False, Feathers either play a role, or may have played a role, in _____. b) The pelvic spines are homologous to legs in four-legged animals. This activity uses a virtual lab created by HHMI Biointeractive. Most sticklebacks from Bear Paw Lake had a reduced phenotype and the rest an absent phenotype. The fossil record analyzed in Experiment 2 only spans 15,000 years, so we cannot draw any conclusions to modern populations, which evolved over a much longer period of time, at least 10,000 years. The production of an evolutionarily independent group of organisms B. Based on these results, if this type of tetraploid formed in the wild, what would be the result? However, research on modern populations is limited to relatively short stretches of time; even 100 years is a short time when it comes to evolution. gene flow A subset of a population of birds leaves its habitat on the mainland and colonizes a nearby island. Measuring three to 10 centimetres long, stickleback fish originated in the ocean but began populating freshwater lakes and streams following the last ice age. What would be the ploidy of the viable gametes produced by a tetraploid individual if nondisjunction of all chromosomes occurred in meiosis I? Kalmbach Lake has no native predatory fishes. if (prefsArray[169] == "0") { How did some ancestral sea-run stickleback populations come to live exclusively in fresh water? Why? (c) Calculate the mass (in grams) of an atom of silicon. 7. What did researchers discover about the genetic mutation causing the loss of pelvic spines? Study with Quizlet and memorize flashcards containing terms like Stromatolite fossils that formed 3.5 billion years ago indicate that _____. A. Quiz Results: Evolving Switches, Evolving Bodies: HHMI BioInteractive document.write("--"); All the stickleback fish in Kalmbach Lake perished. a) life originated 3.5 billion years ago b) the first organisms were eukaryotes c) life must have arisen quite a bit earlier, perhaps 3.9 billion years ago d) the first life-forms were photosynthetic, The "big bang" that produced the universe is thought . The separation of habitats reduced gene flow between the populations. Why do some stickleback populations lack pelvic spines? Hybrids have poor survival and reproduction and thus produce few viable offspring with members of either parent species. 6. the hybrid zone is inhospitable to hybrid survival. Adaptive radiations can be a direct consequence of four of the following five factors. Again, the mechanism is paedomorphosis, as truncation of development removes individual elements one at a time, or removes entire pelvic girdles. 4. 15. The fossil record allows one to observe changes that occur over tens of thousands of years. Summarize, in your own words, the objective of experiment 1. All three answers are correct. The frequencies of reduced and complete pelvic phenotypes fluctuate from layer to layer, but overall, there is no trend in gain or loss of either trait in the population. They can never produce viable offspring. Most or all fish in both lakes have a pelvic vestige that is larger on the right than on the left. Is the following statement true or false? Which of the following is an explanation for why the stickleback is a model organism for studying evolution? All but three lakes (abbreviated O, Br S, and Ti) have fish with both left and right biasthat's why the graph has two bars for all lakes except for those three. A smaller sample (i.e., 20 fish) would be more representative of the population. addition, fresh water is not as rich in calcium and other minerals needed to form pelvic spines. When different people conduct the same experiment, the results are going to be different. Bear Paw Lake and Frog Lake were likely populated by the same sea-run population of stickleback at the end of the last ice age. At room temperature, the edge length of the cubic unit cell in elemental silicon is 5.431 A, and the density of silicon at the same temperature is 2.328 g cm^-3. The pelvic spines are homologous to legs in four-legged animals. spines does not seem to provide the same selective advantage as it does to stickleback living in the ocean.". Dr. Bell's study did not examine fish from these two lakes. Paedomorphosis They found that 100% of sticklebacks in Frog Lake had a complete phenotype. Geographical isolation The stickleback populations in Bear Paw Lake and Frog Lake are both freshwater populations; thus, they are more similar to one another in pelvic morphology than they are to marine and sea-run stickleback populations. You will notice there are many small lakes in this area. Increased fitness of the large-beaked birds, creating a new species, Increased fitness of large-beaked birds, leading to natural selection, True or false? Mutations occur at random in a population causing populations to change over time as those mutations are inherited from one generation to the next. flight Because stickleback in Bear Paw Lake lack pelvic spines, we can infer that over time, the sea-run stickleback that founded this population evolved a reduced pelvis. b) The pelvic spines are homologous to legs in. In a few populations, stickleback have right-biased pelvic asymmetry. 2. The fossil stickleback population was completely different from any modern population of stickleback that we know, and so direct comparisons of traits between them are meaningless. There are different predators in Bear Paw Lake. The pelvic spines are homologous to legs in four-legged animals. One lake represents the control population and the other population is the one we can compare to the control. ____3. A hybrid zone is properly defined as _____. mass extinction The stickleback population in Bear Paw Lake is more similar to marine and sea-run stickleback populations in terms of pelvic morphology than it is to the Frog Lake stickleback population. Because fish don't need hind limbs to walk, many populations of fish evolved to lack pelvic spines. C. Replication of RNA is flawless. allopatric speciation. In lakes with dragonfly larvae, pelvic spines can be disadvantageous, allowing the predatory larvae to grab the fish. Random sampling ensures that the fish that are selected for the research study are most like one another. In 2013, researchers constructed a vesicle with replicated RNA. Data obtained by analyzing living fish in lakes show the selective pressures present in different environments. 1. The plates also make stickleback fish difficult to eat. Most or all fish in Bear Paw Lake and Coyote Lake have a pelvic vestige that is larger on the left than on the right (i.e., left-biased pelvic asymmetry). Polyploidy strengthen prezygotic barriers between horses and donkeys. The isolated population is exposed to different selection pressures than the ancestral population. One reason that pelvis and spine loss may occur is because some freshwater populations live in low calcium environments where building a pelvis may be metabolically costly, and are preyed upon by insects that can grasp onto spines, rather than by fish that can be deterred by the spines. Pelvic spines are homologous to legs in an area where the ranges of two closely related species overlap, but do not interbreed Random sampling is the only way to collect fish when using traps. Explain why it has been so hard to find rocks more than 4 billion years old at Earth's surface. Thus, having spines might actually be a liability in an environment like Bear Paw Lake. In each generation, some individuals may, just by chance, have more offspring than other individuals and their traits will become more common in that population. D. Some strands of RNA replicate less often. Describe how changes in genotype, such as deletion mutations, can lead to change in phenotype. Bell and colleagues studied fish in 27 lakes in the Cook Inlet region and recorded the relative frequencies of specimens with pelvic asymmetry. It is a fact that the left pelvic vestige is larger than the right one in most fossil stickleback with reduced pelvises from the ancient lake that Dr. Bell and colleagues studied. document.write("Investigation - Stickleback Evolution (HHMI) - Google Docs Phylogeny : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.
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