IB ESS HL/SL - Topic 2 (Populations, Niches, Tropic Systems, & Succession)

carrying capacity

the largest number of individuals an environment can sustainably support

producer

any autotrophic organism; the base of any trophic system.

autotroph

an organism that makes its own food

heterotroph

an organism that cannot make its own food and obtains energy from other organisms.

primary consumer

any organism that feeds on producers; the second tier of the trophic system

secondary consumer

any organism that feeds on herbivores; the third tier of the trophic system

carnivore

an animal that obtains energy by eating other animals

herbivore

an animal that obtains energy by eating only plants

decomposer

any organism that breaks down and obtains energy from dead organic matter

saprotroph

a decomposer that secretes digestive enzymes and absorbs the products of digestion

detritivore

a decomposer that digests dead organic matter internally

energy (kJ)

what is lost (to the system) along a trophic pyramid

biomass

what decreases along a trophic pyramid

nutrients

what is recycled along a trophic pyramid

population

group of individuals of the same species that live in the same area

primary succession

type of succession that begins on surfaces where no soil exists, such as volcanic rock

secondary succession

type of succession that occurs in an area with existing soil substrate that was only partially destroyed by disturbances, such as a fire.

pioneer species

first species to populate an area during succession

biotic

a living aspect of an environment

abiotic

a non-living aspect of an environment (eg: pH, water, temperature, wind, salinity, etc.)

GPP (gross primary productivity)

the total amount of solar energy that producers in an ecosystem capture via photosynthesis over a given amount of time

NPP (net primary productivity)

the energy captured by producers in an ecosystem minus the energy producers respire

deflected succession

succession that is stopped or interfered with such as by grazing or lawn mowing

niche

an organism's particular role in an ecosystem

symbiosis

any niche relationship in which two species interact closely together

parasitism

a symbiotic relationship where one organism benefits and the other is harmed

mutualism

a symbiotic relationship where both organisms benefit

commensalism

a symbiotic relationship where one organism benefits and the other is unaffected

predation

any interaction (niche) in which one organism kills another for food.

competition

any interaction (niche) involving the struggle between organisms over shared or limited resources

habitat

the biotic and abiotic environmental aspects of where an organism lives

2nd law of thermodynamics

principle which states that energy transfer between organisms increases entropy of the system; the free energy of the system also decreases and is therefore inefficient

1st law of thermodynamics

principle which states that as energy flows through ecosystems, it can be transformed from one form to another but cannot be created or destroyed.

biomagnification

the increase in chemical concentration in animal tissues as the toxin moves up the food chain

bioaccumulation

the increase in chemical concentration in animal tissues of a toxin over the course of an organism's lifetime

photosynthesis

process by which producers obtain energy