AP Biology : Understanding Building Phylogenies

Study concepts, example questions & explanations for AP Biology

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Example Questions

Example Question #1 : Understanding Building Phylogenies

A characteristic present in a clade, but not its ancestors, is a __________.

Possible Answers:

convergent character

shared derived character

shared ancestral character

polyphyletic character

paraphyletic character

Correct answer:

shared derived character

Explanation:

The characteristic is found among all members of the clade, which makes it shared. It is not present among the ancestors of the clade, but was derived from the last common ancestor and is unique to that clade. These attributes make the trait a shared derived character.

An example of a shared derived character is hair in mammals: all mammals have hair, but no ancestors of mammals (that are not mammals themselves) had hair.

An example of a shared ancestral character is backbones in mammals: all mammals have backbones, and so do other vertebrates. There was a common ancestor between mammals and other vertebrates that had a backbone; however, when comparing all vertebrates to invertebrates, a backbone becomes a shared derived character, as backbones are unique to vertebrates.

Example Question #2 : Understanding Building Phylogenies

What is a clade?

Possible Answers:

The set of descendants from a common ancestor that have become extinct

An ancestor and all of its descendants

An ancestor and none of its descendants

All of the descendants of a common ancestor, but not the ancestor itself

An ancestor and a specific subset of its descendants

Correct answer:

An ancestor and all of its descendants

Explanation:

A clade is a group of related species all descending from a common ancestor, including that ancestor. They have at least one shared derived trait unique to the clade and differentiating them from all other clades. Clades can be nested within each other: the mammalian clade is part of the vertebrate clade, which is part of the animal clade.

Example Question #3 : Understanding Building Phylogenies

Two species sharing the same __________ will be the most closely related

Possible Answers:

family

class

phylum

kingdom

order

Correct answer:

family

Explanation:

In the system of biological classification, organisms are classified in a hierarchy, or taxonomy. The highest levels of classification are the most inclusive, while the lower levels become more and more specific until a single species is identified. From most inclusive to least inclusive, organisms are assigned a kingdom, a phylum, a class, an order, a family, a genus, and finally a species.

Organisms sharing the same classification at less inclusive levels will be more closely related. For example, two organisms sharing the same genus will be more closely related than those who only share the same family. Of the given answer choices, family is the most specific level of classification.

Example Question #4 : Understanding Building Phylogenies

Which is not true about the theory of punctuated equilibrium?

Possible Answers:

Times of change are rapid and rare

It stands in contrast to gradualism 

Species are typically in a state of stasis

Times of change are slow and continuous 

Correct answer:

Times of change are slow and continuous 

Explanation:

Punctuated equilibrium is one theory within evolutionary biology that seeks to explain the rate of evolution over time. This theory describes most species being in a state of stasis, with little change occurring. When change does occur, however, it is rapid. The theory of punctuated equilibrium stands in opposition to the theory of gradualism and is supported by the fossil record.

Example Question #3 : Understanding Building Phylogenies

What is true about the theory of gradualism?

Possible Answers:

It stands in opposition to the theory of punctuated equilibrium

Change is uniform

Change is slow and gradual

All of these

Correct answer:

All of these

Explanation:

Gradualism is a theory of evolutionary biology that stands in contrast to the theory of punctuated equilibrium. In this theory, change (or evolution) is slow, gradual, and uniform. Adaptation occurs over a long period of time and is observed in small changes. 

Example Question #6 : Understanding Building Phylogenies

Which of the following types of data are used to generate phylogenetic trees?

Possible Answers:

Both molecular sequencing data and morphological similarities

Morphological similarities

Neither molecular sequencing data nor morphological similarities

Molecular sequencing data

Correct answer:

Both molecular sequencing data and morphological similarities

Explanation:

Phylogenetics is the study of relationships between organisms and groups of organisms. This is done through the production of phylogenetic trees, which are used to describe these relationships. To make phylogenetic trees, scientists use molecular sequencing and/or morphological similarities in order to characterize the relationships between organisms.

Example Question #7 : Understanding Building Phylogenies

Which of the following best describes the difficulties associated with the study of phylogenetics?

Possible Answers:

Horizontal gene transfer

Horizontal gene transfer and hybridization

Hybridization

Neither horizontal gene transfer nor hybridization

Correct answer:

Horizontal gene transfer and hybridization

Explanation:

Phylogenetics has several difficulties that complicate the development of accurate phylogenetic trees. Relationships between organisms on a genetic level are incredibly complicated, making it difficult for scientist to create clean and precise phylogenetic trees. These difficulties include hybridization, horizontal gene transfer, and convergent evolution.

Example Question #4 : Understanding Building Phylogenies

Fungi belong to the __________ of __________.

Possible Answers:

kingdom . . . eukarya

class . . . archaea

kingdom . . . bacteria

domain . . . bacteria

domain . . . eukarya

Correct answer:

domain . . . eukarya

Explanation:

There are 3 domains in which all organisms are classified - Eukarya, Bacteria, and Archaea. Fungi is the name of one the kingdom classifications. The order for the classification is as follows: domain, kingdom, phylum, class, order, family, genus, species. Therefore, Fungi falls under the Domain of Eukarya.

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