AP Bio Evolution

the selective breeding of domesticated plants and animals to encourage the occurrence of desirable traits

favors individuals at one end of the phenotypic range

favors individuals at both extremes of the phenotypic range

favors intermediate variants and acts against extreme phenotypes

anatomical resemblances that represent variations on a structural theme present in a common ancestor

reveals anatomical homologies not visible in adult organisms

remnants of features that served important functions in the organism’s ancestors

genes shared among organisms inherited from a common ancestor

the evolution of similar features in distantly related groups

arise when groups independently adapt to similar environments in similar ways

the geographic distribution of species

found only in that part of the world and nowhere else

change in allele frequencies in a population over generations

describes how allele frequencies fluctuate randomly from one generation to the next (in small populations)

occurs when a few individuals become isolated from a larger population. allele frequencies in the small population can be different from those in the larger parent population

a sudden reduction in population size due to a change in the environment, such as a
natural disaster. the resulting gene pool may no longer be reflective of the original population’s gene pool

consists of the movement of alleles among populations (immigration and emigration). tends to reduce differences between populations over time

the origin of new species

the existence of biological factors (barriers) that impede two different species from producing viable, fertile offspring

block fertilization from occurring by:
• Impeding different species from attempting to mate.
• Preventing the successful completion of mating.
• Hindering fertilization if mating is successful

Two species encounter each other rarely, or not at all, because they occupy different habitats

Species breed at different times of the day or different seasons

Courtship rituals and other behaviors are unique to a species

Morphological differences can prevent successful mating

Sperm of one species may not be able to fertilize eggs of another species

prevent the hybrid zygote from developing into a viable, fertile adult

weak offspring

sterile offspring

weak or sterile offspring in the next generation

a population forms a new species while geographically isolated

a subset of a population forms a new species without geographic barrier

4.6 billion years ago

3.9 billion years ago

3.5 billion years ago