DNA & Populations

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Let’s Review

What is a cell? How many cells make up an organism?

What is the nucleus?

What is DNA? What is it made up of?

What is a sequence of DNA called?

Why is DNA important? What is one way that DNA

sequences can change?Image sources: http://www.jimmyjanesays.com/sketchblog/2007/04/plant-cell.html (Plant cell)http://www.biologycorner.com/bio1/DNA.html (DNA diagram)

How do we know gene sequences?

Geneticists use a technique called gel electrophoresis

This technique breaks apart a gene in a predictable way, allowing scientists to piece the sequence back together

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Why is this important?

DNA sequences can tell you how species are

related

Species – organisms that can interbreed

Isolation can cause the formation of new species

Species with more similar sequences are more closely related

You can discover the order in which islands were colonized

Example:

Bird A: GTCC

Bird B: GACC

Bird C: GAGC

Bird D: GAGG

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