Environmental Science Definitions
Acidic
A substance that has more hyrogen ion activity than hydroxyl activity.
Adaptation
A genetically-controlled characteristic that helps organisms survive and reproduce in their environment.
Angiosperms
Flowering plants that produce seeds in fruit.
Anther
The upper portion of the stamen containing pollen grains.
Arthropods
Any of the numerous invertebrate organisms which includes insects, spiders, centipedes and millipedes.
Bark
The outer layer of a tree trunk used to protect the tree from insects, disease, and fires.
Basic
A substance that has more hydroxyl ion activity than hydrogen ion activity.
Bole
The trunk of a tree, which is the central support giving the tree its strength and long shape.
Cambium
The part that adds thickness to a tree. The living dividing tissue.
Camouflage
A coloration or form adaptation by a species designed to hide from predators.
Canopy
The uppermost layer of a forest.
Carnivores
A consumer that eats only other consumers.
Chlorophyll
A green pigment found in plants that is necessary for the process of photosynthesis.
Commensalism
A relationship between two species in which one species benefits and the other is neither harmed nor helped.
Community
A group of interacting populations of different species in overlapping habitats.
Competition
The relationship between species that attempt to use the same limited resources.
Coniferous
Needle-leaved trees that usually produce seed cones.
Crown Class
The position of a tree’s height relative to the other trees in the stand.
Cyanobacteria
A group of blue-green bacteria that live through the world, mostly in water, but also on land. Can be a photobiont component of some lichens.
Deciduous
Trees that lose their leaves during a particular season each year.
Decomposers
Organisms that feed on dead plant and animal material.
Dendrochronology
The study of climate change and other past events through the comparison of successive annual growth ring of trees.
Deposition
Rock and organic materials that settle out within a water system.
Detritivores
Decomposers. Receive energy from recycling nutrients by eating dead organisms.
Dissolved Oxygen (DO)
The oxygen in a water solution as molecular oxygen. (O2)
Disturbance
An event that disrupts or changes all or part of an ecosystem.
Diversity
The variety in an ecosystem; usually refers to habitats or species.
Dominant Trees
Trees that are at the top of the canopy.
Ecology
The study of how living things interact with each other and with their nonliving environments.
Ecosystem
All living organisms in a certain area as well as their physical environment.
Erosion
Natural process of weathering by which material is removed from the earth’s surface.
Evenness
In terms of diversity, species evenness is determined by comparing the numbers of individuals within each species.
Food Chain
The sequence in which energy is transferred from one organism to the next as each organism eats and is then eaten by another.
Food Web
The interlocking, complex pattern of food chains in an ecosystem.
Forest Floor
The lowest layer of a forest consisting of many organisms including insects, fungi,moss and lichen.
Frond
The leaf of a fern.
Germination
Ina plant seed, to sprout growth.
Glide
Section of a water system where the water is moving faster than in a pool but without white water.
Gymnosperms
Plants that produce seeds in cones.
Habitat Structure
The shape, size and placement of vegetation- understory, mid-section, and overstory.
Heartwood
The majority of a tree trunk’s mass. Consists of old dead xylem cells that no longer carry water. It is usually darker than other parts of the tree and provides most of the support to a tree.
Herbivores
Plant eaters. First level consumers.
Herb Layer
The layer of a forest in between the shrub layer and the forest floor, made up of small plants.
Host
An organism on which a parasite feeds.
Hydroxyl Ion (OH-)
The highly reactive negative ion in a water molecule. A water molecule that has more hydroxyl ion activity than hydrogen ion activity is considered basic.
Hydrogen Ion (H+)
The highly reactive positive ion in a water molecule. A water molecule that has more hydrogen ion activity than hydroxyl ion activity is considered acidic.
Hypothesis
Implies insufficient evidence to provide more than a tentative explanation. An educated guess that is testable.
Impermeable surfaces
Hard surfaces, like roads or roof tops that water cannot penetrate.
Intermediate Trees
Trees that are just below the canopy in a forest.
Invasive
Non-native species that invade,spread, and out compete the natural species.
Kinetic Energy
The movement of molecules within a substance.
Larva
The immature stage of an organism. Often times very different from the adult form.
