Natural Selection Writing Prompt: Darwin s Finches

Transcription

1 Name Pd Date Natural Selection Writing Prompt: Darwin s Finches Above is a picture of a Finch from South America that DNA evidence has shown to be the ancestor that all finches in the Galapagos came from, below that are drawings of heads that Darwin observed and are alive on the islands today. On your own paper below write a paragraph describing how Natural Selection explains the change in beak type. (Hint: - describe environmental stress the population was under - what are adaptations? Mutations? - Use science vocabulary properly)

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3 Name Pd Date Natural Selection Writing Prompt: Giraffe The structures an organism has develop over time in response to stresses in the environment. This process is called Natural Selection. Describe how natural selection works. Describe the stresses that an organism must adapt to and the role of mutations in those adaptations. Giraffes live on the savanna in Africa. The savanna is a dry grassland with very few trees. The trees that are there are a variety of the Acacia that is about 20 feet tall and has long thorns on it. In the distant past (about 50 million years ago!) the area was covered by lush forest with well developed canopy, understory and forest floor communities. The ancestors of the Giraffe lived there too, but they were MUCH smaller. There are even modern relatives of the Giraffe called an Okapia that still live in the edges of forests. Over time the climate changed from a moist forest biome to a dry savanna.

4 According to Natural Selection, how did the Giraffe develop such a long neck?

5 Name Pd Date Natural Selection Writing Prompt: Green Iguana The structures an organism has develop over time in response to stresses in the environment. This process is called Natural Selection. Describe how natural selection works. Describe the stresses that an organism must adapt to and the role of mutations in those adaptations. The green iguana is the ancestor of the marine iguanas found in the Galapagos Islands. The green iguana is found over a large geographic area, from Mexico to southern Brazil and Paraguay, as well as on the Caribbean Islands. Iguanas live in tropical rainforest areas, generally in lower altitudes in areas near water sources, such as rivers or streams. They spend most of their time high in the forest canopy, about feet above the ground. Iguanas are omnivorous, so they eat both plants and meat. They tend to eat mostly plants, though, especially leaves and fruits. Sometimes green iguanas (especially young ones) will eat eggs, insects, and small vertebrates. The most likely mechanism for their move to the Galapagos is rafting. This occurs when a large chunk of land breaks off during a landslide and is moved out to sea by large rivers. The marine iguana is found on the volcanic islands of the Galapagos 600 miles from the mainland of South America. Many of the islands have steep rock cliffs, low rock ledges and intertidal flats. Iguanas need access to the ocean and a sandy area to lay eggs. They evolved in a habitat that is limited in predators. On Santa Fe an island in the Galapagos the predator are hawks, short-eared owls, snakes, hawk-fish, and crabs. The marine iguana has filled an interesting niche that no other living lizard does. It depends on the marine environment. Its diet consists almost entirely of algae that grow on rocks beneath the water on the edges of the islands and in intertidal zones. Marine iguanas have been observed diving for up to an hour at a time, although dives of 5 to 10 minutes is the norm. To rid itself of the salt consumed while eating, they excrete concentrated salt crystals from a nasal gland. The marine iguana regulates its body temperature by alternating from cold ocean water to basking on rocks near shore.

6 According to natural selection how did the marine iguana evolve from the green iguana?

7 Natural Selection Writing Prompt: Peppered Moth The peppered moth lives in Europe. In England they have been monitoring its population since the 1700 s. There are two varieties, light colored and dark colored. The moths live on pollen from trees, they particularly feed on birch pollen. Birch trees have light colored bark. In the mid 1800 s England underwent the industrial revolution during which a tremendous amount of coal was burned, and therefore tons of dark coal soot covered everything, including the trees. Below is a graph of the number of dark colored individuals in the population over time. At the time of the industrial revolution you can see a dramatic increase in the number of dark colored individuals in the population. ON THE GRAPH draw a graph of what the light colored population most likely underwent during the same time period. Describe how the Peppered Moth is an example of the process of Natural Selection. Be sure to describe what natural selection is and what it is in response to.

8 Name Pd Date According to Natural Selection why did the color of the peppered moth population change?