Biology Phylogeny and Classification Terms Quiz

Questions and Answers

What is phylogeny?

Evolutionary history of a species or group of species.

What is systematics?

A discipline focused on classifying organisms and determining their evolutionary relationships.

What is taxonomy?

The scientific study of how living things are classified.

What is a binomial?

The two-part Latinized name of a species, consisting of the genus and specific epithet. Signup and view all the answers

What defines a genus?

A group of similar species. Signup and view all the answers

What is the specific epithet?

Second part of the scientific name. Signup and view all the answers

What is a family in taxonomic classification?

Group of genera that share many characteristics. Signup and view all the answers

What does the order represent in taxonomy?

Group of similar families. Signup and view all the answers

What is a class in taxonomic hierarchy?

In classification, the taxonomic category above order. Signup and view all the answers

What does phyla refer to?

In classification, the taxonomic category above class. Signup and view all the answers

What are kingdoms in biological classification?

Archaebacteria, Eubacteria, Protista, Fungi, Plantae, Animalia. Signup and view all the answers

What are the domains in biological classification?

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

What is a taxon?

Named taxonomic unit at any level of the hierarchy. Signup and view all the answers

What is a phylogenetic tree?

Evolutionary history of a group of organisms represented in a branching diagram. Signup and view all the answers

What are branch points in a phylogenetic tree?

The representation of the divergence of two or more taxa from a common ancestor. Signup and view all the answers

Define sister taxa.

Groups of organisms that share an immediate common ancestor and hence are each other's closest relatives. Signup and view all the answers

What does 'rooted' mean in the context of a phylogenetic tree?

A branch point within the tree represents the most recent common ancestor of all taxa in the tree. Signup and view all the answers

What is a basal taxon?

Diverges early in the history of a group and originates near the common ancestor of the group. Signup and view all the answers

What is a polytomy?

A branch point from which more than two descendant groups emerge. Signup and view all the answers

Which is the basal taxon in the phylogeny shown?

Domestic cat. Signup and view all the answers

Which are sister taxa?

Coyote and Wolf OR striped skunk and otter. Signup and view all the answers

What does this tree indicate about the evolutionary relationships between the cat, skunk, and wolf?

The branching pattern indicates that the skunk and the wolf share a common ancestor that is more recent than the ancestor they share with the cat. Signup and view all the answers

Which levels of classification do humans share with leopards?

Domain, kingdom, phylum, and class. Signup and view all the answers

Which tree depicted shows a different evolutionary history?

C is different because the branch point results in B and C being sister taxa whereas the other two trees show that C and D are sister taxa. Signup and view all the answers

What is homology?

Similarity resulting from common ancestry. Signup and view all the answers

What is analogy?

Similarity due to convergent evolution. Signup and view all the answers

What are homoplasies?

Analogous structures that have evolved independently. Signup and view all the answers

Are a porcupine's quill and a cactus's spine homology or analogy?

Analogy because they are not closely related. Signup and view all the answers

Are a cat's paw and a human's hand homology or analogy?

Homology because they share a common ancestor but are now using the limb for different purposes. Signup and view all the answers

Are an owl's wing and a hornet's wing homology or analogy?

Analogy; there is not a close ancestor but both had the same need to fly. Signup and view all the answers

Suppose A and B have similar appearances but very divergent gene sequences, while B and C have different appearances but similar gene sequences. Which pair is more likely to be closely related?

B and C because they share similar genes which implies a homologous relationship. Signup and view all the answers

What is cladistics?

Classification based on common ancestry. Signup and view all the answers

What are clades?

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

Define monophyletic.

All descendants came from one common ancestor. Signup and view all the answers

Define paraphyletic.

Consists of an ancestral species and some, but not all, of its descendants. Signup and view all the answers

What is a polyphyletic group?

Includes taxa with different ancestors. Signup and view all the answers

What is a shared ancestral character?

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

What is a shared derived character?

An evolutionary novelty that is unique to a particular clade. Signup and view all the answers

What is an outgroup?

Species or group of species from an evolutionary lineage that is known to have diverged before the lineage that includes the species we are studying. Signup and view all the answers

What is an ingroup?

The species we are studying. Signup and view all the answers

What is a character table in phylogenetics?

Showing presence/absence is basis of a cladistic approach to phylogenetic systematics. Signup and view all the answers

What is maximum parsimony?

Occam's Razor; a principle that states that when considering multiple explanations for an observation, one should first investigate the simplest explanation that is consistent with the facts. Signup and view all the answers

What is maximum likelihood?

States that, given certain rules about how DNA changes over time, a tree can be found that reflects the most likely sequence of evolutionary events. Signup and view all the answers

What is the most basal taxon represented in this tree?

