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the formation of the transcription initiation complex and the disconnection of the mRNA strand from DNA. 652 Chapter 16 | Gene Regulation The Promoter and the Transcription Machinery Genes are organized to make the control of gene expression easier. The promoter region is immediately upstream of the coding sequence. T... |
each bind specifically to a particular DNA sequence motif. When transcription factors bind to the promoter just upstream of the encoded gene, it is referred to as a cis-acting element, because it is on the same chromosome just next to the gene. The region that a particular transcription factor binds to is called the t... |
processing messenger RNA involves the removal of introns that do not code for protein. Spliceosomes remove the introns and ligate the exons together, often in different sequences than their original order on the newly transcribed (immature) messenger RNA. A GTP cap is added to the 5’-end and a poly-A tail is added to ... |
the epigenetic and transcriptional stages of processing, this post-transcriptional step can also be regulated to control gene expression in the cell. If the RNA is not processed, shuttled, or translated, then no protein will be synthesized. RNA Splicing, the First Stage of Post-transcriptional Control In eukaryotic ce... |
, the original mRNA cannot be created again. b. Spliced RNA cannot produce proper proteins. c. Splicing does not occur at all. d. Splicing occurs in the wrong location on mRNA. Think About It What is an evolutionary advantage of alternative gene splicing of introns during post-transcriptional modification of mRNA? Cont... |
Figure 16.13 The protein-coding region of mRNA is flanked by 5' and 3' untranslated regions (UTRs). The presence of RNA-binding proteins at the 5' or 3' UTR influences the stability of the RNA molecule. RNA Stability and microRNAs In addition to RBPs that bind to and control (increase or decrease) RNA stability, other... |
.7 The student is able to refine representations to illustrate how interactions between external stimuli and gene expression result in specialization of cells, tissues, and organs. After the RNA has been transported to the cytoplasm, it is translated into protein. Control of this process is largely dependent on the RNA... |
It will not affect the translation process. It will block the translation of certain proteins. It will produce multiple fragments of polypeptides. Chemical Modifications, Protein Activity, and Longevity Proteins can be chemically modified with the addition of groups including methyl, phosphate, acetyl, and ubiquitin g... |
of altered gene expression that can occur at every level of control, including at the levels of DNA methylation, histone acetylation, and activation of transcription factors. By understanding how each stage of gene regulation works in normal cells, we can understand what goes wrong in diseased states. For example, cha... |
cyclin B, a post-translational event, alters its function. As a result, cells can progress through the cell cycle unimpeded, even if mutations exist in the cell and its growth should be terminated. This post-translational change of cyclin B prevents it from controlling the cell cycle and contributes to the development... |
cancer is often called a “fight against biology.” Explain why the use of p53 supports this statement. a. because normal cells are often negatively affected by cancer treatments, including p53 b. because cancer cells are always affected by current cancer treatments, including p53 c. because normal cells are often negat... |
many researchers are testing how a silenced gene can be switched back on in a cancer cell to help re-establish normal growth patterns. Genes involved in the development of many other illnesses, ranging from allergies to inflammation to autism, are thought to be regulated by epigenetic mechanisms. As our knowledge of h... |
growth of breast cancer cells. These types of studies also suggest that if some miRNAs are specifically expressed only in cancer cells, they could be potential drug targets. It would, therefore, be conceivable that new drugs that turn off miRNA expression in cancer could be an effective method to treat cancer. Cancer ... |
doctors to facilitate the trial and publication of the results. A clinical trial coordinator may have a science background, like a nursing degree, or other certification. People who have worked in science labs or in clinical offices are also qualified to become a clinical trial coordinator. These jobs are generally in... |
