Biology- Test four – Flashcards
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What is the common name of the subspecies that all domestic cats are related to?
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middle eastern wildcat
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One source of DNA information that was used to determine cat ancestry was nuclear microsatellites. What are microsatellites?
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a. Short tandem repeats (STRs)
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Cats show a few morphological differences from their wild ancestors. These include slightly shorter legs, a smaller brain, and
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longer intestines
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The Cat Fancier's Association and the International Cat Association recognize nearly how many breeds of domestic cat?
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nearly 60
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The most common types of antibiotics are beta-lactams, which include penicillin. How do these antibiotics work?
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Interfere with a bacterium's ability to synthesize cell walls
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How did Jean-Baptiste Lamarck incorrectly explain change in species over time?
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Hypothesized that traits acquired in one's lifetime are passed on to offspring
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A phylogenetic tree represents what?
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A grouping of organisms on the basis of their evolutionary history
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What do we call a type of natural selection in which organisms near the middle of the phenotypic range of variation are favored?
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Stabilizing selection
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How many people are sickened by MRSA in the US each year?
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94,000
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What important elemental gas was not present in the atmosphere of ancient earth?
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oxygen
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Which of the following features of Tiktaalik was not shared with other bony fishes?
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A mobile neck
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What type of organism is thought to have been the first to exist?
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Anaerobic unicellular prokaryotes
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What is the estimated age of the oldest known fossils?
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3.5 billion years old
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What is believed to have caused the extinction of the dinosaurs?
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A massive asteroid hit the earth causing the sun to be blocked out
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Shubin and Daeschler searched for "intermediate" fossils on Ellesmere Island because
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Rocks from the era between fish and the first known land vertebrates were exposed there
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The concept that most evolutionary changes occur in bursts as a result of sudden environmental change, rather than gradually, describes
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punctuated equilibrium
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an animal with a bony or cartilaginous backbone
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vertebrate
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Darwin's team for evolution, combining the ideas that all living things are related and that organisms have changed over time.
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descent with modification
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the preserved remains or impressions of once-living organisms
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fossils
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an assemblage of fossils arranged in order of age, providing evidence of changes in species over time
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fossil record
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a scientist who studies ancient life by means of the fossil record.
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paleontologist
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determining the age of a fossil from its position relative to layers of rock or fossils of known age
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relative dating
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an animal without a backbone
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invertebrate
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an organism with four true limbs, that is, bony appendages with jointed wrists, ankles, and digits, mammals, amphibians, birds, and reptiles
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tetrapod
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anatomical, genetic, of developmental similarity among organisms due to common ancestor
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homolgy
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a structure inherited from an ancestor that no longer serves a clear function in the organism that possesses it.
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vestigial structures
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generally speaking, if you are looking at layers of rock, at what level would you expect to find the newest-that is, the youngest-fossils?
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the shallowest layers
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Which of the following Is most likely to leave a fossil?
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wolf
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Tiktaalik fossils have both fishlike and tetrapod- like characteristics. Which characteristics are related to supporting the body out of water?
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elongated bony ribs and weight-bearing pectoral fins that include ankles.
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Tiktaalik fossils are described as "intermediate" or "transitional" fossils. What does this mean? Why are transitional organisms so significant in the history of life?
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Transitional fossils represent midpoints between two groups of organisms, Often they are extinct organisms that represent a transitional form between the ancestors of two groups of extant (that is currently living) organisms. In this case, Tiktaalik represents a transitional form between bony fish and amphibians (or all tetrapods). Often transitional fossils help scientists understand how organisms changed morphologically over time.
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Vertebrate embryos have structures called pharyngeal pouches. What do these structures develop into in an adult human? In an adult bony fish?
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middle ear bones in humans; gills in fish.
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Could you use the presence of the tail to distinguish a human embryo froma chicken embryo? Why or why not?
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depends on the stage of development at which the embryos are observed. At early stages of development, both human and chicken embryos have post-anal tails, so the presence of a tail at that stage cannot be used to distinguish the two. Later, the post anal tail disappears in the human embryo.
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You have three sequences of a given gene from three different organisms. How could you determine how closely the three organisms are related to one another?
