Classification Notes B-5.7 Practice Phylogenetic Trees

How is life classified? Based on structural, cellular, biochemical, and genetic characteristics, living things are classified into groups that reflect the planet’s evolutionary history. Most phylogenetic trees reflect this idea by being rooted, meaning they’re drawn with a branch that represents the common ancestor of all the groups on the tree. The tips of the branches represent the species or other taxa that scientists compare. Branches meet at points called nodes that represent the common ancestor of the two taxa. Scientists call groups that branch out from the same common ancestor sister groups. An ancestor plus all its descendants form a clade.

Example – Phylogenetic Tree Clade: Group of species which share a common ancestor Time: Top is now, Bottom is past Taxon: Separate Species Common Ancestors: X and Y Conclusions: X = Common ancestor of _________________ Y = Common ancestor of _________________ Taxon B is more closely related to ______________

Practice What trait was found in the common ancestor of all 4 species? The Bat shares a more recent common ancestor with the _____. Bats and Birds both have wings due to which pattern of evolution? Co-evolution Divergent Convergent Common ancestry

Based on the tree, Crocodiles are least closely related to _____. Non-avian dinosaurs share a more recent common ancestor with ______. Use evidence from the tree to support the statement, “lizards are most closely related to snakes.”

Animal Phylogenetic Tree Are crustaceans more closely related to mollusks or insects? Why? Which trait separates birds from reptiles? Are crocodiles more closely related to iguanas or birds? Why? What represents the common ancestor to all the animals?

Use the tree to the right to answer the questions: Approximately when did non-avian dinosaurs go extinct? Are frogs and salamanders more closely related to ray-finned fish or lizards? Placentals share a more recent common ancestor with ____.

Adaptive Radiation of Finches The many species of finch is due to which of the following: co-evolution Divergent evolution Convergent evolution