The Galapagos Islands are a home to many endemic species. These species are found nowhere else on Earth. The picture shows some
examples of marine iguanas and how they differ from island to island. On Isabella, they are huge, mostly dark, and have huge spikes down their back. On Espanola, they are very colorful. On Fernandina, they are dark and moderate in size.
How did these iguanas, with such physical differences from island to island, change over time?
A) The different populations of iguanas on each island were established separately. Each population originated from S. America and most likely came over on floating vegetation.
B) According to the theory of evolution, the individual selects which traits are best suited to the environment and chooses to pass these traits on to offspring. Because the island populations are isolated from each other, these differences accumulate over time.
C) Marine iguanas acquire traits that are best suited to them during their lifetime and pass on these traits to their offspring. For example, some iguanas who need protection, will grow larger spikes on their head. This trait will then be passed to their offspring.
D) An original population of land iguanas came over on floating vegetation from South America. Over time, two species evolved, land and marine. Marine iguanas made their way to different islands and once isolated on their own islands, accumulated adaptations most suited to their island.
D) An original population of land iguanas came over on floating vegetation from South America. Over time, two species evolved, land and marine. Marine iguanas made their way to different islands and once isolated on their own islands, accumulated adaptations most suited to their island.
Forests store large amounts of carbon. When fossil fuels are burned, carbon from dead and decayed plants, animals and phytoplankton that lived hundreds of millions of years ago (before dinosaurs existed), is released into the atmosphere in the form of carbon dioxide. .
CFTR protein facilitates the transport of chloride ions and water across the cells. Genetic defect in the CFTR gene results in defective protein synthesis. This defect in CFTR protein disrupts the chloride and water channel across the cell. The CFTR protein acts as a channel across the cell membranes which are specialized to produce mucus, sweat, tears etc. Failure of transport channel will result in symptoms like secretion of thick mucus. This mucus can obstruct the airflow and glands resulting in symptoms of cystic fibrosis.
