Module 4 Intro

Module 4—Mechanisms of Population Change

Module Glossary

 

adaptation: a beneficial variation that helps an organism survive

 

allopatric: speciation that occurs from a geographical barrier

 

analogous structures: body parts in different species that have similar functions but evolved separately

 

barrier: anything that prevents organisms from reproducing

 

biogeography: the study of the past and present geographical distribution of species

 

biological barrier: a factor such as behaviour that keeps species reproductively isolated even when they exist in the same region

 

divergence: the development of one or more new species from a parent species as a result of mutation and adaptation to changing environmental conditions: the parent species continues to exist

 

embryology: the study of similar features in embryos and evolutionary relationships that may exist

 

fossils: the remains of past life found in sedimentary rock

 

geographical barrier: geological formations that keep organisms separated

 

gradualism: the theory that evolution occurs slowly and steadily in a linear fashion

 

gradualism: gradual change occurs in a steady, linear way over time

 

homologous structures: body parts in different species that have the same evolutionary origins and structural elements but may have different functions

 

hypothesis: a statement that provides one possible answer to a question or one possible explanation for an observation

 

inheritance of acquired characteristics: a theory that characteristics acquired during an organism’s lifetime could be passed to its offspring

 

mutagen: something that causes an increased rate of mutation

 

mutation: a change in the genetic material of an organism (DNA)

 

natural selection: the process that results when the characteristics of a population of organisms change because individuals with certain inherited traits survive specific local environmental conditions and, through reproduction, pass on their traits to their offspring

 

paleontology: the study of ancient life through the examination of fossils

 

punctuated equilibrium: evolutionary history is said to consist of long periods of equilibrium, interrupted by periods of speciation

 

punctuated equilibrium: the theory that suggests that evolutionary history consists of long periods of stasis (stable equilibrium), punctuated by periods of divergence

 

selective advantage: an organism’s variations increase its chances of surviving

 

selective disadvantage: an organism’s variations reduce its chances of surviving

 

selective pressure: environmental conditions that select for certain characteristics of individuals and select against other characteristics

 

sexual selection: a type of natural selection where characteristics are selected based on mate preferences

 

speciation: the formation of new species

 

strata: a layer of rock or soil that has a consistent character and is different from layers above and below it

 

transformation: the evolution of one species into another as a result of mutation and adaptation to changing environmental conditions, resulting in the replacement of the old species

 

transitional fossil: the remains or impression of a prehistoric organism that shows intermediary links between groups of organisms and shares characteristics common to these groups

 

variation: visible or invisible differences between individuals

 

viable offspring: offspring that are healthy and able to reproduce and create new offspring

Biology 20 © 2008 Alberta Education