all female mammals produce __________ most mammals have ___________. milk hair
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CLASSIFICATIONAll female mammals produce __________Most mammals have ___________.MilkhairThe science of naming and classifying organisms.taxonomyLinnean taxonomy classifies organisms based on their ________ and _________ similarities.physical structural A group of organisms in a classification system is called a _________.taxonThe basic taxon in the Linnean system is the _________.speciesA system that gives each species a two part scientific name using Latin words.binomial nomenclatureThe first part of the name of a species in binomial nomenclature is called a _______.genusOne or more physically similar species that are thought to be closely related.genusGenus names are always _______ and in ______ or underlined. Species names are always _______ and are also ______ or underlined.capitalizeditalicslowercase italicsThe Linnean system of classification has seven levels or _______.taxaWhat are the taxa for the Linnean Classification system?Kingdom, Phylum, Class, Order, Family, Genus, SpeciesWhat is a limitation of the Linnean classification system?His system focused on physical similarities alone. Comparing genetic traits is more accurate.The evolutionary history for a group of species is called a _________. phylogenyThe most common method used to make evolutionary trees is called_________. cladisticsClassification based on common ancestry.cladisticsAn evolutionary tree that proposes how species may be related to each other through common ancestry.cladogramA group of species that shares a common ancestor.cladeTraits that can be used to figure out evolutionary relationships among a group of species that are shared by some species but are not present in others.derived charactersEach place in a cladogram where a branch splits.nodeWhat is the difference between a clade and a taxon?A taxon is a group of organisms classified together in a system such as that of Linneaus. A clade is any group of organisms that share a common ancestor, so it can contain many taxa of different levels. Why does DNA often have the last word when scientists are constructing evolutionary relationships?Shared or identical sequences of DNA is hard proof of common ancestry, whereas shared traits or similar characteristics can be the result of convergent evolution.What was the method, proposed by Linus Pauling and Emile Zuckerkandl, of evolutionary time? (early 1960s)They compared the amino acid sequences of hemoglobin from a wide range of species. Their findings show that the more distantly related two species are, the more amino acid differences there are in their hemoglobin.Models that use mutation rates to measure evolutionary time.molecular clocks Pauling and Zuckerkadl found that mutations tend to add up at a _________ _____ for a group of related species.constant rateHow may a geologic event be related to a rate of mutation?Geologic events may be the cause to separate or isolate a species. If the species is subjected to a different environment, different mutations may occur and the geologic event was the impetus for genetic differentiation.Pauling and Zuckerkandl confirmed that the number of amino acid differences _________ with the evolutionary time between each group of species.increasesWhy is the comparison between amino acids in hemoglobin between species an important discovery?The amino acid differences are greater the farther back one goes along the evolutionary history(timeline). Humans have 16 differences with mice, 18 with the horse, 35 with a bird, and 79 with a shark.DNA found only in mitochondria. (mt DNA) Always inherited from the mother. (nuclear DNA is a combination of DNA from both parents)mitochondrial DNAA type of RNA useful for studying distantly related species, such as species that are in different kingdoms or phyla.Ribosomal RNA rRNAWhen studying the relationships among species over longer time scales, it is best to use a molecule that has a ___________ mutation rate.lowerWho first used rRNA to establish that archaea diverged from the common ancestor they share with bacteria almost 4 billion years ago?Carl Woese
How are molecular clocks used to measure evolutionary time?The clocks presume that mutations occur at a constant rate for any clade or group of related taxa. Because these changes occur at a relatively constant and predictable rate, the changes can be used to measure how long ago different lineages diverged.
What are the benefits of mitochondrial DNA and ribosomal RNA as molecular clocks?Mitochondrial DNA accumulates mutations relatively quickly, so it is most useful for analyzing relatedness within closely related species or change within a species. Ribosomal RNA has many conservative regions that accumulate mutations relatively slowly, so it is useful for studying taxa that are more distantly related.What molecular clock might be useful to examine the evolutionary relationship between several phyla in the kingdom Plantae?rRNA, because it accumulates mutations relatively slowlyWhy did Woese propose classifying bacteria and archaea into separate domains, rather than just separate kingdoms?The genetic difference between these groups of prokaryotes is greater than the genetic difference between the four eukaryotic kingdoms. What are the three domains in the tree of life?Bacteria, Archaea, EukaryaSingle celled prokaryotes. One of the largest groups of organisms on Earth.BacteriaSingle celled prokaryotes that have the ability to live in extreme environments because of their cell walls.ArchaeaA domain that contains all organisms made of eukaryotic cells. They may be single celled, colonial, or multicellular.EukaryaWhy do some scientists believe that bacteria and archaea have no true species? Many of these organisms transfer genes among themselves outside of typical reproduction. They do not reproduce sexually. We define species as the ability to produce offspring by the combining of a male and female. If bacteria reproduce by binary fission, they cannot by definition be considered species.
Why are protists, plants, fungi, and animals classified into the same domain but into different kingdoms?They all have eukaryotic cells, but are classified in different kingdoms based on differences in other characteristics.If you come across an unusual single celled organism, what parts of the cell would you study in order to classify it into one of the three domains?The nucleus (or lack thereof) and the cell wallExplain, using the traditional definition of species, why it is difficult to classify some bacteria and archaea at the species level.A species can be defined as an interbreeding group of organisms that produce fertile offspring. But bacteria and archaea do not breed to produce offspring; they reproduce by binary fission. In reproduction, parents pass genetic material to their offspring. However, many bacteria and archaea can take up genetic material from their environment a transfer of genes outside of typical reproduction that does not occur in eukaryotes. The Archaea lineage may include the first life on Earth, which began under much different environmental conditions from those present today. What characteristics of archaea help to support this statement?Archaea exist in extreme environments that are similar to those of early Earth. The scientific name for humans is Homo sapiens. What genus do humans belong to?HomoA 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. Mutations occur at a fairly constant rate.Are species in the same family more or less closely related than species in the same class?Class is a more general taxon than family. Organisms in the same family are more closely related than organisms in the same class. How many clades are represented in this cladogram? A B C D
3 one with A, B, C and DOne with B, C and DAnd one with C and DWhat represents the derived characters that were used to construct this cladogram? A B C D
The hash marks 1,2,3 and 4.1234Where are the nodes in this cladogram and what do they represent? A B C D
Nodes are where the side branches intersect with the main branch. They represent the common ancestor of the species in each clade.
Mutations in ___________ have been used to study the migration routes of humans over the past 200,000 years.mitochondrial DNAAn infectious particle made only of a strand of DNA or RNA surrounded by a protein coat.virusAny living organism or particle that can cause an infectious disease.pathogenWhat key characteristics do all living things share?They reproduce, use nutrients and energy, grow and develop, respond to the environment, and have genetic material.Why are viruses not classified as living?They cannot reproduce on their own. They do not grow or develop.
Infectious particles that cause disease in plants and are made of single stranded RNA without a protein coat.viroidsAn infectious particle made only of proteins that can cause other proteins to fold incorrectly. They are at the boundary between living and nonliving. They contain no genetic material. A prionThese play a role in mad cow disease. BSE bovine spongiform encephalopathy. And Creutzfeld Jakob disease.
prionsWhy is a prion even more deadly than a virus?The body has no immune response against a protein.Prions were not widely known to be infectious agents until the 1980s. Give two reasons why this might be so.They are very small, and prion diseases often incubate for many years before taking effect.
An RNA based disease spreads through pollen. Is it likely due to a virus, viroid, or prion? Explain.Viroids, because they are made of RNA, are passed through seeds or pollen, and infect plants.To multiply, viruses must take o