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an organic compound, either RNA or DNA, whose molecules are made up of one or two chains of nucleotides and carry genetic information
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
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)
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 confined inside the microorganisms and is released only when the microorganisms are broken down or die
The study of populations in relation to the environment, including environmental influences on population density and distribution, age structure, and variations in population size.
evolutionary effects on systems of mating and rearing offspring; these need not be conscious strategies
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
(ecology) the status of an organism within its environment and community (affecting its survival as a species)
in a community competition for resources between members of different species
in a biological community various populations sharing environmental resources through specialization thereby reducing direct competition
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
the assimilation of atmospheric nitrogen by soil bacteria and its release for plant use on the death of the bacteria
the cyclic movement of phosphorus in different chemical forms from the environment to organisms and then back to the environment
the continuous process by which water moves from Earth's surface to the atmosphere and back
The hierarchical levels of the food chain through which energy flows from primary producers to primary consumers, secondary consumers and so on.
Important environmental benefits, such as clean air to breathe, clean water to drink, and fertile soil in which to grow crops, that ecosystems provide
The amount of biologically productive land and water needed to support a person or population.
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
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