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By comparing the three sequences to one another in a pairwise fashion. By counting the number of differences between each pair of sequences, a quantitative measure of similarity can be established. He more similar the sequence, the more likely it is that they are closely related. Sequence evidence from a single gene is often combined with evidence from other genes to establish relationships between organisms. DNA sequence data is just one means by which to determine such relationships. Comparisons of morphological traits, such as the arm bones, are another way to gather evidence to establish such relationships.
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If in a humans, the DNA sequence TTCTAGGAATA encodes the amino acid sequence phenylalanine- leucine- glycine- isoleucine, what amino acid sequence will that same DNA sequence specify in bacteria?
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With only a few rare exceptions, the genetic code is universal for all living organisms known on this planet. Therefore, the same piece of DNA encodes the exact same amino acids in bacteria as it does in humans.
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Understand how fossils are formed
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- Organism must be covered quickly upon death or create an imprint in special types of sediment.
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What type of organism is less likely to be found in the fossil record?
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- Animals that don't have hard parts such as bones or shells, because they can decay quickly
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How does the fossil record provide evidence for Darwin's concept of Descent with Modification
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- Fossils show a continual series of change , with the most recent fossils being the most similar to modern organisms, and the more ancient fossils being more different.
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How is Relative Dating used to determine the age of fossils
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- They can we dated indirectly by their position with respects to rocks or fossils of a known age.
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What two groups of organisms did Tiktaalik seem to form an evolutionary link between?
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fish and tetrapods
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List four fishlike features that Tiktaalik exhibited
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- Gills - Forelimbs are fins with webbing and no distinct external digits - Scales - Small pelvic fin
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List four tetrapod-like features that Tiktaalik exhibited.
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- Head is long and flat - Neck is mobile, not fused to shoulder - Pectoral fins are weight-bearing with distinct, jointed wrist and fingerlike bones - Ribs are long and sturdy to support the body on land.
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Why would being able to leave the water and hunt on the land be an advantage in the Devonian?
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- They can find food sources in two locations
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How does forelimb homology support the idea that modern tetrapod vertebrates evolved from fish
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- The number order and underlying structure of the forelimb bones are similar in all the groups illustrated below. The differences in the relative width,length, and strength of each fore bone contributes to the specialized function of each forelimb. This is strong evidence that they all shared a common ancestor in the distant past. Variation in bone shape and function reflect evolutionary adaptations to different environments.
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How does this same line of evidence demonstrate how Tiktaalik forms the link between fish and tetrapods?
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- They are inherited from the same ancestors
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What structures do pharyngeal pouches found in all vertebrate embryos give rise to in humans, reptiles and fish?
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- Middle ear bones are homologous with the jaw bones of reptiles and bones supporting gills in fish.
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How do vestigial structures support the idea of common ancestry?
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- Features inherited from an ancestor in whom they served a purpose for
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What is meant by the universal genetic code and how does it support the idea of a common ancestor of all living things?
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- All molecules of DNA are made up of the same four nucleotides.
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How are differences in DNA sequences related to the accumulation of mutations over time (the molecular clock)?
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- Over time neautral and advantageous mutations will be preserved, while harmful muations will tend to be selected against and eliminated.
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Understand how organisms with fewer differences in DNA sequence are more closely related (more recently diverged) than organisms with more differences
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- There DNA is closer so that they are more genetically similar
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Where did Shubin and Daeschler search for fossils?
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- Remote island of ellsmere
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Why did they select this place to search for an organism that would be an intermediate form between fish and amphibians?
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- Once was an active streambed
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What was the time-span of the Devonian?
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- 400-350 million years ago
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What was the estimated age of the Tiktaalik fossils?
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- 383 million years old
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What percent similarity exists between human and chimp DNA?
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- 99%
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How long ago is a common ancestor for humans and chimps estimated to have lived?
