Unit 1 Vocabulary Notes

Unit 1 Vocabulary

Environment

• The surroundings or conditions in which an organism lives.

Ecosystem

• A community of interacting organisms and their physical environment.

Biotic

• Living or derived from living organisms.

Abiotic

• Non-living chemical and physical parts of the environment.

Sustainability

• The ability to meet the needs of the present without compromising the ability of future generations to meet their own needs.

Hypothesis

• A testable explanation for a phenomenon.

Independent Variable

• The variable that is manipulated in an experiment.

Dependent Variable

• The variable that is measured in an experiment.

Null Hypothesis

• A statement that there is no relationship between two variables.

Control Group

• A group in an experiment that does not receive the treatment.

First Law of Thermodynamics

• Energy cannot be created or destroyed, only transformed, E \neq 0.
• Also known as the law of conservation of energy.

Second Law of Thermodynamics

• When energy is converted from one form to another, some energy is converted to heat, which increases the entropy of the universe.
• Entropy is always increasing.

Community Ecology

• The study of interactions between different species living in the same area.

Symbiosis

• Interaction between two different organisms living in close physical association, typically to the advantage of both.

Biosphere

• The regions of the surface, atmosphere, and hydrosphere of the earth occupied by living organisms.

Competition

• The interaction of individuals that vie for a common resource that is in limited supply.

Competitive Exclusion Principle

• Two species competing for the same limiting resource cannot coexist at constant population values.

Resource Partitioning

• When species divide a niche to avoid competition.

Predation

• An interaction in which one organism (the predator) kills another organism (the prey) for food.

Parasitoid

• An insect whose larvae live as parasites that eventually kill their hosts.

Parasitism

• A relationship between two species where one organism benefits and the other is harmed.

Pathogen

• A bacterium, virus, or other microorganism that can cause disease.

Herbivory

• The consumption of plants by animals.

Mutualism

• A relationship between two species where both organisms benefit.

Photosynthesis

• The process by which green plants and some other organisms use sunlight to synthesize foods from carbon dioxide and water.
• 6CO2 + 6H2O + light \rightarrow C6H{12}O6 + 6O2

Commensalism

• A relationship between two species where one organism benefits and the other is neither harmed nor helped.

Native Species

• Species that naturally occur in a region.

Exotic Species

• Species that are introduced to a region where they do not naturally occur.

Invasive Species

• Exotic species that cause harm to the environment, economy, or human health.

Biome

• A large naturally occurring community of flora and fauna occupying a major habitat, e.g., forest or tundra.

Terrestrial Biome

• A biome found on land.

Aquatic Biome

• A biome found in water.

Habitat

• The natural home or environment of an animal, plant, or other organism.

Tundra

• A vast, flat, treeless Arctic region in Europe, Asia, and North America in which the subsoil is permanently frozen.

Permafrost

• A thick subsurface layer of soil that remains frozen throughout the year, occurring chiefly in polar regions.

Boreal Forest

• A biome characterized by coniferous forests consisting mostly of pines, spruces, and larches.

Temperate Rainforest

• A biome characterized by high levels of precipitation and moderate temperatures.

Temperate Seasonal Forest

• A biome characterized by moderate temperatures and seasonal precipitation.

Shrubland

• A biome characterized by vegetation dominated by shrubs.

Temperate Grassland

• A biome characterized by grasses and few trees.

Tropical Rainforest

• A biome characterized by high temperatures and high rainfall.

Savanna

• A biome characterized by grassland with scattered individual trees.

Hot Desert

• A biome characterized by high temperatures and very low rainfall.

Freshwater Biomes

• Aquatic biomes that contain water with low salt concentration.

Littoral Zone

• The area closest to the shore of a lake or pond

Limnetic Zone

• The open water area of a lake or pond.

Phytoplankton

• Microscopic plants that live in aquatic enviornments, which are the primary producers in most aquatic food chains

Profundal Zone

• A deep-water zone that is below the limits of effective light penetration.

Benthic Zone

• The ecological region at the lowest level of a body of water such as an ocean or a lake, including the sediment surface and some sub-surface layers.

Oligotrophic Zone

• A body of water with low nutrient levels, low algal production, and high water clarity.

Mesotrophic Zone

• A body of water with moderate nutrient levels.

Eutrophic Zone

• A body of water with high nutrient levels, high algal production, and low water clarity.

Freshwater wetland

• An ecosystem that is flooded by water, either permanently or seasonally.

Estuary

• A partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea.

Salt Marsh

• A coastal ecosystem in the upper coastal intertidal zone between land and open salt water that is regularly flooded by the tides.

Mangrove Swamp

• A coastal ecosystem found in tropical and subtropical regions and characterized by mangrove trees.

Intertidal Zone

• The area of the shore that is covered during high tide and exposed during low tide.

Coral Reef

• An underwater ecosystem characterized by reef-building corals.

Open Ocean

• The oceanic zone lying beyond the continental shelf.

Photic Zone

• The upper layer of a body of water that receives sunlight.

