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Vocab for Unit 4, fall 2011


an extremely small organism which causes disease in humans, animals and plants

Protein Coat

The substance that PROTECTS a virus's genetic material and helps it get inside a cell:

Nucleic Acid

an organic compound, either RNA or DNA, whose molecules are made up of one or two chains of nucleotides and carry genetic information

Sporadic Disease

Disease that occurs occasionally in a population

Endemic Disease

a disease that is constantly present to a greater or lesser degree in people of a certain class or in people living in a particular location


a widespread outbreak of an infectious disease


an epidemic that is geographically widespread


any disease-producing agent (especially a virus or bacterium or other microorganism)


the relation between two different species of organisms that are interdependent


the relation between two different species of organisms that are interdependent


the relation between two different kinds of organisms when one receives benefits from the other without damaging it


the relation between two different kinds of organisms in which one receives benefits from the other by causing damage to it (usually not fatal damage)


the act of competing as for profit or a prize


the act of preying by a predator who kills and eats the prey

Binary Fission

a form of asexual reproduction in single-celled organisms by which one cell divides into two cells of the same size


a toxin that is secreted by microorganisms into the surrounding medium


a toxin that is confined inside the microorganisms and is released only when the microorganisms are broken down or die


organism that breaks down and obtains energy from dead organic matter


symbiotic relationships between fungal hyphae and plant roots


the branch of biology concerned with the relations between organisms and their environment


of or relating to living organisms



Population distribution

how population is spread out in an area

Population density

number of individuals per unit area

Population ecology

The study of populations in relation to the environment, including environmental influences on population density and distribution, age structure, and variations in population size.

Reproductive Strategies

evolutionary effects on systems of mating and rearing offspring; these need not be conscious strategies

Age Structure Pyramids

graphical representations of populations' ages.

Fertility rates

a measure of population growth through reproduction; often expressed as the average number of births per 1,000 people in the total population or the average number of children a woman would be expected to have


(ecology) a group of interdependent organisms inhabiting the same region and interacting with each other


the type of environment in which an organism or group normally lives or occurs


(ecology) the status of an organism within its environment and community (affecting its survival as a species)


the condition or result of being changed


the property of a sound that has a rich and pleasing timbre


the quality of being balanced

Interspecific competition

in a community competition for resources between members of different species


the act of forcing out someone or something

Resource Partitioning

in a biological community various populations sharing environmental resources through specialization thereby reducing direct competition


process by which two species evolve in response to changes in each other


an animal or plant that lives in or on a host (another animal or plant)


insects lay their eggs in hosts (often paralyzed), young hatch, eat host alive

Keystone Species

a species whose impact on its community or ecosystem are much larger and more influential than would be expected from mere abundance


a system formed by the interaction of a community of organisms with their physical environment

Energy Flow

The passage of energy through the components of an ecosystem

Carbon Cycle

the organic circulation of carbon from the atmosphere into organisms and back again

Nitrogen cycle

the circulation of nitrogen

Nitrogen Fixation

the assimilation of atmospheric nitrogen by soil bacteria and its release for plant use on the death of the bacteria

Phosphorous Cycle

the cyclic movement of phosphorus in different chemical forms from the environment to organisms and then back to the environment

Water Cycle

the continuous process by which water moves from Earth's surface to the atmosphere and back

Trophic Levels

The hierarchical levels of the food chain through which energy flows from primary producers to primary consumers, secondary consumers and so on.


the selective absorption and concentration of molecules by cells

Ecosystem Services

Important environmental benefits, such as clean air to breathe, clean water to drink, and fertile soil in which to grow crops, that ecosystems provide

Habitat Destruction

the loss of a natural habitat


separating something into fine particles

Invasive Species

plants and animals that have migrated to places where they are not native


exploitation to the point of diminishing returns


the removal of trees


the gradual transformation of habitable land into desert

Climate Change

a change in the world's climate

Greenhouse effect

warming that results when solar radiation is trapped by the atmosphere

Greenhouse Gas

a gas that contributes to the greenhouse effect by absorbing infrared radiation

Ecological Footprint

The amount of biologically productive land and water needed to support a person or population.

Carbon Footprint

measure of the impact human activities have on the environment in terms of the amount of greenhouse gases produced, measured in units of carbon dioxide


The ability to keep in existence or maintain. A sustainable ecosystem is one that can be maintained

Vampire Power

Things that are still using power even when you're away and not using them

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