Today: Genetically Modifying Plants (see section 38.3)

Human resource production and use

Worldwide Grain Production per Person

Land use in USA, 1997

from TeosinteMaize By artificial selection that began ~10,000 years ago. Fig Artificial Selection

Hunter- Gatherer Agricultural Industrial

Genetic Engineering: Direct manipulation of DNA Fig 20.2

We can now insert new genes or modify existing genes of plants

Agrobacterium infect plants, inserting some of their DNA into the plants genome and forming a gall.

Fig Agrobacterium infect plants, inserting some of their DNA into the plants genome.

After inserting a gene into the Agrobacteria, they will insert that gene into the plant's DNA. Fig 20.25

Global area planted with GM crops And Texas=70ha

The agricultural release of genetically modified organisms is the largest scale experiment that has ever been performed.

Why Change a Plant’s DNA? Can change plant so that it has new or different characteristics –Insect resistance (Bt toxin) –Herbicide resistance (Round-up) –Drought or other stress resistance

Why Change a Plant’s DNA? Can change plant so that it has new or different characteristics –Insect resistance (Bt toxin) –Herbicide resistance (Round-up) –Drought or other stress resistance

What happened to this root?

Flooding, constant submersion… Why would the plant respond like this? Fig 39.27

What about when water is scarce?

Fig Structural adaptations of a plant that grows in an arid environment Oleander

Structural adaptations of a plant that grows in an arid environment: Thick cuticle Thick epidermis Recessed stomata Oleander Fig 36.18

Structural adaptations of a plant that grows in an arid environment: Reduced leaves Fig 36.18

Structural adaptations of a plant that grows in an arid environment: Reduced leaves spines/hairs Fig 36.18

Irrigating crops eventually leads to increased soil salinity

Freshwater is not pure water. It contains many salts, such as: sodium 6mg/L; chloride 7mg/L; calcium 15mg/L; sulfate 11mg/L; silica 7mg/L; magnesium 4mg/L; and potassium 3mg/L

Why Change a Plant’s DNA? Can change plant so that it has new or different characteristics –Insect resistance (Bt toxin) –Herbicide resistance (Round-up) –Drought or other stress resistance

% of Total US Acres Common GM Crops in the U.S. ce/2007/09/mon santo-is- hap.html

Have GMO's been beneficial, and what are the risks?

more precise application vs unintended release

Human impacts: Dead zone in Gulf of Mexico from Mississippi River es- picayune/2007/06/despit e_promises_to_fix_it_th e.html

Pollen is easily transferred from plant to plant, and to related species.

GM crops illegal GM crops found in Oaxaca and other MX states Genetic information moves.

GM crops illegal GM crops found in Oaxaca and other MX states Genetic information moves, and is self-replicating.

Monsanto's is one of the largest sellers of GMO's Monsanto Stock price

Have GMO's been beneficial, and what are the risks?

Next: Animals