Hox Genes

Description:  Hox genes control the body plan of organisms with each hox gene coding for a specific body part. Hox gene mutations (e.g. a fruit fly with a leg in the place of an antenna) can lead to investigations on development. Similarities in hox genes across various animals can show phylogeny.

Web Resource: Hox genes - Wikipedia

What underlies the incredible diversity of life on Earth? How have complex life forms evolved? The journey from water to land, the return of land mammals to the sea, and the emergence of humans all suggest that creatures past and present are members of a single tree of life.

The Potential And Ethics Of CRISPR

Description: CRISPR stands for Clustered Regularly Interspaced Short Palindromic Repeats. It is an immune system in bacteria that has been co-opted by scientists to create a powerful DNA editing tool. It is a powerful tool that can be used in research and may eventually eliminate certain diseases. However it also could allow humans to create designer babies and through the use of gene drives eliminate certain problem species (like mosquitoes) forever. CRISPR, as a new technology, can be used to give meaning to a unit on inheritance and variation.

Web Resources:  CRISPR - Wikipedia, The Ethics of CRISPR - Fast Company

In this video Paul Andersen explains how the CRISPR/Cas immune system was identified in bacteria and how the CRISPR/Cas9 system was developed to edit genomes. Do you speak another language?

Hemingway’s Polydactyl Cats

Description:  The author Ernest Hemingway was given a six-toed cat that his son named Snow White. His former home in Key West, Florida was turned into a museum and houses nearly 50 cats that are ancestors of this original cat. Cats with extra digits are called polydactyl cats and have inherited a dominant gene. Roughly half of the cats are polydactyl. This phenomenon could be used to study inheritance and variation.

Web Resources:  Hemingway Cats: The Felines That Rule Papa's Key West Estate - Paw Culture, Polydactyl Cats - Wikipedia

Two of Ernest Hemingway's cats at the Hemingway House in Key West, Florida. One of them is polydactyl, and has six toes.

Malaria and Sickle Cell Anemia

Description:  Sickle-cell anemia is caused by a single nucleotide mutation in the β-globin gene of red blood cells. This creates incorrectly structured proteins and red blood cells with a characteristic "sickle" shape. This harmful mutation does not affect carriers of the disease. However this mutation can be beneficial in certain areas because it offers protection from malarial infections. This phenomenon can be used in a unit on genetics or evolution.

Web Resources:  The Making of the Fittest: Natural Selection in Humans - HHMI, Sickle-cell Disease - Wikipedia

In some parts of the world, the infectious parasitic disease malaria and the genetic disease sickle cell anemia are intimately connected. What is sickle cell anemia? What is malaria? And how can one be linked to the other? Answer these questions for your students using this educational video on human evolution.

Shrew Caravan

Description:  Shrews spend most of their lives underground and therefore have very poor eyesight. They rely primarily on their highly developed senses of smell and hearing. When a mother shrew wants to move all of her offspring from one location to another (particularly above ground) each shrew will hold onto the shrew in front forming a long caravan. This could be used as a phenomenon to introduce animal behaviors, especially those of a parent to ensure the safety of their offspring.

Web Resource:  Common Shrew - Wikipedia

SUBSCRIBE for more BBC highlights: https://bit.ly/2IXqEIn Programme website: http://bbc.in/1GNSBqn Shrew babies do what looks like a conga led by their mum. It's her way of making sure they don't get lost when outside the burrow.

Why Do Humans Have Different Colored Skin?

Description:  Human skin color can change in response to environmental changes (i.e. getting a sunburn or a suntan). However the root cause of our skin color is genetic and comes from our ancestors. UV radiation causes damage to the DNA in our cells and can lead to various forms of cancer. If your ancestors lived in an area that received large amounts of UV radiation (i.e. closer to the equator) humans evolved darker skin for protection through the process of natural selection. However light is also important since it allows humans to synthesize vitamin D. Therefore if your ancestors lived in an area that receives little light (i.e. near the poles) they evolved lighter skin.

Web Resources: Human Skin Color - Wikipedia, The Biology of Skin Color - HHMI

View full lesson: https://ed.ted.com/lessons/the-science-of-skin-color-angela-koine-flynn When ultraviolet sunlight hits our skin, it affects each of us differently. Depending on skin color, it'll take only minutes of exposure to turn one person beetroot-pink, while another requires hours to experience the slightest change.