Available online
Description
This programme brings together old and new ideas on the development of an individual organism and its relevance and importance in evolution. Terms such as heterochrony, neotony and progenesis are i...ntroduced and explained.
This programme brings together old and new ideas on the development of an individual organism and its relevance and importance in evolution. Terms such as heterochrony, neotony and progenesis are i...ntroduced and explained.
| Module code and title: | S364, Evolution |
|---|---|
| Item code: | S364; 13 |
| First transmission date: | 17-09-1981 |
| Published: | 1981 |
| Rights Statement: | |
| Restrictions on use: | |
| Duration: | 00:24:28 |
| + Show more... | |
| Producer: | P. L Firstbrook |
| Contributors: | Mae-Wan Ho; Peter Skelton |
| Publisher: | BBC Open University |
| Keyword(s): | Aphids; Chimpanzee; Epigenetic landscape; Evolution; Genetics; Newts; Parthenogenesis; Progenesis |
| Footage description: | Film shots of a gorilla, lizards, ducks, platypus and insects. Commentary by Peter Skelton introduces the programme. Pointing out the importance of development in the evolution of organisms, Skelton examines a method, mathematical transformation, which illustrates how developmental change can occur. Animated diagrams show the shape of a porcupine fish changed to that of a sunfish by geometrical transformation. Mae-Wan Ho, with the aid of time lapse film of a teleost from initial cell division to embryo stage, looks at the developmental process, particularly at the growth patterns as they occur. Peter Skelton points out three, main aspects of development, change in size, change in shape and timing of sexual maturation. An animated diagram shows human development from infant to adult. The closely coordinated relationship between these changes and their timing, a process known as heterochrony, are discussed by Mae-Wan Ho. She uses, as an analogy, a cloak mechanism and goes on to examine some examples of heterochrony in amphibians. Film shots of newts, of Mexican axolotl (a giant salamander) and of proteus. Using a studio model of an unconventional clockface, Peter Skelton represents the development of the newt and then that of the axolotl. He contrasts the two and explains that the development of the axolotl as shown on the model is an example of neotony. Film shots of aphids reproducing by parthenogenesis. The film shows, particularly, a developmental short circuit where reproduction occurs in young and immature forms. This process is known as progenesis. Peter Skelton represents this on his clockface model. With the aid of animated diagrams of human and chimpanzee skulls and shots of children playing in school, Skelton looks at the developmental process of humans. He goes on to represent this on his model clockface. Over shots of a human dwarf, of soap bubbles stretched over metal frames and of radiolaria skeletons, Mae-Wan Ho explains that particular developmental pathways can be influenced by environmental as well as genetic factors. Shots of bithorax phenocopy drosophila. This condition was induced by exposing eggs from normal flies to ether. To explain how normal and abnormal development can be influenced by genetic and environmental factors, an epigenetic landscape is set up in the studio. Mae-Wan Ho rolls balls down this landscape from several starting points. The balls represent the development of an individual organism. The path of the ball is then disturbed by changes made to the landscape (genetic 'mutation') and by an air jet acting on the ball (environmental disturbance). Peter Skelton summarises the programme. |
| Master spool number: | HOU3824 |
| Production number: | FOUS206S |
| Videofinder number: | 2064 |
| Available to public: | no |
