community
  noun
  an interacting population of various kinds of individuals (as species) in a common location

conservation
 noun
  a careful preservation and protection of something; especially : planned management of a natural resource to prevent
  exploitation, destruction, or neglect

consumer
  noun
  an organism requiring complex organic compounds for food which it obtains by preying on other organisms or by eating
 particles of organic matter -- compare PRODUCER

egg
  noun
  an animal reproductive body consisting of an ovum together with its nutritive and protective envelopes and having the capacity
 to develop into a new individual capable of independent existence food chain

food pyramid
  noun
  an arrangement of the organisms of an ecological community according to the order of predation in which each uses the next
 usually lower member as a food source food web

food web
  noun
  the totality of interacting food chains in an ecological community

generation
  noun
  the average span of time between the birth of parents and that of their offspring

habitat
 noun
  the place or environment where a plant or animal naturally or normally lives and grows hibernation

hibernate
  verb
  to be or become inactive or dormant

larva
 noun
  the early form of an animal (as a frog or sea urchin) that at birth or hatching is fundamentally unlike its parent and must
  metamorphose before assuming the adult characters

life cycle
  noun
  a series of stages through which something (as an individual, culture, or manufactured product) passes during its lifetime

metamorphosis.
  noun
  a marked and more or less abrupt developmental change in the form or structure of an animal (as a butterfly or a frog)
 occurring subsequent to birth or hatching

migrate
  verb
    to pass usually periodically from one region or climate to another for feeding or breeding population

population
  noun
  the total of individuals of the same species occupying an area

producer
 noun
 any of various organisms (as a green plant) which produce their own organic compounds from simple precursors
  (as carbon dioxide and inorganic nitrogen) and many of which are food sources for other organisms pupa

pupa
  noun
  a stage of a metamorphic insect (as a bee, moth, or beetle) that occurs between the larva and the adult, usually enclosed in a
 cocoon or protective covering, and undergoes internal changes by which larval structures are replaced by those typical of the
 adult

reproduction
  noun
  to produce (new individuals of the same kind) by a sexual or asexual process

species
 noun
  a class of individuals having common attributes and designated by a common name an individual or kind belonging to a  biological group

system
  noun
 a group of related natural objects or forces
 

Dictionary definitions courtesy of:
Merriam-Webster On-line Collegiate Dictionary
http://www.m-w.com/home.htm