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Posted (crates) in biology, nature, Personal Stuff on June-17-2007

 This (June 16) is one of my long days beginning just after 6 am and ending in a couple more hours around 2 am. 

I’m trying an experiment by not putting a heading for this entry yet.  Yesterday I tried to add to a previous entry that had a heading and got error messages about the heading when I published it.  I ended up losing the original entry. So I will publish this entry and will try again later in the day, adding a heading, and will see what happens.

I just took a personality test (Meyers-Brigg typology test)  here, and found out that I’m classified as an INTJ or a  mastermind rational, also see here.

This is 18 hours later.  I had a nice afternoon eating lunch with Jessica and her fiance.  It was a nice Father’s Day and I appreciated being invited very much.  I also talked with my father.  From last summer throughout the fall and early winter, it was very dry in that part of Texas and the lake had already retreated far out from the normal shoreline when I was there last summer.  However, they have been having lots of rain now and the lake is full to overflowing, and it keeps on raining.  Nobody, of course, wants to complain about the rain since it’s alway on the verge of being too dry there.

Last summer we walked down the dry lake bed that extended up to where his house was and found the dry bed littered with dead freshwater mussels.  There are at least 18 species of mussel in this area and about 52 species in Texas as compared to almost 300 species in the entire United States and only 12 species in Europe.  See here for a photographic collection of these critters that are found in the Dallas area. 

The life cycle of these molluscs are interesting.  The female has to suck in spermatozoa from males which release their sperm into the water.  They enter through the siphon and fertilize the females.  The young are released as larvae (glochidia)  which must temporarily parasitize fish for a while before dropping off to complete their development in the bottom of the river or lake.

Some mussel species mimic small fish or other food items like worms or insects in order to attract fish.  When the fish is sensed by the mussel the larvae are released and thus have a better chance of finding a temporary fish home without which they would perish.

     In many places of course mussels are endangered and efforts are sometimes late in trying to perserve them.  Besides having interesting sex lives and of great interest to biologists and people interested in nature, they are often indicators of water quality, and a flourishing population indicates a healthy freshwater ecosystem.

    

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