The Great Clade Race 10/24/18

Organize the 8 cards into distinct groups using any criteria Attempt #1 Organize the 8 cards into distinct groups using any criteria

Scenario Imagine a race through the woods. All participants in the race start at the same starting line at one end of the woods. As the race continues, the path through the woods repeatedly splits, and runners are free to take either fork. Each series of forks leads to a separate finish line at the other end of the forest. As the runners make their way through the woods, each carries a card that must have stamped at check-in stations along the way.

Challenge Draw a map of the racecourse, complete with check-in stations. Rules 1. All runners must complete the race. They cannot stop part of the way down a path. 2. When the path branches, it only branches into two new paths, never three or more. 3. Once two paths have branched off from one another, they can never reunite. 4. Check-in stations are located along straightaways between the branching points.

Definitions Clade: a group of organisms believed to have evolved from a common ancestor, according to the principles of cladistics. Synapomorphy: a characteristic present in an ancestral species and shared exclusively (in more or less modified form) by its evolutionary descendants. Cladogram: shows evolutionary relationships between groups of living things. It is like a family tree for species.

Take the new 9th card and place it into the cladogram New Challenge Take the new 9th card and place it into the cladogram

Definitions Homology: characteristic shared by two or more organisms but is absent from their common ancestor or from a later ancestor in the lineage leading to one of the organisms. Homoplasy: The acquisition of a similar form or structure between species of different lineages as a result of convergent evolution

Parsimony This principle tells us to choose the simplest scientific explanation that fits the evidence. In terms of tree-building, that means that, all other things being equal, the best hypothesis is the one that requires the fewest evolutionary changes.