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- 60 and 100 million years ago
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a group of organisms of the same species living together in the same geographic area
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population
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change in allele frequencies in a population over time
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evolution
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the relative ability of an organism to survive and reproduce in a particular environment
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fitness
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differential survival and reproduction of individuals in response to environmental pressure that leads to change in allele frequencies in a population over time
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natural selection
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the response of a population to environmental pressure, so that advantageous traits become more common in the population over time
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adaptation
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a type of natural selection in which organisms with phenotypes at one end of a spectrum are favored by the environment
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directional selection
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a type of natural selection in which organisms near the middle of the phenotypic range of variation are favored
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stabalizing selection
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a type of natural selection in which organisms with phenotypes at both extremes of the phenotypic range are favored by the environment
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diversifying selection
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Darwin's term for evolution, combining the ideas that all living things are related and that organisms have changed over time
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descent with modification
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the definition of a species as a population whose members can interbreed to produce fertile offspring
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biological species concept
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the process of identifying, naming, and classifying organisms on the basis of shared traits
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taxonomy
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the evolutionary history of a group of organisms
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phylogeny
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the highest category in the modern system of classification; Bacteria, Archaea, and Eukarya are the three types of this
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domain
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a specific group of domestic animals or plants with a homogeneous appearance, behavior and other characteristics that distinguish it from other animals or plants of the same species, and arrives at through artificial selection
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breed
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the offspring produced as a result of breeding animals of one breed with other animals of another breed
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cross breed
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when bred together, animals of the same breed pass on predictable traits to their offspring, and this is a requirement for a breed
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breeding true
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Mechanisms that prevent mating between members of different species
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reproductive isolation
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the total of all genes and alleles in a particular species
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gene pool
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a taxonomic category that ranks below species, usually a fairly permanent geographically isolate race
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subspecies
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change over time
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evolution
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the process where by a population of animals or plants is changed at the genetic level through a process of selection, in order to accentuate traits that benefit humans
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domestication
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STR (short tandem repeat) areas of the nuclear genome
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microsatellites
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the intentional breeding for certain traits, or combination of traits
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artificial selection
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the direct manipulation of an organisms genome using biotechnology
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genetic engineering
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process of producing genetically similar populations of genetically identical individuals that occurs in nature when organisms such as bacteria, insects or plants reproduce asexually
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cloning
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the total collection of alleles in a population
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gene pool
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the relative proportion of an allele in a population
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allele frequency
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any change in allele frequency that does not by itself lead a population to become more adapted to its environment; the causes of non- adaptive evolution are mutation, genetic drift, and gene flow
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nonadaptive
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random changes in the allele frequency of a population between generations; tends to have more dramatic effects in smaller populations than in larger ones.
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genetic drift
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a type of genetic drift in which a small number of individuals leaves one population and establishes a new population; by chance, the newly established population may have lower genetic diversity than the original population
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founder effect
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a type of genetic drift that occurs when a population is suddenly reduced to a small number of individuals, and alleles are lost from the population as a result.
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bottleneck effect
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the principle that, in a non-evolving population, both allele and genotype frequencies remain constant from one generation to the next.
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Hardy-Weinberg equilibrium
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the negative reproductive consequences for a population associated with having a high frequency of homozygous individuals possessing harmful recessive alleles.
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inbreeding depression
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the movement of alleles from one population to another, which may increase the genetic diversity of a population
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gene flow
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mechanisms that prevent mating (and therefore gene flow) between members of different species
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reproductive isolation
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the definition of a species as a population whose members can interbreed to produce fertile offspring.
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biological species concept
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the genetic divergence of populations owing to a barrier to gene flow between them, leading over time to reproductive isolation and the formation of new species.
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speciation
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the uses of radioactive isotopes as a measure for determining the age of a rock or a fossil.
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radiometric dating
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a unstable form of an element that decays into another element by radiation, that is, by emitting energetic particles.
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radioactive isotope
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the time it takes for one half of a substance to decay
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half-life
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the elimination of all individuals in a species; extinction may occur over time or in a sudden mass die off.
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extinction
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the spreading and diversification of organisms that occur when they colonize a new habitat
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adaptive radiation
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the theory that most species change occurs in periodic bursts as a result of a sudden environmental change.
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punctuated equilibrium
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the study of how organisms are distributed in geographical space.
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biogeography
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the movement of the earth's upper mantle and crust. which influences the geographical distribution of landmasses and organisms.
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plate tectonics
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the process by which organisms that are not closely related evolve similar adaptions as a result of independent episodes of natural selection
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convergent evolution
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the changes in the amino acid sequences of proteins that take place during evolution and speciation, and from which the dates of branchings of taxonomic groups can be deduced.
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molecular clock
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the study of how biological life could arise from inorganic matter through natural processes
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abiogenesis
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the study of the origin, evolution, distribution, and future of life in the universe
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astrobiology
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The term "MRSA" as it is used today refers to
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Staphylococcus aureus bacteria that are resistant to many antibiotics
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What are the two major mechanisms by which bacterial populations generate genetic diversity?
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Gene exchange and mutation
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What is the environmental pressure in the case of antibiotic resistance?
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The presence or absence of antibiotics in the environment
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What is the evolutionary meaning of the term "fitness"?
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It describes the ability of an individual to survive and reproduce in a given environment. An organism that has a higher fitness will be able to reproduce and pass its genes to the next generation at a higher frequency than a less fit individual.
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The evolution of antibiotic resistance is an example of
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directional selection
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In humans, very-large-birth-weight babies and very tine babies do not survive as well as midrange babies. What kind of selection is acting on human birth weight?
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stabilizing selection
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If we take the most fit bacterium from one environment-one in which the antibiotic amoxicillin is abundant, for example-and place it in an environment in which a different antibiotic is abundant, will it retain its high degree of fitness?
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Not necessarily, fitness depends on the ability of an organism to survive and reproduce, and it may not do this as well in a different environment
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Put the following terms in order, from most inclusive to least inclusive
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Domain, kingdom, phylum, genus, species
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A phylogenetic tree represents
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A grouping of organisms on the basis of their evolutionary history
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Why was classification of the kingdom Monera split into two domains? What are these two domains?
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DNA evidence showed that is made up of two distinct groups of organisms. These were later separated into the current domain of Bacteria and Archea.
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Which number on the tree below shows the most recent common ancestor of humans and corn?
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3
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MRSA: Which organism causes the infection?
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Staphylococus aureus "staph"
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The most common types of antibiotics are beta-lactams, which include penicillin. How do these antibiotics work?
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By interfering with a bacterium's ability to synthesize cell walls.
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What does it mean when you are "colonized" but not infected?
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If you carry staph of any strain but aren't sick
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Name another mechanism by which bacteria may acquire new alleles.
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Through a mutation, they introduce new alleles into the population.
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How is fitness related to allele frequency?
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The greater an organism's fitness, the more likely that alleles carried by that organism will be passed on to future generations and increase in frequency.
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Explain why evolution occurs in populations, not in individuals.
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Evolution must be seen at a large scale because an individual solely represents one generation, and evolution occurs over millions of years through random mutations in offspring.
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List the 3 major patterns of natural selection.
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- directional selection - stabilizing selection - diversifying selection
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How did the work of Charles Lyell affect Darwin's thinking?
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Lyell argued that earth was much older than 6,000 years old, and its geology had been shaped entirely by incremental forces operating over a vast expanse of time. Darwin studied the plants, animals, and geology at each stop on his trip, collecting fossils and specimens of local flora and fauna wherever he went.
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a. What reasoning did charles darwin provide for the disappearance of the giant sloth along the shore of Argentina?
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He realized the presence of shells at a distinct point, and the dead animal's position in the cliff below them, meant that the animal had lived in the area before it was an ocean environment. Many layers of earth sat on top of the sloth fossil. Darwin reasoned, when the landscape changed the animals had been unable to adapt and had become extinct.
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Which descriptive phrase did Darwin use instead of "evolution"?
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descent with modification
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Was the first to provide a mechanism for evolution
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Robert Chambers
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What did Alfred Wallace send to Charles Darwin?
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Wrote out his idea on evolution that he thought Darwin would appreciate.
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What was the name of Darwin's book and when was it published?
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On the Origin of Species by Means of Natural selection, November 1859
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This article by alfred wallace was groundbreaking, but what did it lack?
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It lacked an explanation-a mechanism- of exactly how one species might have evolved from another.
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Who is responsible for the biological species concept?
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wallace
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List the eight categories used for sorting organisms
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Domain Kingdom Phylum Class Order Family Genus Species
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Which two names are used for the scientific name?
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genus and species
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What is found at the root of a phylogenetic tree?
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The common ancestor shared by all organisms on the tree.
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Know how to read an evolutionary tree Is a crocodile more closely related to a bird or lizard?
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Bird
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What types of evidence are used to construct a phylogenetic tree?
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Fossil record, physical traits, and shared DNA sequences
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Before the 18th century, what 2 categories were all living things divided into?
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animals and plants
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Which branch was added in the mid-19th century?
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protists
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What 3 domains are all organisms divided into today
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Bacteria, Archaea, Eukarya
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What domain do plants, animals, and fungi belong to?
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eukarya
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How many people are sickened by MRSA in the US each year? How many of them die?
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sickens 94,000 kills 19,000
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What type of selection occurred in Carlos, Rebecca, and Ricky?
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MRSA, staph
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Why were Wallace and Darwin absent from the meeting in 1858?
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Wallace was traveling in Malaysia, and Darwin was mourning the death of his young son.
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What was the title of Wallace's major work?
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Darwinism
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What is the most popular pet in the world?
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cats
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What is different about the domestication of cats from most other domesticated animals?
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The house cat contributes little to human survival, and cats chose to live among humans because of opportunities they found for themselves (mice).
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How many different subspecies are recognized of the wildcat?
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5
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Where did people think cats were domesticated before the discovery of the grave on Cyprus?
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egyptians
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Give 2 reasons why the discovery of a cat skeleton on the island of Cyprus leads scientists to believe that cats were domesticated and living with humans by the time this cat died.
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a) cat buried and placed in tiny grave with human, its body oriented in the same westward direction as the human's b) Cats are not native to Mediterranean islands - must have been brought over by boat by people
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What led to the special relationship between cats and humans?
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Cats chose to live among humans because of opportunities they found for themselves.
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What other animal drew cats to areas where humans lived?
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mice
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Give two examples of genetic engineering in cats.
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a) Allerca GD cat= $8950 b) Ashera GD cat= $29,950
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How is cloning different from genetic engineering?
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Cloning is producing a genetic copy Genetic Engineering is adding DNA from different species
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What is the name of the first cloned cat?
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C.C (copy cat)
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When was the first cat cloned?
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2001
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What is the name of the first cloned dog?
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snuppy
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When was the first dog cloned?
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April 24th 2005
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Which was sequenced first, the cat or dog genome?
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dog
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Which animal has more chromosomes, cats or dogs?
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dog
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How do the number of genes compare between cats and dogs?
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Dogs have about 20,000 genes while cats have the same too
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What are the two hypotheses for how dog domestication began?
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Hyp. 1: 10,000 years ago in Middle East Hyp. 2: 30,000 years ago in East central Asia
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What is the closest living relative of the wildcat, Felis silvestris?
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Martelli's wildcat (felis lunensis)
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Most modern breeds of cats were developed where and when?
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Burmese cats, brought from Burma to America in 1930
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What is the estimated age of the oldest known fossils?
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3.5 billion years ago
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What type of organism is thought to have been the first to exist?
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unicellular prokaryotes
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When are the first photosynthetic organisms thought to have evolved?
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3.0 to 2.5 billion years ago
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When did multicellular eukaryotic organisms arise?
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1.2 billion years ago
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How do mass extinctions pave the way for explosions of diversity through adaptive radiation?
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Adaptive radiation is the spreading and diversification of organisms that occur when they colonize a new habitat. So, when a huge change such as in the climate occurs some species die off while others adjust to the new change.
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Be able to describe the theory of punctuated equilibrium.
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The theory that most species change occurs in periodic bursts as a result of sudden environmental change. For example, it was said the dinosaurs went extinct from a massive asteroid. Also weather change can make this occur, if it gets too hot we won't be able to adjust to it, making us all die out suddenly.
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How have land mass movements contributed to the distribution and divergence of life forms on earth
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At one time land was close together, so animals in Europe could have moved to North America. For example, the earliest penguins were found near New Zealand, but now penguins live in Antarctica. This occurred because New Zealand and Antarctica were close to one another early in time.
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What is meant by convergent evolution?
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It is the process by which organisms that are not closely related evolve similar adaptations as a result of independent episodes of natural selection.
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How is the evolution of two different antifreeze molecules in Arctic and Antarctic fish an example of this type of evolution?
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In frigid waters of Antarctic Ocean, fish have a unique adaptation that keeps them from becoming ice cubes: their blood is pumped full of "antifreeze." Arctic fish, at the earth's other pole, also have antifreeze proteins, but the genes that code for them are different.
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How did the first photosynthetic organisms pave the way for the evolution of complex eukaryotic organisms?
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With the emergence of proliferation of unicellular photosynthetic organisms, between 3.0 to 3.5 billion years ago, did oxygen begin to accumulate in the atmosphere, opening the door for complex eukaryotic organisms'.
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What event is thought to have contributed to the extinction of dinosaurs?
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A 6-mile-wide massive asteroid hit earth.