needed for translation histone acetylation epigenetic modification that leads to gene silencing; commonly found in cancer cells. inducible operon operon that can be activated or repressed depending on cellular needs and the surrounding environment initiation complex protein complex containing eIF2-2 that starts transl... |
ophan amino acid that can be synthesized by prokaryotic cells when necessary untranslated region segment of the RNA molecule that are not translated into protein. These regions lie before (upstream or 5') and after (downstream or 3') the protein-coding region CHAPTER SUMMARY 16.1 Regulation of Gene Expression While all... |
is present, the repressor protein does not bind to its operator. Only when both conditions are met will RNA polymerase bind to the promoter to induce transcription. 666 Chapter 16 | Gene Regulation 16.3 Eukaryotic Epigenetic Gene Regulation In eukaryotic cells, the first stage of gene expression control occurs at the ... |
asm, or decreased, leading to shortened time and less protein synthesis. RNA stability is controlled by RNA-binding proteins (RPBs) and microRNAs (miRNAs). These RPBs and miRNAs bind to the 5' UTR or the 3' UTR of the RNA to increase or decrease RNA stability. Depending on the RBP, the stability can be increased or dec... |
happen if the operator sequence of the trp operon contained a mutation that prevented the repressor protein from binding to the operator? a. b. c. d. In the absence of tryptophan, the genes trpA-E will not be transcribed. In the absence of tryptophan, only genes trpE and trpD will be transcribed. In the presence of tr... |
the lac operon contained a mutation that prevented the repressor protein from binding the operator? 668 Chapter 16 | Gene Regulation a. decreased transcription because transcription factors would not bind to transcription binding sites b. decreased transcription because enhancers would not be able to bind to transcrip... |
-2 from binding to RNA. b. The mutation prevents eIF-2 from being phosphorylated. c. The mutation prevents eIF-2 from binding to GTP. d. The mutation prevents eIF-2 from binding to the 40S ribosomal subunit. 18. The addition of a ubiquitin group to a protein does what? a. increases the stability of the protein b. decre... |
perform highly-regulated gene expression whereas eukaryotes perform less-regulated gene expression. d. Eukaryotic cells are more complex and perform less-regulated gene expression whereas prokaryotic cells perform highly-regulated gene expression. 25. Which statement is correct regarding the distinction between prokar... |
the lac operon? a. Mutation in structural genes will stop transcription. b. Mutated lacY will produce an abnormal β galactosidase protein. c. Mutated lacA will produce a protein that will transfer an acetyl group to β galactosidase. d. Transcription will continue but lactose will not be metabolized properly. 29. In so... |
, arrows indicate the transformation of one substance into another. Square lines, or the lines with no arrowheads, indicate inhibition of the product below the line. Based on this, how would increased wnt gene expression affect the expression of Bar-1? Figure 16.16 34. Describe how RBPs can prevent miRNAs from degradin... |
ylation of proteins. b. RNA binding proteins are modified through phosphorylation. c. External stimuli can cause deacetylation and demethylation of the transcript. d. UV rays can cause dimerization of the RNA binding proteins. 36. Protein modifications can alter gene expression in many ways. Describe how phosphorylatio... |
ribe two ways in which gene regulation differs and two ways in which it is similar in prokaryotes and eukaryotes. a. Prokaryotes show co-transcriptional translation whereas eukaryotes perform transcription prior to translation; in both cell types, regulation occurs through the binding of transcription factors, activato... |
DNA will have many acetyl molecules. c. The DNA will have few methyl groups. d. The histones will have few acetyl groups. 48. Chapter 16 | Gene Regulation 673 gene? 50. a. deletion 1 b. deletion 2 c. deletion 3 d. deletion 4 The diagram provided shows different regions (1-5) of a pre-mRNA molecule, a mature-mRNA molec... |
c. No DNA damage will occur in response to UV exposure. d. No peeling of skin will occur in response to UV exposure. 55. Which of the following will not occur in response to UV exposure if a p53 mutation inactivates the p53 protein? 1. Damage to DNA 2. p53 activation 3. p21 activation 4. Apoptosis This OpenStax book i... |
