The Best Selection Topic 6

Darwin’s Theory Charles Darwin is the main contributor to the theory of natural selection. He sailed around the world collecting specimens and data. He noticed the vast amounts of biological diversity. He also noticed the finches. He continued to study the finches and created a theory about how the fittest or the best- adapted organisms for a specific environment survived.

Natural Selection The theory, proposed by Charles Darwin, can be summed up in four statements 1.All organisms produce more offspring than can possibly survive. 2.There is incredible variation within each species. 3.Some of those variations increase the chances of an organism surviving to reproduce. 4.Over time, variations that are passed on lead to changes in the genetic characteristics of a species.

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Selecting Desirable Traits Artificial Selection – Process of selecting and breeding individuals with desirable traits to produce offspring that have these desired traits – Ex. Horses, dogs, livestock, corn

Clones A genetically identical copy of an entire organism or of its cells or genes Cloning is the process of creating a clone Ex. Cutting from a plant move-on-to-competition move-on-to-competition Cloning horses g g The island trailer

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Artificial Reproductive Technology 1.Artificial Insemination – Sperm are harvested from a desirable male and injected into a female – Ex. Livestock breeding 2.In Vitro Fertilization – Fertilization that happens outside the body, usually in a petri dish (embryo is placed in female) – Ex. Livestock breeding

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Genetic Engineering Definition: a technique involved in moving pieces of DNA from one cell to another. – Ex. Human-producing gene for insulin is inserted into bacterial DNA. Bacteria reproduces quickly and can produce insulin quickly and cheaply. – Ex. Moving protein-making genes into the transgenic (or genetically modified) animals who will produce the human proteins necessary to aid those who are deficient in a certain protein. Transgenic animals are created by inserting human genes into the fertilized eggs of the animal.

Biotechnology in Food Production Ex. An “antifreeze” gene has been inserted into fish from areas of decreasing populations. Ex. A cold-resistant gene from fish has been inserted into tomatoes to help them withstand cold during growth. Ex. Crops have been inserted with genes that help them resist pests and insects. Ex. Cotton, corn and potatoes have been engineered to produce Bt Toxin. Insects that eat the engineered plant die, no pesticides are needed.

Biotechnology and Society Risks in Animals – Decreased genetic diversity – More susceptible to disease – Cattle cloning – unsuccessful pregnancies, birth defects and deaths

Biotechnologies in Society Risks in Plants – Genetically engineered canola could interbreed with weeds making their offspring resistant to herbicides.

Review Questions 1.How does artificial selection differ from what you learned about natural selection? Use examples. 2.How have reproductive technologies benefited agricultural industries in Alberta? Provide examples. What human needs do these technologies reflect? 3.What are some advantages of biotechnology such as cloning? What are some disadvantages? 4.Scientists have created crops that contain a toxin that kills any insect that eats them. Some farmers have been growing corn plants that contain this toxin. Corn without the toxin is a food supply to corn weevil, which destroys the corn crop, and the monarch butterfly, which is a protected species. What advice would you give to farmers growing this crop?

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