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How does the rate of evolutionary change hypothesized by punctuated equilibrium compare to the Darwinian view of the rate of evolutionary change?
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They both compare because they both state that over-time as climate and other things change so are the organisms.
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What was the name of the first supercontinent?
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Pangea
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What do uranium -238, carbon-14, and potassium-40 have in common?
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- They are all radioisotopes that decay at steady and predictable rates, changing into other elements.
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To date what you suspect to be the very earliest life on earth, which isotope would you use: uranium-238, carbon-14, or potassium-40? Explain your answer.
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- You would use uranium-238 because it has the longest half-life (4.5 billion years). Other isotopes with shorter half-lives will be barely detectable in a sample that is extremely old, having long ago decayed to levels that are below detectable limits.
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Place the following evolutionary milestones in order from earliest to most recent, providing approximate dates to support your answer.
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- The first prokaryotes (3.0 billion years ago) - An increase in oxygen in the atmosphere (2.5 billion years ago) - The first multicellular eukaryotes (1.2 billion years ago) - The Cambrian Explosion (545 million years ago) - The First Animals (540 million years ago) - The Permian extinction (248 million years ago) - The extinction of dinosaurs (65 million years ago)
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If an igneous rock contains 75% lead, how old is that rock?
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- 9 billion years old
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9. What did the arrangement of landmasses on earth look like between 135 and 65 million years ago? What happened to these landmasses, and how does this change help explain the distribution of organisms found on the planet?
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- The continents were then generally close together than they are now. Since that time, because of plate tectonics-the movements of independent continental plates in the earth's mantle or crust-the continents have largely drifted apart. One major exception is the Indian continent, which has since collided with the Asian continent, forming the Himalayan mountain range. As landmasses moved and separated, so did the organisms that lived on those landmasses.
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A cactus called ocotillo, which grows in New Mexico, looks very much like Alluaudia procera, a species of plant that grows in the deserts of Madagascar, these two plant species are not closely related-why then do they look so alike?
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- The two species may look alike because they have evolved similar traits independently because they are adapting to similar environments. This is an example of convergent evolution.
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Both bats and insects fly, but bat wings have bones and insect wings do not. Would you consider bat and insect wings to be a result of convergent evolution, or of homology- evolution based on inheritance of similar structures from a common ancestor? Explain.
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- Bats are mammals and hence share a common ancestor with all mammals. This common ancestor is not thought to have possessed any structures homologous to insect wings that could have been inherited. Therefore, it is more likely that bat wings evolved separately. This is another example of convergent evolution.
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What was Edwin Hubble's contribution to the theory?
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-galaxies in the universe are moving away from one another (the universe is expanding) -This discovery resulted in the formulation of the Big Bang hypothesis
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Be able to briefly explain the Big Bang theory.
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-the cosmic explosion that marked the beginning of the universe -Universe started very small - all matter and energy compacted to a point -Universe still expanding today -Occurred about 14 billion years ago
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What is the estimated age of the universe?
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about 14 billion years ago
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What is the estimated age of the earth and the solar system.
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-4.54 billion years
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What are radioactive isotopes? Understand the example of Uranium-238 and Lead-206
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- Atoms of elements such as uranium, potassium, and rubidium that are unstable and decay into other atoms. They decay by releasing high-energy particles from the nucleus, a change that causes one element literally to transform into another.
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What is a half-life and how can it be used to date rocks from different strata?
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-The time it takes for half the isotope in a sample to break down. Some rock types contain radioactive minerals that can be used to determine the age of the rock.
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Why is carbon-14 of limited use in dating the fossil record?
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-The half-life is relatively short, it decays to nitrogen-14 in just 5,730 years. Because the isotopes decay at a known rate, they can be used to determine the age of the materials in which they are found.
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Genetic diversity is measured in terms of allele frequencies. A population of 3,200 manatees has 4,200 dominant G alleles and 2,200 recessive g allele. What frequency of g alleles in the gene pool?
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0.34
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a bottleneck is best described as?
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-a reduction in the size of an original population followed by an expansion in its size as the surviving members reproduce.
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The biological species concept defines a species:
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on the basis of the ability to mate and produce fertile offspring.
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Why is inbreeding detrimental to a population?
