Chapter 21 Evidence of Evolution Chapter 22- Origin of Species

Transcription

1 Domain- Evolution Chapter 20- Genes within Populations (pages ) Chapter 21- Evidence of Evolution (pages ) Chapter 22- Origin of Species (pages ) Chapter 23- Systematics, Phylogenies, and Comparative Biology (pages ) Chapter 24- Genome Evolution (pages ) Chapter 25- Evolution of Development (pages ) Chapter 26- Origin and Diversity of Life (pages ) Chapter 21 Evidence of Evolution Chapter 22- Origin of Species Chapter 21- begins on page 418 o Explain how the Grant s verified Darwin s research regarding the finches. Provide detailed, supporting information. Mrs. Stahl 1

2 o How did climatic variations drive evolutionary change in medium ground finches? Peppered Moths and Industrial Melanism o Explain and support with details, industrial melanism and how the peppered moth is a textbook example of selection. Explain the relationship between pollution and color evolution in peppered moths. Artificial Selection: Human Initiated Change o Define artificial selection- Mrs. Stahl 2

3 o Which type of selection does artificial selection represent: stabilizing, directional, or disruptive? o Which organism is the favorite subject for scientists when it comes to artificial selection? o What specific things have geneticists imposed on these creatures? o List four examples, two livestock and two crops, which have been manipulated genetically, that they are drastically different from their ancestors. o Explain what happened to the silver fox, how was it domesticated, BE SPECIFIC? How does this example relate to pleiotropy? o Support and back up with evidence the claim that artificial selection produces only minor changes, is incorrect. Mrs. Stahl 3

4 Fossil Evidence of Evolution o Fossils provide us with the most direct evidence that evolution has occurred, what is a fossil? o List four ways fossils can be preserved: o Rock fossils are created when three events occur: o 1. o 2. o 3. o Why do we only know about a small amount of fossils? o Explain the importance of the discovery of transitional fossils. o Which transitional fossil is the most famous? o The latter is the intermediate fossil of which two organisms? o Explain how it s related to both, or falls in the middle. o The Evolution of Horses- the prime example. o The earliest horse genus known is What did it look like? What did it eat? Mrs. Stahl 4

5 o Explain how horses have evolved by looking at the following characteristics (also use Figure 21.11): Characteristic Changes in size What happened? How did it change? Why? Toe reduction Tooth size and shape Why might the evolutionary line leading to Nannippus have experienced an evolutionary decrease in body size? (Research it) Mrs. Stahl 5

6 Anatomical Evidence for Evolution AP Biology Type of Anatomical Evidence Homologous Structures Why do they all share these structures? Define Detailed Examples Embryonic Development Vestigial Structures o Some structures are imperfectly suited; provide two detailed examples supporting this. Mrs. Stahl 6

7 Vestigial trait and genomes o Example- Icefish: see through fish that lives in Antarctica. o Transparency results from and. o Why do these fish not need special molecules, like hemoglobin, to carry oxygen? o What did scientists find when they examined the DNA of the icefish? o Did its ancestors have hemoglobin? o How did the fish s ability to get rid of hemoglobin come about? o When a trait disappears, and the gene does not diminish, but rather mutates into an inactive form and other mutations begin to accumulate is known as a or. Convergent Evolution o Define biogeography- o Define convergent evolution- o MARSUPIAL MAMMALS and PLACENTAL MAMMALS- best known case of convergent evolution o Marsupials are Mrs. Stahl 7

8 o Placentals are o Why do scientists believe that marsupials and placentals exhibit convergent evolution? o When species interact with the environment in similar ways due to being exposed to similar selective pressures they develop similar adaptations. Provide three examples discussed in the text. o What is a scientific theory? Mrs. Stahl 8

9 Chapter 22- The Origin of Species o Define sympatric- o Do animals know that they are different even if they have a similar phenotype? o Define subspecies- o Example- o What can account for both the distinctiveness of sympatric species and the connectedness of geographically separate populations of the same species? o What is the biological species concept? o How do species become reproductively isolated? o Organisms that become reproductively isolated become their own species, essentially. o What causes reproductive isolation? o What is the difference between prezygotic isolating mechanisms and postzygotic isolating mechanisms? Mrs. Stahl 9

10 REPRODUCTIVE ISOLATING MECHANISM CHART- see page 438, Table 22.1 Mechanism Description Example- You must read for these PREZYGOTIC ISOLATING MECHANISM Ecological Isolation Behavioral Isolation Temporal Isolation Mechanical Isolation Prevention of Gamete Fusion POSTZYGOTIC ISOLATING MECHANISM Hybrid Inviability or infertility Mrs. Stahl 10

11 o Sympatric species avoid mating with members of the wrong species in a variety of ways such as: o Communication (list the three the text provides) o Pheromones or Chemical Signals How do sympatric species differ in pheromone usage? o Postzygotic isolation o If hybrid mating does occur and zygotes are produced, there are still many factors that can prevent the zygotes from becoming fertilized and developing properly. o Development is complicated. o List some issues related to hybridization and why it can be unsuccessful. o Why is a mule unsuccessful? o Ecological Species Concept o Based on the idea that o selection maintains the species adaptations. o has little effect because Mrs. Stahl 11

