Essential idea: Reproduction in flowering plants is influenced by the biotic and abiotic environment.
The commonly held view is that flowering is influenced by abiotic factors such as day length. The importance of biotic factors such as pollination (e.g. by bats), and seed dispersal whether involuntarily or voluntarily (e.g. fruit ingestion) is being increasingly realised. Biotic factors commonly influence flowering by introducing a selective pressure, which influences the genetics of a population. The control of flowering is ultimately controlled by gene expression.
Understandings, applications and skills
|9.4.U1||Flowering involves a change in gene expression in the shoot apex.|
|9.4.U2||The switch to flowering is a response to the length of light and dark periods in many plants.|
|9.4.U3||Success in plant reproduction depends on pollination, fertilization and seed dispersal. [Students should understand the differences between pollination, fertilization and seed dispersal but are not required to know the details of each process.]|
|9.4.U4||Most flowering plants use mutualistic relationships with pollinators in sexual reproduction.|
|9.4.A1||Methods used to induce short-day plants to flower out of season. [Flowering in so-called short-day plants such as chrysanthemums, is stimulated by long nights rather than short days.]|
|9.4.S1||Drawing internal structure of seeds.|
|9.4.S2||Drawing of half-views of animal-pollinated flowers.|
|9.4.S3||Design of experiments to test hypotheses about factors affecting germination.|
[Text in square brackets indicates guidance notes]
Two interesting and thought provoking video lectures from TED.
Presentation and Notes
The presentation is designed to help your understanding. The notes outline is intended to be used as a framework for the development of student notes to aid revision.
Use the Cornell style template to collate your own notes for Topic 9 - Plant biology
Nature of science
Paradigm shift—more than 85% of the world’s 250,000 species of flowering plant depend on pollinators for reproduction. This knowledge has led to protecting entire ecosystems rather than individual species. (2.3)