1. Unit 1: Plant Origins & Classification
Chapters 1 & 2

2. Unit 1: Plant Origins & Classification
Unit 1 Objectives
Understand the importance of taxonomic systems and their uses
Basic knowledge of divisions of plants
Appreciation for how today’s crops were developed, and the importance of continued research

3. Unit 1: Plant Origins & Classification
Introduction
Traditionally: two basic kingdoms
Animalia
Plantae
Classified due to several factors:
Stationary
Manufacture their own food
Continuous growth highly affected by the environment
However, many do not fit well into either category, so other kingdoms have been established

4. Unit 1: Plant Origins & Classification
Monera
Bacteria and blue-green algae
Protista
All other algae and protozoans
Mycota
Fungi
Plantae
Mosses, ferns, seed plants
Animalia

5. Unit 1: Plant Origins & Classification
Evolution of Plants
Scientists date life back 3.5b yrs.
Bacteria
Blue-green algae
Algae is responsible for supplying oxygen to the atmosphere to support other life forms
Land plants begin to appear ~400m yrs. ago

6. Unit 1: Plant Origins & Classification
Geographical Distribution of Plants
Plants are not found only in the most extreme climatic conditions
What are they?
Distribution can vary depending on the plant
Some extremely adaptable
Some very specific
What can they be adaptable/specific to? Why are they this way?

7. Unit 1: Plant Origins & Classification
Climate is the major determining factor
Most varied plant population occurs at/near the equator
Moisture and temperature are almost never limiting
How do plants adapt?
Dry climates
Develop Xeromorphic Characteristics (dry form)
Small, thick leaves
Spines

8. Unit 1: Plant Origins & Classification
Dense hairiness
Water-storage organs
Colder climates
Growth close to the ground
Protected growing points at/just beneath the ground
Climatic Zone
Plants in a similar area form a characteristic vegetation type
Biome
Large area encompassing characteristic vegetation and animal life

9. Unit 1: Plant Origins & Classification
Major biomes include:
Tropical forest
Desert
Tundra
Roles of Plants
Basis of the food chain and energy flow
Ability to convert inorganic compounds into organic compounds in living tissues
Extra energy not used for critical plant life processes is converted to new tissue (biomass)

11. Unit 1: Plant Origins & Classification
Edible Plants
Concentrated portions of a plant
Seeds, fruits, tubers, foliage
Most important food plants are of the grass family
Wheat, rice, corn, sorghum, barley
Plant foods consist of 88% of world’s calories, and 80% of proteins
Inverse relationship between high plant based diet and development of a country

12. Unit 1: Plant Origins & Classification
Plants also a major source of world’s beverages
Can you name them, and what they are used in?
Industrial Uses
Plants play a major role in virtually all products that we have today
Ex. How many products can we name that originate from trees?

13. Unit 1: Plant Origins & Classification
Medicinal Uses
Compounds from plants can be converted to very useful medicines
In nature, and at the wrong concentration, they may be poisonous
Oils
Food reserves stored by the plant in seeds or fruits
Name some of the most common oil plants!

14. Unit 1: Plant Origins & Classification
Taxonomy
Ways to classify plants
Phylogenetic – how they look
Environmental – where they grow
Agricultural – what use they are grown for
Natural/Morphological – how their structure compares

15. Unit 1: Plant Origins & Classification
Terminology
Taxonomy
System used to organize plants into a classification
Nomenclature
System used to assign names to plants
Artificial Classification Systems
Climatic or agricultural classification systems
Depends on:
The climate the plant grows in
Its uses
How the environment impacts it

16. Unit 1: Plant Origins & Classification
Botanical Systems
The first method used for plant classification
Classification by morphology (size, form, texture)
Not used much today, but its influence is still very apparent
Taxonomic Classifications
Divisions within a taxonomic system are called taxa (ex. kingdom)

17. Unit 1: Plant Origins & Classification
Most agricultural plants are considered to be members of subkingdom Embryota (land plants)
Divisions
Thallophyta – algae and fungi, no tissue differentiation
Bryophyta – green plants w/out roots (mosses)
Pterodophyta – green plants w/ vascular tissue, roots, leaves, stems, no flowers
Spermophyta – plants w/ true flowers and seeds

18. Unit 1: Plant Origins & Classification
Spermatophyta
Produce true seeds
Contain an embryo that will germinate under specific conditions
True leaves, stems, roots, and vascular tissue
Make up the greater majority of vegetation
Two classes:
Gymnospermae
Naked-seeded
Woody, perennial, mostly evergreen

19. Unit 1: Plant Origins & Classification
Reproductive structures are cones
Leaves may be fernlike, scale like, strap-shaped, needle-shaped
Angiospermae
Flowers and seeds that are always protected by fruit
Further divided by the number of seed leaves found in the seed (cotyledons)
Monocotyledoneae – one cotyledon in the seed, parallel veined leaves, flower parts in 3’s or 6’s, no pith or bark on the stem but can be treelike
Ex. Grasses, cattails, lilies, bananas, bamboo

