HS - LS4.A - Genetic Information - ASSIGNED (WND 4/23/2014)

Module: Evidence of a Common Ancestry

DCI: LS4.A Genetic information, like the fossil record, provides evidence of evolution. DNA sequences vary among species, but there are many overlaps; in fact, the ongoing branching that produces multiple lines of descent can be inferred by comparing the DNA sequences of different organisms. Such information is also derivable from the similarities and differences in amino acid sequences and from anatomical and embryological evidence.

PE: HS-LS4-1 Communicate scientific information that common ancestry and biological evolution are supported by multiple lines of empirical evidence.

[Clarification Statement: Emphasis is on a conceptual understanding of the role each line of evidence has relating to common ancestry and biological evolution. Examples of evidence could include similarities in DNA sequences, anatomical structures, and order of appearance of structures in embryological development.]

The ideas here are: 

- genetic information provides evidence that evolution has taken place

- DNA sequences vary from one species to another,, but there are overlaps

- overlaps in DNA sequences can help us understand lines of descent

- We can also gather information about common ancestry from comparing similarities in differences in amino acid sequences

- Another type of information supporting common ancestry is found by comparing anatomical and embryological development

The main idea is that there are multiple sources of information which support the ideas of common ancestry and biological information.  Students need to be able to describe how each type of evidence contributes to our current understandings.  We wrote a middle school batch with similar content, so we can look to those questions for ideas. 

Possible Question Starters: 

Which of the following would provide evidence that two types of organisms shared a common ancestor? 

A chart comparing the base sequences of homologous segments of DNA from various primates is provided.  The information in the chart can be used to support the claim that which pair of organisms have the most recent common ancestor?