a calciumbinding compound should prevent heterocyst differentiation. b. A strain that overexpresses the patS gene should develop many more heterocysts in a low nitrogen environment. c. d. In an environment with abundant fixed nitrogen, free calcium levels should be high in all cells, preventing heterocysts from develo... |
patients suffering from intestinal failure. More details about this exciting research can be found here (http://openstaxcollege.org/l/ 32grwinmouse). 678 Chapter 17 | Biotechnology and Genomics 17.1 | Biotechnology In this section, you will explore the following questions: • What are examples of basic techniques used ... |
from these technologies including the safety of GMOs and privacy issues. Information presented and the examples highlighted in the section support concepts outlined in Big Idea 3 of the AP® Biology Curriculum Framework. The Learning Objectives listed in the Curriculum Framework provide a transparent foundation for the... |
are in medicine (production of vaccines and antibiotics) and agriculture (genetic modification of crops, such as to increase yields). Biotechnology also has many industrial applications, such as fermentation, the treatment of oil spills, and the production of biofuels. Basic Techniques to Manipulate Genetic Material (... |
in nature and very difficult to inactivate. Similar to DNA, RNA extraction involves the use of various buffers and enzymes to inactivate macromolecules and preserve the RNA. Gel Electrophoresis Because nucleic acids are negatively charged ions at neutral or basic pH in an aqueous environment, they can be mobilized by ... |
PCR, is used to amplify a specific sequence of DNA. Primers—short pieces of DNA complementary to each end of the target sequence—are combined with genomic DNA, Taq polymerase, and deoxynucleotides. Taq polymerase is a DNA polymerase isolated from the thermostable bacterium Thermus aquaticus that is able to withstand t... |
surface of the membrane can then be probed with specific radioactively or fluorescently labeled probe sequences. When DNA is transferred to a nylon membrane, the technique is called Southern blotting, and when RNA is transferred to a nylon membrane, it is called northern blotting. Southern blots are used to detect the... |
(MCS). The MCS is a short DNA sequence containing multiple sites that can be cut with different commonly available restriction endonucleases. Restriction endonucleases recognize specific DNA sequences and cut them in a predictable manner; they are naturally produced by bacteria as a defense mechanism against foreign D... |
c. There will be blue and white colonies. d. The will be white colonies only. This OpenStax book is available for free at http://cnx.org/content/col12078/1.6 Chapter 17 | Biotechnology and Genomics 687 View an animation of recombination in cloning (http://openstaxcollege.org/l/recombination) from the DNA Learning Cent... |
reproduction of mammals in the laboratory. Parthenogenesis, or “virgin birth,” occurs when an embryo grows and develops without the fertilization of the egg occurring; this is a form of asexual reproduction. An example of parthenogenesis occurs in species in which the female lays an egg and if the egg is fertilized, i... |
and Genomics 689 Figure 17.7 Dolly the sheep was the first mammal to be cloned. To create Dolly, the nucleus was removed from a donor egg cell. The nucleus from a second sheep was then introduced into the cell, which was allowed to divide to the blastocyst stage before being implanted in a surrogate mother. (credit: m... |
genes provides researchers with clues about gene function. The methods used to disable gene function are collectively called gene targeting. Gene targeting is the use of recombinant DNA vectors to alter the expression of a particular gene, either by introducing mutations in a gene, or by eliminating the expression of ... |
the genes of microorganisms cloned into vectors to mass produce the desired antigen. The antigen is then introduced into the body to stimulate the primary immune response and trigger immune memory. Genes cloned from the influenza virus have been used to combat the constantly changing strains of this virus. Antibiotics... |
ensure ecological stability. Staples like corn, potatoes, and tomatoes were the first crop plants to be genetically engineered. This OpenStax book is available for free at http://cnx.org/content/col12078/1.6 Chapter 17 | Biotechnology and Genomics 693 Transformation of Plants Using Agrobacterium tumefaciens Gene trans... |
farmers as a natural insecticide. Flavr Savr Tomato The first GM crop was in 1994. It was a tomato that resisted rotting and maintained flavor for longer periods of time. Antisense RNA technology was used to slow down the process of softening and rotting caused by fungal infections, which led to increased shelf life o... |
