Biology Chapter 18 Review

Questions and Answers

The science that specializes in the classification of organisms is _______________.

taxonomy

Solely from its name, you know the Rhizopus nigrians must be _______________.

in the genus Rhizopus

A useful classification system does NOT ____________.

use different scientific names for the same organisms

In classifying organisms, orders are grouped together into _________________.

classes Signup and view all the answers

The largest and most inclusive of Linnaeus's taxonomic categories is the ____________________.

kingdom Signup and view all the answers

Which of the following shows the evolutionary relationships among a group of organisms?

Cladogram Signup and view all the answers

A unique trait that is used to construct a cladogram is called a ______________.

derived character Signup and view all the answers

The three domains are:

Bacteria, Archae, Eukarya Signup and view all the answers

A kingdom that includes only heterotrophs is:

Fungi Signup and view all the answers

Why do biologists assign each organism a universally accepted name?

To provide consistency and avoid confusion. Signup and view all the answers

What criteria are used to classify an organism?

evolutionary relationships and structural similarities. Signup and view all the answers

What features of binomial nomenclature make it useful for scientists of all nations?

Each name is unique, a combination of genus name and species term. Signup and view all the answers

Sequence Linnaeus's seven taxonomic categories from smallest to largest.

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

Explain the goal of evolutionary classification.

To group organisms based on their evolutionary history. Signup and view all the answers

What is a derived character? Give an example of a derived character.

A character that appears in recent parts of lineage but not in older members; e.g., a molted exoskeleton in crustaceans. Signup and view all the answers

How is a cladogram used in classification?

It traces the process of evolution in a group of organisms through unique shared derived features. Signup and view all the answers

How do biologists use DNA and RNA to help classify organisms?

They compare sequences to determine how closely related species are. Signup and view all the answers

What is phylogeny?

The study of evolutionary relationships among organisms. Signup and view all the answers

Describe how a molecular clock is used to estimate the length of time that two related species have been evolving independently.

It relies on a repeating process, a mutation, to estimate time based on DNA sequence comparisons. Signup and view all the answers

How do domains and kingdoms differ?

A domain is more inclusive and larger than a kingdom. Signup and view all the answers

What characteristics are used to place an organism in the domain Bacteria?

Members are all unicellular and prokaryotic; cell walls contain peptidoglycan. Signup and view all the answers

What domain consists of prokaryotes whose cell walls lack peptidoglycan?

They are placed in the kingdom Archaea. Signup and view all the answers

Describe the four kingdoms that comprise the domain Eukarya.

The four kingdoms are Protista, Fungi, Plantae, and Animalia. Signup and view all the answers

What characteristic(s) differentiate the kingdom Animalia from the kingdom Plantae?

Members of Animalia are heterotrophic, lack cell walls, and are motile. Signup and view all the answers

Study Notes

Taxonomy and Classification

Taxonomy is the science specializing in classifying organisms.
The naming convention "Rhizopus nigrians" indicates it belongs to the genus Rhizopus.
A useful classification system should show relationships but not use different scientific names for the same organism.
Orders are classified into broader categories known as classes.
The largest taxonomic category in Linnaeus's system is the kingdom.

Evolutionary Relationships

A cladogram visually represents evolutionary relationships among organisms.
Derived characters are traits unique to certain lineages and help in constructing cladograms.
The three domains of life are Bacteria, Archaea, and Eukarya.
The Fungi kingdom consists solely of heterotrophic organisms.

Binomial Nomenclature

Biologists use universally accepted names to maintain consistency and reduce confusion in classification.
Classification criteria include evolutionary relationships and structural similarities.
Binomial nomenclature provides each species with a unique name, aiding global communication among scientists.

Linnaeus's Taxonomic Hierarchy

Taxonomic hierarchy from smallest to largest is: species, genus, family, order, class, phylum, kingdom.

Evolutionary Goals and Characteristics

The goal of evolutionary classification is to group organisms based on evolutionary history rather than just physical traits.
A molecular clock estimates evolutionary time between species through genetic mutations.

DNA and RNA in Classification

Similar DNA and RNA sequences among organisms indicate closer evolutionary relationships.
Phylogeny is the study of evolutionary relationships among organisms.

Domains and Kingdoms

Domains are broader and more inclusive than kingdoms.
Characteristics of the Bacteria domain include being unicellular and prokaryotic with peptidoglycan in cell walls.
Archaea consists of prokaryotes lacking peptidoglycan.

Eukarya Domain

The domain Eukarya includes four kingdoms: Protista, Fungi, Plantae, and Animalia.
The Animalia kingdom is differentiated from Plantae by being heterotrophic, lacking cell walls, and having motility.

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Description

Test your knowledge with this review on Chapter 18 of Biology, focusing on classification and taxonomy. Use these flashcards to solidify your understanding of key concepts and definitions related to organisms and their classifications.