Term | Definition |
symmetry | the ability to divide something in a way that all aspects of the division are copies of the others |
asymmetrical | Not identical on both sides of a central line. (sponges are an example) |
bilaterally symmetrical | found in organisms that have heads and tails; the ability to divide something in half so each part of the half is a mirror image of the other |
radially symmetrical | found only in sea animals; the ability to divide something in half by a variety of different means(sea anemone and starfish are examples) |
invertebrate | any member of the Kingdom Animalia that lacks a backbone; body symmetry can help scientists further classify invertebrates |
vertebrate | any member of the Kingdom Animalia that has a backbone and internal skeleton that protects their soft tissue |
endothermic | any animal whose body controls and regulates its temperature by controlling the internal heat it produces; their body temperatures are not influenced by the temperature of their environment, they are “warm-blooded” |
exothermic | aka ectothermic – any animal whose body does not produce much internal heat; since these organisms’ body temperatures are influenced by the temperature of their environment, they are considered “cold-blooded” |
asexual reproduction | any type of reproduction that involves only one parent that produces offspring that are identical to the parents (genetic clones) |
sexual reproduction | any type of reproduction that involves two parents who combine their genetic material to produce a new organism which differs from both parents |
gamete | a sex cell |
sperm | the male sex cell |
egg | the female sex cell |
fertilization | the process by which a sperm and egg cell join to form a zygote |
zygote | the result of fertilization; the first cell of any organism produced by sexual reproduction |
internal fertilization | the process by which sperm and egg unite within the body of the female of the species; often, this type of fertilization means either (a) the young will develop in eggs with shells OR (b) the young will develop within the body of the female |
external fertilization | process by which sperm and egg unite outside of the body of the female; to aid free-swimming sperm, this occurs in water; fish: release of roe by female happens first, and then milt is released by male; frogs: release of eggs and sperm happen at same time |
external development | an organism develops outside of the mother’s body; all animals that are the result of external fertilization develop externally; animals that are the result of eggs also develop externally |
internal development | an organism develops inside of the mother’s body; examples include almost all mammals, but some species of fish and reptiles also develop internally and are born via live birth |
milt | a fluid released by male fish during spawning which contains millions of free-swimming sperm |
fry | A newly-hatched fish with attached yolk sac that feeds the fry until it is big enough to find its own food (a juvenile fish) |
roe | the eggs released by a female fish during spawning |
yolk sac | a flap containing energy-rich materials that feed the fry after it hatches |
complete metamorphosis | the life cycle of certain types of insects; during the process, the insect goes through a dramatic change over four stages: egg, larva, pupa, adult |
incomplete metamorphosis | the life cycle of certain types of insects; during the process, the insect goes through a small change over three stages: egg, nymph, adult |
reproduction by regeneration | a means of asexual reproduction in which a portion of the parent organism yields an entirely new organism that is a clone of the parent |
budding | means of asexual reproduction in which the parent organism creates a bud, a small cell that contains a copy of the parent’s nucleus but a lesser amount of cytoplasm, that will eventually break off and grow into full-sized version of the original organism |