7.1 The student can connect phenomena and models across spatial and temporal scales. Learning Objective Essential Knowledge 3.10 The student is able to represent the connection between meiosis and increased genetic diversity necessary for evolution. 3.A.3 The chromosomal basis of inheritance provides an understanding ... |
genetics) proposed that traits were determined by what are now known as genes, other researchers observed that different traits were often inherited together, and thereby deduced that the genes were physically linked by being located on the same chromosome. The mapping of genes relative to each other based on linkage ... |
polymorphisms (RFLP), variable number of tandem repeats (VNTRs), microsatellite polymorphisms, and the single nucleotide polymorphisms (SNPs). RFLPs (sometimes pronounced “rif-lips”) are detected when the DNA of an individual is cut with a restriction endonuclease that recognizes specific sequences in the DNA to gener... |
of genetic mapping and is not affected by increased or decreased recombination frequency. Sequence mapping resulted from DNA sequencing technology that allowed for the creation of detailed physical maps with distances measured in terms of the number of base pairs. The creation of genomic libraries and complementary DN... |
ic characteristic, such as iris pigmentation (eye color). Select the species you want to study, and then press Enter. The genome map viewer will indicate which chromosome encodes the gene in your search. Click each hit in the genome viewer for more detailed information. This type of search is the most basic use of the ... |
regions of the DNA are sequenced. In 2010, whole-exome sequencing was used to save a young boy whose intestines had multiple mysterious abscesses. The child had several colon operations with no relief. Finally, whole-exome sequencing was performed, which revealed a defect in a pathway that controls apoptosis (programm... |
.12 A dideoxynucleotide is similar in structure to a deoxynucleotide, but is missing the 3' hydroxyl group (indicated by the box). When a dideoxynucleotide is incorporated into a DNA strand, DNA synthesis stops. This OpenStax book is available for free at http://cnx.org/content/col12078/1.6 Chapter 17 | Biotechnology a... |
both ends of each fragment are analyzed for overlap. Pairwise-end sequencing is, therefore, more cumbersome than shotgun sequencing, but it is easier to reconstruct the sequence because there is more available information. Next-generation Sequencing Since 2005, automated sequencing techniques used by laboratories are ... |
the human protein than the bacterial protein. c. The bacterial protein will be more similar to the yeast protein than the human protein. d. The bacterial and yeast protein will share a similar sequence, but the human protein will be unrelated. Use of Whole-Genome Sequences of Model Organisms The first genome to be com... |
to deep sequencing. c. Sanger sequencing is suitable when there is only one nucleotide different between chains whereas deep sequencing is suitable when there is one or more than one nucleotide different between chains. d. Sanger sequencing reads and sequences a genome multiple times whereas deep sequencing accurately... |
Human Genome project, has expanded the applicability of DNA sequence information. Genomics is now being used in a wide variety of fields, such as metagenomics, pharmacogenomics, and mitochondrial genomics. The most commonly known application of genomics is to understand and find cures for diseases. Predicting Disease ... |
treatment. What do you think? Should all healthy men be screened for prostate cancer using the PCA3 or PSA test? Should people in general be screened to find out if they have a genetic risk for cancer or other diseases? a. b. c. In general, all men should be screened as it is necessary to take the risk. In general, al... |
new species more rapidly and to analyze the effect of pollutants on the environment (Figure 17.15). Figure 17.15 Metagenomics involves isolating DNA from multiple species within an environmental niche. Microbial Genomics: Creation of New Biofuels Knowledge of the genomics of microorganisms is being used to find better... |
a useful product or enhance an existing product, such as making a drought-sensitive crop more tolerant of the dry season. 17.5 | Genomics and Proteomics In this section, you will explore the following questions: • What is a proteome? • What is a protein signature and what is its relevance to cancer screening? Connecti... |
