15 - Ecotoxicology, Foodwebs, and Biomagnification

Foodwebs

Interconnected feeding relationships in an ecosystem

Food chain

A sequence of organisms in which each organism is the food source for the next

Biomagnification

Increase of environmental chemicals in organisms with hierarchical increases in a food chain

Box Models

Models used to represent the flow of organic matter in ecosystems, depicting the input and output

Biosphere

The part of the Earth where life exists, including organic matter

Atmosphere

The layer of gases surrounding the Earth

Biological release

Release of substances by living organisms, such as through wildfires

Dead biomass

Organic matter that is no longer living

Living autotrophs

Organisms that can produce their own food through photosynthesis

Living heterotrophs

Organisms that obtain their food by consuming other organisms

Uptake

Absorption or intake of gases, particulates, vapours, herbivores, carnivores, omnivores, or detritus by organisms

Mineralization

The conversion of organic matter into inorganic minerals

Atmospheric deposition

The deposition of substances from the atmosphere onto the Earth's surface

Output

The removal or release of substances from an ecosystem

Lithosphere

The solid outer part of the Earth, including soils and rocks

Formation of secondary minerals

The creation of new minerals through chemical reactions

Aquasphere

The part of the Earth that consists of water

Top predator

The highest level predator in a food web

Intermediate species

Species that occupy a middle position in a food web

Basal species

Species that occupy the lowest level in a food web

Node

A point in a network where lines intersect or branch

Trophic Pyramids

Diagrams that show the distribution of energy or biomass among trophic levels

Ecological Efficiency

The efficiency of energy transfer between trophic levels in an ecosystem

how does ecological efficiency change as you go up the pyramid?

it decreases, meaning it can support less individuals

Energy transfer

The movement of energy from one organism to another in a food chain

Consumer

An organism that obtains energy by consuming other organisms

Producer

An organism that produces its own food through photosynthesis

Trophic Efficiency

The percentage of energy transferred from one trophic level to the next (10%)

Bioconcentration

Equilibrium distribution of a chemical within an organism and its concentration in the environment through passive absorption and excretion (org:enviro)

Passive absorption

Absorption of a chemical in an organism through the gills or skin

Excretion

The elimination of a chemical from an organism

Bioaccumulation

Build-up of a chemical in an organism through bioconcentration and food inputs

Bioaccumulation factor

The ratio of the concentration of a chemical in an organism to its concentration in the environment, considering all sources

biomagnification

the relative increase of environmental chemicals in the tissues of organisms with hierarchical increases in a food chain, taking into account both bioconcentration AND bioaccumulation

Biomagnification factor

The ratio of the concentration of a chemical in an organism to its concentration in the environment, taking into account bioconcentration and bioaccumulation

Net Trophic Transfer Efficiency

The efficiency of transfer of a chemical through trophic levels in a food chain

ecosystem

A community of organisms and their abiotic environment

why is the ecological system perspective useful?

it allows to understand how everything is dependent on each other - how there are so many factors which influence a living being, allowing us to understand where inputs and outputs are coming from, why they exist, etc.

what is an ecosystem composed of (spheres)?

atmosphere, biosphere, lithosphere, hydrosphere

how can particles move between compartments of ecosystems?

biological processes (consumption, decomposition, excretion), physical processes (weathering, sedimentation, erosion, mineralization), hydrological processes (water cycle, groundwater movement), and atmospheric processes (gas exchange (nitrogen, oxygen, carbon cycle), deposition)

why can a human be described using the ecosystem model?

biotic and abiotic factors; biosphere is human body and organisms living on it, including interactions between cells, organs etc.; hydrological and atmospheric processes; cycling elements/nutrients through the body similar to how ecosystem does it