AP Biology Chapter 26 Flashcards

Questions and Answers

What is systematics? How is it used to develop phylogenetic trees?

Systematics is a discipline focused on classifying organisms and determining their evolutionary relationships. Phylogenetic trees display the systematics.

What is phylogeny?

The evolutionary history of a species.

What is taxonomy?

How organisms are named and classified.

What is your binomial? What does it mean?

Homo sapiens - 'wise man'. Signup and view all the answers

What are the two components of every binomial?

Genus (capitalized) and species (specific epithet with a Latin ending). Signup and view all the answers

What are the orders of taxonomy (hierarchical categories)?

Species, genus, family, order, class, phylum, kingdom, domain. Signup and view all the answers

What is a taxon?

A group of organisms in a classification system. Signup and view all the answers

Which are more closely related, organisms in the same phylum or those in the same order?

Order. Signup and view all the answers

Label the common ancestor (each branch point) of the striped and otters, and then label the common ancestor of cats and dogs.

Otter/Skunk is the line right before the genus, dog/cat is right after the order. Signup and view all the answers

What is a phylogenetic tree?

A display of the evolutionary history of a group of organisms. Signup and view all the answers

What are sister taxa?

Groups of organisms that share an immediate common ancestor not shared by any other group. Signup and view all the answers

What is a basal taxon?

A lineage that diverges from all other members of its group early in history. Signup and view all the answers

What is an outgroup?

A more distantly related group of organisms that serves as a reference group. Signup and view all the answers

What is molecular systematics? How is it a valuable tool to sort homology from analogy?

Molecular systematics studies similar DNA sequences = homologies. Signup and view all the answers

What is a clade?

Placement of a species into groups that include ancestral species and all of its descendants. Signup and view all the answers

What does it mean to be monophyletic?

A group that consists of an ancestral species and all of its descendants. Signup and view all the answers

What does it mean to be paraphyletic?

The most recent common ancestor is included and some of the descendants are included, but not all. Signup and view all the answers

What does it mean to be polyphyletic?

A group that includes distantly related species but not their most recent common ancestor. Signup and view all the answers

What are shared derived characters?

A character originated in an ancestor of the taxon. Signup and view all the answers

Explain why for mammals, hair is a shared derived character, but a backbone is not.

All vertebrates have a backbone, not just mammals. Hair diverged from a more recent common ancestor than the backbone. Signup and view all the answers

What is maximum likelihood?

When considering multiple phylogenetic hypothesis, one should take into account the hypothesis that reflects the most likely sequence of evolutionary events. Signup and view all the answers

What is maximum parsimony?

Simplest explanation that is consistent with facts -- fewest evolutionary changes. Signup and view all the answers

DNA that codes for what changes relatively slowly over years?

rRNA (ribosomal RNA). Signup and view all the answers

DNA that codes for what evolves rapidly?

mtDNA (mitochondrial DNA). Signup and view all the answers

Which method (rRNA or mtDNA) reveals that fungi are more closely related to animals than to green plants?

rRNA. Signup and view all the answers

Which method (rRNA or mtDNA) reveals that the Pima of Arizona and Yanomami of Venezuela are descendants of the same Native American species?

mtDNA. Signup and view all the answers

What are the two homologous genes?

Paralogous and orthologous. Signup and view all the answers

What are orthologous genes?

Homology as a result of speciation and occurs between genes found in different species. Signup and view all the answers

What are paralogous genes?

Homology results from gene duplication within a species. Signup and view all the answers

What are molecular clocks?

An approach for measuring the absolute time of evolutionary change based on the observation that some genes evolve at constant rates. Signup and view all the answers

If a molecular clock is used, approximately when did HIV emerge?

1930s. Signup and view all the answers

What are the three domains?

Bacteria, Archaea, and Eukarya. Signup and view all the answers

What two domains include all prokaryotes?

Bacteria and Archaea. Signup and view all the answers

Which two domains are most closely related?

Eukarya and Archaea. Signup and view all the answers

Which kingdom is made obsolete by the three-domain system? Why?

Monera is obsolete because it would have members from different domains in it. Signup and view all the answers

Which kingdom crumbled because it is polyphyletic?

Protista. Signup and view all the answers

What is horizontal gene transfer?

Process in which genes are transferred from one genome to another. Signup and view all the answers

Study Notes

Systematics and Phylogeny

Systematics classifies organisms and determines their evolutionary relationships.
Phylogenetic trees visually represent these relationships and evolutionary history.
Phylogeny refers to the evolutionary history of a species, essential for understanding organism relationships.

Taxonomy

Taxonomy is the method of naming and classifying organisms.
A binomial consists of two parts: the genus (capitalized) and the species (specific epithet in Latin).
Taxonomic hierarchy includes species, genus, family, order, class, phylum, kingdom, and domain.

Phylogenetic Trees

A phylogenetic tree displays evolutionary history, illustrating patterns of descent among organisms.
Sister taxa are groups that share the same immediate common ancestor.
A basal taxon diverges early in a lineage, making it distinct from other members.

Clades and Taxa

A clade includes an ancestral species and all its descendants, showing monophyly.
Monophyletic groups include all descendants, while paraphyletic groups include some, and polyphyletic groups include unrelated species without a recent common ancestor.
Shared derived characters are traits that originated in an ancestor of a particular taxon.

Molecular Systematics

Molecular systematics uses genetic data to identify homologies (similar DNA sequences) versus analogies (similar traits due to convergent evolution).
rRNA evolves slowly and helps analyze ancient taxa, while mtDNA evolves quickly, useful for recent evolutionary events.

Evolutionary Analysis

Maximum likelihood and maximum parsimony are methods for evaluating phylogenetic hypotheses based on DNA sequences and the simplest explanations, respectively.
Molecular clocks estimate evolutionary timelines, with some genes evolving at constant rates.

Domains of Life

There are three domains: Bacteria, Archaea, and Eukarya.
Bacteria and Archaea encompass all prokaryotes, while Eukarya is closely related to Archaea.
The kingdom Monera becomes obsolete as it mixes organisms from different domains, and the kingdom Protista is considered polyphyletic due to its diverse members.

Horizontal Gene Transfer

Horizontal gene transfer refers to genetic exchange between organisms, complicating phylogenetic analysis and resulting in inconsistent relationships in trees derived from different genes.

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Description

Test your knowledge on phylogeny and the tree of life with these flashcards from AP Biology Chapter 26. This chapter covers systematics, phylogeny, and taxonomy, making it essential for understanding evolutionary relationships among organisms.