Supplemental Instruction
Iowa State University / Leader: / Andre
Course: / BIOL 211
Instructor: / Dr. Debinski, Dr. Heath
Date: / August 30, 2016
What are the five fundamental characteristics of life?
Energy, Cells, Information, Replication, Evolution
Compare and contrast, and explain 2 examples of each:
Theory:Hypothesis:
What is a domain? What are the 3 domains of life? Which domains are prokaryotic or eukaryotic?
Eukarya, Bacteria, and Archaea are the 3 domains. Bacteria and Archaea are Prokaryotes, meaning that they lack a membrane-bound nucleus.
Construct a timeline of the critical points in the history of life as discussed in lecture.
This will be covered in a different SI session.
Explain the Tree of Life.By what process does the tree expand to list more species? What are phylogenetics and taxonomy, and how do they compare?
The Tree of Life basically proves the concept that all organisms evolved from a Single Common Ancestor. Evolution (which acts on a population) and natural selection (which acts on the individuals) occur by the adaptation of traits. These traits must be 1. heritable and varying, and 2. advantageous for reproduction. The point of these traits is to increase fitness, or reproductive strength.
Speciation is the divergence process by which the tree expands into more species, and occurs when evolution acts upon a population.
Phylogeny is the genealogical relationship between organisms.
Taxonomy is the process by which the organisms are named.
-The Linnaeus system is the way that organisms are named: Genus species
-A taxon itself is a class of organisms in a tree. It can be at ANY level of classification (ex: can be as large as a Kingdom or as small as a Genus), and is monophyletic.
Draw a phylogenetic tree, labeling and explaining clades, branch lengths, and rootings.
In regards to phylogenetic trees, what are the differences between homoplasy and homology? How are these related to the differences between paraphyletic groups, polyphyletic groups, and monophyletic groups?
A clade is any monophyletic group. For example, HIJ are all in the same clade, as their common ancestor is shared between all of its descendants.
A node is a location where a branch splits due to speciation, such as the common ancestor of B+C+D.
The root is basically the oldest common ancestor of a tree. In this tree, it’s the node furthest left.
Branchlengths can have meaning depending on the tree. They can show genetic difference between species, or the duration of time between the nodes.
Examples of a paraphyletic group include the Wasp family. The group commonly referred to as “Wasps” is actually a clade consisting of 7 types of insects, of which 2 are the ants and bees. Only 5 of those 7 are actually wasps, so that makes the group paraphyletic.
Examples of a polyphyletic group include “pandas.” The red panda and the panda bear, to be exact. Both are not closely related to each other, with the red panda being closer to raccoons and skunks. When we refer to the “pandas,” the two animals’ most recent common ancestor is not referred to as being a “panda.” Therefore, the group is polyphyletic.
Homoplasy is when two species develop similar traits separately from each other, meaning they did not inherit them from a recent common ancestor. This is related to polyphyletic classification, because the red panda and the panda bear developed similar looks despite being minimally related.
Homology is when two species inherit their traits from a common ancestor, and is a derived trait that shows an evolutionary relationship. For example, humans and most primates have opposable thumbs. This trait was inherited from a common ancestor between humans and primates.