Transcript Unit 1: Plant Origins & Classification

Unit 1: Plant Origins &
Classification
Chapters 1 & 2
Unit 1: Plant Origins &
Classification
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Unit 1 Objectives
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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
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Introduction
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Traditionally: two basic kingdoms
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Animalia
Plantae
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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 &
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Monera
Bacteria and blue-green algae
Protista
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Mycota
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Fungi
Plantae
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All other algae and protozoans
Mosses, ferns, seed plants
Animalia
Unit 1: Plant Origins &
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Evolution of Plants
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Scientists date life back 3.5b yrs.
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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 &
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Geographical Distribution of Plants
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Plants are not found only in the most
extreme climatic conditions
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What are they?
Distribution can vary depending on the
plant
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Some extremely adaptable
Some very specific
What can they be adaptable/specific to? Why
are they this way?
Unit 1: Plant Origins &
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Climate is the major determining factor
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Most varied plant population occurs at/near the
equator
Moisture and temperature are almost never
limiting
How do plants adapt?
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Dry climates
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Develop Xeromorphic Characteristics (dry form)
Small, thick leaves
Spines
Unit 1: Plant Origins &
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Colder climates
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Growth close to the ground
Protected growing points at/just beneath the ground
Climatic Zone
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Dense hairiness
Water-storage organs
Plants in a similar area form a characteristic
vegetation type
Biome
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Large area encompassing characteristic
vegetation and animal life
Unit 1: Plant Origins &
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Major biomes include:
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Tropical forest
Desert
Tundra
Roles of Plants
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Basis of the food chain and energy flow
Ability to convert inorganic compounds into
organic compounds in living tissues
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Extra energy not used for critical plant life
processes is converted to new tissue (biomass)
Unit 1: Plant Origins &
Classification
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Edible Plants
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Concentrated portions of a plant
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Most important food plants are of the grass
family
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Seeds, fruits, tubers, foliage
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 &
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Plants also a major source of world’s beverages
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Can you name them, and what they are used in?
Industrial Uses
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Plants play a major role in virtually all products
that we have today
Ex. How many products can we name that
originate from trees?
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Medicinal Uses
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Compounds from plants can be converted to
very useful medicines
In nature, and at the wrong concentration, they
may be poisonous
Oils
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Food reserves stored by the plant in seeds or
fruits
Name some of the most common oil plants!
Unit 1: Plant Origins &
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Taxonomy
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Ways to classify plants
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Phylogenetic – how they look
Environmental – where they grow
Agricultural – what use they are grown for
Natural/Morphological – how their structure
compares
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Terminology
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Taxonomy
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Nomenclature
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System used to organize plants into a classification
System used to assign names to plants
Artificial Classification Systems
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Climatic or agricultural classification systems
Depends on:
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The climate the plant grows in
Its uses
How the environment impacts it
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Botanical Systems
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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
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Divisions within a taxonomic system are called
taxa (ex. kingdom)
Unit 1: Plant Origins &
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Most agricultural plants are considered to be
members of subkingdom Embryota (land
plants)
Divisions
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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 &
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Spermatophyta
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Produce true seeds
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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:
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Gymnospermae
 Naked-seeded
 Woody, perennial, mostly evergreen
Unit 1: Plant Origins &
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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
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Unit 1: Plant Origins &
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Lower Subdivisions
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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
Order, Family, Genus, Species, Form,
Variety/Cultivar/Clone
Plant ID and Nomenclature
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Most all names are derived from Latin or Greek
Can give hints to characteristics of the plant
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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
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Can have a third cultivar name or botanical variety
 Botanical variety is a plant that is similar, but
different from the wild version
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Cultivar refers to cultivated variety
The future of taxonomy
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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.
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Origin & Development of Cultivated
Plants
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Two main regions:
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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 &
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Unit 1: Plant Origins &
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New Crops & New Uses
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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
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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 &
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Some where exported back to Europe
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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
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Tobacco, rice, cotton, timber
Unit 1: Plant Origins &
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Beginnings of Agricultural Research
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USDA founded in 1862
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First focus was to collect seeds for distribution to
farmers and for research
Hatch Act 1887
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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 &
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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 &
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Agricultural Adjustment Act 1938
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Response to severe surpluses and lack of export
market
Established 4 national research stations
geographically based on crops grown in that area
WW II
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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 &
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Postwar Research
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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 &
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New Sources of Demand
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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 &
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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
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Guayule – for rubber production
Kenaf – substitutes for wood pulp in paper
production
Crambe – industrial oil
Unit 1: Plant Origins &
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The Future
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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
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Protection of Germ Plasm
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<.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 &
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Unit 1 Assignment: