Answer :

In general, the faster the embryo divides, the higher the environmental temperature. At 37°C, the sea urchin eggs reached the first cell cleavage 40 minutes after fertilization and the second cell cleavage 65 minutes later. At 37°C, abnormalities in the gastrulating embryo were observed.

This urchin can withstand temperatures ranging from 41o to 74oF. (5o-23.5oC). Massive die-offs occur when water temperatures exceed 79oF (26oC).

How does sea urchin fertilization take place?

Male and female sea urchins can be easily coaxed into shedding massive amounts of eggs or sperm. When the eggs are released, they are mature and can be fertilized externally simply by mixing egg and sperm. The resulting embryos are optically transparent and develop synchronously in sea water alone.

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