lecture_notes:04-23-2010
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lecture_notes:04-23-2010 [2010/04/28 18:17] jmagasin |
lecture_notes:04-23-2010 [2010/05/01 16:00] (current) jlong Link to Slides of John and Jan |
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| ====== Slides ====== | ====== Slides ====== | ||
| - | Jeffrey Long has slides from Janet Leonard and he will be uploading them.\\ | + | The slides from the presentation of John and Janet can be dowloaded here,[[http://compbio.soe.ucsc.edu/slugGenome/|http://compbio.soe.ucsc.edu/slugGenome/]] .\\ |
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| John originally worked with sea urchins and sea stars primarily. | John originally worked with sea urchins and sea stars primarily. | ||
| - | Janet joined the lab about twelve years ago to study marine slugs.\\ | + | Janet joined the lab about twelve years ago to study marine slugs. |
| She was interested in hermaphrodite mating behavior. Banana slugs' | She was interested in hermaphrodite mating behavior. Banana slugs' | ||
| - | rare behavior of apophallation became a research focus. No one had\\ | + | rare behavior of apophallation became a research focus. No one had |
| really studied banana slugs [academically] since the forties. Alice | really studied banana slugs [academically] since the forties. Alice | ||
| - | Bryant Harper (Aptos naturalist, works with Santa Cruz Museum of\\ | + | Bryant Harper (Aptos naturalist, works with Santa Cruz Museum of |
| Natural History) wrote __The Banana Slug__ (1988), the best book on | Natural History) wrote __The Banana Slug__ (1988), the best book on | ||
| them. | them. | ||
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| Banana slugs habitat is very diverse. Though often found in conifer | Banana slugs habitat is very diverse. Though often found in conifer | ||
| - | forests and considered an animal of the Northwest (first found in\\ | + | forests and considered an animal of the Northwest (first found in |
| Washington or Oregon), they've been found in drier habitats: San | Washington or Oregon), they've been found in drier habitats: San | ||
| - | Diego, Napa's McLaughlin Reserve (by small springs), abandoned rice\\ | + | Diego, Napa's McLaughlin Reserve (by small springs), abandoned rice |
| patties in the Sacramento River Delta, oceanside iceplants in Pacific | patties in the Sacramento River Delta, oceanside iceplants in Pacific | ||
| - | Grove. High variation in the numbers you'll see on any day/site: none\\ | + | Grove. High variation in the numbers you'll see on any day/site: none |
| or dozens. | or dozens. | ||
| They eat feces, hemlock, poison oak, mushrooms (reported but | They eat feces, hemlock, poison oak, mushrooms (reported but | ||
| - | John has not seen), sorrel, ferns, ice plants, humus soil. In the lab\\ | + | John has not seen), sorrel, ferns, ice plants, humus soil. In the lab |
| they eat hamburger, cat food, apples, beans, zucchini, mushrooms, | they eat hamburger, cat food, apples, beans, zucchini, mushrooms, | ||
| yams, lettuce and milk. | yams, lettuce and milk. | ||
| Colors may camouflage them, //e.g.// dead leaves often turn bright | Colors may camouflage them, //e.g.// dead leaves often turn bright | ||
| - | yellow, the color of species in Santa Cruz and the SF Bay area. In\\ | + | yellow, the color of species in Santa Cruz and the SF Bay area. In |
| other areas you'll find spotted slugs -- but they may be a different | other areas you'll find spotted slugs -- but they may be a different | ||
| species. | species. | ||
| There predators may include [seemed uncertain] garter snakes, | There predators may include [seemed uncertain] garter snakes, | ||
| - | salamanders and newts, birds and some small mammals. It is possible\\ | + | salamanders and newts, birds and some small mammals. It is possible |
| that some specific carnivorous snails and slugs eat banana slugs. | that some specific carnivorous snails and slugs eat banana slugs. | ||
| //Aphallarion buttoni// originally thought to be a different species | //Aphallarion buttoni// originally thought to be a different species | ||
| - | because no penes were found when dissected (late 19th century).\\ | + | because no penes were found when dissected (late 19th century). |
| However, a Stanford professor later found some with penes and so sent | However, a Stanford professor later found some with penes and so sent | ||
| - | students into the field to study. They observed apophallation. That\\ | + | students into the field to study. They observed apophallation. That |
