Evolution Last Common Ancestor Last Common Ancestor You

Last Common Ancestor You share a common ancestor with all living organisms. The most

Cladistics Common ancestry is expressed through cladograms.

Cladistics (cont. ) A group which includes an ancestor and all of its descendants

Cladistics (cont. ) However, a grouping of just Species A and Species B would

Cladistics (cont. ) A group (also called a taxon) that includes an ancestor and

Cladistics (cont. ) a monophyletic grouping (clade) includes an LCA and all of its

Molecular Clock Remember mutations? By analyzing the genetic differences between two organisms, one can

Assignment: In partners/groups of three, choose two animals from the list on the next

Assignment: Horse Human Dog Velociraptor Lobster Gorilla House Fly Pig Antelope Woodpecker Blue Whale

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Evolution Last Common Ancestor

Last Common Ancestor You share a common ancestor with all living organisms. The most recent common ancestor is called the Last Common Ancestor (LCA). The LCAs of you and your siblings are your parents. The LCAs of you and your cousins are your grandparents.

Cladistics Common ancestry is expressed through cladograms.

Cladistics (cont. ) A group which includes an ancestor and all of its descendants is referred to as a monophyletic grouping, or a clade. In this image, the grouping of Species A, Species B, and Species C together, would form a clade. Likewise, a group of just Species B and Species C would represent a clade.

Cladistics (cont. ) However, a grouping of just Species A and Species B would not represent a clade, because it does not include ALL of the descendants of the LCA.

Cladistics (cont. ) A group (also called a taxon) that includes an ancestor and only some of its descendants is called a paraphyletic grouping.

Cladistics (cont. ) a monophyletic grouping (clade) includes an LCA and all of its descendants. a paraphyletic grouping includes an LCA and only some of its descendants. In evolutionary biology, we are primarily concerned with clades, as they tell us how organisms are related to one another.

Primate Cladogram

Mammal Cladogram

Molecular Clock Remember mutations? By analyzing the genetic differences between two organisms, one can determine how recently they shared a common ancestor. It’s the same principle as paternity tests. http: //www. youtube. com/watch? v=YAfw 0 IE 2 DV 8

Assignment: In partners/groups of three, choose two animals from the list on the next page. Make sure at least one member of your group has a smartphone. Using your smartphones, try to figure out how recently those two animals shared a common ancestor. Also, try to determine which animals (from the list) would be needed to make the group a clade.

Assignment: Horse Human Dog Velociraptor Lobster Gorilla House Fly Pig Antelope Woodpecker Blue Whale Great White Shark Pig