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Description
The programme suggests ways in which cells arose early in the earth's history and how the simplest prokaryote cells sucha s bacteria and blue green algae may have evolved into the more complex euka...ryote cells.
The programme suggests ways in which cells arose early in the earth's history and how the simplest prokaryote cells sucha s bacteria and blue green algae may have evolved into the more complex euka...ryote cells.
| Module code and title: | S364, Evolution |
|---|---|
| Item code: | S364; 01 |
| First transmission date: | 19-03-1981 |
| Published: | 1981 |
| Rights Statement: | |
| Restrictions on use: | |
| Duration: | 00:22:58 |
| + Show more... | |
| Producer: | Roger Jones |
| Contributors: | Lynn Margulis; Peter Skelton |
| Publisher: | BBC Open University |
| Keyword(s): | Eukaryote cells; Evolution; Fossils; Hawaii; Mitochondriaa; Prokaryote cells |
| Footage description: | Shots of Hawaii and some of the diverse animal species found there. Commentary introduces the programme. Shots of fossils of extinct species (including homo erectus) going back to the Cambrian. Commentary by Peter Skelton reviews the geological past. He points out that the fossil record goes back much further than this to about 4,000 million years. Shots of a dividing fertilised egg of a sea star under magnification. Shots of living plant cells. Skelton classifies these as eukaryote cells and points out their distinguishing features. Shots of prokaryote bacterial cells under magnification. Skelton points out the features of this type of cell. Shots of algal prokaryote cells. Skelton speculates that eukaryote cells evolved from simpler prokaryote cells. Over shots of a simulated pre-Cambrian sea, Skelton speculates on the chemical nature of the early oceans and the origins of life there. He goes on to discuss the rise of blue green algae which were probably the first forms of aerobic metabolism. Lynn Margulis looks at some blue green algae in a pond and speculates on how the ancestors of these cells in the pre-Cambrian transformed the atmosphere by oxidising water and giving off oxygen. She goes on to explain how, by symbiosis with blue green algae, normally anaerobic bacteria learned to live in an oxygen environment. She speculates that such symbiotic complexes developed into modern eukaryote cells and that these bacteria became ancestral mitochondria. Skelton looks at micrographs of an eukaryote cell with its mitochondria, at film and stills of an amoeba which harbours bacteria in a symbiotic relationship; (the bacteria metabolise lactic acid wastes for the amoeba as substitute for the mitochondria). Skelton goes on to discuss how chloroplasts may have evolved in a way similar to mitochondria. Shots of paramecium bursaria. This animal harbour blue green algae which photosynthesise substances useful to the paramecium. Shots of flatworm (Convoluta). This animal also harbours blue green algae which become life support systems for the worms. Shots of several other animals which have evolved a symbiotic relationship with blue green algae. Several diagrams and micrographs are also shown. Skelton goes on to discuss the origins of cillia and flagella in unicellular animals. He speculates that these originated as bacteria in symbiosis with another cell. Shots of paramecium swimmimg in water and then of a protozoan Myxotricha paradoxa which has what appear to be cillia but are attached bacteria. Skelton goes on to speculate that microtubules found in eukaryote cells also originated from such bacteria. Skelton looks at the fossil evidence for the evolution of ancient prokaryote and eukaryote cells. Also shots of man-made microspheres which have some of the properties of living cells. He compares these with microfossils which look remarkably similar. Skelton explains how these microspheres are made and how they may have been ancestral to life. |
| Master spool number: | HOU3514 |
| Production number: | FOUS117B |
| Videofinder number: | 2052 |
| Available to public: | no |