| was the end of //buttoni// as a separate taxon. It became //Ariolimax | was the end of //buttoni// as a separate taxon. It became //Ariolimax | ||
| columbianus.// | columbianus.// | ||
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| All banana slugs have an opening on the right side of the "head" for | All banana slugs have an opening on the right side of the "head" for | ||
| - | defecation, breathing, and copulation. The only way to distinguish\\ | + | defecation, breathing, and copulation. The only way to distinguish |
| species is by dissection of the genitalia. [See slide *//Ariolimax | species is by dissection of the genitalia. [See slide *//Ariolimax | ||
| - | Arilimax columbians// genitalia* for overview of genitalia.] The\\ | + | Arilimax columbians// genitalia* for overview of genitalia.] The |
| gonad has a mix of testes and ovaries, and they can play both roles at | gonad has a mix of testes and ovaries, and they can play both roles at | ||
| - | same time curing copulation. How is sperm kept separate during\\ | + | same time curing copulation. How is sperm kept separate during |
| copulation? It is not necessarily. They can fertilize themselves. | copulation? It is not necessarily. They can fertilize themselves. | ||
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| //Ariolimax Meadarion californicus// is found in San Mateo county. | //Ariolimax Meadarion californicus// is found in San Mateo county. | ||
| - | Santa Cruz has //dolichophallus//. [See slide comparing their\\ | + | Santa Cruz has //dolichophallus//. [See slide comparing their |
| genitalia.] Mead thoought //dolichophallus// and //californicus// | genitalia.] Mead thoought //dolichophallus// and //californicus// | ||
| were sufficiently different to be a separate species. | were sufficiently different to be a separate species. | ||
| A collaborator in Belgium has been sequencing banana slug | A collaborator in Belgium has been sequencing banana slug | ||
| - | mitochrondrial DNA. They see at least five clades but cannot yet\\ | + | mitochrondrial DNA. They see at least five clades but cannot yet |
| connect them. ~"Morphologically distinct and molecularly distinct are | connect them. ~"Morphologically distinct and molecularly distinct are | ||
| not the same thing." [See slide.] | not the same thing." [See slide.] | ||
| Interestingly the distribution of the salamander genus //Ensatia// is | Interestingly the distribution of the salamander genus //Ensatia// is | ||
| - | similar to that of banana slug [//dolichophallus//? -- see slide]. Is\\ | + | similar to that of banana slug [//dolichophallus//? -- see slide]. Is |
| this a remnant of five million years ago when there were islands in | this a remnant of five million years ago when there were islands in | ||
| - | the Monterey Bay? Morphologically distinct but molecularly\\ | + | the Monterey Bay? Morphologically distinct but molecularly |
| [mito. DNA] indistict suggests recent change. | [mito. DNA] indistict suggests recent change. | ||
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| Janet's interest is in sex selection. Eberhard's hypothesis: [That we | Janet's interest is in sex selection. Eberhard's hypothesis: [That we | ||
| - | can ] classif[y] based on genitalia (as done with insects, spiders,\\ | + | can ] classif[y] based on genitalia (as done with insects, spiders, |
| //etc.//) suggests the importance of sex selection. Genitalia | //etc.//) suggests the importance of sex selection. Genitalia | ||
| - | differences in nearby counties are not explicable by natural\\ | + | differences in nearby counties are not explicable by natural |
| selection, //e.g.// how would NS explain [improved fitness by a | selection, //e.g.// how would NS explain [improved fitness by a | ||
| different vaginal muscle in the same geographical area.] | different vaginal muscle in the same geographical area.] | ||
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| //Ariolimax stramineus// courtship: antiparallel alignment of slugs is | //Ariolimax stramineus// courtship: antiparallel alignment of slugs is | ||
| - | standard. They line up right sides of their heads until the alignment\\ | + | standard. They line up right sides of their heads until the alignment |
| allows copulation. The first copulation takes place in about twenty | allows copulation. The first copulation takes place in about twenty | ||
| - | minutes with subsequent occuring over about two hours. No apophallation in the\\ | + | minutes with subsequent occuring over about two hours. No apophallation in the |
