Morphological divergence among vertebrate forelimbs starting with the bones of a stem reptile The number and position of many skeletal elements were preserved when these diverse forms evolved notice the ...

To read this circular table of the genetic code start with the inner ring which contains the nucleotide in the first position nucleotide of a codon The second-position nucleotide is ...

Evolutionary tree diagram for the chordates based on morphology and genetic comparisons Colored boxes denote some of the clades that nest within the chordate clade and will be discussed again ...

Nondisjunction which can occur during anaphase I or II of meiosis Of the two pairs of homologous chromosomes shown here one fails to separate during anaphase I A zygote that ...