Chapter 26 Phylogeny And The Tree Of Life

Front 1

1. Distinguish between phylogeny and systematics.

Back 1

Phylogeny is the evolutionary history of an organism and systematics are all the methods used to determine phylogenic relationships.

Front 2

2. Explain the following characteristics of the Linnaean system of classification:
a. Binomial nomenclature
b. Hierarchical classification.

Back 2

Bionomial nomenculture- genus is always capitialized. Specific epithet not apitalized ever. Canus lupas
Hierachical classification. At each level of the linnaean classification system, species are placed into groups belonging to more comprehensive groups.

Front 3

3. Explain the statement: “A phylogenetic tree represents a hypothesis about evolutionary relationships.”

Back 3

The tree of life is like an estimation of evolution in the past

Front 4

4. Explain why it is crucial to distinguish between homology and analogy before selecting characters to use in the reconstruction of phylogeny. Describe how homology and analogy can be distinguished from each other.

Back 4

Homology- similarity in characteristics resulting from a shared ancestry.
Analogy- similarity between two species that is die to convergant evolution rather than decent from a common ancestor with the same trait

Front 5

5. Explain why bird and bat wings are homologous as vertebrate forelimbs but analogous as wings.

Back 5

Bat wings are most of hand. Bird wings use on finger. Came from different tetrapod ancestors.

Front 6

6.Define molecular systematics. Explain some of the problems that systematists may face in carrying out molecular comparisons of nucleic acids.

Back 6

The discipline that uses DNA and other molecular data to determine evolutionary relationships. comparable nucleic acid sequences in distantly related species usually have different bases at many sites and may have different lengths.

Front 7

7.Define a clade. Distinguish between a monophyletic clade and paraphyletic and polyphyletic groupings of species

Back 7

Clade- A kind of group of species that include an ancestral species and all of its decendants.
Monophyletic- pertaining to a group of taxa that conists of a common ancestor and all its decendants.
Polyphletic- pertaining to a group of taxa derived from two or more different species

Front 8

8.Distinguish between shared ancestral characters and shared derived characters.

Back 8

shared ancestral character- a character shared by members of a particular clade. that originated in an ancestor that is not a member of the clase.
Shared derieved character- An evolutionary novelty that is unique to a particular clade.

Front 9

9.Explain why shared derived characters are useful in establishing a phylogeny, while shared ancestral characters are not.

Back 9

Shared derived characters are unique to particular clades. Because all features of organisms arose at some points in the history of life, it should be possible to determine the clade in which each shared derived character first appeared and to use that information to infer evolutionary relationship

Front 10

Distinguish an ingroup from an outgroup.

Back 10

Outgroup is a species or group of species from an evolutionary lineage that is know to have diverged before the lineage that includes the species we are studying
Ingroup- A Species or group of species wose evolutionary relationship we seek to determine.

Front 11

Discuss how systematists use the principles of maximum parsimony and maximum likelihood in reconstructing phylogenies.

Back 11

According to the principle of maximum parsimony. we should first investigate the simplets explanation that is consistent with the facts. The priciple of maxiumum likelihood states that given certain rules about how DNA changes over time, a tree can be found that reflects the most likely sequence of evolutinary events.

Front 12

Distinguish between orthologous and paralogous genes. Explain how gene duplication has led to families of paralogous genes.

Back 12

The term orthologous gene refers to homologous genes that are found in different species because of speciation.
Paralogous genes result from gene duplication, so they are found in more than one copy in the same genome.

Front 13

Explain how molecular clocks are used to determine the approximate time of key evolutionary events. Explain how molecular clocks are calibrated in actual time.

Back 13

Number of nucleotide sequences is proportional to the time that has passed since branching from a common ancestor. We can calibrate the molcular clock of a gene that has a reliable average rate of evoltion by graphing the number of genetic differences.

Front 14

Describe some of the limitations of molecular clocks.

Back 14

Some DNA changes are favored over others. Extension of molecular clocks past fossil evidence ( have to assume uniform rates of DNA change) Avoid problems with sequencing many genes to average out the different rates of change

Front 15

Explain the neutral theory of evolutionary change

Back 15

The hypothesis that much evolutionary change in genes and proteins has no effect on fitness and therfore not influenced by darwinian natural selection

Front 16

Define Cladogam

Back 16

A depiction of patterns of shared characteristics among taxa.

Front 17

Define convergent evolution

Back 17

The evolution of similar features in indepenent evolutionary lineages.