| one shown on film. | one shown on film. | ||
| Mating film for //brachyphallus//: This is one of the three under | Mating film for //brachyphallus//: This is one of the three under | ||
| - | //Ariolimax Meadarian//. Note the initial biting and head swinging\\ | + | //Ariolimax Meadarian//. Note the initial biting and head swinging |
| which seem to cause no damage. The biting helps line up the head | which seem to cause no damage. The biting helps line up the head | ||
| - | regions. Banana slugs cannot reverse so the cirlcing helps get them\\ | + | regions. Banana slugs cannot reverse so the cirlcing helps get them |
| get into position for mating. | get into position for mating. | ||
| Mating film for //californicus//: Unilateral copulation (after two hours | Mating film for //californicus//: Unilateral copulation (after two hours | ||
| - | biting, head swinging). It is hard to tell which plays the role of\\ | + | biting, head swinging). It is hard to tell which plays the role of |
| male and female but Janet thinks they alternate over a copulation | male and female but Janet thinks they alternate over a copulation | ||
| session. | session. | ||
| Mating film for //dolicophallus//: Example of apophallation (by the | Mating film for //dolicophallus//: Example of apophallation (by the | ||
| - | first to withdraw). How costly is this for a hermaphrodite? It is\\ | + | first to withdraw). How costly is this for a hermaphrodite? It is |
| pretty rare: 5 out of 100 copulations end in apophallation. | pretty rare: 5 out of 100 copulations end in apophallation. | ||
| Why does apophallation occur and when? They have observed it only nine | Why does apophallation occur and when? They have observed it only nine | ||
| - | times and never by virgins. Is it done as retaliation if one partner does not give\\ | + | times and never by virgins. Is it done as retaliation if one partner does not give |
| any sperm? Do they run out, and perhaps later in life focus on egg laying? | any sperm? Do they run out, and perhaps later in life focus on egg laying? | ||
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| The rapid morphological changes are among the evidence for sex | The rapid morphological changes are among the evidence for sex | ||
| - | selection, as well as the high cost of courtship/mating. There is\\ | + | selection, as well as the high cost of courtship/mating. There is |
| some evidence for sperm competition. | some evidence for sperm competition. | ||
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| Their egg laying habits in the field are uncertain. Perhaps under | Their egg laying habits in the field are uncertain. Perhaps under | ||
| - | leaflitter. They do not dig holes in moist soil like garden\\ | + | leaflitter. They do not dig holes in moist soil like garden |
| snails. In the lab at 19^C, they take seven weeks to hatch, | snails. In the lab at 19^C, they take seven weeks to hatch, | ||
| - | sometimes two to three weeks longer. The record for a clutch is\\ | + | sometimes two to three weeks longer. The record for a clutch is |
| seventy-five eggs (but this could have been multiple clutches since | seventy-five eggs (but this could have been multiple clutches since | ||
| - | they don't check every day). Egg size varies. //Dollicophallus//\\ | + | they don't check every day). Egg size varies. //Dollicophallus// |
| eggs are almost the size of jellybelly and weigh up to half a gram. | eggs are almost the size of jellybelly and weigh up to half a gram. | ||
| For //californicus// they're usually under 0.3g. | For //californicus// they're usually under 0.3g. | ||
| Egg laying starts in fall and copulation is associated with foggy | Egg laying starts in fall and copulation is associated with foggy | ||
| - | nights (late summer, Santa Cruz). Eggs are laid October through\\ | + | nights (late summer, Santa Cruz). Eggs are laid October through |
| December when the rains come and usually finished by February. | December when the rains come and usually finished by February. | ||
| - | Hypothesis: Low pressure systems trigger egg laying. (This is based\\ | + | Hypothesis: Low pressure systems trigger egg laying. (This is based |
| on lab observations, and makes sense since dehydration is the highest | on lab observations, and makes sense since dehydration is the highest | ||
| - | mortality source. You want to lay eggs at the start of the rainy season\\ | + | mortality source. You want to lay eggs at the start of the rainy season |
| in a moist place.) | in a moist place.) | ||
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