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lecture_notes:04-23-2010 [2010/04/28 18:38] karplus removed extraneous \\ returns |
lecture_notes:04-23-2010 [2010/05/01 16:00] 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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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.) | ||