12 Read the article by NatGeo Polar Bear-Grizzly Hybrid A stuffed "grolar bear," or "pizzly" grizzly-polar bear hybrid looms over the living room of Jim Martell in Glenn Ferry, Idaho, in Martell shot the animal (picture), the first recorded grolar bear, in Canada's Northwest Territories in As the Arctic thaws as a result of global warming, polar bears will increasingly be forced to stay onshore, where they're likely to bump into their grizzly cousins some of which are moving north as temperatures rise. Arctic Ocean sea ice, which polar bears rely on to hunt marine mammals, is predicted to disappear in summer before the end of the century, experts say. The two bear species are among the 22 Arctic marine mammal species most likely to interbreed, or hybridize, in a new Arctic "melting pot," according to a commentary published this week in the journal Nature. For the paper, scientists combed through studies and museum collections to find evidence of hybridization already underway in some species, and concluded that as many as 34 hybrids may occur. What's more, of the 22 types of animals, 14 are listed or may be listed as endangered, threatened, or of special concern by one or more nations. The polar bear and grizzly are currently on the U.S. endangered species list. Hybridization "can be the final straw in loss of species," commentary lead author Brendan Kelly, a research biologist at the U.S. National Marine Mammal Laboratory in Juneau, Alaska, told National Geographic News. Species in healthy numbers can interbreed naturally without disappearing, Kelly noted. But "when humans alter habitat particularly abruptly, they can greatly accelerate and make more likely these hybridizations and extinctions," he added. As for the pizzly, a second-generation individual with a grizzly bear father and a hybrid mother was killed this year in Canada, according to the Nature paper. Christine Dell'Amore Narwhal-Beluga Hybrid? Among the 22 marine mammal species deemed most likely to interbreed, beluga whales (left) and narwhals produced the first "hints of Arctic hybrids," Kelly and colleagues note in the new paper. In the late 1980s a skull of a whale thought to be a narwhal-beluga mix was found in western Greenland (see map). Local hunters have also reported seeing whales that look Mrs. Stahl 12

13 like narwhal-beluga crosses. So "biologists should not be surprised" that hybrids can occur in the Arctic, the paper said. Hooded Seal-Harp Seal Hybrid? Both the hooded seal (left) and the harp seal breed on pack ice of the North Atlantic Ocean and migrate into the Arctic Ocean in summer. Neither of the seals are considered rare or threatened, but hybrids may proliferate as the animals vie for space on the disappearing ice. Molecular analysis shows that that the two species which are from different genera have interbred in the past. Of course, "not all cross-species matings will produce viable or indeed any offspring," the commentary points out. But "the chance is enhanced in Arctic marine mammals, because their number of chromosomes [a type of DNA structure] has changed little over time." (Get a genetics overview.) Right Whale-Bowhead Hybrid? The Atlantic bowhead whale (bottom) inhabits the Arctic Ocean and adjacent seas. Right whales dwell in the North Pacific and North Atlantic. Both rare species will likely travel north as the Arctic melts, according to the Nature paper. And as diminishing ice causes the animals' ranges to overlap, the two species may begin interbreeding themselves out of existence. In fact, the hybridization may have already begun a possible bowhead whale-north Pacific right whale hybrid was photographed in the Bering Sea in May 2009, according to the paper. Spotted Seal-Harbor Seal Hybrid? Harbor seals (bottom) are found across temperate and sub-arctic waters. But as the Arctic warms, the mammals will likely will move north and run into spotted seals (top), according to the new paper. That newfound proximity may result in a new, hybrid species, if it hasn't already. Kelly and colleagues found a possible spotted seal-harbor seal hybrid specimen at the University of Alaska Fairbanks. Dall's Porpoise-Harbor Porpoise The harbor porpoise (bottom), native to the North Atlantic and North Pacific, will increasingly move north into the North Pacific habitat of the Dall's porpoise (top) as Arctic ice melts. (Read more about harbor porpoises in National Geographic magazine.) Mrs. Stahl 13

14 Scientists have already documented extensive hybridization between the two porpoise species off the coast of British Columbia, Canada, according to the paper. Similar events will likely occur as the species mingle in newly colonized Arctic habitats, where there are likely to be low numbers of each species and fewer candidates for mating the authors note. Interspecies Sex: Evolution's Hidden Secret? James Owen for National Geographic News March 14, 2007 The act of mating with a species other than your own may not be as ill advised or peculiar as it seems. Recent research indicates that hybridization is not only widespread in nature but it might also spawn many more new species than previously thought. A growing number of studies has been presented as evidence that two animal species can combine to produce a third, sexually viable species in a process known as hybrid speciation. Newly identified examples include both insects and fish. This evolutionary process, while known to be common in plants, has long been considered extremely rare among animals. Animals are generally thought to evolve the opposite way, when a single species gradually splits into two over many generations. But some scientists now believe that the behavior that has been called animals' sexual blunders could be an important force in their evolution. "Given the fact there have been several reported cases of hybrid speciation in animals, I think it's possible that's just the tip of the iceberg," said biologist James Mallet of University College London in the United Kingdom. Mallet said that advances in technologies for decoding genes are only now giving scientists the opportunity to make such discoveries. Hybrid-formed species are usually extremely difficult to detect because of their close physical resemblance to their parent species, he said. But today scientists are able to collect the detailed molecular data needed to identify previously unrecognized hybrids. Fast Evolving Groups Plenty of opportunities exist for hybrid species to emerge, especially among diverse and fastevolving groups of animals, Mallet said. In a review of the field appearing in the current issue of the journal Nature, the scientist notes that, on average, 10 percent of animal species and 25 percent of plant species are now known to hybridize. "In the past people have often viewed hybridization as a mistake," Mallet said. "But this is probably not an unnatural phenomenon." And, he said, "sex with another species may be very Mrs. Stahl 14