set of metabolites that are related to the genetic makeup of an organism. Metabolomics offers an opportunity to compare genetic makeup and physical characteristics, as well as genetic makeup and environmental factors. The goal of metabolome research is to identify, quantify, and catalogue all of the metabolites that a... |
a DNA-binding domain (BD) and an activator domain (AD). The binding domain is able to bind the promoter in the absence of the activator domain, but it does not turn on transcription. A protein called the bait is attached to the BD, and a protein called the prey is attached to the AD. Transcription occurs only if the p... |
present in the genome of the organism of interest 708 Chapter 17 | Biotechnology and Genomics linkage analysis procedure that analyzes the recombination of genes to determine if they are linked lysis buffer solution used to break the cell membrane and release cell contents metabolome complete set of metabolites which ... |
DNA sequencing shotgun sequencing method used to sequence multiple DNA fragments to generate the sequence of a large piece of DNA single nucleotide polymorphism (SNP) variation between individuals in a single nucleotide Southern blotting transfer of DNA from a gel to a nylon membrane systems biology study of whole bio... |
, pharmaceuticals, and pollution control. The basic principle of all modern-day sequencing strategies involves the chain termination method of sequencing. Although the human genome sequences provide key insights to medical professionals, researchers use whole-genome sequences of model organisms to better understand the... |
lysing the cells in the sample d. polymerase chain reaction (PCR) 8. What is genomics? 3. What is the role of the plasmid in molecular cloning? a. They are used to create clones. b. They are used as vectors to insert genes into bacteria. c. They are a functional part of binary fission. d. They contain the circular chr... |
-joining of DNA artificially. d. It requires radiation hybrid mapping. 14. The chain termination method of sequencing uses what? a. labeled ddNTPs b. only dideoxynucleotides c. only deoxynucleotides d. labeled dNTPs 15. What sequencing technique is used to identify regions of similarity between cell types or species? a... |
? a. a provisional listing of the genome of a species b. a unique metabolite used to identify an individual c. a method used for protein analysis d. the complete set of metabolites related to the genetic makeup of an organism 26. How would you describe a set of proteins with altered expression levels? a. a group of bio... |
crop yield. b. Genome mapping is directly required to produce recombinants, in FISH detection, and detecting the methylated parts of genetic material. c. Genome mapping is useful for knowing the pedigree of diseases in humans and tracing the movement of transposons in plants. d. Genome mapping identifies human disease... |
termination method - automated sequencers are used to generate sequences of short fragments; Shotgun sequencing method cutting DNA into random fragments, sequencing using chain termination, and assembling overlapping sequences; Next-generation sequencing - incorporation of ddNTP during DNA replication 36. What is the ... |
What is the reason for studying mitochondrial genomics that is most directly important for humans? a. Mitochondria evolved from bacteria; therefore, their genome is important to study. b. Mitochondria undergo rapid mutation and it is essential that this pattern be studied. c. Mitochondria contain DNA, and it is passed... |
RNA. 45. There are many techniques for investigating human genomic disorders. Western blotting looks for protein, Eastern blotting looks for post-translational changes, Northern blotting looks at mRNA, and Southern blotting looks at DNA. If you were to look at sickle cell anemia, a disorder affecting hemoglobin produc... |
staining chromosomes); radiation hybrid maps (fragments with x-rays); and sequence maps (comparing DNA sequences). Which of the following accurately describes the three methods? 716 Chapter 17 | Biotechnology and Genomics 49. How many cells with different genetic variations are possible after a single round of meiosis?... |
each feature of the diagram: ___ viral DNA ___ degraded viral DNA ___ cell membrane ___ cellular DNA ___ cas protein ___ stored viral DNA template ___ excised viral DNA ___ cas protein-RNA complex ___ cas protein-RNA-viral DNA complex The CRISPR system was discovered in cultures of yogurt in 2002. Subsequently, resear... |
