

Ecosystem productivity

the rate of production of biomass for an ecosystem

Ecological efficiency

the amount of energy transfer between trophic levels to the next (10% rule)

Incomplete consumption (definition)

predators don’t consume the entire prey, which contain energy that is not transferred to the next level

Incomplete consumption (example)

not eating the bones or shell of an animal

Energy lost through excretion

animals dispose of waste materials

Indigestible matter (definition)

some parts of the organism are difficult to digest and provide little energy to the consumer

Indigestible matter (examples)

cellulose in plants or chitin in arthropods

pyramid of energy (definition)

shows the amount of energy available at each trophic level and the decrease in energy as it moves up the food chain

pyramid of energy (photo)

pyramid of biomass (definition)

shows the amount of biomass available at each trophic level and the decrease in biomass as it moves up the food chain

pyramid of biomass (photo)

pyramid of numbers (definition)

represents the number of individual organisms at each trophic level in an ecosystem

pyramid of numbers (photo)

how to make pyramid of energy

upright, with each successive trophic level representing a smaller amount of energy compared to the one below it

how to make pyramid of biomass

typically upright, with each higher trophic level having less biomass than the one below it

how to make pyramid of numbers

in some cases, this pyramid may be upright, with each higher trophic level having fewer individuals than the trophic level below it. In others, the pyramid can be inverted.

why are some pyramid of numbers inverted?

this can occur when there is a large number of small primary producers supporting a smaller number of larger consumers

primary succession process

pioneer species → more complex plants, soil forms → climax community, nutrient rich soil

primary succession pioneer species

lichens and mosses

primary succession complex plants

grass and shrubs

primary succession climax community

larger, diverse plants (trees)

which succession reaches climax community faster?

secondary succession

secondary succession process

soil still present, regeneration of species from seeds → early successional species, fast-growing and opportunistic species → climax community, nutrient rich soil