Reproduction/ Development
Telling the difference between a female and a male sea urchin is very difficult. Scientist use their location on the sea bottom to determine the sex of a sea urchin. Males tend to choose location out in the open/ exposed and females choose quite and hidden places (1). Urchins reach sexual maturity at 2 years old (3). Sea Urchins breed in January, February and March and they breed yearly. Urchins have one set of sex chromosomes. Sea urchins haploid number is 21 to 22 (4). Sea Urchins reproduce in water. First a female purple sea urchin releases eggs into the water and when a male fertilizes the eggs. The male and the female do not interact with each other. When purple sea urchins are born they do not have any interaction with their parents. When a free-swimming urchin sperm cell finds an egg whose surface proteins are compatible, the two gametes have a instant connection. The egg immediately erects a cellular barrier to prevent access by other sperm from other sea urchins (2).
Sea Urchins are R selcetion they lay many eggs but few survive (5).
Females release about one million eggs and males realease about 10 to 100 billions white sperm cells (2).
Sources:
1.
2. http://rinr.fsu.edu/issues/2009summer/feature01_b.asp
3. http://animaldiversity.ummz.umich.edu/accounts/Strongylocentrotus_purpuratus/
4. http://www.answerbag.com/q_view/2044704 5. http://www.faculty.biol.ttu.edu/carr/RESOURCES/Sex%20and%20Reproduction%20Part%20I.
5.
Sea Urchins are R selcetion they lay many eggs but few survive (5).
Females release about one million eggs and males realease about 10 to 100 billions white sperm cells (2).
Sources:
1.
2. http://rinr.fsu.edu/issues/2009summer/feature01_b.asp
3. http://animaldiversity.ummz.umich.edu/accounts/Strongylocentrotus_purpuratus/
4. http://www.answerbag.com/q_view/2044704 5. http://www.faculty.biol.ttu.edu/carr/RESOURCES/Sex%20and%20Reproduction%20Part%20I.
5.