field, the amino acids move; how the amino acids are separated as they move; and which amino acid moves furthest. Figure 17.18 B. A biologist wants to determine whether a new protocol is successful in constructing and amplifying a molecular clone of a segment of DNA introduced as a plasmid. After the procedure is comp... |
has been determined. Design a plan for collecting data that could be used to assign a function to the protein encoded by this sequence. (Hint: Don’t worry about the number of experiments that might need to be conducted to implement your plan. An automated technique called high-throughput screening robotically supports... |
to another. The algal genes code for products that repair and maintain chloroplasts eaten by the slug. You can read more about it at this website (http://openstaxcollege.org/l/32slug). [1] 1. Biol. Bull. 227: 300–312. (December 2014) 720 Chapter 18 | Evolution and Origin of Species 18.1 | Understanding Evolution In th... |
evolve in different directions from a common point, such as the forelimbs of humans, dogs, birds, and whales. Although Darwin’s theory was revolutionary for its time because it contrasted with long-held ideas (for example, Lamarck proposed the inheritance of acquired characteristics), evidence drawn from many scientif... |
evidence provided by data sets in relation to a particular scientific question. Learning Objective Essential Knowledge 1.12 The student is able to connect scientific evidence from many scientific disciplines to support the modern concept of evolution. 1.A.4 Biological evolution is supported by scientific evidence from... |
Over time, however, scientists came to understand that life was constantly evolving on Earth. Georges Cuvier found that fossilized remains or organisms changed as he dug into deeper rock layers (strata), indicating that the organisms present in the area had changed over time. This observation led Jean-Baptiste de Lama... |
and Darwin both observed similar patterns in other organisms and they independently developed the same explanation for how and why such changes could take place. Darwin called this mechanism natural selection. Natural This OpenStax book is available for free at http://cnx.org/content/col12078/1.6 Chapter 18 | Evolutio... |
is the only mechanism known for adaptive evolution. Papers by Darwin and Wallace (Figure 18.3) presenting the idea of natural selection were read together in 1858 before the Linnean Society in London. The following year Darwin’s book, On the Origin of Species, was published. His book outlined in considerable detail hi... |
Figure 18.4 A field biologist tranquilizes a polar bear for study. (credit: Karen Rhode) One objective of many field biologists includes discovering new species that have never been recorded. Not only do such findings expand our understanding of the natural world, but they also lead to important innovations in fields ... |
an adaptation for living in the cold. The cheetahs’ fast speed is an adaptation for catching prey. These adaptations can occur through the rearrangements of entire genomes or can be caused by the mutation of a single gene. For example, dogs have 78 chromosomes while cats have 38. A large number of the characteristics ... |
wings, which are adaptations to flight. However, the wings of bats and insects have evolved from very different original structures. This phenomenon is called convergent evolution, where similar traits evolve independently in species that do not share a common ancestry. The two species came to the same function, flyin... |
. Figure 18.7 The similar construction of these appendages indicates that these organisms share a common ancestor. Some structures exist in organisms that have no apparent function at all, and appear to be residual parts from a past common ancestor. These unused structures without function are called vestigial structur... |
tails at some point in their early development. These disappear in the adults of terrestrial groups but are maintained in adult forms of aquatic groups such as fish and some amphibians. Great ape embryos, including humans, have a tail structure during their development that is lost by the time of birth. Biogeography T... |
modification of one copy by mutation, selection, or drift (changes in a population’s gene pool resulting from chance), while the second copy continues to produce a functional protein. Direct Observations Scientists have also observed evolution occurring in both the laboratory and in the wild. A common example of this ... |
. Misconception: Humans are not currently evolving. Correction: The environmental pressures humans face are different than the ones they faced several thousands of years ago, but they are still there, and they are still producing (slowly!) evolutionary change. c. Misconception: Evolution produces individuals that are p... |
