Crossword Puzzle

Biology Crossword


  1. a process started by an event (e.g. forest fire, harvesting, hurricane, etc.) that reduces an already established ecosystem (e.g. a forest or a wheat field) to a smaller population of species (secondarysuccession)
  2. pertains to the leaving of a place of residence or habitat with the intent of living in another place. (emigration)
  3. A colorless insecticide that kills on contact. It is poisonous to humans and animals when swallowed or absorbed through the skin. (ddt)


  1. any member of the mammalian group characterized by the presence of an organ, which facilitates exchange of nutrients and wastes between the blood of the mother and that of the fetus (placentalmammal)
  2. the science of vital and social statistics, as of the births, deaths, diseases, marriages, etc., of populations. (demographics)
  3. the conversion of atmospheric nitrogen into a combined form (such as ammonia) through chemical and especially biological action (such as that of soil rhizobia) (nitrogenfixation)
  4. The directional movement of an organism or a living motile cell in response to certain diffusible chemicals in the environment (chemotaxis)
  5. the process in which toxins are concentrated in an organism as larger animals continue to eat smaller animals. This process moves toxins up the food chain to larger organisms and is of particular concern with regards to concentrating dangerous toxins in larger species. (biomagnification)
  6. The bodily movement of a motile organism in response to light, either toward the source of light ( positive ______ ) or away from it ( negative _____ ). (phototaxis)
  7. a plant's natural growth response to the effects of gravity (gravitropism)
  8. a relationship between individuals of two species in which one species obtains food or other benefits from the other without either harming or benefiting the latter. (commensalism)


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