Cladistics and Evolutionary Biology

Questions and Answers

The best classification system is that which most closely _____.

Unites organisms that possess similar morphologies

Reflects the basic separation of prokaryotes from eukaryotes

Reflects evolutionary history (correct)

Conforms to traditional, Linnaean taxonomic practices

The existence of antlers in beetle, fly, and deer species with strong male-male competition is an example of _____.

Homology

Convergent evolution (correct)

Parsimony

A synapomorphy

Which of the following pairs are the best examples of homologous structures?

Bones in the bat wing and bones in the human forelimb (correct)

Bat wing and bird wing

Owl wing and hornet wing

Eyelessness in the Australian mole and eyelessness in the North American mole

The importance of computers and of computer software to modern cladistics is most closely linked to advances in _____.

Molecular genetics Signup and view all the answers

The four-chambered hearts of birds and mammals are best described as _____.

Homoplasies Signup and view all the answers

Which of the following would be useful in creating a phylogenetic tree of a taxon?

I, II, and III Signup and view all the answers

What is the most likely reason your professor gave you a lily when constructing a phylogenetic tree of orchids?

To serve as an outgroup Signup and view all the answers

Which of the following statements best describes the rationale for applying the principle of parsimony in constructing phylogenetic trees?

Similarity due to common ancestry should be more common than similarity due to convergent evolution. Signup and view all the answers

Phylogenetic trees constructed from evidence from molecular systematics are based on similarities in _____.

Mutations to homologous genes Signup and view all the answers

If cynodonts had whisker-like hairs around their mouths, then hair is a shared _____.

Derived character of mammals, but only if cynodonts are reclassified as mammals Signup and view all the answers

Which of the following would be the best outgroup for building a phylogenetic tree of cats?

Wolf Signup and view all the answers

Eukaryotes that are not closely related can still be placed together on the same phylogenetic tree by comparing their _____.

Homologous genes that are highly conserved Signup and view all the answers

Sequencing which of the following would probably be most useful in sorting out evolutionary relationships among similar species of damselflies?

Mitochondrial DNA Signup and view all the answers

Which statement represents the best explanation for the observation that the nuclear DNA of wolves and domestic dogs has a high degree of sequence homology?

Dogs and wolves share a very recent common ancestor Signup and view all the answers

The most important feature that permits a gene to act as a molecular clock is _____.

A reliable average rate of mutation Signup and view all the answers

Neutral theory proposes that _____.

A significant proportion of mutations are not acted upon by natural selection Signup and view all the answers

Which portion of the figure may ultimately be better depicted as a 'ring'?

The trunk of the tree Signup and view all the answers

Which statement about phylogeny is true?

The term 'monophyletic' refers to a taxon that includes an ancestral species and all of its descendants. Signup and view all the answers

Which of these are homologous structures?

Ivy leaf and pine needle Signup and view all the answers

Identify the monophyletic taxon from the options provided.

Birds and dinosaurs and their common ancestor Signup and view all the answers

Select the correct statement about phylogenetic trees.

Phylogenetic trees may expand quickly to maximum width and then narrow over time. Signup and view all the answers

Study Notes

Classification and Evolution

The optimal classification system reflects evolutionary history rather than traditional practices.
Convergent evolution explains the similarity of antler-like structures among beetles, flies, and male deer due to strong male-male competition.
Homologous structures, such as bones in bat wings and human forelimbs, indicate common ancestry.

Cladistics and Molecular Genetics

Advances in molecular genetics significantly enhance the application of computers and software in constructing cladistic analyses.
The four-chambered hearts of birds and mammals are considered homoplasies rather than indicative of shared ancestry.
Creating phylogenetic trees effectively uses morphological, genetic, and behavioral data.

Phylogenetic Analysis Techniques

Outgroups, like lilies in orchid studies, serve to contextualize relationships among species.
The principle of parsimony helps in phylogenetic tree construction, favoring common ancestry over convergent traits.
Similarities in homologous genes, especially mutations, form the basis for molecular systematics.

Evolutionary Traits and Common Ancestors

Whisker-like hairs in cynodonts would characterize hair as a derived trait of mammals upon reclassification.
Wolves serve as a suitable outgroup in feline phylogenetic trees based on evolutionary relationships.
Highly conserved homologous genes enable the grouping of distantly related eukaryotes.

Speciation and Genetic Connection

Mitochondrial DNA is the most useful for analyzing evolutionary relationships in closely related damselfly species.
High sequence homology in DNA between wolves and domestic dogs suggests a recent common ancestor.
Molecular clocks rely on a reliable mutation rate to track evolutionary timeframes.

Theories of Speciation

Neutral theory postulates that many mutations are not influenced by natural selection, emphasizing genetic drift.
The trunk of a phylogenetic tree may represent a structure better depicted as a "ring," reflecting interconnected evolutionary paths.

Understanding Phylogenetic Structures

Phylogeny illustrates the evolutionary history of organisms through homologous characteristics.
A monophyletic group includes an ancestral species and all its descendants, essential for accurately depicting evolutionary relationships.
Phylogenetic trees can vary in shape, illustrating the dynamic nature of evolution, sometimes expanding and contracting over time.

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Description

Explore the intricacies of classification systems and phylogenetic analysis in this quiz. Learn about homologous structures, convergent evolution, and advanced techniques in cladistics using molecular genetics. Test your knowledge on how these concepts reflect evolutionary history.