this average value will be different as a result of evolution. Although some individuals may survive from the first time to the second, they will still have the same bill size; however, there will be many new individuals that contribute to the shift in average bill size. Evolution Explains the Origin of Life It is a c... |
a gene, did not arise by mutation because of the application of the antibiotic. The gene for resistance was already present in the gene pool of the bacteria, likely at a low frequency. The antibiotic, which kills the bacterial cells without the resistance gene, strongly selects individuals that are resistant, since th... |
AP® Courses Speciation explains the diversity of organisms that inhabit the Earth. Although all life shares various genetic similarities, only certain organisms combine genetic information by sexual reproduction and produce viable and fertile offspring that, in turn, can successfully reproduce. Scientists call such or... |
than in animals, though some examples in animals exist. For example, two groups of cichlid fish in Africa’s Lake Victoria, which have distinct morphologies and diets, may be in the early stage of sympatric speciation without polyploidy, as genetic differences arise between the two groups. Information presented and the... |
Big Idea 3 6.4 The student can make claims and predictions about natural phenomena based on scientific theories and models. 1.24 The student is able to describe speciation in an isolated population and connect it to change in gene frequency, change in environment, natural selection, and/or genetic drift. Living system... |
, even though domestic dogs (Canis lupus familiaris) display phenotypic differences, such as size, build, and coat, most dogs can interbreed and produce viable puppies that can mature and sexually reproduce (Figure 18.10). Figure 18.10 The (a) poodle and (b) cocker spaniel can reproduce to produce a breed known as (c) ... |
several genetic changes in their body cells, but if these changes do not occur in a sperm or egg cell, the changed trait will never reach the next generation. Only heritable traits can evolve. Therefore, reproduction plays a paramount role for genetic change to take root in a population or species. In short, organisms... |
etic charts that are drawn today to illustrate the relationships of species. (b) Modern elephants evolved from the Palaeomastodon, a species that lived in Egypt 35–50 million years ago. For speciation to occur, two new populations must be formed from one original population and they must evolve in such a way that it be... |
flow. However, if 736 Chapter 18 | Evolution and Origin of Species two rodent populations became divided by the formation of a new lake, continued gene flow would be unlikely; therefore, speciation would be more likely. Biologists group allopatric processes into two categories: dispersal and vicariance. Dispersal is w... |
Figure 18.15. This OpenStax book is available for free at http://cnx.org/content/col12078/1.6 Chapter 18 | Evolution and Origin of Species 737 Figure 18.15 The honeycreeper birds illustrate adaptive radiation. From one original species of bird, multiple others evolved, each with its own distinctive characteristics. No... |
individuals who continue to live and reproduce in the same habitat? The answer is yes. The process of speciation within the same space is called sympatric speciation; the prefix “sym” means same, so “sympatric” means “same homeland” in contrast to “allopatric” meaning “other homeland.” A number of mechanisms for sympa... |
. Polyploidy results from an error in meiosis in which all of the chromosomes move into one cell instead of separating. Figure 18.17 Autopolyploidy results when mitosis is not followed by cytokinesis. For example, if a plant species with 2n = 6 produces autopolyploid gametes that are also diploid (2n = 6, when they sho... |
to occur. Then design a plan for collecting data to support the claim that speciation has occurred. Think About It • Two species of fish had recently undergone sympatric speciation. The males of each species had a different coloring through which the females could identify and choose a partner from her own species. Af... |
species exhibit temporal reproductive isolation. (a) Rana aurora breeds earlier in the year than (b) Rana boylii. (credit a: modification of work by Mark R. Jennings, USFWS; credit b: modification of work by Alessandro Catenazzi) In some cases, populations of a species move or are moved to a new habitat and take up re... |
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