Chapter 26 - Biology - Phylogeny And Tree Of Life

Chapter 26 Biology Phylogeny And Tree Of Life
Created Feb 8, 2011
by bvolos
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Systematics
This is the discipline focused on classifying organisms by evolutionary relationships
Taxonomy
This is the term for how organisms are named and classified
Binomial nomenclature
This is the two-part format of scientific name instituted by 18th century Linnaeus. The first...
Homo sapien in latin
wise man
Hierarchal Classification
This method, founded by Linnaeus, groups species into hierarchy of increasingly inclusive categories....
Order of hierarchal classification 
From smallest to largest: species, genus, family, order, class, phyla, kingdom, domain
taxon
term for the unit at any level of hierarchy
PhyloCode
Systematists propose classification be based entirely on evolutionary code and relationships,...
Advantage of Phylogenetic tree
This is because this represents a hypothesis about evolutionary relationships.
Branch points
These represent relationships depicted as series of dichotomies. Each of these represents divergence...
Sister taxa
these are groups that share immediate common ancestors; closest relatives to one another
rooted tree
this is a branch point within a phylogenetic tree that represents the last common ancestor...
Polytomy
this is a branch point from which more than 2 descendants emerged
Limitations of Phylogynetic trees
These include its inability to indicate the real ages of a species; not time sensitive unless...
Advantages of Phylogenetic trees
These include information we can learn. For example, when mapping this for maize, or corn,...
What systemologists use to infer phylogeny
Morphology, genes, and biochemistry of relevant organisms.
Dna and genes are homologous if...
...they are descended from sequences carried by common ancestors
Just because two species have a great morphological divergence doesn't mean...
...they have a large genetic divergence. example: the hawaiin silversword looks different on...
Analogy
this is the term for similarity due to convergent evolution rather than shared ancestry
convergent evolution
this occurs when similar environmental pressure and natural selection produce similar, or analogous,...
How bats and birds illustrate the importance of distinguishing homology from analogy. 
Because both fly, one may assume the both come from the same ancestor. But really bone structure...
Homoplasies
analogous structures that arose independently
How to find homoplasies
complexity: the more points of resemblance 2 complex structures have, the more likely...
the 4 bases made up of nucleotides in DNA
A (adenine) G (guanine) C (cytosine) and T (thymine)
Steps for finding molecular homologies
first, sequence molecule's DNA, then align comparable sequences of 2 different species. If...
Molecular systematics
This is the discipline that uses DNA and other molecular data to determine evolutionary relationships
Cladistics
This is an approach to inferring phylogeny based only on common ancestry.
Clades
these are the groups biologists place species into. The include ancestral species and all its...
Monophyletic (clade)
This signifies a clade is like a taxon because it consists of an ancestor and all its descendants.
paraphyletic (clade)
this clade consists of an ancestor but on some descendants.
polyphyletic (clade)
This clade includes descendants with different ancestors 
Shared ancestral character
This is a character that originated in the ancestor of a taxon. example: backbone
shared derived character
this is an evolutionary novelty unique to a particular clade or generation. example: hair on...
Outgroup
this is a species or group of species from an evolutionary lineage known to have diverged before...
ingroup
this is the group being studied and lineage thereof.
Maximum parsimony
this is used in creating phylogenetic trees. The principle is based on Occam's Razor,...
Maximum likelihood
given certain rules about how DNA changes over time, a tree can be found that reflects the...
phylogenetic bracketing
this is a prediction (via parsimony) that features shared by 2 groups are present in an ancestor...
Advatanges of Molecular systematics
Firstly, these help us understand phylogenetic relationships that cannot be found nonmolecularly,...
gene families
groups or related genes within an organism's genome
orthologous genes 
these are homologous genes that are found in different species because of speciation. example:...
paralogous genes
these result from gene duplication; they are found in more than one copy in same genome. example:...
Molecular clocks
these help track evolutionary time; they are a yardstick for measuring the absolute time of...
Problems with molecular clocks
These include the problem that these things can only show, in most cases, certain trends because...
Neutral Theory
this theory states that much evolutionary change in genes and proteins has no effect on fitness...
First two kingdoms arranged by scientists
Plants and Animals, with bacteria in plants because it had a rigid cell wall. unicellular eukaryotes...
Animal requirements to be placed in first ever kindgom
unicellular organisms that move and digest food. 
5 Kingdoms
Monera (prokaryotes), protista (diversa; mostly unicellular organisms), plantae, fungi, animalia....
Fundamental problem with  5 kingdoms
some prokaryotes differed from each other as much as they did from eukaryotes
3 domains
bacteria, archea, and eukarya 
Bacteria Domain
This contains most of the known prokaryotes
Archea Domain
This contains a diverse group of prokaryotes that inhabit a variety or environments 
eukarya
This contains organisms that have cells that contain true nuclei; single celled organisms,...
Single celled organisms
this type composes the majority of life on earth historically
Monera and Protista
both of these kingdoms are obsolete because both are polyphyletic.
First major Split in the history of life
This event is when bacteria diverged from other organisms
rRNA genes
these have evolved so slowly that homologies between distantly related organisms can still...
Horizontal gene transfer
This is the process in which genes are transferred from one genome to another thru mechanisms...
Ring of life
This hypothesis is an alternative to traditional thinking about the tree of life. Horizontal...


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