Introduction

What is Economic Botany?

History of the varied and complex interactions of humans with plants.

Early Origins

Earth is about 4.5 billion years old

Earliest fossils - 3.5 billion years old, small, simple bacteria-like cells

Early atmosphere - nitrogen, carbon dioxide and water vapor, NO OXYGEN

Anaerobic conditions - only very simple organisms that could survive without respiration would be present. These organisms obtained their energy by process called glycolysis Glucose---> 2 Lactic acid + 2H2O

Photosynthetic organisms evolved 3.4 billion years ago. They use light energy to drive the Calvin cycle:

This allowed the development of aerobic organisms (organisms that respire)

Respiration is a much more efficient process in terms of energy production:

Glycolysis yields 6 ATP per molecule of glucose.

Respiration yields 24 ATP per molecule of glucose.

ATP is a high energy compound that is used to drive metabolic processes.

Early photosynthetic prokaryotes created conditions that allowed the evolution of more complex organisms that respired (Eukaryotes).

There are many types of photosynthetic organisms

Cyanobacteria (prokaryotic)

Golden algae

Yellow-green algae

Diatoms - primary source of food for water dwelling animals

Dinoflagellates

Euglenoids

Red algae

Brown algae

Green algae

LAND PLANTS

Bryophytes - no significant economic importance.

Ferns & fern allies - minor economic importance.

Gymnosperms - mostly wood products.

Angiosperms - flowering plants, most economically important.

Basically humans survive by eating plants and animals (which are fed plants). We also use plants for:

1. Drugs

2. Structures

3. Spices/perfumes

4. Beverages

5. Paper

6. Dyes

7. Recreation/horticulture

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