Unit 1: Plant Origins & Classification

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: