EARTH 122 Definitions

Environmental Science

The study of how the natural world works, how our environment affects us, and how we affect our environment.

Interdisciplinary

A field of study that employs concepts and techniques from numerous disciplines and brings research results from those disciplines together into a broad synthesis.

Environmentalism

Is a social movement, not scientific, dedicated to protecting the natural world, and by extension humans as well, from undesirable changes brought about by human choices.

Resource Management

Strategic decision making and planning aimed at balancing the use of a resource with its protection and preservation, or to balance the rate of use with the rate of removal or regeneration.

Carrying Capacity

The measure of the ability of a system to support life, quantified as the number of individuals of a particular species that can be sustained by the biological productivity of a given area of land without incurring permanent damage.

Tragedy of the Commons

Each individual in a population or community withdraws whatever benefits are available from the common property as quickly as possible until the resource becomes overused and depleted.

Ecological Footprint

Expresses the environmental impact of an individual or a population in terms of the area of land and water required to provide the raw materials that person or population consumes and to absorb and recycle their wastes.

Sustainable Development

Development anywhere in the world that meets the needs of the present without sacrificing the ability of future generations to meet their needs.

Scientific Method

A process or technique for testing ideas in science by making observations and by gathering evidence.

Theory

A widely accepted, well-tested explanation of one or more cause-and-effect relationships, which has been extensively validated by extensive research.

Matter

All material in the universe that has mass and occupies space is made up of matter, often in one of the three common states: solid, liquid, or gas. The Law of Conservation of Matter states that matter can be transformed between states, but cannot be created or destroyed.

Organic Compounds

Consist of carbon atoms (and generally hydrogen atoms) joined by covalent bonds, often with other elements, such as nitrogen, oxygen, sulphur, and phosphorous.

Inorganic Compounds

Are also fundamentally important to life (e.g. water), and some may contain carbon, but they are not organic because they lack the carbon-carbon bonds characteristic of those compounds.

Energy

The capacity to change the position, physical composition, or temperature of matter, or a force that can accomplish work. Often separated into Potential and Kinetic.

Autotrophs

Organisms that can produce their own food strictly from energy derived from the sun, which include green plants, algae, and cyanobacteria.

Heterotrophs

Organisms which gain their energy by feeding on other organisms, which can include both plants or other animals.

Plate Tectonics

The movement of large lithospheric plates across the surface of our planet. The three main types of boundaries are divergent, convergent, and transform.

Rock Cycle

The heating, melting, cooling, eroding, weathering, transport, deposition, re-lithification of earth materials into rock.

Nutrients

Elements and compounds, both organic and inorganic, that organisms consume and require for survival.

System

A network of relationships among parts, elements, or components that interact with and influence one another through the exchange of energy, matter, or information.

Feedback Loops

Negative: Output that results from a system moving in one direction acts as input that moves the system in the other direction;

Positive: Outputs drive the system towards one extreme

Homeostasis

The tendency for a system to maintain a constant or stable internal condition

Earth’s Major Subsystems

The geosphere, atmosphere, hydrosphere (and cryosphere), biosphere, and atmosphere

Ecosystem

Consists of all organisms and nonliving entities that occur and interact in a particular area at the same time, and is related to the concept of a biological community

Ecotones

A transitional zone between two different ecosystems, or the boundary where two ecosystems meet. In an ecotone, a mix of adjacent ecosystems can be found

Nutrient or Biogeochemical Cycles

Materials and nutrients that move through ecosystems are called biogeochemical because the processes involved are biological, geological, and chemical (as well as physical). Examples provided are the Hydrological, Carbon, Nitrogen, and Phosphorous cycles.

Evolution

Used specifically for biological evolution which consists of genetic changes in organisms across generations, which an lead to changes in appearance, functioning, or behaviour

Speciation

The process by which new species are created, an example of which is allopatric speciation

Endemic

Species that occur in only one region and nowhere else on the planet

Habitat

The specific environment which a species lives, consisting of both living and non-living elements, rock, soil, leaf litter, and moisture, as well as other organisms

Population Density

Describes the number of individuals in a population per unit area, for example, people per square kilometre

Carrying Capacity

The maximum population size of a species that a given environment can sustain without becoming degraded

Competition

When multiple organisms seek the same limited resources or space

Resource Partitioning

When species divide, or partition, the resource the use in common by specialising in different ways

Amensalism

A variation on competitive relationships, in which one organism is harmed and the other is apparently unaffected, or does not benefit from the interaction

Parasitism

A variation on competitive relationships, in which one organism, the parasite, depends on another, the host, for nourishment, support, or some other benefit, while simultaneously doing some harm to the host

Herbivory

When animals feed on the tissues of plants

Mutualism

A relationship in which two or more species benefit from interaction with one another, where each partner provides some resource or service that the other needs

Commensalism

A species interaction in which one species benefits while the other is unaffected

Producers

Also called autotrophs, they compose the first trophic level, using energy from the sun to produce their own food

Consumers

Organisms that derive their food energy from other organisms, also called heterotrophs. Consumers that eat Primary Producers are called Secondary Consumers and comprise the 2nd trophic level. Consumers that eat other consumers occupy the third trophic level, or Tertiary consumers

Detritivores and Decomposers

Organisms that consume non-living matter, and break down this matter into simpler things that can then be taken up by and used by plants

Primary Succession

Follows a disturbance or stress so severe that no vegetation or soil life remains from the community that occupied the site

Pioneer Species

Species that arrive first and colonise the new ground after a major disturbance during primary succession, they are often well adapted for colonisation, having traits such as spores or seeds that can travel long distances

Climax Community

The ecological system which remains in place, with little modification, until some major disturbance restarts succession. It can be seen as a fully formed natural landscape

Biome

A major regional complex of similar communities - a large ecological unit recognised primarily by its dominant plant type(s) and vegetation structure

IPAT Model

Often denoted as Impact = Population Affluence Technology * Sensitivity. It represents how our total impact on the environment can result from the interactions of the stated variables

Demography

The study of statistical change within human populations, which advanced out of the field of population ecology

Population Pyramids

An 'Age Structure' diagram, which is a tool used for visual representations of a population, split by sex and classified by age groups, often in 5 or 10 year spans

Total Fertility Rate

The average number of children born per female member of a population, during her lifetime

Demographic Transition

A model used to explain the economic and cultural shift in a population from high death and birth rates, to lower death and birth rates

Soil

Is not just the loose material derived from erosion of rocks, but it is also a complex plant-supporting system that does consist of weathered rock, but also organic matter, water, gases, nutrients, and life. It is fundamental to the support of almost all life on this planet

Parent Material

The base geologic material (e.g. rocks or bedrock) in a given location from which the soil is derived / formed from

Weathering

Describes the physical, chemical, and biological processes that break down rocks and minerals, turning large particles into smaller particles, and sometimes altering their chemical composition

Soil Profile

A cross-section of a soil column from surface to bedrock, often classified into specific horizons based on the physical and chemical changes through depth

Soil Degradation

A term used to describe soils that have become eroded and degraded over time, due to loss of soil or over use from agricultural practices

Universal Soil Loss Equation

Developed as a tool for estimating erosion losses by water from cultivated fields, and to show how different soil management factors influence soil erosion

Desertification

A natural process by which formally productive lands become a desert as a result of climatic change or prolonged drought, or which is brought on by human activities, such as increased agriculture

Agriculture

The practice of raising crops and/or livestock on farms for human use and consumption

Intensification

The gradual increase in productivity from the same area of land, due to refined technique and advancements in technology

Extensification

A form of increasing resource productivity by bringing more land into production (the opposite of Intensification above)

Subsistence Agriculture

One of the oldest forms of traditional agriculture, occurs where farming families produce only enough food for themselves and do not make use of modern irrigation, farm machinery, or teams of animals

Green Revolution

The enormous increase in agricultural production through the efficient use of energy, increasing the frequency of planting and harvesting schedules, vastly improving irrigation techniques, and utilizing many different types of fertilizers

Inorganic Fertilizers

Also called Industrial Fertilizers, these are mined or synthetically manufactured mineral supplements, mainly various forms of Nitrogen, Phosphorous, and Potassium, or N-P-K

Organic Fertilizers

Consist of natural materials, including animal manure, crop residues, fresh vegetation, and compost

Pesticides

Poisons that are designed to target specific pests, while leaving other organisms unharmed

Integrated Pest Management

Numerous techniques are integrated to achieve long-term suppression of pests, including biocontrol, use of chemicals, close monitoring of populations, habitat alteration, crop rotation, use of GMO crops, and mechanical pest removal