Lizard and snake lineages (closest to root), after the shared ancestor, crocodile is the most basal. Signup and view all the answers

Would hair be a useful character to distinguish a particular clade of mammals within the clade of the class Mammalia?

No, all mammals have hair so it would not be useful to distinguish by this. Signup and view all the answers

What can make the most parsimonious tree inaccurate?

It can be inaccurate if convergent evolution has happened/ is happening or other complicating factors. Signup and view all the answers

Define orthologous genes.

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

Define paralogous genes.

Homology results from gene duplication; multiple copies of these genes have diverged from one another within a species. Signup and view all the answers

How can comparing proteins of two species yield data about their evolutionary relationships?

When you compare proteins for two species, you can see how they have changed and how they are similar. This allows us to trace it to a common ancestor. Signup and view all the answers

Suggest a sequence that results in Gene A differing considerably between species, yet A and B show little divergence from each other.

This suggests that the evolutionary lineages for 1 and 2 diverged before gene duplication in 1 that produced gene B from A. Signup and view all the answers

What is a molecular clock?

Model that uses DNA comparisons to estimate the length of time that two species have been evolving independently. Signup and view all the answers

What assumptions underlie the use of molecular clocks?

A molecular clock measures evolutionary time by tracking gene mutations and changes; the clocks act on the assumption that the genes change at a constant rate. Signup and view all the answers

Explain how a molecular clock dating of two taxa could conflict with fossil evidence.

The clocks are not always accurate and do not always change at equal paces; taxa were slower to diverge than estimated. Signup and view all the answers

What is horizontal gene transfer?

The transfer of genes from one genome to another through mechanisms such as transposable elements, plasmid exchange, viral activity, and perhaps fusions of different organisms. Signup and view all the answers

Why is the kingdom Monera not a valid taxon?

The kingdom Monera included bacteria and archaea, but we now know that these organisms are in separate domains. Signup and view all the answers

Why can phylogenies based on different genes yield different branching patterns?

Due to horizontal gene transfer, some genes in eukaryotes are more closely related to bacteria, while others are more closely related to archaea. Signup and view all the answers

What does 'King Phillip Came Over for Great Soup' represent?

Kingdom, Phylum, Class, Order, Family, Genus, Species. Signup and view all the answers

Unless branch lengths are proportional to time or genetic change, a phylogenetic tree indicates only ________________.

patterns of descent Signup and view all the answers

Much information can be learned about a species from its evolutionary history, thus ___________________________________________________

phylogenies are useful in a wide range of applications Signup and view all the answers

Organisms with similar morphologies or DNA sequences are more likely to be more _______________ than organisms with very different structures and DNA sequences.

closely related Signup and view all the answers

What is the purpose of computer programs in phylogenetics?

Align comparable DNA sequences and distinguish molecular homologies from coincidental matches between taxa that diverged long ago. Signup and view all the answers

What does it mean that humans and chimpanzees are sister species?

This indicates that we share a more recent common ancestor with chimps than we do with any other living primate species. Signup and view all the answers

Why is it necessary to distinguish homology from analogy to infer phylogeny?

Homologous characters result from shared ancestry. Thus, differences in homologous characters can be used to infer phylogeny. Signup and view all the answers

Explain the logic of using shared derived characters to infer phylogeny.

Shared derived characters are unique to particular clades and provide insight into evolutionary history. Signup and view all the answers

What is the main difference between Linnaean classification and phylogenetic trees?

Linnaean classification is based on traits, while phylogenetic trees explore relationships through evolutionary descent. Signup and view all the answers

Is it better to compare orthologous or paralogous genes when reconstructing phylogenies? Explain.

Orthologous genes reflect evolutionary history; paralogous genes show mutations across species but do not indicate ancestral connections. Signup and view all the answers

Molecular clocks suggest that the most common strain of HIV jumped from primates to humans in the early ____________.

1900s Signup and view all the answers

Describe some assumptions and limitations of molecular clocks.

Molecular clocks assume nucleotide substitutions occur at fixed rates. Limitations include variable rates of change and the impact of natural selection. Signup and view all the answers

Phylogenies based on rRNA genes suggest that eukaryotes are more closely related to archaea, while data from some other genes suggest a relationship to ____________.

bacteria Signup and view all the answers

What do genetic analyses indicate about horizontal gene transfer?

Extensive horizontal gene transfer has occurred throughout the evolutionary history of life. Signup and view all the answers

Why was the five-kingdom system abandoned for a three-domain system?

Genetic data indicated that many prokaryotes differed as much from each other as they did from eukaryotes. Signup and view all the answers

In a comparison of birds/mammals, the condition of having 4 limbs is:

A shared ancestral character. Signup and view all the answers

To apply parsimony in a phylogenetic tree, one must:

Choose the tree with the fewest evolutionary changes (DNA or morphology). Signup and view all the answers

In Figure 26.4, which similarly inclusive taxon descended from the same common ancestor as Canidae?

