Plant Diversity Notes

BIO112: Plant Diversity

  • Course lecturers: Ms I. Makhura, Prof. B. Moseki.
  • Assessment: One CA Test (Plant Diversity only), including lecture and lab work. Refer to The Plant Diversity Manual for details.

Course Overview

  • Survey of the Plant Kingdom/land plants from simple to complex.
  • Evolutionary approach, aquatic to terrestrial environments.
  • Focus on adaptations for land survival.

Importance of Plants

  • Essential for life due to photosynthesis.
  • Base of the food chain; many plant types used as food.
  • Source of nutrients: carbohydrates, proteins, lipids, water, vitamins, and minerals.
  • Provide spices, beverages, starch, oils, and food additives.
  • Source of oxygen and remove carbon dioxide.
  • Regulate water cycle.
  • Aesthetic uses and source of natural products like fibers.
  • Habitat for organisms and provide ecosystem services (e.g., soil erosion control, nitrogen fixation by legumes).
  • Source of medicine; some plants are poisonous (e.g., Datura sp., Nerium oliander).

Plant Characteristics

  • Multicellular, photosynthetic eukaryotes.
  • Produce sugars from carbon dioxide and release oxygen via photosynthesis.
  • Cells have rigid cell walls.
  • Protected embryo and unique development/regeneration.

Plant Classification

  • Using Sadava et al. 2011 classification.
  • Kingdom Plantae: Vascular (Tracheophytes) and Non-Vascular Plants (Non-Tracheophytes).
  • Vascular plants have conducting cells (tracheids); non-vascular plants do not.
  • Sadava et al. recognizes 10 groups (clades).

Plant Groups

  • Non-Vascular: Hepatophyta (Liverworts), Anthocerophyta (Hornworts), Bryophyta (Mosses).
  • Vascular (Seedless): Lycopodiophyta (Club mosses), Pteridophyta (Ferns & fern allies).
  • Vascular (Seed): Spermatophyta (Gymnosperms: Cycadophyta, Ginkgophyta, Gnetophyta, Coniferophyta; Angiosperms: Flowering plants).

Algae

  • Algae are discussed in the course and may be included in the Plant Kingdom.
  • Algae have plant-like characteristics and are included in ‘Green Plants’ by Sadava et al.

Course Purpose

  • Survey the Plant Kingdom.
  • Understand plant origin and evolution by studying plants and algae.

Role of Algae

  • Algae significantly shaped the Earth.
  • Involved in the evolution of eukaryotic cells (endosymbiotic theory).
  • Blue-green algae contributed to the origin of chloroplasts.
  • Algae created an oxygen-filled atmosphere, enabling the evolution of aerobic organisms.
  • O2O_2 accumulated in the atmosphere
  • Green algae are considered ancestors of plants.