Law
Implies a statement of order and relation in nature that has been found to be invariable under the same conditions.
Leaves
The food processing part of a tree where (generally) photosynthesis takes place.
Lichen
A fungi, which has formed a successful alliance (a symbiotic relationship) with an algae.
Macroinvertebrates
Animals without backbones large enough to identify with the unaided eye; often aquatic insects.
Meander
Refers to water systems that follow a winding and turning course.
Mutualism
A relationship between two species in which both benefit.
Niche
The role of an organisms in an ecosystem.
Nitrogen
A nutrient that is released when organic matter decomposes. The nutrient is critical to stimulating plant growth.
Nymph
One of the young of any insect that undergoes incomplete metamorphosis.
Omnivore
A consumer that eats both plants and animals.
Overtopped Trees
Trees under the dominants and intermediate crown class layers in a forest.
Ovule
A rudimentary seed of a plant that develops into a seed after fertilization.
Parasitism
The relationship where a parasite receives resources from its host without killing it.
Petals
Serve as a banner to attract pollinators and a landing platform.
pH
The measure of the acidity or basicity of a substance.
Phloem
A series of small tubes that transports the sap (food) from the leaves down to the roots of a tree.
Phosphorus
A nutrient found in soil which aids in plant growth.
Photobiont
The photosynthetic component of lichen.
Photosynthesis
The process green plants use to produce food as sugar from carbon dioxide, water and sunlight.
Pistil
The central organ of a flower which contains the female parts:stigma,style,ovary.
Pool
Deep areas in a water system where the water is slow or swirling.
Pollen
Fine, yellowish powder-like grains, which contain the male germ cells of a plant.
Pollination
The transfer of pollen from another (male) to the stigma (female) of a plant from fertilization.
Population
A group of individuals of the same species that live in a particular habitat.
Potassium
A nutrient found in soil, which aids in plant growth and survival.
Predation
The act of killing and eating another organism.
Prey
An organism upon which a predator feeds.
Riffle
Fast moving portion of a stream, characterized by white water. Also called rapids. Riffles are well oxygenated sections that provide great conditions for many aquatic organisms.
Riparian Area
The vegetated area along the banks of a stream that is influenced by stream water.
Scavengers
Organisms that feed on dead organisms.
Sensitive Species
Referring to aquatic organisms that cannot survive in poor water quality conditions.
Shrub Layer
The layer of the forest in between the understory and herb layers, made of shrubs.
Springwood
Tree cambium (xylem) cells that are created in the beginning of the growing season. Usually larger and appear lighter than summerwood.
Stamen
The male organ of the flower consisting of anther and filament, which produces the pollen.
Stigma
The most elevated part of a flower’s pistil, which receives the pollen.
Stomata
Small holes in leaves, where oxygen and water is released into the atmosphere.
Streamflow
The total volume of water that passes in a water system. Often expressed in cubic feet per second. (cfs)
Substrate
The composition of rock materials and organic matter that make up a stream bottom.
Succession
A pattern of on-going changes (a process) over time in the types of species in a community.
Summerwood
Tree cambium (xylem) cells that are created towards the end of the growing season. Usually appear smaller and darker than springwood.
Surface Runoff
The water that flows over the surface to the lowest point on the landscape after precipitation.
Suspended Sediments
Floating materials in water that blocks light causing turbidity.
Sustainability
Ability of the Earth’s various systems, including human cultural systems and economies, to survive and adapt to changing environmental conditions indefinitely.
Temperature
The measurement of moving molecules of kinetic energy within a substance.
Theory
A proposed but unverified explanation. Implies greater range of evidence and greater likelihood of truth than a hypothesis.
Tipping Point
Threshold level at which an environmental problem causes a fundamental and irreversible shift in the behavior of a system.
Trophic Level
A step in the transfer of energy through an ecosystem. The level of a food chain that an organisms occupies. A category of organisms classified by what they eat.
Turbidity
The amount of suspended matter in a water body. The measure of how cloudy or clear water is.
Understory
The next layer down from the canopy of a forest. Also called a sub-canopy.
Velocity
The measurement of how fast something is traveling, i.e, water
Xylem
Living xylem moves water and nutrients from the roots up to the top of the tree and branches to the leaves also called sapwood.
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