What You Never Knew About Sex

Synopsis: Reptiles exhibit enormous differences: some snakes are born live, others hatch from eggs; turtles disregard their young while crocodilians show an almost human concern for the welfare of their young. Reptiles show the greatest diversity, however, in the methods of sex determination, as shown from research on alligators. The sex of crocodilians and many other egg-laying reptiles is determined by the eggs’ incubation temperature, with just a few degrees difference changing the result from all male to all female or vice versa. This response to temperature may have evolutionary significance in making the species more robust. Lizards are a family which exhibit a wide range of sex-determining mechanisms including chromosomal and temperature regulation, and one that results in all-female clones. Recent findings show that a species of gecko exhibits both chromosomal and temperature regulated sex determination, possible evidence that this species is at an evolutionary crossroads.
Series: Biology: Form and Function, Course S203
Language: English
Country: United States
Medium: Video; Videocassette. Standard formats. col. 24 min.
Year of production: 1991
Availability: Off-air recording licence
Sale; 1998 sale: £145.00 (+VAT +p&p)
Subjects: Biology
Keywords: gecko; lizard; physiology - animal; reptiles; sex determination; snakes

Producer

Barrie Whatley

Cast

Julie Berry

Name: Open University Worldwide
Web: http://www.ouw.co.uk External site opens in new window
Phone: +44 (0) 1908 274066
Address: Walton Hall
Milton Keynes
MK7 6AA
Notes: NB. As of May 2016 Open University Worldwide are no longer distributing DVDs. They have posted this message on their website: ‘Unfortunately Open University Worldwide Limited has decided that product sales are no longer viable given the reduced funding to Higher Education institutions and diminishing demand for the products we have traditionally stocked. At present the Open University Students Association (OUSA) will continue to sell the "Good Study Guide", and we are in discussion with other possible distributors to continue to make The Open University’s products available for purchase. As soon as we have any information on other channels of distribution we will update this notice’. Some products are still available via second hand dealers on Amazon.co.uk

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