Pollination

The process where male sex cells (pollen) fertilise female sex cells of the same or another plant. For many plants, this process is achieved by assistance through the wind and insects, like bees

Genetic Engineering

Any process where scientists directly manipulate an organisms genetic material in the lab by adding, deleting, or changing segments of its DNA

Transgenic

An organism that contains DNA from another species

Feedlots

Also known as Factory Farms or Concentrated Animal Feeding Operations, these are essentially huge warehouses or pens designed to deliver energy rich food to animals living at extremely high densities

Sustainable Agriculture

Agricultural practices that does not deplete soils faster than they form, or farming and ranching that does not reduce the amount of healthy soil, clean water, and genetic diversity of the region

Biodiversity

The sum total of all organisms in an area, taking into account the diversity of species, their genes, their populations, and their communities

Genetic Diversity

Encompasses all the varieties in DNA present among individuals within species, subspecies, and populations

Species Diversity

A value that can be expressed different ways to quantify the number and variety of species in the world, or in a specific region

Ecosystem Diversity

Refers to the total number and variety of ecosystems in a given area based on variations in climate, topography, soils, and other factors. This can also be referred to has Habitat Diversity

Extinction

Occurs when the last living member of a species dies, and therefore that species ceases to exist

Extirpation

The disappearance of a particular population or species from a given area, but not globally

Conservation Biology

A scientific discipline devoted to understanding the factors, forces, and processes that influence the loss, protection, and restoration of biological diversity

Habitat Fragmentation

The process, often caused by human population growth and demand for resources, which chops up large continuous expanses of wilderness and habitat into smaller disconnected ones

Biodiversity Hotspot

A concept developed to prioritizing regions that are important globally for biodiversity conservation. A hotspot is a region that supports a great number of endemic species

Micro- and Macro- Nutrients

Nutrients that are required by living organisms only in small amounts are called micronutrients, whereas, those required in larger amounts are called macronutrients

Agroforestry

The method of planting trees in close proximity to agricultural crops for aid in the water and nutrient cycles

Forest

A land area with significant tree cover, also where the canopy (upper levels of leaves and branches) is largely closed, or when viewed from above, an almost continuous tree surface

Understory

The shrubberies and groundcover plants of the forest floor, and the lowest levels of growth

Reforestation

The prompt planting of trees after logging or human removal for other reasons

Afforestation

The planting of trees in areas where forest cover has not existed for at least 50 years

Maximum Sustainable Yield

A principle of renewable resource management, which is based on harvesting only as much resource that can be regenerated within a year

Ecosystem Based Management

An attempt to manage the harvesting of resource in ways that minimize impacts on the ecosystems and ecological processes of the forest

Prescribed or Controlled Burns

In an attempt to reduce the overall fuel load in a forest, management agencies have initiated the action of controlled fires, or burns, in selected parts of a forest, in an attempt to reduce the likelihood of any future large scale or catastrophic fire

Fresh Water

Water that is relatively pure, with few dissolved salts, but can have some dissolved minerals, and makes up approximately 2.5% of all global waters by volume

Tributary

A smaller river, stream, or creek, that flows into and merges with a larger river, stream, or creek

Drainage Basin/Watershed

The area of land drained by a river, stream, or creek, and its tributaries, where surface water also flows out of a defined outlet point

Floodplain

The flat areas directly adjacent and nearest to a rivers shoreline, and is flooded periodically during high water events

Riparian Zone

The forested and vegetated areas that border a river, stream, or creek, with high biodiversity and species richness

Littoral Zone

The region that fringes or borders along the shoreline of a lake, or along the beaches of an oceanic coastline, where water is shallow enough to provide proper habitats for many aquatic plant and animal species

Benthic Zone

This region extends along the bottom of an entire water body from the littoral zone to the deepest point

Limnetic Zone

The open portion of a lake or other water body, away from shore, where sunlight can still penetrate through the depths

Profundal Zone

The region below the Limnetic zone, in the aphotic zone (without light), where sunlight can no longer penetrate through the depths

Aquifers

Subsurface regions containing large quantities of fresh water, where large porous formations of rock, sand, or other sediments, contain water in the pore spaces / voids. These can be classified as unconfined or surface aquifers, or confined aquifers, cut off from surface interaction by aquatards