Unit 1 Flashcards
How long have land plants been on earth?
400 million years (estimated)
Where and when were plants first domesticated
Mesopotamia, 10,000 years ago (modern day Iran, Iraq, turkey, and Syria)
What were the first domesticated plants?
Wheat, Barley, Lentils, and peas
Other early civilization plats that were domesticated were?
Rice (Asia) and potatoes (South America)
What are 3 common traits selected during crop domestication?
Larger in size, reduced shattering, and eliminating crop dormancy.
What were the benefits of plant domestication?
- Allowed fewer people to provide more food
- Stability (predictable food production)
- Created time for people (did not have to hunt all day)
- Resources for trading
- Advancements in tool production
- Formation of cities – the first villages and cities were built near fields of domesticated plants
What are three recently domesticated wild species?
Sugar beet, Sunflower, Wild rice
Where would you find a plants species greatest biodiversity?
Its center of origin
Center of Origin of Crop Plants
Origin of crop plants is now basic to plant breeding in order to locate wild relatives, related species and new genes (example disease resistance)
Where are global plant genes stored?
In a germplasm (dooms day vault)
Global issues
- Increased human population
- Energy use (50% increase in global energy use expected in the last fifty years)
- Drought
Plant Scientist are working to help global problems
by?
- More drought tolerant crops
- Require less fertilizer or water
- Crops more resistant to pathogens
- Crops more nutritious
How many households are food insecure in the United States?
Estimated 10.5 percent of U.S. households were food
insecure in 2020, meaning that they had difficulty at
some time during the year providing enough food for all
their members.
What is VAD
Vitamin A Deficiency
Has killed millions of children in less-developed countries (over 2 million in the early 1990s alone)
What else can we use plants for?
Plants produce hundreds of compounds we use as medicines or drugs
Plants can be a source of biofuels
Plants produce an amazing assortment of chemicals
Many discoveries were first described in plants
Number of plants in the world?
How many do we grow for food?
- There are 450 families of flowering plants and well over 350,000 different species.
- It is estimated that 3000 have been used by humans for food.
- Fewer than 300 have been domesticated.
- Only 20 plants that stand between humans and large-scale global starvation.
Definition of plants
- Plants are living organisms that contain chlorophyll and use it to manufacture their own food
- 335,000 species of plants
- Cell walls
- 500,000+ different kinds of plants and plantlike organisms
Plants have the ability to change over time (to evolve)
Population vs Evolution
Population – interbreeding group of organisms that share a gene pool
Evolution – accumulated changes in the gene pool
A. Natural selection
B. Artificial selection
Natural Selection
Natural selection due to pollinator preference lead to different species of monkeyflowers
Artificial Selection
Selection imposed by humans on population
Brassica oleracea lead to kale, brussels sprouts, broccoli, Cabbage, cauliflower.
How do we classify plants?
- Plant taxonomy based on system by physician and botanist Carl Linnaeus (1707-1778)
- Classification based on flower and reproductive parts of a plant
What is Morphology
What is the order of plant Taxonomic hierarchy
Kingdom
Phylum (division)
Class
Order
Family
Genus
Species
Classification – Scientific Name
- They are organized and evaluated
according to a definite system of laws and
rules - Plant distributed throughout the world
have the same valid scientific name - A plant can have only one valid name
- Only one plant may have this valid name
- A scientific name is very often descriptive
of the plant
Classification – Common Names
- They are the only names known
and familiar to most people - They are usually simple and
relatively easy to remember (ex.
windflower, mayflower, etc) - Descriptive of the plant (ex.
Bleeding heart)
Fabaceae Family
Legume
Variety
- Subspecies, denotes a fairly
consistent, natural occurring
variation - This second specific name is
preceded by the abbreviation - Ex Gleditsia triacanthos var.
inermis
Annual life cycle
An annual plants entire life cycle from seed germination to seed production occurs in one growing season, and then the plant dies
Biennial
A biennial plant starts from seed and produces vegetative structures and food storage organs in its first full season. A rosette of basal leaves persists through winter. During the second season, the plant’s life cycle is completed with flowers, fruit and seed.
Perennial
Is a plant that lives for more than two years. Typically, perennials die back in the fall and
return in the spring because of some sort of
overwintering structure, such as a rhizome or crown.
Woody plants
Woody plants - have stems that live for several years, adding new growth (height and width) each year. Woody plants may be classified as trees, shrubs or vines.
Herbaceous plants
Herbaceous plants – plants that have stems that die back to the ground each year. Herbaceous plants may be annual, perennial or biennial
Monocots
Dicots
Genotype vs Phenotype
- Genotype – The genetic make-up of an organism (collection of genes)
- Phenotype – The external
visible appearance of an
organism
What are the key points of seed maturity
- Most seeds can germinate before physiological
maturity - Some seeds only reach maximum germination after
slow drying - Few species can germinate at low oxygen tension
