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Unit 1: Plant Origins & Classification
Chapters 1 & 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
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
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
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
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?
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
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
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)
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
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?
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!
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
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
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)
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
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
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
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
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
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.
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
Unit 1: Plant Origins & Classification
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
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
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
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
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
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
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
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
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
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
Unit 1: Plant Origins & Classification
Unit 1 Assignment:
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