Aphotic Zone

• The portion of a lake or ocean where there is little or no sunlight.

Chemosynthesis

• The synthesis of organic compounds by bacteria or other living organisms using energy derived from reactions involving inorganic chemicals, typically in the absence of sunlight.

Biogeochemical Cycle

• The cycling of nutrients between the biotic and abiotic components of an ecosystem.

Reservoirs

• A place where a quantity of a resource is accumulated or stored

Carbon Cycle

• The series of processes by which carbon compounds are interconverted in the environment, chiefly involving the incorporation of carbon dioxide into living tissue by photosynthesis and its return to the atmosphere through respiration, the decay of dead organisms, and the burning of fossil fuels.

Aerobic Respiration

• The process by which cells use oxygen to break down glucose and produce energy.
• C6H{12}O6 + 6O2 \rightarrow 6CO2 + 6H2O + energy

Steady State

• A state in which inputs equal outputs, so that the system is not changing over time.

Greenhouse Gases

• Gases in the atmosphere that absorb and emit radiant energy within the thermal infrared range.
• Examples: Carbon dioxide, methane, and water vapor.

Global Warming

• A gradual increase in the overall temperature of the earth's atmosphere generally attributed to the greenhouse effect caused by increased levels of carbon dioxide, CFCs, and other pollutants.

Limiting Nutrient

• The nutrient in shortest supply that limits growth.

Nitrogen Cycle

• The series of processes by which nitrogen and its compounds are interconverted in the environment and in living organisms, including nitrogen fixation and decomposition.

Nitrogen Fixation

• The chemical processes by which atmospheric nitrogen is assimilated into organic compounds, especially by certain microorganisms as part of the nitrogen cycle.

Nitrification

• The process by which ammonia is converted to nitrite and then to nitrate.

Assimilation

• The process by which plants and animals incorporate the NO3- and ammonia formed through nitrogen fixation and nitrification.

Mineralization

• The decomposition or oxidation of the organic matter in soil or rocks, resulting in the release of plant nutrients in inorganic forms.

Denitrification

• The process by which nitrates are reduced to gaseous nitrogen.

Anaerobic

• Lacking or not requiring oxygen.

Aerobic

• Requiring oxygen.

Leaching

• The process by which water-soluble nutrients are removed from the soil.

Phosphorus Cycle

• The biogeochemical cycle that describes the movement of phosphorus through the lithosphere, hydrosphere, and biosphere.

Algal Bloom

• A rapid increase in the population of algae in an aquatic system.

Hypoxic

• Deficient in oxygen.

Dead Zone

• An area in an aquatic ecosystem where oxygen levels are too low to support life.

Hydrologic Cycle

• The continuous circulation of water between the atmosphere, oceans, and land.

Transpiration

• The process by which water is carried through plants from roots to small pores on leaves, where it changes to vapor and is released to the atmosphere.

Evapotranspiration

• The sum of evaporation and plant transpiration from the Earth's land surface to the atmosphere.

Runoff

• The draining away of water (or substances carried in it) from the surface of an area of land, a building or structure, etc.

Autotrophs

• Organisms that produce their own food from inorganic substances, using light or chemical energy.

Cellular Respiration

• The set of metabolic reactions and processes that take place in the cells of organisms to convert biochemical energy from nutrients into adenosine triphosphate (ATP), and then release waste products.

Anaerobic Respiration

• Respiration that does not require oxygen.

Primary Productivity

• The rate at which energy is converted by photosynthetic and chemosynthetic autotrophs to organic substances.

Gross Primary Productivity

• The total rate of photosynthesis in a given area.

Net Primary Productivity

• The rate of energy storage as organic matter after respiration.
• NPP = GPP - Respiration

Biomass

• The total mass of organisms in a given area or volume.

Standing Crop

• The total amount of biomass at a given time.

Consumer

• An organism that obtains energy by feeding on other organisms.

Herbivore

• An organism that eats plants.

Carnivore

• An organism that eats animals.

Secondary Consumer

• An organism that eats herbivores.

Tertiary Consumer

• An organism that eats secondary consumers.

Trophic Levels

• The position an organism occupies in a food chain.

Food Chain

• A linear sequence of organisms through which nutrients and energy pass as one organism eats another.

Scavenger

• An organism that feeds on dead or decaying matter.

Detritivore

• An organism that feeds on dead organic material (detritus).

Decomposers

• Organisms that break down dead or decaying organisms.

Ecological Efficiency

• The proportion of energy that is transferred from one trophic level to the next.

10% Rule

• Only about 10% of the energy stored as biomass in a trophic level is passed on to the next trophic level.

Trophic Pyramid

• A graphical representation of the biomass or bio productivity at each trophic level in an ecosystem.

Food Web

• A system of interlocking and interdependent food chains.

Negative Feedback Loop

• A type of regulation that responds to a change in conditions by initiating responses that will counteract the change. Maintains a steady state.

Positive Feedback Loop

• A type of regulation that responds to a change in conditions by initiating responses that will amplify the change. Takes organism away from a steady state.