15 occasionally quite a good idea." Hybridization can increase genetic variability within a population, perhaps offering adaptations particularly suited to new or altered environments. "It might be worth throwing the dice every now and then to try for something really weird and see if it works out," he said. Occasionally the act produces sexually fertile hybrids that may have the opportunity to evolve into separate species. This process in animals involves so-called homoploid speciation, in which the hybrid offspring's DNA is packaged into the same number of chromosomes as the parents' (get a genetics overview). Homoploid speciation has traditionally been seen as unlikely, because the hybrid could easily breed with its parent species and thus not evolve into its own genetically distinct creature. But recently identified examples suggest how hybrid species might be able to give themselves room to develop separately. Last year a team led by Jesus Mavarez of the Smithsonian Tropical Research Institute published details about a hybrid butterfly species from Venezuela and Colombia that appears to use several tactics to isolate itself. The hybrid butterfly, Heliconius heurippa, inherited yellow wing markings from one parent species and red from the other. The study team found that both wing colors where needed to attract a mate, so the butterfly tended to breed only with its own kind. The hybrid insect was also found to live at a slightly higher altitude than either of its two parent species. And the butterfly's caterpillar appears to prefer different plants as food. Another study reported in 2005 indicated that a hybrid fruit fly from the northeastern United States had made a distinct niche for itself by basing its lifecycle around a non-native plant, the honeysuckle. Likewise, a hybrid sculpin fish discovered in Germany appears to have put evolutionary distance between itself and its forebears by inhabiting muddy canal waters that don't suit its parent species. Mallet said such examples suggest that "the weight of evidence is in favor of hybrid speciation being reasonably common." But as Mallet himself admits other scientists are far more cautious. Critics say that the likelihood of a hybrid establishing in reproductive isolation from its parents is very low, and that hybrids form less than 0.1 percent of animal populations. Given this low number, animal hybrid species are likely to always be rare no matter how sophisticated or exhaustive the genetic analysis is. More examples may emerge, skeptics add, but these are likely to be the exceptions and not the rule. Natural Selection and Reproductive Isolation o Speciation results in diversity of life forms. Define speciation- o Species can be geographically isolated (i.e. ocean or mountain) or through pre and post zygotic mechanisms (reproductive isolation) which can prevent gene flow. o How do new species arise over many years? o What is reinforcement? Use the flycatcher example to support your answer. Mrs. Stahl 15

16 o When surviving hybrids reproduce with members of either population what do they serve as and what happens to the gene pool? The Role of Genetic Drift and Natural Selection in Speciation o What is genetic drift? o Describe the effects of genetic drift on a population. o Adaptation can lead to speciation, explain how, and justify with examples. Mrs. Stahl 16

17 The Geography of Speciation o Speciation is a two part process. What are the two parts? o 1. o 2. o What is the problem with this process? o What is another term for geographically separated? o List three ways populations can become geographically isolated from one another. See Figure o 1. o 2. o 3. o How does the little paradise kingfisher exhibit geographic isolation? What are the phenotypes that differ? o What is sympatric speciation? o In many cases of sympatric speciation, a mutation could occur that makes the individual vastly different from others of its species; typically resulting in death. There are always exceptions to the rule and one is known as polyploidy, often seen in plants. What is polyploidy? o Polyploid individuals can arise in two ways: autopolyploidy and allopolyploidy. Mrs. Stahl 17

18 Autopolyploidy means that Why might this happen? What are tetraploids? Allopolyploidy means that What do the resulting offspring have? List some plants that have a polyploid episode? Adaptive Radiation and Biological Diversity o Define adaptive radiation- o List two examples: o What is key innovation? Examples of key innovation- Mrs. Stahl 18

19 Adaptive radiation requires both and to different habitats. When can adaptation to new habitats occur? What is character displacement? Example- the three spined stickleback evolved a high degree of reproductive isolation. What were the evolutionary differences in the two populations so that they could minimize competition for food? o The book references four examples of adaptive radiation. Choose two to describe in detail how they exhibit adaptive radiation. Mrs. Stahl 19

20 The Pace of Evolution AP Biology o Define gradualism- o Define punctuated equilibrium- o Why would species exist for thousands, or even millions of years without changing? Mrs. Stahl 20