Chapter 18

What is binomial nomenclature?

Binomial nomenclature is when each species is assigned a two-part scientific name. The first part is the organism's genus and the second part is specific to the organism.

What is the principle behind cladistic analysis?

Cladistic analysis identifies and considers only those characteristics of organisms that are evolutionary innovations.

Would a barnacle's DNA be more similar to the DNA of a crab or that of a limpet?

Crabs and barnacles are more closely related to each other because they have a larger amount of similar genes such as segmented bodies, joined limbs, or an external skeleton that is shed during growth.

Which kingdoms include only prokaryotes? Which kingdoms include only heterotrophs?

Eubacteria and Archea are both prokaryotic. Fungi and Animalia are all heterotrophic.

Look at Figure 18-5 above. Are foxes more closely related to sea stars or to snakes? Explain.

Foxes are more closely related to snakes because the sea star only makes it onto the top bar, but the snake makes it to the second bar along with the fox.

How are genes used to help scientists classify organisms?

Genes help scientists classify organisms because organisms with a similar gene in the past are in a similar genus.

How is information about evolutionary, or phylogenetic, relationships useful in classification?

Information about phylogenetic relationships is useful in classification because they can study if certain relationships in the past are similar to certain relationships in the present.

Describe the system that Linnaeus developed.

Linnaeus' system is a hierarchy of classification using seven different levels that break down the organism into it's smallest classification. The levels from smallest to largest are species, genus, family, order, class, phylum, and kingdom.

How are living things organized for study?

Living things are broken down into different categories that suit them. For example, a flying animal with feathers has been classified into a bird, so that all scientists know what each other is talking about.

Why was the kingdom Monera divided into two separate kingdoms?

Monera was divided because scientists realized that there was a major difference in the organisms in Monera almost as big as the difference between plants and animals.

What gene indicates that yeasts and humans share a common ancestor?

Myosin indicates that yeasts and human share a common ancestor.

Why do scientists avoid using common names when discussing organisms?

Scientists avoid using common names when discussing organisms because they can differ in different languages and closely related regions.

How are members of the kingdom Fungi different from members of the kingdom Plantae? How are member of the two kingdoms similar?

The kingdom Plantae contains multicellular and autotrophic organisms while the kingdom Fungi contains heterotrophic organisms. They are similar because they can both be multicellular.

Why might kingdom Protista be thought of as the "odds and ends" kingdom?

The kingdom Protista has the most variation: it has multicellular and unicellular, photosynthetic and heterotrophic, and some share characteristics with plants or fungi and some with animals.

What are the seven taxonomic categories of Linnaeus' classification system? Rank these taxa in hierarchical order, beginning with the largest level and ending with the smallest.

The seven taxonomic categories from largest to smallest are kingdom, phylum, class, order, family, genus, and species.

Describe the relationship between evolutionary time and the similarity of genes in two species.

The similarity of genes in two species takes time to become similar because they both have to adapt and then they both get similar genes.

What are the six kingdoms of life as they are now identified?

The six kingdoms of life as they are now identified are Eubacteria, Archaebacteria, Protista, Fungi, Plantae, and Animalia.

What are the three domains of life?

The three domains of life are Eukarya, Bacteria, and Archaea.

cladogram

a diagram that shows the evolutionary relationships among a group of organisms

genus

a group of closely related species

domain

a more inclusive category than any other-larger than a kingdom

order

broad taxonomic category composed of similar families

derived characters

characteristics that appear in recent parts of a lineage but not in its older members

protista

composed of eukaryotic organisms that cannot be classified as animals, plants, or fungi

class

composed of similar orders

eukarya

consists of all organisms that have a nucleus

taxon

each level in taxonomic nomenclature

binomial nomenclature

each species is assigned a two-part scientific name

phylogeny

evolutionary relationships among organisms

family

group of genera that share many characteristics

fungi

heterotrophs

phylum

includes many different organisms that share important characteristics

kingdom

largest and most inclusive category

animalia

multicellular and heterotrophic

Plantae

multicellular organisms that are photosynthetic autotrophs

taxonomy

scientists classify organisms and assign each organism a universally accepted name

archaebacteria

the domain Archaea corresponds to this domain

eubacteria

the domain Bacteria corresponds to Eubacteria

evolutionary classification

the strategy of grouping organisms together based on their evolutionary history

bacteria

unicellular and prokaryotic

archaea

unicellular and prokaryotic and live in some of the most extreme environments

molecular clock

uses DNA comparisons to estimate the length of time that two species have been evolving independently