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#+title: Nature Talk on Horseshoe Crabs

- tags :: [[id:7b5c0db6-16c7-447c-bd45-ace0f5ae1cdc][Friday Nature Hike]] [[id:b0dc724c-f5ae-4fbb-9dff-849ccc05f531][Home Science]] [[id:af22eafe-c3b1-439d-bb3e-55d9a2a0c255][Horseshoe Crab]]

* Fun facts?? :ATTACH:
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** What's in a name?
- Latin name for Horseshoe crab: Limulus Polyphemus
- A lot of eyes, but a photo-receptor right in the middle
 
[[attachment:_20200914_162915Horseshoe_crab_eyes.jpg]]

** Blue blooded!
- Copper makes their blood a blue color when it is exposed to air
- Copper pipes "oxidize" in air, turning from gold/copper color to greenish blue
- Same with the blood of horse shoe crabs
** Not a crab, or even a crustacean :ATTACH:
- Horseshoe crabs are actually most closely related to spiders
- Oldest evidence of a creature like horseshoe crab in fossils? 450 million years ago
- Horseshoe crabs are called "living fossils" because they existed in such a similar form long enough ago to leave fossils

[[attachment:_20200914_163952Ordovician.jpg]]

* How much would a cup of their blood cost?
- Thousands of dollars
- Bacterial toxins cause their blood to clot or become close to a solid
- Used to detect bacteria in medical tool and medicine manufacture
- Before, used rabbits, had check rabbit every 30 min for hours to see if they got a fever
- Possible to make synthetics, but it's been hard
- Harvesting of horseshoe grabs near NYC has drastically reduced their population
* What don't we know?
** Why they live where they live
- The live in North America and Asia, but only on the East coasts,
- They don't live in Europe or on the coasts of Africa
** Captive breeding wont work
- They breed in the same sand where they were born
- No one knows why the do this, or how they know which sand they were born in
- Do you remember the place you were born in? Well enough to go back their to give birth to your kids?
* Ordovician
** One third less oxygen in the air than we have now
** One mega continent where antartica is now
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- Gondwana
- Evidence for the continents from this period come from the spread of fossils around the world
** Sea level 600 feet higher than they are now
- We know this because of where we find fossils from this period