Plants and Agriculture

All life is dependent on the transformation of solar energy into chemical energy by plants.

Illinois is a major agricultural state.

Speaker Notes:

Corn and soybeans are the most common crops in Illinois

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Reading Assignment

• In chapter 30 read pages 626-630, 634-636 and pages 639- 648.

Speaker Notes:

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Uses of plants

• Besides consuming CO2 and producing O2, traditionally plants are major sources of:

  • Food

  • Fuel – wood

  • Fiber for clothing, ropes and paper

  • Color

  • Medicine

Speaker Notes:

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Ecosystem Services

• Humans are biological (rather than economic or cultural) entities first and foremost

• We have found many substitutes for plants as a source of fuel, fiber, color and medicine, but human life needs a ‘healthy’ environment

  • FOOD, Clean fresh water, clean air

  • Plants effect the earth in many ways

    • Soils, climate, shelter, and others

Speaker Notes:

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Sustainability

• Life on earth is due to the capacity of plants to use light energy from the sun to build complex macromolecules.

• Materials (elements) cycle through living systems, but that cycling is dependent on the constant input of solar energy.

• Sustainable systems are ones where inputs and outputs are balanced so reservoir (or pool) has constant size.

Speaker Notes:

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Ancient Greening of the Earth

• A species in the Green algae lineage gained the ability to grow on land.

• Land plants have water-conducting tissues which supply water to photosynthetic tissue.

• Plants covered most of the terrestrial earth as they improved capacity to conduct water.

• Large amounts of carbon were moved from the air into dead biomass which became coal.

Speaker Notes:

Oil depositions are believed to result from accumulations of marine organisms.

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Plants species have been changed by humans

• Almost all vegetable crops are very different from their wild progenitors.

• We already talked about cabbage, broccoli, Brussels sprouts, kale, collard greens being selected from a single wild species.

• Corn – so modified there are still debate if teosinte is the only species contributing to maize (corn).

Speaker Notes:

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The Grass Family

• Seeds of the Grass family (grains) provide most human calories.

  • Wheat

  • Rice

  • Corn

• All crops are highly modified by selection from the wild species. The process is referred to as domestication.

• Grasses are all wind or self pollinated.

Speaker Notes:

Barley and rye are also crops from the grass family as is sugarcane.

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Land Plants

• Plants growing on land - their shoots are seeking light from the sun and carbon dioxide from the air, while their roots seek water and nutrients from below the surface.

• The growth of roots -to assure a supply of water for the plant- required the sending of organic matter below the surface.

• Organic matter below the surface leads to the development of soil.

Speaker Notes:

Soil does not exist without living components.

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SOIL

• The soil at the surface of the earth is a complex mixture that is the result of activity by plants and animals.

• Space for gases to be exchanged and for water to infiltrate are very important. Pore space is the technical term for that space.

Speaker Notes:

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Parts of Soil

• Mineral particles

• Organic matter

• Water

• Air

• Organisms

• The best soils are about 25% water, 25% air, 45% mineral particles and 5% organic matter.

Speaker Notes:

Living organisms are also a ‘part’ of soil.

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Mineral particles

• Soil texture is based on the mineral particles in the soil.

• The fine-earth fraction includes all particles below 2 mm in diameter;

• SAND 2 mm – 0.05 mm

• SILT 0.05 mm – 0.002 mm

• CLAY <0.002 mm

Speaker Notes:

Between the thumb and finger sand feels like grit, silt is smooth or silky, clay feels slimmy.

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Illinois in 1800

Speaker Notes:

This map was made by Roger C. Anderson at Illinois State University

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A quality prairie

Speaker Notes:

The purple flowers are lead plant, the white is wild quinine, the grass is northern dropseed. Weston Cemetery in Mclean Co.

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IL before and after

Speaker Notes:

Prairie in the foreground (compass plant is yellow flower) has been replaced by corn in back ground (left) and soybeans (right).

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Soybeans as far as the eye can see

Speaker Notes:

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Illinois Agriculture

• The major crops are CORN and SOYBEANS.

• Agriculture uses predominantly plants with an ANNUAL life cycle.

• CORN is in the Grass family

• SOYBEAN is in the Legume family

Speaker Notes:

Annuals overwinter as seeds.

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Plant Life Cycles

• The major life cycles types are:

  • Annual, Plant dies after producing its seeds, which is how plant overwinters.

  • Biennial, plant does not flower in first year, but it dies in second year after flowering and producing seed.

  • Perennial, plant lives more than two years. Typically, this type flowers and produces seed every year after maturity is reached.

Speaker Notes:

The seed is the result of fertilization of ovule by pollen. All woody plants are perennials.

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Materials transport associated with Agriculture

• CH2O, carbohydrate, is the main product produced by plants.

• The harvested grains contain nitrogen and phosphorus which are transported to city.

• Soils can be depleted of Nitrogen, Phosphorus and other minerals. Nitrogen and Phosphorus are added to soil by farmers in IL.

Speaker Notes:

The carbon atoms in the carbohydrate of plants come from the carbon dioxide in the atmosphere. The Hydrogen and oxygen come from water.

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Innovations allowing life on Land

Speaker Notes:

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Reproduction in dry environments

• Gametes produced in complex multicellular structures which protect them from drying and mechanical damage.

  • Separate sexes from beginning

• Embryo retained on the parent plant and nourished by the parent.

Speaker Notes:

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Alternation of generations

• The basic eukaryotic life cycle has a haploid stage and a diploid stage or phase.

• In alternation of generations both the haploid and the diplod phase are multicellular.

• In plants haploid stage called gametophyte and diploid stage is sporophyte. Diploid stage begins with union of 2 haploid cells (fertilization) and ends with meiosis (a special cell division restoring haploidy).

Speaker Notes:

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Gametophyte

• In mosses the gametophyte is the big, most likely to be seen part of the life cycle.

• In the vascular plants the sporophyte is the big phase and the gametophyte is reduced.

• Despite the complex terminology of stages in plants, the basic features (fertilization and meiosis) are true of all eukaryotes.

Speaker Notes:

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Sexes in plants

• The flower of plants contains both female (ovule) and male (anther) parts.

• If the female part is fertilized by pollen from the male part of the same flower, the plant is said to have selfed (self fertilization).

• The petals of flowers often attract animal visits which bring pollen from other individuals resulting in outcrossing.

Speaker Notes:

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Vocabulary

• Agriculture

• Annual

• Biennial

• Ecosystem service

• Erosion

• Flower sex

• Gametophyte

• Grass family

• Selfed

• Silt

• Sporophyte

• Sustainable

Speaker Notes: