IB ESS Semester 1 Review

Entropy

A measure of the amount of disorder, chaos or randomness in a system; the greater the disorder, the higher the level of entropy.

2nd Law of Thermodynamics

Energy goes from concentrated to dispersed form. Available energy decreases with time as order take energy (Ex. Energy of nature lost through heat, continues because of sunlight)

1st Law of Thermodynamics

Energy cannot be created nor destroyed (Ex. Energy from sunlight passes along as biomass)

Open System

A system in which both matter and energy are exchanged with its surroundings.

Closed System

A system in which energy, but not matter, is exchanged with its surroundings.

Isolated System

A system that exchanges neither matter nor energy with its surroundings.

Negative Feedback

Lessens effects and promotes stability (EX. predator and prey)

Positive Feedback

Amplifies change and causes differences in stability

Steady-State Equilibrium

Maintains a stable system due to constants flow of inputs and outputs

Static Equilibrium

Always in balance (doesn't apply to nature)

Transfer vs. Transformation

Transfer involves flows through the systems with only change in location, not in state, while Transformation is an interaction within a system that results in the formation of a new end product of a change in state. (EX. Runoff v.s evaporation)

Species

Group of organisms that can interbreed and produce fertile offspring

Population

Group of organism of the same species living in the same area at the same time

Community

A group of populations living and interacting with each other in a common habitat.

Habitat

The environment in which a species normally lives

Food Chain

Show how matter and energy move through an ecosystem, linkage of who feeds whom

Food Web

Shows all possible chains in the system

Ecosystem

Biological community of interdependent organisms and the physical environment they inhabit

Trophic Level

The position that an organism occupies in a food chain, or a group of organisms in a community that occupy the same position in food chains.

Primary Sucession

An ecological succession that begins in an area where no biotic community previously existed

Secondary Succession

Succession on a site where an existing community has been disrupted

Pioneer Community

Small community, with many offspring who produce many generations, experiencing fierce competition. R-selective species

Climax Community

Large community with few offspring producing one generation per season, resulting in reduced competition. K-slective

Gross Primary Productivy

The total gain in energy or biomass per unit area per unit time fixed by photosynthesis in green plants.

Net Primary Productivity

The gain by producers in energy or biomass per unit area per unit time remaining after allowing for respiratory losses (R). (GPP-R)

Gross Secondary Productivity

The total gain by consumers in energy or biomass per unit area per unit time through absorption. (Food eaten-Fecal Loss_

Net Secondary Productivity

The gain by consumers in energy or biomass per unit area per unit time remaining after allowing for respiratory losses (R). (GSP-R)

Biomass

The mass of organic material in organisms or ecosystems, usually per unit area.