A3.2 Classification and Cladistics Flashcards
Define “taxonomy”
is the science of classifying organisms.
List the levels of classification in the traditional hierarchy of taxa.
Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species
(dear king phillip came over for good soup)
Define clade.
groups of organisms (or viruses) with a common ancestry and shared traits.
draw a clade
question 4
State that DNA and amino acids sequences can be the basis for constructing cladograms.
If two species have very similar DNA or amino acid sequences, it means they are more closely related. If their sequences are different, it shows they are more distant relatives. By looking at these similarities and differences, scientists can build a cladogram
Define “parsimony” as used in a biological context.
choosing the simplest explanation or solution to an observed data
Outline how the principle of parsimony relates to evolutionary divergence between the members of a clade.
The principle of parsimony suggests that evolutionary divergence within a clade occurred with the smallest number of changes.
Define “cladogram”.
Cladograms are tree diagrams which show the most probable sequence of divergence between clades
Outline what is represented by a “root”, “node” and “terminal branch” on a cladogram.
Root: The starting point that represents the most recent common ancestor of all organisms in the diagram.
Node: the point on a cladogram where a common ancestor diverges into two or more groups.
Terminal Branch: is an endpoint of a cladogram representing one group.
Outline the reason and evidence for the reclassification of the figwort family.
**Reason: **DNA studies showed that classifying plants based on appearance wasn’t correct.
Evidence:
* Many plants were found to be more closely related to other families
* Genetic trees showed new evolutionary connections that didn’t match the old system.
* Because of this, some plants were moved to different families for a more accurate classification.
List the three domains of life.
Archaea (archaeans)
Eubacteria (bacteria)
Eukarya (eukaryotes)
Discuss evidence from rRNA base sequences that led to the reclassification of life from two cell types (prokaryotic and eukaryotic) to three domains.
Originally, life was classified into two types: prokaryotic (simple) and eukaryotic (complex) cells. However, by comparing rRNA sequences, scientists discovered that Archaea (a type of prokaryote) was more closely related to eukaryotes than to other prokaryotes like Bacteria. This led to the reclassification into three separate domains based on genetic evidence.
