Using Crossbreeding and Hybrids

Next Generation Science/Common Core Standards Addressed:

• MS LS2 1. Analyze and interpret data to provide evidence for the effects of ‐ ‐resource availability on organisms and populations of organisms in an ecosystem.

• RST.6 8.1 Cite specific textual evidence to support analysis of science and ‐technical texts. (MS-LS1-6),(MS-LS2-1),(MS-LS2-4)

• RI.8.8 Trace and evaluate the argument and specific claims in a text, assessing whether the reasoning is sound and the evidence is relevant and sufficient to support the claims. (MS-LS2-4)

• WHST.6 8.1 Write arguments to support claims with clear reasons and ‐relevant evidence. (MS-LS2-4)

• 6.RP.A.3 Use ratio and rate reasoning to solve real-world and mathematical problems. (MS-LS2-5)

Bell Work!

• Discuss the importance of improved organisms to agriculture.

• Identify methods used in agriscience to improve organisms.

• Identify breeding systems used in animal science.

• Why are crossbreeding and hybrids important financially?

Terms:• Hybrid• Hybrid vigor• Crossbreed• Linbreeding• Heterosis• Inbreeding• Genetic

• Manipulation• Urbanization

Why is improving organisms important to agriculture?

• Three main factors driving this goal:

• Rising World Population

• Urbanization

• Fewer people in production agriculture

Rising World Population

• Life expectancy continues to rise and infant mortality rates continue to drop• All of these people need to eat. • It is the job of agriculture to make sure

there is enough food produced.

Urbanization• As the world’s population increases, people need places

to live, work and play. • The world’s cities continue to grow, swallowing up

more and more land that was used for farming.

• Because of this, producers are expected to produce more food using less land.

Fewer people in production agriculture

• Burden of feeding the world on fewer and fewer people.

• Average age of the producer is very high. 2013 – Average American Farmer is 58 yrs. of age.

Average Japanese Farmer is 66 yrs. Of age.

Hybrid seed

•One example of a major breakthrough in organism improvement occurred in the 1930s. Hybridization of corn began!

•Hybrids produce 25% to 50% greater yields than traditional corn varieties and are fairly tolerant to varying soil and climatic conditions.

Hybrid Livestock• Another example of organism improvement can be found in the

animal industry.

• Today cattle and hogs can reach market weight several days sooner using less feed. (Feed Efficiency has improved)

• Cross bred animals grow faster than pure bred parental stock. This is known as “hybrid vigor”.

What methods are used in agriscience to improve organisms?

• Two major approaches are used: • Controlled breeding • Genetic manipulation.

Controlled breeding

•Breeding plants or animals to achieve certain characteristics in the offspring. •Considered a natural method of improving plants and animals. •Scientists control the natural breeding process.

Kinds of controlled breeding:

• Selection• Choosing a few parents with the desired traits with

the intent of increasing the amount of desired qualities in the offspring.

Kinds of controlled breeding:

• Inbreeding • Breeding offspring of the same parents to each other. ( father x daughter, father x granddaughter etc.)

• Used to produce a new generation without the introduction of any new genes. Desired result is to compound desirable characteristics.

Hybridization• Crossing of two different plants or animals• Combines the traits of different parent strains. • Many hybrids are not able to reproduce.

Genetic manipulation• Artificial means of producing desirable traits. • Genes can be moved from one species to another. • Gene splicing is the moving of hereditary characteristics from

one organism to another often unrelated organism.

What are the different breeding systems used in animal science?

Inbreeding

•Mating of closely related animals.

•Mating of these individuals allows for the concentration of genes to make animals more homozygous for all traits.

Linebreeding

•A specific type of inbreeding is called linebreeding. •Linebreeding is the mating of related animals that are not immediate family members.

Crossbreeding or outbreeding

•Mating of animals that are not related.• The phenomenon of heterosis is often

observed in crossbred animals. •Heterosis or hybrid vigor, is the

increase in a performance trait that exceeds the average of the parents.

Review / Summary• Discuss the importance of improved organisms to agriculture.• Identify methods used in agriscience to improve organisms.• Identify breeding systems used in animal science.

The end!