Evidence for Biological Change over Time

Comparative Anatomy

Determining the relatedness between species based on anatomical similarities.

Embryology

Comparative study of embryos to determine the relationship between their species

Homologous structures

Similar physiological structures shared by different organisms stemming from a common ancestor

Vestigial Homologous structures

A structure in an organism that is no longer useful, indicating that the organism evolved from an ancestor that needed the structure.

Divergent Evolution

Differences between species accumulate and lead to speciation

Analogue Structures

The same key features between organisms that evolved separately due to convergent selection

Convergent Evolution

Unrelated organisms evolving similar adaptations due to similar environments

Molecular Homology

Determining relatedness between species based on their DNA and amino acid sequences

DNA Hybridization

Hybridizing DNA from different species and testing the strength of its connection. the stronger the connection, the more related the species.

Chain Termination Method

Sequencing and comparing DNA, adding dideoxynucleic acids which will terminate the strand if attatched instead of a nucleic acid upon attachment. eventually all combinations can theoretically be made.

Edman Degradation

A chemical attaches to the N terminal amino acid and breaks it off, the amino acid is sequenced. process is repeated for each individual amino acid.

Phylogenetic Trees

Depicts relatedness between species, measuring the evolutionary distance by amino acids using branches

Phylogram

Phylogenic tree that has a time scale, depicting how long ago each species diverged

Cladograms

Phylogenic tree that does not have a time scale, measuring the relationship between the species based on similarities in DNA sequences.