AP Bio Unit 8

Primary production

The total amount of light energy converted into chemical energy by primary producers; this is gross primary production (GPP).

Gross primary production (GPP)

The total primary production: the amount of light energy converted into chemical energy.

Net primary production (NPP)

The energy remaining after primary producers use some energy for respiration; NPP = GPP − R.

Respiration (R)

Energy used by primary producers for cellular respiration; subtracting it from GPP gives NPP.

Primary production units

Primary production can be expressed as energy per unit area per unit time or as biomass of vegetation added per unit area per unit time.

Limiting factors of primary production

On large geographic scales, temperature and moisture are key controls; locally, mineral nutrients in soil can limit production.

Secondary production

The amount of chemical energy in consumers' food that is converted into their own new biomass during a given time period.

Energy transfer efficiency

The fraction of energy transferred from one trophic level to the next; the slides state it is usually less than 20%.

Autotroph

An organism that produces organic energy-rich compounds; the slides identify plants as primary producers and describe photosynthesis and chemosynthesis as ways autotrophs obtain energy.

Photosynthesis

The process by which light energy from the sun is converted into chemical energy; the slides connect it to primary productivity.

Chemosynthesis

A process in which organisms make energy from small inorganic molecules in their environment; oxygen is not required according to the slides.

Heterotroph

An organism that derives energy by breaking down carbohydrates, lipids, and proteins obtained by consuming autotrophs or other heterotrophs.

Pyramid of production

A representation of the multiplicative loss of energy along a food chain; also associated with the 10% law.

10% law

The approximate rule that only about 10% of energy is transferred from one trophic level to the next, illustrating major energy loss along food chains.

Pyramid of biomass

A representation of the biomass at different trophic levels; it generally narrows toward top-level carnivores because energy transfer is inefficient.

Pyramid of numbers

A representation showing the number of individuals present at each trophic level.

Short turnover time

A rapid rate of growth, reproduction, and consumption; phytoplankton have a short turnover time, which can produce an upside-down biomass pyramid.

Metabolic rate

In the slide's context, the amount of oxygen consumed for cellular reproduction/secondary production.

Endotherm

An organism that uses internally generated heat to maintain body temperature; body temperature tends to remain steady despite environmental temperature changes.

Ectotherm

An organism that depends mainly on external heat sources and regulates temperature largely through behavior; body temperature changes with environmental temperature.

Endothermy vs. ectothermy

Endotherms generally tolerate a smaller range of internal temperatures and are active across a greater range of external temperatures; endothermy is more energetically expensive.

Ectothermic adaptation

A physiological or behavioral adjustment used by ectotherms to regulate body temperature, such as moving into sun/shade, shivering to increase heat production, or crowding with others.

Parthenogenesis

A form of asexual reproduction in which an egg develops into a new individual without fertilization.

Ecosystem

All organisms living in a community plus the abiotic factors with which they interact; ecosystem dynamics involve energy flow and chemical cycling.

Trophic level

A feeding position in an ecosystem's food relationships, beginning with producers and continuing through consumers.

Primary producer

An autotroph that forms the starting trophic level by producing organic energy-rich compounds.

Consumer

A heterotroph that obtains energy by consuming organisms or their organic matter.

Primary consumer

A consumer that feeds at the first consumer level, typically by consuming producers.

Secondary consumer

A consumer that feeds on primary consumers.

Tertiary consumer

A consumer that feeds at a higher trophic level, commonly on secondary consumers.

Detritivore

A heterotroph that consumes dead organic material; the slides group detritivores with decomposers.

Decomposer

An organism that breaks down organic material; the slides identify decomposers as a type of heterotroph/detritivore.

Carnivore

A consumer that eats animals.

Omnivore

A consumer that eats both plant and animal food.

Herbivore

An animal that eats plants.

Scavenger

A consumer that feeds on dead organisms.

Biogeochemical cycle

A nutrient circuit involving both biotic and abiotic components of ecosystems.

Energy flow vs. nutrient cycling

Energy does not cycle through ecosystems and is lost at each trophic level, so constant input is required; nutrients cycle through ecosystems.

Nitrogen cycle

The cycling of nitrogen among the atmosphere, soil, organisms, and other ecosystem reservoirs through processes such as fixation, assimilation, ammonification, nitrification, and denitrification.

Nitrogen fixation

Conversion of atmospheric N₂ into ammonia (NH₃) or other usable nitrogen forms by nitrogen-fixing bacteria.

Ammonification

Conversion of organic molecules into ammonium (NH₄⁺) by decomposers.

Nitrification

Conversion of ammonium (NH₄⁺) to nitrite (NO₂⁻) and then nitrate (NO₃⁻) by nitrifying bacteria.

Assimilation

Uptake of nitrate (NO₃⁻) or ammonium (NH₄⁺) and incorporation into organic molecules by organisms in the food web.

Denitrification

Conversion of nitrate (NO₃⁻) back to atmospheric N₂ by denitrifying bacteria.

Nitrogen-fixing bacteria

Prokaryotes that convert atmospheric nitrogen gas into usable nitrogen compounds.

