4C Naturally occurring diversity among and between components within biological systems affects interactions with the environment.

1. Define robustness: A biological system that possesses many different components often has greater flexibility to respond to changes in its environment 2. Cells with multiple copies of genes or heterozygous genes possess a wider range of functions compared to cells with less genetic diversity 3. Environmental factors influence the phenotypic expression of an organism’s genotype

4. Flower color in some species of plants is dependent upon the pH of the environment (hydrangea)

5. Environmental factors such as temperature 5. Environmental factors such as temperature or density can affect sex determination in some animals (common in reptiles, sometimes occurs in birds) 6. Plant seed dormancy can increase the survival of a species 7. The ability of a population to respond to a changing environment (fitness) is often measured in terms of genomic diversity

8. Species with little genetic diversity, such as a population of plants that reproduces asexually or a very small population exhibiting a genetic bottleneck effect , are at risk with regard to long- term success and survival 9. Ecosystems with little species diversity are often less resilient to changes in the environment 10. Keystone species, predators , and essential abiotic and biotic factors contribute to maintaining the diversity of an ecosystem

4C1 Variation in molecular units provides cells with a wider range of functions

Define antibody and give an example – a protein called immunoglobulin that is produced by lymphocytes in response to a foreign substance (antigen) and released into the bloodstream Define antigen and give an example - a foreign substance, usually a protein or polysaccharide, that triggers(stimulates) an immune response Variations within molecular classes provide cells and organisms with a wider range of functions.

Why is it so important for the human body to have various types of antibodies? Because each antigen has a specific antibody that will attack and destroy that antigen

1. A heterozygote may be a more advantageous genotype than a homozygote under particular conditions, since with two different alleles, the organism has two forms of proteins that may provide functional resilience in response to environmental stresses. 2. Gene duplication creates a situation in which one copy of the gene maintains its original function, while the duplicate may evolve a new function. Multiple copies of alleles or genes (gene duplication) may provide new phenotypes.

Antifreeze Gene in Fish Antarctic Toothfish Antifreeze Gene in Fish

Earth's oceans get colder than one might think possible Earth's oceans get colder than one might think possible. Because of their high salt content, the waters of the Arctic and Antarctic Oceans can drop to -2 degrees Celsius Fish like the Antarctic toothfish, live at these temperatures on a daily basis — so why doesn't their blood turn to ice? Such fish survive with the help of an evolutionary innovation that would impress any auto mechanic: antifreeze Describe what the gene is and how it has helped certain fish to survive

The antifreeze with which we're most familiar keeps the fluids in a car's motor from freezing during the winter. The antifreeze of the Antarctic toothfish does the same sort of job but works a bit differently. Automotive antifreeze is made from alcohol, but this biological antifreeze (called an antifreeze glycoprotein) is made of proteins and sugars. This substance circulates in the blood of the fish and suppresses the growth of ice crystals, keeping the blood liquid.

How does an adaptation as unusual as antifreeze evolve? In the case of the Antarctic toothfish, it seems that, long ago, parts of a gene that normally code for a pancreatic digestive protein were copied. These duplicated bits of the genome, now no longer used in digestion, experienced natural selection that shaped them to aid survival in lower temperatures. Eventually, this ancient gene evolved into the modern day gene that codes for the fish's antifreeze glycoproteins How does an adaptation as unusual as antifreeze evolve?