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- inbreeding is detrimental because it decrease the number of heterozygous in a population, increasing the proportion of individuals which are homozygous for recessive alleles. Many recessive alleles are mutations that are detrimental but which do not confer a phenotype in heterozygous individuals because the nonmutated gene is a dominant allele, however, in a homozygous recessive individual, these traits are expressed, usually with extremely negative consequences including decreased fitness, fertility, or viability. This phenomenon is called inbreeding depression..
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When was the manatee first listed as "endangered"?
answer
1967
question
The population has since increased. Give two reasons why biologists are still concerned about their long-term survival.
answer
-Continued threat from human influences such as coastal development, which forces manatees out of their preferred habitats -Florida's population of manatees Is geographically isolated from manatees in other regions and thus is in danger of being subdivided further.
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What can you say about a population whose allele frequencies are changing?
answer
- A population can evolve, these changes can have lasting effects sometimes good sometimes bad.
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Explain why a mutation is considered a type of nonadaptive evolution.
answer
- Because it introduces new alleles to a population, also alters allele frequencies, but since the process is random it does not in itself lead to adaptation. Without mutation introducing variation into a population there would be no evolution at all.
question
The founder effect reduces genetic diversity (see infographic 15.2). Explain why the genetic diversity of the new population is lower than the genetic diversity of the original population.
answer
- The founder effect is a type of genetic drift, in which chance events influence the allele frequencies in a new "founding" population. In this case, the chance event is the specific alleles that happen to be present in the small group of founders that leaves a large population. If, by chance, alleles from the original population are absent from the founders, they will also be absent from the new population.
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What may be a cause of the bottleneck effect? explain why bottlenecks are more consequential when the initial population is small.
answer
-Can occur from natural causes. In a small population, the loss of population member sis more likely to result in loss of alleles, and therefore a dramatic change in the allele frequency and genetic diversity of the "restored" population.
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Why is genetic diversity important?
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-A diverse gene pool gives a population more flexibility to survive in a changing environment: the more genetically diverse a population is, the more ways it has to adapt.
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What happens to allele frequencies in a nonevolving population?
answer
-They do not change overtime. Genotype frequencies remain unchanged from one generation to the next , which is a condition known as Hardy-Weinberg equilibrium.
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In a small population, closely related members of the population may mate with each other (inbreeding). Explain how inbreeding depression can lower fitness.
answer
-The accumulation of harmful recessive phenotypes can lower fitness.
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The Florida manatees seem to be preserving their genetic diversity. How are they able to keep genetic diversity in the population ?
answer
-Gene flow works in the opposite direction: increasing the genetic diversity of a local population by introducing alleles from its neighbors.
question
Based on the biological species concept, should a horse and a donkey be considered the same species?
answer
- No because the mule is not a fertile offspring.
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12. List the different factors that can cause reproductive isolation
answer
- Different mating time - Location - Mating ritual
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When a barrier prevents gene flow between two gene pools, the separated gene pools will evolve independently of each other. What may happen if enough genetic changes accumulate between the two populations?
answer
-The two populations may diverge into separate species, known as a speciation.
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At least 13 finch species, found on the Galapagos Islands, diverged from an original South American species. What caused speciation on the islands?
answer
- They spread from island to island, and encountered different environments, including available food sources, which influenced bill size and shape in each new island population. They evolved so much that each separated population could no longer interbreed.
question
How many species exist in the family Felidae?
answer
37
question
How many genes were used for DNA comparison in all living cat species?
answer
30
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DNA studies revealed 8 lineages. These 8 lineages are shown in the cat family tree. The domestic cat shares a lineage with 4 other species. What are they?
answer
- Wild cat - Sand cat - Jungle cat - Black footed cat
question
Explain how a rise in sea levels can lead to speciation
answer
-Animals on the continents are isolated
question
Explain why the saber-tooth cat is not considered the last common ancestor of all cat species.
answer
-Cat called Pseudaelurus is placed back in time 11 million years ago
question
Why do cats migrate?
answer
- Found places with no placental carnivores?
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Which species was almost eradicated by the eruption of Toba (a massive volcano on Borneo)?
answer
tigers
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How many domestic cats exist worldwide?
answer
600
question
Manatees are not fast swimmers. What is their maximum speed?
answer
5 mph
question
Are manatees more closely related to elephants or dolphins?
answer
elephants
question
Manatees prefer warmer temperatures. What alternative hot spots have manatees found since access to warm areas of the Everglades have been blocked?
answer
-In the warm water emitted by coal fired power plants