20. Unit 1: Plant Origins & Classification
Dicotyledoneae – two cotyledons in the seed, net-veined leaves, flower parts in 4’s or 5’s or those multiples, various flower types/forms
Ex. Willows, roses, magnolia, honeysuckle
Lower Subdivisions
Order, Family, Genus, Species, Form, Variety/Cultivar/Clone
Plant ID and Nomenclature
Most all names are derived from Latin or Greek
Can give hints to characteristics of the plant

21. Unit 1: Plant Origins & Classification
Binomial Nomenclature
Plant has 2 parts to its name (Genus & Species)
Naming is based on flowers and/or reproductive structure
Very effective because these parts are not influenced by the environment
Knowledge of flowers and its parts essential to good plant ID
Other Subgroups
Can have a third cultivar name or botanical variety
Botanical variety is a plant that is similar, but different from the wild version

22. Unit 1: Plant Origins & Classification
Cultivar refers to cultivated variety
The future of taxonomy
Will include:
Chemical analysis
Specific protein analysis
DNA analysis – genetic finger print
More use of highly powered microscopes to very closely examine plant processes, hormones, etc.

23. Unit 1: Plant Origins & Classification
Origin & Development of Cultivated Plants
Two main regions:
Asia in the Old World
Central Mexico to Chile in the New World
Neither area new what the other had until transatlantic exploration began

24. Unit 1: Plant Origins & Classification

27. Unit 1: Plant Origins & Classification
New Crops & New Uses
Has been a major focus in America since Colonial times
Using surpluses and decreasing demand on foreign products both in agricultural and industrial sectors
Early American Adaptations
Americans have always been responsive to market needs
Corn, potatoes, squash, and tobacco has been grown in the U.S. for many centuries

28. Unit 1: Plant Origins & Classification
Some where exported back to Europe
Corn and Potatoes where adopted quickly because of their relative ease of production and high use
Tomatoes were suspected to be poisonous and took many centuries to adopt
Americans had to turn to other crops in order to control surpluses in order to compete w/ Europe
Tobacco, rice, cotton, timber

29. Unit 1: Plant Origins & Classification
Beginnings of Agricultural Research
USDA founded in 1862
First focus was to collect seeds for distribution to farmers and for research
Hatch Act 1887
Set up experiment stations at land-grant colleges
Initial research focused on increasing productivity w/ better practices and varieties
Created surplus problems
Research had to turn to additional uses for commodities

30. Unit 1: Plant Origins & Classification
WWI had a great impact on the development of new plants and uses in the U.S. due to supply cutoff
Specifically medicinal plants
Overproduction of cotton threatened the market in the southern U.S.
Through research and development, Carver convinced many growers to plant peanuts and sweat potatoes
Founded peanut oil
Peanut acreage grew 4x from 1910 to 1940
Carver also founded new uses for cotton and soybeans

31. Unit 1: Plant Origins & Classification
Agricultural Adjustment Act 1938
Response to severe surpluses and lack of export market
Established 4 national research stations geographically based on crops grown in that area
WW II
Stimulated research due to needs for the war
Many new products/uses developed
Synthetic rubber, dehydrated foods, etc.
Mass production of penicillin

32. Unit 1: Plant Origins & Classification
Postwar Research
Attention again focused on dealing w/ surpluses due to soaring production as a result of advancements in chemicals/machinery
Development of many other products
Frozen orange juice – stimulated production of O.J. concentrate from 226,000 g in 1945 to 84,000,000 g in 1960
Other frozen foods
Instant potato flakes
Wrinkle-resistant cotton

33. Unit 1: Plant Origins & Classification
New Sources of Demand
Response to rising surpluses, increased productivity, and dependence on foreign materials
High oil prices of 1970’s stimulated research in ethanol and soy ink
Much focus has been centered on biodegradability and conservation of natural resources

34. Unit 1: Plant Origins & Classification
Most research has focused on increased uses for current products
Less research on the introduction of new plants due to difficulty in getting them to grow in the climate and resistance of farmers to grow new crops
Guayule – for rubber production
Kenaf – substitutes for wood pulp in paper production
Crambe – industrial oil

35. Unit 1: Plant Origins & Classification
The Future
We have the research base and facilities to greatly expand our research if/when needed
Demand for research will continue to be great to meet needs for new crops and decrease demand on foreign imports
New uses and products would increase the need for manufacturing and process plants which would stimulate the economy

36. Unit 1: Plant Origins & Classification
Protection of Germ Plasm
<.1% of plant species are used in agriculture
Scientists are concerned about preserving this resource
Genes can be used in the future to create new plants, new product uses, or have crops that will adapt to adverse environments
More genes will be added to the pool for future uses

37. Unit 1: Plant Origins & Classification
Unit 1 Assignment: