Smithsonian National Zoological Park l Friends of the National Zoo




Activity Budget
Documentation of how an animal divides its time among daily or seasonal activities.
Living or growing in or on the water.
The sum of all the given elements divided by the total number of those elements. To calculate an average, add up all the values measured to get a sum (or total), then count how many elements were used to get the sum, and finally divide the sum by the number of elements.
A wide area of water extending inland land from a lake or sea.
The observable actions of an animal.
The richness and variety of life forms in a given ecosystem, or of the entire Earth, also called biological diversity.
Blue Crab
Common name for Callinectes sapidus, a crustacean in the family of swimming crabs. This species is found in North America along the coasts and in the coastal inlets and bays of the southern Atlantic Ocean and the Gulf of Mexico, and seasonally in associated estuaries and rivers. Mature males have bright blue claws and legs. Mature females are also blue, but their claws characteristically have bright orange tips.
Chesapeake Bay
An estuary formed where a large, wide area of the Atlantic Ocean extends inland; it is bordered by Delaware, Maryland and Virginia.
The measurable clearness, or transparency, of water and thus an indication of how deeply light can penetrate into water. Low clarity in a natural body of water indicates runoff, erosion, or algae blooms. Water with very high clarity generally does not support diverse plant and animal life.
The systematic grouping of organisms or objects into groups based on shared characteristics or traits.
Systematically arrange or organize according to common attributes, qualities, or traits.
A group of interdependent organisms inhabiting the same region and interacting with each other.
An organism that obtains its food (i.e, complex organic compounds) by eating other organisms or organic matter.
Collected information which can be quantitative (numerical) or qualitative (descriptive). Factual information used as a basis for reasoning, discussion, or calculation.
An organism that eats dead or decaying organisms.
To break down organic matter from complex to simpler forms or smaller parts, mainly through the actions of fungi, insects, worms, and bacteria; or to undergo this process.
(verb) Write, record, or photograph information so it can be used as evidence.
The scientific study of the relationship of living things to one another and to their environment.
A unit consisting of all the living organisms in a given area (the community), as well as their relationship to the non-living (abiotic) surrounding environment. Thus, an ecosystem’s components may include plants, animals, and microorganisms, soil, rocks, and minerals, water sources, and atmosphere.
The process by which soil or land is worn away by wind, water, ice, gravity, and human land-use, including activities that increase runoff, such as farming, logging, and road building.
The region of interaction between rivers and nearshore ocean waters where tidal action and river flow create a mixing of fresh and salt water.
A list of a species’ behaviors and the actions that define them.
The hard protective shell covering an insect or crustacean’s body.
Field Guide
Reference book that contains illustrations of flora or fauna, maps of their natural habitats, and descriptions of their characteristics and behaviors. Some field guides may focus on specific animal-related artifacts, such as animal tracks, bird eggs, and so on.
Members of the kingdom, Fungi, which includes mushrooms, molds, mildews, smuts, rusts, and yeasts. These organisms lack chlorophyll and function as decomposers.
A place providing appropriate living conditions for an organism, species, or community.
An area 10,000 square meters in size; in a scientific plot, this is usually shaped as 100 x 100 meters.
Herbaceous Plant
A green, leafy plant lacking a permanent woody stem such as a tree or shrub would have. Typically, in the temperate zone the above-ground growth of a herbaceous plant dies back in winter.
Develop a tentative explanation for a set of observations or relationships, testable through additional observations or experiments.
An animal that lacks a backbone.
The early immature form of any animal that at birth or hatching is fundamentally unlike its parent and must metamorphose before assuming adult characteristics.
Life Cycle
The series of form and/or functional stages through which an organism passes during its life.
The sexual process by which animals generate others of the same species.
A brief second stage in the blue crab life cycle (see Zoea). At about 45 days post-hatching, the megalopa molts into a tiny juvenile crab.
To change locations periodically, especially to move seasonally from one region to another.
To gather information and direct evidence by using the senses or scientific instruments.
A living thing, such as a plant, animal, virus, or bacterium.
A variable and measurable characteristic.
The process by which green plants convert sunlight into energy.
Pie Chart
A diagram in the shape of a circle, divided into triangular sections that represent specific quantities of data in percentages, adding up to 100%.
Contaminants introduced into an environment that cause harm to the health of plants and animals in that environment.
All the individuals of one species that occupy the same given area at the same time.
A description of what one thinks will take place in the future, based on previous knowledge.
An order of mammals that have large brains and complex hands and feet; includes humans, apes, and monkeys.
An organism (such as a green plant, or a bacteria) that produces its own food through photosynthesis (using light energy) or through chemosynthesis (using chemical energy).
A set of research procedures that results in the same data being collected the same way every time they are collected; a detailed set of instructions that allow duplication of research iterations.
Extensive data collection characterized by repeatedly using the same collection methods each time.
The share of precipitation or irrigation water that runs off of land into streams and other surface water.
A measure of the concentration of dissolved mineral substances in water.
Sampling Square
A defined area of land that is used in a scientific study.
Secchi Disk
A round disk, divided into black and white quarters, which is lowered into a body of water to measure that water’s clarity. By measuring the distance from the water’s surface to the depth at which the disk is no longer visible, called the Secchi disk depth, a researcher can determine the maximum extent of water clarity in that location.
Small pieces of soil, rock, plant and animal matter, including both nutients and pollutants, transported from land into water by wind and precipitation.
(verb) A method used to classify organisms according to their reproductive function, as either male or female.
An upright dead tree.
Social Bond
An attachment formed between two or more animals through interactions such as playing, grooming, and sharing food.
Particles formed when minerals and organic materials from plant and animal remains are broken down by live organisms and changes in climate.
A group of similar organisms that can reproduce amongst themselves, with viable offspring.
Species Richness
The number of species found within a prescribed area.
The distance traveled in a step. Stride length is measured from one heel to another heel of an animal’s feet. This distance varies depending on the animal’s size, species, and speed.
To collect detailed information for a study of a particular subject.
A mark, or marks, representing a number.
An area in which an animal spends most of its time, which it may defend against intruders of the same species.
Dragging a large net along the bottom of a body of water to collect organisms, usually for commercial fishing or scientific research.
One iteration of a test or experiment.
A measurement of the materials suspended in water that affect the water’s clarity by blocking the sunlight’s ability to pass through it. Soil erosion, pollution, runoff, flooding, algae growth, and even marine life movements that agitate sediment can all increase turbidity.
A geographic land area in which water, sediments and dissolved materials drain into a common outlet (e.g. stream, river, bay). Large watersheds, such as that of the Chesapeake Bay, are formed of several smaller watersheds.
The first post-hatching stage in the blue crab life cycle. A Zoea floats in the ocean currents to feed and molts seven times before becoming a Megalopa at age 4-5 weeks.