Definition of Terms
by Renee R.
Adapt: the process or state of changing to fit a new environment or different conditions, or the resulting change
Advanced Trait: a characteristic that evolved more recently in an organism’s history
Branch: a line on a cladogram that grows out from a node
Clade: a group of animals including their common ancestor and all the animals that have evolved from that common ancestor
Cladistics: a system of classification that groups organisms on the basis of their observed shared characteristics in order to find the common ancestors and other evolutionary relationships
Cladogram: a tree-shaped diagram showing evolutionary relationships and the points where species appear to have diverged from common ancestors
Common Ancestor: an organism from whom other organisms are directly descended, shared by at least two organisms
Evolution: the theoretical process by which all species develop from earlier forms of life. According to this theory, there are four points of natural selection organisms must follow: 1. Variance exists among individuals within a species 2. Organisms produce more offspring than the environment can support 3. Competition takes place within species for the essentials to survive 4. The traits that best help organisms to survive are passed down to the next generations
Node: a point on a cladogram, where a trait evolves and represents a common ancestor of all the animals branching from that point
Primitive Trait: a quality evolved at the first stages of an animal’s evolution
Trait: a characteristic; a physical or behavioral change that is represented by a node on a cladogram
Last updated April 6, 2007.