Chapter 17 Biology
Which of the following can be used to link molecular clocks to real time? A: geologic events B: historical events
A: geologic events
What is a phylogeny?
The evolutionary history of a species or taxonomic group
Current technology allows scientists to examine organisms at the molecular level. How has this technology exposed limitations in Linnaean taxonomy?
The limitations in the Linnaean taxonomy are that they rely on physical and structural similarities, where technology could expand it to the molecular level that could prove some original external organism thoughts wrong.
What does a node represent on a cladogram?
The most recent common ancestor
How is mtDNA useful as a molecular clock?
The mutation rate is 10x faster than that of nuclear DNA and can be used to study closely related species
What was the major change between 1700 and 1800?
Two kingdoms were formed (animalia and plantae)
What are some characteristics of the Eukarya domain?
eukaryotes with distinct nuclei and membrane-bound organelles
mitochondrial DNA
DNA only found in mitchondria, often used as a molecular clock
How many groups are in the current classification scheme?
6 kingdoms
What are molecular clocks?
A theoretical clock that use the rate of mutations to measure and estimate evolutionary time
cladistics
method of organizing species by evolutionary relationships in which species are grouped according to the order that they diverged from their ancestral line
What is useful for studying closely related species? mitchondrial DNA or ribosomal RNA
mitochondrial DNA
What is a model that uses mutation rates to measure evolutionary time?
molecular clock
Mitochondrial DNA and ribsomal RNA provide two types of ______ ________.
molecular clocks
What types of evidence are used for classifying organisms based on evolutionary relationships?
molecular like ancestry and cladograms and the like
Biologists use molecular clocks by linking ______ data to _______ _______.
molecular, real time
Are species in the same family more or less related than species in the same class? Explain your answer.
more
What types of evidence are used for classifying organisms in the Linnaean classification system?
physical and structural similarities
The Linnaean system of classification groups organisms based on ______ physical or ________ characteristics.
physical, strucutural
Where is the taxon being classified on the diagram?
the words on the branch out
molecular clock
theoretical clock that uses the rate of mutation to measure evolutionary time
What can be concluded if the genes of two species are found to be nearly identical?
They were descended from a common ancestor
These evolutionary relationships (17.2- cladistics) can be presented in a branching diagram called a ________.
cladogram
They can then _____ the rate of _____ for these species.
measure, evolution
Organisms can be classified based on ______ similarities.
physical
Organisms can be classified based on _______ similarities.
physical
taxon
(plural: taxa) level within the Linnaean system of classification (kingdom, phylum, class, order, family, genus, or species) that is organized into a nested hierarchy
bacterium
(plural:bacteria) organism that is within the Kingdom Bacteria
A particular DNA sequence accumulated three mutations over 10,000 years. After how much time would you expect this sequence to have accumulated six more mutations? Explain.
20,000 years if it follows the pattern of every 3 a 10000 years
On a cladogram, what is a node and what does it represent?
A node is the intersection of the branches. It represents the most recent common ancestor shared by the entire clade.
How many clades are represented in this diagram?
4 as they are the letters
Klados is Greek for "branch" and -gram is a suffix meaning "something written or drawn." Explain how this meaning relates to cladogram.
A cladogram is written diagram with many branches (depending on the organisms).
Phylo- comes from the Greek word meaning "class," and the suffix -geny means "origin." How do these meanings apply to the term phylogeny?
A class is a taxonomic group which has an evolutionary history, hence "origin."
What is a species?
A group of organisms that can breed and reproduce
What is a clade?
A group of organisms that share certain traits derived from a common ancestor
Which of the following represents strait difference of a cladogram? A. nodes B. derived characters
A. nodes
Which of the following is the correctly written scientific name for a maple tree (assuming they are italicized)? A: Acer rubrum B: ACER rubrum C: acer rubrum
A: Acer rubrum
What is the basis of Linnaean taxonomy? A: physical and structural similarities B: habitat C: food source
A: physical and structural similarities
Which of the following is a feature of a cladogram? A: taxons B: sticks
A: taxons
Which animal would you expect to be classified in the same group as a lion? A: tiger B: turtle C: bear
A: tiger
Identify the domain made up of prokaryotes that often live in extreme environments.
Archaea
What are known for their ability to survive in extreme environments?
Archaea
What distinguishes the three domains in the tree of life from one another?
Archaea and Bacteria have different cell walls, no nucleus, and no organelles compared to each other and then to Eukarya.
What are some kingdoms included in the Archaea domain?
Archaea kingdom
How can a phylogeny be shown?
As branching tree diagrams
What is classified by their shape, need for oxygen, and whether they cause disease?
Bacteria
Why can't mtDNA be used to study the evolutionary relationship between the species of bacteria?
Bacteria don't have mitchondria to study
What are some kingdoms included in the Bacteria domain?
Bacteria kingdom
______ and ______ are unicellular prokaryotes, but the genetic and cellular differences between these groups are greater than the differences between any two other kingdoms together in comparison.
Bacteria, Archaea
The ______ and _____ domains include all organisms in the _____ and ______ kingdoms, respectively.
Bacteria, Archaea, Bacteria, Archaea
The three domains in the tree of life are _____, _____, and _____.
Bacteria, Archaea, Eukarya
Two species with similar adaptations are found to have key differences at the molecular level. Scientists conclude that these species are not as closely related as previously thought. Why should the molecular evidence outweigh physical similarities that the species share?
Because they are more accurate
______ is a common method used to group species on the order in which they were ______ from a common ancestor.
Cladistics
______ is classification based on common ancestry.
Cladistics
How are the words cladistics and cladogram related?
Cladistics is the system a cladogram is used for or to show.
_________ are constructed by identifying which _______ characters are shared by which species in the group being analyzed.
Cladograms, derived
mitochondrial DNA
DNA found only in mitochondria, often used as a molecular clock
Describe mtDNA.
DNA only found in mitochondria, only from mother, often used as a molecular clock
Give two examples of molecular evidence that can be used to help determine species' relatedness.
DNA sequences, comparing proteins, hormones, and genes
What have cells with a distinct nucleus and membrane-bound organelles?
Eukarya
Which domain is made up of organisms whose cells have a distinct nucleus?
Eukarya
The domain ______ includes all organisms with eukaryotic cells- kingdoms _____, ______, _____, and _____.
Eukarya, Protista, Fungi, Plantae, Animalia
How are the seven levels of Linnaeus's classification system organized?
From the most general groupings of organisms to the most specific
Describe Woese's discovery and the impact it had on the tree of life.
His discovery was that there were two genetically different groups of prokaryotes in the kingdom monera, which led to the split of monera into bacteria and archaea. It's impact on the tree of life included the above and the beginning of the formation of domains.
The scientific name for humans is Homo sapiens. What genus do humans belong to?
Homo
What does a cladogram show?
How species are related to each other through common ancestors
Describe the trend in the levels, or taxa, as move down from kingdom to species.
It grows smaller and more specific as you move down to the bottom (species).
Scientists have used mtDNA as a molecular clock to trace human evolution and early migration routes. Explain how mtDNA would be more useful in this research than rRNA.
It has a fast mutation rate
How has the kingdom system changed over the last three hundred years?
It has grown in number of kingdoms.
The original Linnaean system of classification had two kingdoms. Biologists now use six kingdoms. What does this change suggest about the nature of classification?
It is always changing
How is rRNA unique?
It is inside a ribosome, which makes protein in cells
How is rRNA useful as a molecular clock?
It is useful to study different kingdoms or phyla because it can study longer term relationships because it has a slow mutation rate
What is the significance of grouping the six kingdoms into three domains? How does the domain model more clearly represent the diversity of prokaryotes than a system with the six kingdoms as its broadest divisions?
It shows how many eukaryotes are alike and how bacteria and archaea are not that different. It represents it as it shows that you can't actually specify (species-ify) the bacteria and archaea that accurately that separately as they blur the lines by sharing genes and exchanging genes.
Why do scientists today rely on molecular and genetic similarities to classify organisms?
It's more accurate than what meets the eye.
How is mtDNA unique?
It's only found in mitchondria, and the mother is the only one who passes it down, so it is easier to trace back (and it is unshuffled)
Name the seven levels of organization in Linnaean taxonomy, from the most general to the most specific.
Kingdom Phylum Class Order Family Genus Species
What is the order of classification?
Kingdom, phylum, order, class, family, genus, species
Words from the _______ language are used in binomial nomenclature.
Latin
What are molecular clocks?
Models that use mutation rates to measure evolution
_____ ______ provide clues to evolutionary history.
Molecular clock
_______ _______ provide clues to evolutionary history.
Molecular clocks
_____ tend to accumulate at a constant rate for a group of related species.
Mutations
In a cladogram, what does a node represent?
Newest branch-off= most recent
Why did Linnaeus base his system of classification on physical similarities alone, as opposed to including molecular and genetic similarities?
Nothing was known of molecular or genetic similarities at the time.
What would a set DNA sequences that illustrate molecular evolution look like?
One sequences to (10 million years later) two once-changed sequences to (10 million years later) two twice-changed sequences
What molecular clock can be used to examine the evolutionary relationship between wolves and dogs?
One with a fast mutation rate (mtDNA for example)
How is mitochondrial DNA inherited?
Only from the mother
What basic idea does cladistics use to classify groups of organisms?
Physical and structural similarities plus evolutionary relationships
What are some kingdoms included in the Eukarya domain?
Protista, plantae, fungi, and animalia
What is the genus in Quercus alba?
Quercus
Describe rRNA.
RNA inside a ribsome
ribosomal DNA
RNA that is in the ribosome and guides translation of mRNA into protein; also used as a molecular clock
ribosomal RNA (rRNA)
RNA this in the ribosome and guides translation of mRNA into a protein; also used as a molecular clock
What is useful for studying species in different kingdoms or phyla?
Ribosomal RNA
_______ _____ and _______ ________ provide two types of molecular clocks, used to measure evolution at different _____ scales.
Ribosomal RNA, mitchondrial DNA, time
Why is it important for biologists to include scientific names when reporting their research to other biologists around the world?
So everyone can understand
How are derived characters used in making a cladogram?
They separate the organisms by what characteristics they do and do not have.
What is true about two organisms that show the same common ancestor?
They show the derived character represented by the hash mark
Why is it so difficult to classify bacteria and archaea down to the species level?
They transfer genes to reproduce, so it blurs the lines a little bit. They also have near the same genes.
What was the second major change between 1900 and 2000?
The addition of the kingdom fungi to previous four kingdoms
What was the first major change between 1900 and 2000?
The addition of the kingdom monera to the previous three kingdoms
What was the major change between 1800 and 1900?
The addition of the kingdom protista to the previous two kingdoms
Where is a clade on the diagram?
The bracket spanning all three
What was the third and most recent change between 1900 and 2000?
The split of the kingdom monera into bacteria and archaea, forming the final six kingdoms
What is a characteristic of organisms in domain archaea?
Their ability to live in extreme environments
Where are the nodes in this cladogram and what do they represent?
They are the break-off of species where the ancestral characteristics break off
The prefix archaeo- comes from the Greek word arkhaio, which means "ancient" or "primitive." Explain how this meaning related to Archaea.
They are very ancient organisms with primitive structures equipped to survive the harshest conditions.
Why are physical similarities among species not always the result of being closely related?
They could have those traits as a result of convergent evolution.
Why are bacteria so different to classify at the species level?
They exchange genes and don't have distinct species
Why is classfication considered a work in progress?
This is because every year scientists discover new things about organisms that could cause them to be moved domains, or even enough to create a whole new domain. It also occurs in part because of evolution.
Explain how species become more and more different at the molecular level, after they have diverged from a common ancestor.
Through many mutations
Describe the main goal of cladistics.
To place species in the order in which they are descended from a common ancestor
How can scientists estimate mutation rates for use in developing a molecular clock?
Using the number of amino acid substitutions in proteins and number of mutations plus closely timed geologic events. The mutation rate= x amount of mutations over x amount of time. They also use fossil evidence.
Why are evolutionary trees often changed?
When new evidence surfaces, they are changed. New evidence often surfaces.
cladogram
a diagram that is based on the patterns of shared derived traits and that shows the evolutionary relationships between groups of organisms
derived character
a feature that involved only within a particular taxonomic group
cladistics
a phylogenic classification system that uses shared derived characteristics and ancestry as the sole criteria for grouping taxa
Binomial nomenclature
a system for giving an organism a two-word scientific name which consists of a genus name followed by a species name
If two organisms are in the same phylum, what other taxon do they have in common? a: kingdom b: class c: family d: genus
a: kingdom
Taxon
any named taxonomic group of any rank in the hierarchical classification of organisms; for example, family, genus, or species
In what domain would you classify a newly discovered single-celled organism with small chloroplasts? a. bacteria b. eukarya c. archaea
b. eukarya (it sounds like a plant)
Scientists isolate this organism from marsh water. Based on this illustration, the organism would most likely be classified as a....
bacterium
Species are named according to their _____ _______, which gives each species a two-part scientific name using Latin words.
binomial nomenclature
Birds and snakes share a common ancestor from over 250 million years ago, but now they show many physical differences. These differences are mostly directly the result of....
c. the long-term accumulation of mutations
Scientists notice very few differences in the DNA sequences of individual cheetahs. This indicates that modern cheetahs likely descended from only a few individuals because....
c. the mutation rate depends on population size
The domains are based on fundamental differences at the ______ level.
cellular
Which kingdom is not included in kingdom Eukarya? a. protista b. fungi c. plantae d. bacteria
d. bacteria
Mammals are multi cellular organisms with about 3 billion base pairs in their genome. Yeasts are single-celled organisms with about 1.3 million base pairs in their genome. Both of these groups are classified as eukaryotes because they...
d. have a similar basic cellular structure
Traits that are shared by some species of a group being studied, which other species in that group do not have, are called ________ characters.
derived
cladogram
diagram that displays evolutionary relationships among a group of species
Modern classification is based on ______ relationships.
evolutionary
Modern classification is based on _______ relationships.
evolutionary
phylogeny
evolutionary history of a group or related species
Bacteria
extremely small, single-celled organisms that usually have a cell wall and that usually reproduce by cell division (singular, bacterium)
genus
first name in binomial nomenclature; the second most specific taxon in the Linnaean classification system that includes one or more physical similar species, which are thought to be closely related
In the binomial nomenclature naming system, each species is given a unique scientific name that includes a _____ and a ______ descriptor.
genus, species
The system is a nested _________ with seven ______, or levels
hierarchy, taxa
Nuclear DNA is often hard to trace back generations because ______
it gets mixed because its from the mother and father
The Linnaean classification has __________.
limitations
The _____ that two species are separated after diverging from a common ancestor, the more different the two species will be at the _______ level.
longer, molecular
Depending on how closley related speciesare, scientists must choose a molecule with an appropriate _____ rate to use a molecular clock.
mutation
The DNA sequences above show a conserved gene among four related plants. The highlighted differences are most directly the result of....
mutation
Molecular clocks use ______ to estimate evolutionary time.
mutations
binomial nomenclature
naming species in which species is given a two-part scientific name (genus and species) using Latin words
Taxonomy is the science of _______ and _______ organisms.
naming, classifying
Eukarya
one of the three domains of life. contains all eukaryotes in kingdoms Protisita, Plantae, Fungi, and Animalia
Archaea
one of the three domains of life; containing single-celled prokaryotes in the Kingdom Archaea
Bacteria
one of the three domains of life; containing single-celled prokaryotes in the Kingdom Bacteria
Eukarya
one of the three domains, contains all eukaryotes in the kingdoms protista, animalia, plantae, and fungi
Linnaean taxonomy classifies _______.
organisms
Linnaean taxonomy names _______.
organisms
Linnaean taxonomy classifies _______ based on _______ into groups called ________.
organisms, physical and structural similarities
Linnaean taxonomy classifies _______ based on _______.
organisms, physical and structural similarities
Linnaean taxonomy names ______ using a system called _______.
organisms, taxon
Linnaean taxonomy names ________ using a system called ________ which gives each species a _______.
organisms, taxon, scientific name
Classification is always considered a work in _______.
progress
Archaea
prokaryotes (most of which are known to live in extreme environments) that are distinguished from other prokaryotes by differences in their genetics and in the makeup of their cell wall; members of the domain Archaea (singular, archaeon)
Mutations accumulate more slowly in ribosomal RNA than in mitochondrial DNA. Which of these molecules would provide a better molecular clock for studying the evolution of species from different kingdoms?
ribosomal RNA
taxonomy
science of classifying and naming organisms
Linnaeus developed the _____ _____ _____ still used today.
scientific naming system
In the past 150 years, the classification of life has changed through the addition and restructing of kingdoms and domains. The system is always changing because.....
scientific study keeps producing more data
Linnaeus's classification has _______ levels.
seven
What are some characteristics of the Bacteria domain?
single-celled prokaryotes
What are some characteristics of the Archaea domain?
single-celled prokaryotes with different cell walls than those in the Bacteria domain
Within all domains are a total of _____ kingdoms.
six
The most specific level in Linnaeas's system is a ______.
species
Molecular evidence reveals ______ _______.
species' relatedness
What is the science of naming and classifying organisms?
taxonomy
phylogeny
the evolutionary history of a species or taxonomic group
Where is the derived character on the diagram?
the hash
Genus
the level of classification that comes after family and contains several similar species
What represents the derived characters that were used to construct this cladogram?
the numbers
Taxonomy
the science of naming, describing, and classifying organsims
Where is a node on the diagram?
the splitting of the branch/the branching off
The current three of life has _____ domains.
three
The current tree of life has ______ domains.
three
derived character
trait that differs in structure or function from that found in the ancestral line for a group of species; used in constructing cladograms