Mustelidae. Signup and view all the answers

What type of group includes a shared ancestor with multiple descendant species?

A paraphyletic group. Signup and view all the answers

Based on the tree below, which statement is incorrect?

Lizards are more closely related to salamanders than to humans. Signup and view all the answers

If you were using cladistics to make a phylogenetic tree of cats, which would be the best outgroup?

Wolf. Signup and view all the answers

What do the relative lengths of the frog and mouse branches in a tree indicate?

The homolog has evolved more slowly in mice. Signup and view all the answers

What is convergent evolution?

Evolution toward similar characteristics in unrelated species. Signup and view all the answers

What does divergent evolution entail?

When two or more species sharing a common ancestor become more different over time. Signup and view all the answers

What does genome evolution show?

Homologous genes are found in many species. Signup and view all the answers

What is the endosymbiotic theory?

A theory that states that certain kinds of prokaryotes began living inside larger cells and evolved into the organelles of modern-day eukaryotes (chloroplast and mitochondrion). Signup and view all the answers

Study Notes

Phylogeny and Classification Terms

Phylogeny: Describes the evolutionary history and relationships of species or groups.
Systematics: Discipline that classifies organisms based on their evolutionary relationships.
Taxonomy: Scientific study focused on classifying living things.
Binomial Nomenclature: Two-part Latin name method, consisting of genus and specific epithet.
Genus: A classification grouping of similar species.
Specific Epithet: The second part of a scientific name.
Family: A grouping of related genera.
Order: A taxonomic category above family, grouping similar families.
Classes: Taxonomic category above order.
Phyla: Taxonomic category above class.
Kingdoms: Six primary groups: Archaebacteria, Eubacteria, Protista, Fungi, Plantae, and Animalia.
Domains: Three overarching groups: Bacteria, Archaea, Eukarya.
Taxon: Any named grouping at any taxonomic level.

Phylogenetic Trees

Phylogenetic Tree: A branching diagram representing evolutionary relationships.
Branch Points: Indicates divergence of taxa from a common ancestor.
Sister Taxa: Groups that share a common ancestor and are each other's closest relatives.
Rooted Tree: Tree where branch point represents the most recent common ancestor of all taxa.
Basal Taxon: Early diverging lineage from a common ancestor.
Polytomy: Branch point where more than two descendant groups emerge.

Evolutionary Relationships

Homology: Similar structures in species due to shared ancestry.
Analogy: Similar traits due to convergent evolution, not common ancestry.
Homoplasies: Structures that evolved independently with similar functions.

Molecular and Genetic Concepts

Cladistics: Classification based on common ancestry.
Clades: Groups including an ancestral species and all its descendants.
Monophyletic: Group where all descendants come from one ancestor.
Paraphyletic: Includes the ancestor and some, but not all, descendants.
Polyphyletic: Group includes species from different ancestors.
Ingroup: Study subject group.
Outgroup: Species that diverged before the lineage being studied.

Techniques and Applications

Character Table: Displays presence or absence of traits, used in cladistics.
Parsimony Principle: Choose the simplest explanation or tree with the fewest changes.
Molecular Clock: Estimates evolutionary time using genetic data.
Horizontal Gene Transfer: Gene transfer across species, complicating phylogenies.

Evolutionary Patterns

Convergent Evolution: Unrelated species develop similar features.
Divergent Evolution: Related species become more different over time.
Gene Types:
- Orthologous Genes: Homologs from speciation events present in different species.
- Paralogous Genes: Result from gene duplication within a species.

Phylogenetic Analysis Insights

Importance of Homology: Essential for accurate phylogenetic inference.
Eukaryotes and Archaea: Phylogenetic studies suggest closer relations between these groups compared to bacteria.
Limitations of Molecular Clocks: Rate variation and natural selection can affect accuracy.

Evolving Classification Systems

Shift from Five-Kingdom to Three-Domain System: Genetic data led to a better understanding of relationships, separating prokaryotes into distinct domains.

Miscellaneous

Endosymbiotic Theory: Proposes that some organelles originated from prokaryotes living inside larger cells, forming mitochondria and chloroplasts.
Mnemonic for Taxonomic Hierarchy: "King Phillip Came Over for Great Soup" helps remember Kingdom, Phylum, Class, Order, Family, Genus, Species.

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Description

Test your knowledge of phylogeny and classification in biological science. This quiz covers essential terms and concepts including systematics, taxonomy, and various taxonomic ranks. Prepare to delve into the structure of the tree of life and understand the relationships between different organisms.