Biodiversity of plants

Strand 1: Diversity, Change and Continuity

Life exists in a wide variety of forms which live in different niches. This section enables learners to be exposed to an array of life forms from microorganisms to macroscopic plants and animals. These are organised according to a man-made system of classification based on observable features. Learners explore the roles of organisms in an ecosystem including microorganisms that are a major cause of diseases. This strand also includes some evolutionary development in plant and animal phyla.

TOPIC

Biodiversity of Plants

(3 weeks 12 hours)

(Focus on the Developmental Lines and Not on In-Depth Studies of Life Cycles)

Learners should have a basic understanding of Phylogenetic Trees as reconstructions of evolutionary pathways and cladograms

Reproduction in Plants

CONTENT

Grouping of bryophytes, pteridophytes, gymnosperms and angiosperms according to the presence/absence of:

– vascular tissue (xylem and phloem)

– true leaves and roots

– seeds or spores

– fruit.

Decreasing dependence on water for reproduction from Bryophytes to Angiosperms

Asexual and sexual reproduction, name advantages and disadvantages of each.

Flowers as reproductive structures

Adaptations for pollination through (different pollinators) wind, insects and birds (South African examples only) differences and similarities.

The Significance of Seeds

– seed banks;

– seeds as a food source;

– endemic species in South Africa.

INVESTIGATIONS

Observe and draw relevant macroscopic parts to provide examples of each of the following divisions:

– bryophytes: moss plant

– pteridophytes: rhizome, frond with sori

– gymnosperms: needles, cones and seeds; and

– angiosperms: flower, fruit and seeds

Draw a phylogenetic tree showing the evolutionary history of the four plant groups and major structural changes in their history of development.

• Dissect an example of each of the following types of flowers:

– wind pollinated

– insect pollinated

– bird pollinated.

Record observations in a comparative table.

Optional: Germinate seeds: record process.

RESOURCES

Introduction to Plant groups (download to computer as it is 15 min long but VERY useful)

Telematics PowerPoint on Plant diversity in English and Afrikaans by Lorraine Kuun

Telematics PP on reproduction in Plants and Animals by Lorraine Kuun –VERY useful

Reproduction in flowering plants – 3 very useful PP’s from Lorraine Kuun – information on pollinators and seed banks included

Reproduction in Flowering Plants Part 1

Reproduction in Flowering Plants Part 2

Reproduction in Flowering Plants Part 3

Life cycles in plants – another very useful PP from Lorraine Kuun

Plant biodiversity – good for background, including evolutionary relationships and some diagrams

Life cycle of plants from Spark notes

Life cycle of mosses – great interactive animation

Life cycle of angiosperms -– great interactive animation

Useful links from SANBI