Bio H - Independent Unit Exam SG

Ocean ecosystems

Ocean ecosystems are the most common and cover 70% of the Earth’s surface. The 3 basic types are: shallow ocean, deep ocean water, and deep ocean surfaces

Freshwater ecosystems

Freshwater ecosystems are the rarest, covering only 1.8% of the Earth’s surface. Lakes, rivers, streams, and springs are this type. They support a variety of fish, amphibians, reptiles, insects, phytoplankton, fungi, and bacteria

Terrestrial ecosystems

Terrestrial ecosystems are also known for their diverstiy. They are grouped into large categories called biomes, like rain forests, savannas, deserts, coniferous forests, deciduous forests, and tundra

Disturbance

Changes in an ecosystems enviornment that effect their compositions

Resistance

The ability of an ecosystem to remain at equilibrium after being disturbed

Resilience

The speed at which an ecosystem recovers equilibrium after being disturbed

Biomass

The total mass in an unit area at the time of measurement, of living or preioiusly living organisms within a trophic level

Net primary productivity

The energy that remains in the primary producers after accounting for the organisms’ respiration and heat loss

Trophic level

There’s a single path through a food chain, andeach organism in that food chain is assigned a level based on if theyre producers, consumers, species, or groups of species

Biomagnification

The increasing concentration of persistent, toxic substances in organisms at each trophic level

Biogenochemical cycle

The recycling of inorganic matter between living organisms and their enviornment

Hydrosphere

The area of the Earth where water movement and storage occurs

Residence time

The measure of the average time an individual water molecule stays in a particular reservoir

Surface runoff

The flow of fresh water either from rain or melting ice

Nonrenewable resource

A resource that is either regenerated very slowly or not at all, ex: fossil fuels

Symbiotic

Involving interaction between two different organisms living in close physical association, benefits both parties

Nitrogen fixation

The conversion of N2 into a usable form

Rhizobium

A type of bacteria that live symbiotically in the root nodules of legumes (peas, beans, nuts) and provide them with the organic nitrogen they need

Eutrophication

A process whereby nutrient runoff causes the excess growth of microorganisms, depleting dissolved oxygen levels and killing ecosystem fauna

Dead zone

An area within freshwater or marine ecosystem where large areas are depleted of their normal flora and fauna, these zones can be caused by eutrophication, oil spills, dumping of toxic chemicals, and other human activites

Acid rain

Caused by rainwater failling to the ground through mostly sulfur dioxide gas, turning it into weak sulfurous acid

Grass	Primary producer
Grasshopper	Primary consumers
Mouse	Secondary consumers
Snake	Teterairy Consumer
Eagle	Apex Consumer
Dotted line	The waste from the eagle gets absorbed by the earth and turned into nutrients to help the grass grow