Final Exam Flashcards
What is a phylogenetic tree?
A graphical description of evolutionary history. Focus on nodes when interpreting.
Define “phylogeny”
Evolutionary history meaning “kind or type of production
What are the different parts of a phylogenetic tree?
- Root: Base of the tree
- Branch: Horizontal lines represents a specific species as it changes through time
- Node: Branches splits into two or more descendant groups during a speciation event.
- Tips: Labeled name of the taxon represented at each tip
What is a taxon?
A taxon represents any named group.
What is a monophyletic group?
A group that consists of an ancestry and all of its descendants (also known as lineages). Natural evolution group due to shared ancestory.
What is homoplasty?
Similarity in traits that is due to independent evolution.
What is a synapomorphy?
Any characteristic or trait that is shared by other members of monophyletic group but is not found in other groups.
Arise once an ancestor has split into descendant groups.
What is homology?
Similarity in traits that is due to common ancestry. Like birds and humans being bipedal
On a phylogenetic tree, what is the outgroup?
Outgroups are linage that is not part of the monophyletic group that is focus of the tree. An outgroup can have no members associated with it (remebmer invertabrae question)
What is the single origin hypothesis and why do scientists like it?
Single origin states that we come from once common ancestor. They like it because of parsimony (simple = correct)
What is the difference between a clade and not a clade?
What are the ancient greeks four prevailing views about organisms?
- Species are static, meaning that they do not change through time
- Variation among individuals within species is extremely limited, and in its inconsequential.
- Species were created independently, meaning that they were not related to each other; and
- Species were created recently
What is the 19th century theory of evolution?
Species change over time because certain traits in populations lead to higher fitness.
Currently, life scientists update this claim by pointing out that natural selection and other evolutionary processes change allele frequencies in every species in every generation.
What is the evidence of change throughout time?
Fossil Record that has two types of data:
- Extinction: Species ceases to exist
- Transitional Forms: In addition to finding fossils from species that are no longer present, many species that are alive today have no representative in the fossil record.
Fossil record is the reason we know species are related.
If earth formed January first, when would we see life begin? When would we see photosynthesis begin? Plants on land?
Life: April
Photosynthesis: June
Plants on land: November
What is macroevolution?
Describes trends and changes that occur across different taxa
What are two important structures to understand macroevolution?
- Homology (Structural, Molecular)
- Fossil Record
What are the different forms of fossils?
- Actual Remains
- Indirect evidence - foot print in rock
- Molecular in nature - ancient DNA
- Very small fossilized spores
What are transitional fossils?
Fossils from an early version of an important adaptation. The estimated time of these fossils give us an idea of what the adaptations occured.
What is important about the African Rift Lake?
They house an enormous amount of varius chichlid species that demonstrate rapid adaptive radiation creating new species to occupy new niches.
What is adaptive radiation?
The rapid diversification of a single lineage into a large number of species, each adaptation allows them to exploit a different resource and habitat.
What are the three significant domains from the tree of life?
- Archea
- Bacteria
- Eukaryote
What are bacteria?
A monophyletic group that all share the common characteristics of:
- Almost all unicellular
- Almost all have a single circular chromosome, though many also have small, circular, auxiliary DNA molecules called plasmids.
- Some are able to perform photosynthesis and obtain energy from outside sources.
What is a key synapomorphy of bacteria?
Cell walls that feature a structural carbohydrate called peptidoglycan which is a lattice made of sugars lined with hlycosidic bonds, but also have short chains of peptide-bonded amino acids that:
- Protrude from them
- Line adjacent chains