Nitrifying bacteria

Aerobic bacteria that oxidize ammonium into nitrate through nitrification.

Denitrifying bacteria

Bacteria that use oxygen from nitrate and release N₂ back into the atmosphere.

Carbon cycle

The cycling of carbon atoms through Earth's biosphere and organisms; photosynthesis, cellular respiration, combustion, and decomposition move carbon among reservoirs.

Photosynthesis in the carbon cycle

A process that moves CO₂ into the biosphere by incorporating carbon into organic compounds.

Cellular respiration in the carbon cycle

A process that moves CO₂ out of the biosphere.

Combustion

Burning, including burning fossil fuels, that moves carbon into the atmosphere.

Decomposition in the carbon cycle

Breakdown of biomass that returns carbon to the soil according to the slides.

Phosphorus cycle

The cycling of phosphorus through reservoirs such as rocks, living things, and oceans; processes include weathering, consumption, decomposition, and sedimentation.

Phosphate (PO₄³⁻)

The most important inorganic form of phosphorus; it is taken up by producers.

Phosphorus importance

Phosphorus is found in essential molecules including ATP, GTP, DNA, RNA, and phospholipids.

Weathering

A process that releases phosphate from rocks into soil and groundwater.

Hydrologic (water) cycle

The cycling of water among reservoirs such as oceans, surface water, atmosphere, and living organisms.

Evaporation

Creation of water vapor by heating.

Condensation

Cooling of water vapor into water droplets, such as in clouds.

Precipitation

Water falling as rain, sleet, ice, snow, or similar forms.

Transpiration

Release of water by plants.

Cultural eutrophication

Human-caused disruption of freshwater ecosystems caused by nutrient enrichment, especially nitrogen and phosphorus.

Eutrophication

Nutrient enrichment of aquatic systems that can cause an algal bloom, reduce available oxygen, and kill aquatic animals.

Algal bloom

An explosive increase in algae caused by excess nutrients entering an aquatic system.

Biological magnification

Increase in toxin concentration at successive trophic levels of a food web.

Toxic chemicals in ecosystems

Human-produced substances that can accumulate in the fatty tissues of animals and become more concentrated through biological magnification.

DDT

A pesticide used historically that demonstrated biological magnification; the slides note it was later banned.

Greenhouse effect

The phenomenon in which greenhouse gases cause Earth to retain some energy that would otherwise escape the atmosphere.

Greenhouse gases

Atmospheric gases that retain some of Earth's outgoing energy; the slides specifically identify CO₂ as one greenhouse gas.

Global warming

A rise in Earth's average temperature associated in the slides with increasing atmospheric CO₂.

Community

An assemblage of species living close enough together for potential interaction.

Species richness

The total number of species in a community.

Relative abundance

The proportions/numbers of individuals belonging to the different species in a community.

Species diversity

Biodiversity determined by both species richness and relative abundance.

Competition

An interaction in which organisms compete for resources; interspecific competition occurs between species when resources are limited.

Interspecific competition

Competition between different species for limited resources.

Competitive exclusion principle

Two species with similar needs for the same limiting resources cannot coexist in the same place; equivalently, two species cannot coexist if their niches are identical.

Ecological niche

The total use of abiotic and biotic resources by an organism; it describes the organism's role in its environment.

Fundamental niche

The potential niche of a species in the absence of limiting interspecific competition; the slides contrast it with the realized niche.

Realized niche

The niche actually occupied by a species after effects such as interspecific competition; competition can make it smaller than the fundamental niche.

Resource partitioning

Differentiation of niches that enables similar species to coexist in a community.

Predation

An interaction in which a predator eats prey.

Predator

An organism that eats another organism, its prey.

Prey

An organism that is eaten by a predator.

Predator adaptations

Traits such as claws, teeth, fangs, poison, heat-sensing organs, speed, or agility that help predators capture prey.

Prey defense

A trait or behavior that helps an organism avoid or deter predators, including fleeing, hiding, self-defense, noises, mobbing, camouflage, spines, odors, and toxins.

Camouflage

Predator-avoidance coloration or markings, including cryptic coloration and deceptive markings.

Cryptic coloration

Camouflage that helps an organism blend into its surroundings.

Mechanical defense

A physical defense against herbivores or predators, such as spines.

Chemical defense

A defense involving chemicals such as odors or toxins.

Aposematic coloration

Warning coloration that signals danger or unpalatability, sometimes associated with toxins.

Mimicry

When one organism resembles another species.

Batesian mimicry

A harmless species mimics a harmful species.

Müllerian mimicry

Two or more unpalatable species resemble one another.

Parasite

An organism that derives nourishment from a host while harming the host.

Endoparasite

A parasite that lives inside its host.

Ectoparasite

A parasite that lives on the surface of its host.

Pathogen

A disease-causing organism that can be considered a predator.

Parasitism

A symbiotic interaction in which a parasite benefits by obtaining nourishment from a harmed host.

Mutualism

A symbiotic interaction in which both species benefit.