Wednesday, February 1, 2017

Mermaid's Purse

Mermaid’s Purse
See the little baby shark inside this egg case?  When found empty on the shore, after the shark is born, we call these  
cases “mermaid’s purses,” so precious was its content.

Dad Shark fertilizes Mom’s egg internally (shark sex!)  She lays the egg in a safe place, like the kelp forest, where it can hide for the nine months it takes to grow and hatch on its own.  (To our Aquarium guests I say, “She lays the egg and then she says, Goodbye! Good Luck!”  “Au Revoir, Bon Chance!” to the French guests.) 

Of the 400 different kinds of sharks, nearly half, the coastal ones, give birth this way.  (Open ocean sharks keep their babies inside until birth; no place to hide the egg case.)

Nine months all on its own!  How will it survive?  Mom Shark “packs it a lunch” (in the words of a British shark expert.)  The egg case includes a nutritious yoke (you can see that too), and when it’s gone, it’s time for birth. 

But the egg wall is not a solid shell, like a chicken’s.  No, the wall is permeable.  Ocean water can flow in and out, bringing in a nutritious sea soup and neatly draining away waste.  The scientists call this “osmo-regulating,” like osmosis, which means “to push” in Greek.  Mom has pushed, and now the ocean pushes and pulls through the permeable egg membrane.

Each of our own human cells has a permeable membrane – food in, waste out.  We need some  kind of cell walls or we would slop and bleed all over each other.  But without the push and pull of osmosis permeating through the membrane, we would starve and be poisoned by waste. 

Baby sharks have permeable egg walls.  We humans have osmo-regulaing cell walls.  Are they like national borders?  I was surprised to read in Outside Magazine about a group of ranchers and biologists who are concerned about the proposed expansion of the wall between the US and Mexico, because of the many border animals whose food, migration and reproduction are already being walled up and in.

Precious things we humans, and mermaids, keep in our purses.  But without food and flow, nothing survives.  Osmosis diplomacy.  We just booked another weekend youth group in March and a clergy couple spending a sabbatical week with us in May.  May 9 we host a Blue Theology Retreat and Resource Day for clergy and religious educators, following Jesus’ model of spending key ministry moments “By the Sea.”  Be in touch.

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